JP4590295B2 - Coordinate input device, control method therefor, and program - Google Patents

Description

  The present invention relates to a coordinate input device that detects a designated position on a coordinate input region, a control method therefor, and a program.

  A coordinate input device used to control a connected computer or to write characters, figures, etc. by inputting coordinates on a coordinate input surface by pointing with a pointing tool (for example, a dedicated input pen, finger, etc.) Exists.

  Conventionally, as this type of coordinate input device, various types of touch panels have been proposed or commercialized, and it is easy to operate terminals such as personal computers on the screen without using special equipment. Since it can be used, it is widely used.

  There are various coordinate input methods such as those using a resistive film and those using ultrasonic waves. For example, Patent Document 1 discloses a method using light. In Patent Document 1, a retroreflective sheet is provided outside the coordinate input area, and an illumination unit that illuminates light disposed at a corner end of the coordinate input area and a light receiving unit that receives the light are used in the coordinate input area. Discloses a configuration in which an angle between a light shielding unit and a light shielding unit that shields light such as a finger is detected, and an instruction position of the shielding material is determined based on the detection result.

  Further, as disclosed in Patent Documents 2 and 3 and the like, a coordinate input device is disclosed in which a retroreflective member is configured around a coordinate input region to detect the coordinates of a portion (light shielding portion) where the retroreflected light is shielded. .

  In these apparatuses, for example, in Patent Document 2, the angle of the light-shielding part relative to the light-receiving part is detected by detecting the peak of the light-shielding part by the shielding object received by the light-receiving part by waveform processing calculation such as differentiation, and the detection The coordinates of the shielding object are calculated from the result. Patent Document 3 discloses a configuration in which one end and the other end of a light shielding part are detected by comparison with a specific level pattern, and the center of those coordinates is detected.

  Here, a method of detecting coordinates and calculating coordinates as in Patent Documents 1 to 3 is hereinafter referred to as a light shielding method.

  Furthermore, in such a coordinate input device of the light shielding method, in particular, when the size of the coordinate input area is large, a plurality of operators are allowed to input simultaneously, improving convenience, There is a demand for more efficient applications such as meetings. Therefore, a coordinate input device corresponding to a plurality of simultaneous inputs has been devised.

  In Patent Documents 4 to 6, in order to input a plurality of coordinates simultaneously, the angles of a plurality of light shielding portions are detected by one light receiving sensor, and several input coordinate candidates are calculated from combinations of the angles of the respective sensors. Furthermore, a technique for discriminating the actually input coordinates from the input coordinate candidates is disclosed.

  For example, in the case of two-point input, the coordinates of a maximum of four points are calculated as input coordinate candidates, and two of the four points actually input are determined and output. That is, in this determination, actual input coordinates and false input coordinates are selected from a plurality of input coordinate candidates, and the final input coordinates are determined. This determination will be referred to as “false determination” here.

  As a concrete method of this truth determination, in Patent Document 5 and Patent Document 6, a distance sufficient to accurately calculate the coordinates instructed in the coordinate input area at both ends of one side of the conventional coordinate input area. In addition to the first and second sensors installed apart from each other, the first and second sensors are separated from each other by a distance sufficient to accurately calculate the coordinates indicated in the input area from the first and second sensors. A third sensor is provided at a position between the sensors. And the technique which performs this truth determination with respect to several angle information detected by the 1st and 2nd sensor based on the angle information different from the angle information of the 1st and 2nd sensor in this 3rd sensor is disclosed. Has been.

On the other hand, by arranging a plurality of sensor units around the coordinate input area with a predetermined interval and observing almost the same direction and almost the same area, even if a plurality of shading shadows overlap, A method has been proposed to avoid detection that is completely hidden behind the shadow of the camera. Also, a method has been proposed in which when a plurality of shadows overlap, the direction in which the shadow exists is detected by observing one end of each shadow.
U.S. Pat. No. 4,507,557 JP 2000-105671 A JP 2001-142642 A JP 2002-055570 A JP 2003-303046 A Patent registration No. 2896183

  In the above-described light shielding type coordinate input apparatus, all sensors must accurately detect shadows formed by blocking light based on standards consistent with each other in terms of the number, position, and shadow intensity. However, the size of the shadow detected by the sensor is not always constant. For example, the shadow is small when the pointing tool is far from any sensor, and the shadow is large when the pointing tool is near. Become. In addition, variations in sensitivity among sensors, the shape of the pointing tool, and the like also affect the shadow detection state.

  Thus, if there is a difference in the size of the shadow, for example, a shadow that should originally be detected simultaneously from a plurality of predetermined sensors is detected at a predetermined position from a specific sensor, and another specific There is a possibility that a problem of missing a shadow to be detected at a predetermined position from the sensor may occur. That is, if the original shadow cannot be detected, the coordinates cannot be reliably detected.

  In particular, this problem has a great effect when a plurality of inputs are performed simultaneously with a plurality of pointing devices. In this case, there is a possibility that an erroneous coordinate is detected as if the pointing tool has been input at a position that is not possible.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a coordinate input device that can accurately detect input coordinates, a control method therefor, and a program.

In order to achieve the above object, a coordinate input device according to the present invention comprises the following arrangement. That is,
A coordinate input device for detecting a designated position on a coordinate input area,
A plurality of sensor means provided around the coordinate input area, comprising: a light projecting unit that projects light to the coordinate input area; and a light receiving unit that receives incoming light;
Reflecting means provided around the coordinate input area and recursively reflects incident light;
The coordinate input based on the number of shadows that are in the range exceeding the first threshold and the number of shadows in the range that exceeds the second threshold in the light intensity distribution obtained from each of the plurality of sensor units by the instruction from the instruction unit Determination means for determining whether the instruction input by the instruction means in the region is singular, plural, or multiple shadows are overlapped , and
The first threshold value is a threshold value for detecting, as the shadow, a range of a relatively low level of light intensity from the light intensity distribution,
The second threshold value is a threshold value for detecting a range of a relatively high light intensity level as the shadow from the light intensity distribution,
The determination means includes
In the set of sensor means selected from the plurality of sensor means, the number of shadows of the shadow exceeding the second threshold in the light intensity distribution with respect to one sensor means is 1, and the other sensor means of the set of sensor means When the number of shadows of the shadow exceeding the first threshold in the light intensity distribution for is 1, it is determined that the instruction input by the instruction means is singular,
The number of shadows of the shadow exceeding the second threshold in the light intensity distribution obtained from the one sensor means is 2, and the number of shadows of the shadow exceeding the first threshold in the light intensity distribution for the other sensor means is In the case of 1, it is determined that there are a plurality of instructions input by the instruction means, and the shadow obtained from the other sensor means is determined as a plurality of shadows overlapping .

In order to achieve the above object, a method for controlling a coordinate input device according to the present invention comprises the following arrangement. That is,
A plurality of sensor means provided around the coordinate input area, including a light projecting unit that projects light to the coordinate input area and a light receiving unit that receives incoming light, A method for controlling a coordinate input device that detects a designated position,
An acquisition step of acquiring a light intensity distribution obtained from the plurality of sensor means according to an instruction by the instruction means;
Based on the number of shadows that are a range exceeding the first threshold and the number of shadows that is a range exceeding the second threshold in the light intensity distribution obtained from each of the plurality of sensor means acquired by the acquisition step, A determination step of determining whether the instruction input by the instruction means in the coordinate input area is singular, plural, or multiple shadows are overlapped , and
The first threshold value is a threshold value for detecting, as the shadow, a range of a relatively low level of light intensity from the light intensity distribution,
The second threshold value is a threshold value for detecting a range of a relatively high light intensity level as the shadow from the light intensity distribution,
The determination step includes
In the set of sensor means selected from the plurality of sensor means, the number of shadows of the shadow exceeding the second threshold in the light intensity distribution with respect to one sensor means is 1, and the other sensor means of the set of sensor means When the number of shadows of the shadow exceeding the first threshold in the light intensity distribution for is 1, it is determined that the instruction input by the instruction means is singular,
The number of shadows of the shadow exceeding the second threshold in the light intensity distribution obtained from the one sensor means is 2, and the number of shadows of the shadow exceeding the first threshold in the light intensity distribution for the other sensor means is In the case of 1, it is determined that there are a plurality of instructions input by the instruction means, and the shadow obtained from the other sensor means is determined as a plurality of shadows overlapping .

In order to achieve the above object, a program according to the present invention comprises the following arrangement. That is,
A plurality of sensor means provided around the coordinate input area, including a light projecting unit that projects light to the coordinate input area and a light receiving unit that receives incoming light, A program for causing a computer to execute control of a coordinate input device that detects a designated position,
An acquisition procedure for acquiring a light intensity distribution obtained from the plurality of sensor means according to an instruction by the instruction means;
Based on the number of shadows that are a range exceeding the first threshold and the number of shadows that are a range exceeding the second threshold in the light intensity distribution obtained from each of the plurality of sensor means acquired by the acquisition procedure, Causing the computer to execute a determination procedure for determining whether the instruction input by the instruction means in the coordinate input area is singular, plural, or plural shadows ,
The first threshold value is a threshold value for detecting, as the shadow, a range of a relatively low level of light intensity from the light intensity distribution,
The second threshold value is a threshold value for detecting a range of a relatively high light intensity level as the shadow from the light intensity distribution,
The determination procedure is as follows:
In the set of sensor means selected from the plurality of sensor means, the number of shadows of the shadow exceeding the second threshold in the light intensity distribution with respect to one sensor means is 1, and the other sensor means of the set of sensor means When the number of shadows of the shadow exceeding the first threshold in the light intensity distribution for is 1, it is determined that the instruction input by the instruction means is singular,
The number of shadows of the shadow exceeding the second threshold in the light intensity distribution obtained from the one sensor means is 2, and the number of shadows of the shadow exceeding the first threshold in the light intensity distribution for the other sensor means is In the case of 1, it is determined that there are a plurality of instructions input by the instruction means, and the shadow obtained from the other sensor means is determined as a plurality of shadows overlapping .

In order to achieve the above object, a coordinate input device according to the present invention comprises the following arrangement. That is, a coordinate input device that detects a designated position on a coordinate input area,
A plurality of sensor means;
Based on the light intensity distribution obtained from each of the plurality of sensor means and the first threshold value and the second threshold value by the instruction by the instruction means , the instruction input by the instruction means in the coordinate input area is singular or plural. Or a determination means for determining whether a plurality of shadows overlap .
The first threshold value is a threshold value for detecting, as the shadow, a range of a relatively low level of light intensity from the light intensity distribution,
The second threshold value is a threshold value for detecting a range of a relatively high light intensity level as the shadow from the light intensity distribution,
The determination means includes
In the set of sensor means selected from the plurality of sensor means, the number of shadows of the shadow exceeding the second threshold in the light intensity distribution with respect to one sensor means is 1, and the other sensor means of the set of sensor means When the number of shadows of the shadow exceeding the first threshold in the light intensity distribution for is 1, it is determined that the instruction input by the instruction means is singular,
The number of shadows of the shadow exceeding the second threshold in the light intensity distribution obtained from the one sensor means is 2, and the number of shadows of the shadow exceeding the first threshold in the light intensity distribution for the other sensor means is In the case of 1, it is determined that there are a plurality of instructions input by the instruction means, and the shadow obtained from the other sensor means is determined as a plurality of shadows overlapping .

  ADVANTAGE OF THE INVENTION According to this invention, the coordinate input device which can detect the input coordinate accurately, its control method, and a program can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Embodiment 1>
FIG. 1A is a diagram illustrating a configuration of a light-shielding coordinate input device according to a first embodiment of the present invention.

  In FIG. 1A, reference numerals 1L and 1R denote sensor units having a light projecting part and a light receiving part. In the case of the first embodiment, as shown in FIG. 1A, parallel to the X axis of the coordinate input effective area 3 as a coordinate input surface, They are arranged at a position symmetric with respect to the Y-axis and separated by a predetermined distance. The sensor units 1L and 1R are connected to the control / arithmetic unit 2, receive a control signal from the control / arithmetic unit 2, and transmit the detected signal to the control / arithmetic unit 2.

  Reference numeral 4 denotes a retroreflective portion having a retroreflective surface that reflects incident light in the direction of arrival, and is disposed on the outer three sides of the coordinate input effective area 3 as shown in the drawing, and within a range of approximately 90 ° from the left and right sensor units 1L and 1R. Is retroreflected toward the sensor units 1L and 1R.

  The retroreflective portion 4 has a three-dimensional structure when viewed microscopically. At present, the retroreflective portion 4 is mainly arranged by regularly arranging bead-type retroreflective tape or corner cubes by machining or the like. Retroreflective tape to wake up is known.

  The light retroreflected by the retroreflecting unit 4 is detected one-dimensionally by the sensor units 1L and 1R, and the light intensity distribution is transmitted to the control / arithmetic unit 2.

  The coordinate input effective area 3 is configured as a display screen of a display device such as a PDP, a rear projector, or an LCD panel, and can be used as an interactive input device.

  In such a configuration, when an input instruction is given to the coordinate input effective area 3 by an instruction means such as a finger or an indicator, the light projected from the light projecting portions of the sensor units 1L and 1R is blocked (light-shielding portion). Since the light receiving portions of the sensor units 1L and 1R cannot detect the light of the light shielding portion (reflected light due to retroreflection), it is possible to determine from which direction the light could not be detected.

  Therefore, the control / arithmetic unit 2 detects a plurality of light-shielding ranges of the portion instructed to be input by the pointing tool from the light intensity change detected by the left and right sensor units 1L and 1R, and from the edge information of the light-shielding range, The direction (angle) of the end of the light shielding range with respect to each of the sensor units 1L and 1R is calculated. When the pointing tool has a signal transmission unit, the pen signal receiving unit 5 receives a pen signal from the pointing tool.

  Then, based on the number of detected light-shielding ranges, data obtained from the light-shielding ranges used for coordinate calculation is determined, the calculated directions (angles (θL and θR in FIG. 1A)), sensor units 1L and The light shielding position of the pointing tool on the coordinate input effective area 3 is geometrically calculated from the distance information between 1R and the like, and the external terminal such as a host computer connected to the display device is connected to the interface 7 (for example, USB, The coordinate value is output via IEEE 1394).

  In this way, the operation of the external terminal such as drawing a line on the screen or operating an icon displayed on the display device can be performed by the pointing tool.

  Particularly, in the present invention, the light intensity distribution including the light shielding range (shadow) detected by the sensor unit is compared with the reference light intensity distribution when there is no reference input (no light shielding state). In this comparison, with respect to the relative light intensity distribution obtained by using the light intensity distribution to be processed and the reference light intensity distribution, it is determined which part of the relative light intensity distribution is shielded at what ratio. And a second threshold for determining a portion having a greater degree of light shielding than the first threshold (see FIG. 1B).

  Then, by comparing the first and second threshold values with the intensity of the shadow obtained by the light shielding (input) obtained from the relative light intensity distribution (the reduction rate or depth of the light intensity due to the light shielding), a plurality of Even when inputs are performed in parallel, coordinates are accurately calculated without erroneous detection of those inputs.

<Explanation of issues>
Here, the problem in the present invention will be described again in detail with reference to the drawings.

  FIG. 2 is a diagram for explaining the problem in the present invention.

  In the conventional configuration, the threshold for determining the above-described shadow intensity is configured using a single threshold.

  For example, when a coordinate input operation is executed at point P in FIG. 1A, a relative light intensity distribution as shown in FIGS. 2A and 2B is obtained according to the input state. In this case, in FIGS. 2A and 2B, a shadow is generated at the positions of θL and θR by the input at the point P.

  Here, FIG. 2A is a relative light intensity distribution obtained from the sensor unit 1L in a state where coordinate input is performed by the pointing tool. FIG. 2B shows the relative light intensity distribution obtained from the sensor unit 1R at the moment when the pointing tool enters or exits the coordinate input effective area.

  As is clear from comparison between FIG. 2A and FIG. 2B, even in one coordinate input operation, depending on the detection timing, a shadow (light shielding range) formed by light shielding in the relative light intensity distribution. ) Has a large deviation. This deviation is determined by factors such as the input position, the optical characteristics of the sensor units 1L and 1R, and the thickness of the pointing tool.

  In particular, when the position of the point P is close to the sensor unit 1L and far from the sensor unit 1R, the shadow in the relative light intensity distribution detected by the sensor unit 1L has a large width and depth. On the other hand, the shadow in the relative light intensity distribution detected by the sensor unit 1R is small in both width and depth.

Here, for example, as shown in FIG. 2A, if the threshold for determining the presence or absence of a shadow is thsh0 (for example, relative light intensity corresponding to 50% when the maximum relative light intensity is 100%), In the sensor unit 1L,
dpthL> thsh0
Is satisfied, the sensor unit 1L detects a shadow with respect to the instruction input at the point P.

On the other hand, in the sensor unit 1R,
dpthR <thsh0
When satisfying the above, the sensor unit 1R does not detect a shadow for the instruction input at the point P.

  As a result, the position coordinates of point P cannot be calculated.

In order to avoid such a situation, even if the value of thsh0 (for example, the relative light intensity corresponding to 30% when the maximum relative light intensity is 100%) is set large, FIG. As shown, when the shadow detected by each sensor unit is small, such as the moment when the pointing device enters the coordinate input effective area 3 or the moment when it comes out,
dpth'R <thsh0
There will always be a case. That is, a shadow may be detected only in the sensor unit 1L, and a shadow may not be detected in the sensor unit 1R. Therefore, even in such a case, the position coordinates of the point P cannot be calculated.

  Thus, in a single coordinate input operation (hereinafter also abbreviated as “single input”), the shadow to be detected by each sensor unit is caused by a difference in the distance between the input positions of each sensor unit and the indicator. Thus, there is a case where the indicator is not detected by one of the sensor units when the pointing tool enters or exits the coordinate input effective area. In this case, coordinate calculation cannot be executed.

  This fact becomes a big problem particularly in a coordinate input device that allows a plurality of inputs at the same time. Hereinafter, this problem will be described with reference to FIG. 3 and the subsequent drawings, some of the various components shown in FIG. 1A are omitted from the drawings corresponding to FIG. 1A.

  FIG. 3 shows a case where a plurality of inputs are made to point Pa (for example, P12 in FIG. 3) and point Pb (for example, P21 in FIG. 3).

  In this case, in each sensor unit, as shown in FIG. 4, the sensor unit 1L detects shadows at the positions θL1 and θL2, and the sensor unit 1R detects shadows at the positions θR1 and θR2.

  Then, based on these two sets of angle data (θL1 and θL2, θR1 and θR2), four coordinate candidate points P11, P12, P21, and P22 are calculated. From these coordinate candidate points, by determining the true or false, for example, it is determined that P11 and P22 are virtual images, and P12 and P21 are real images, and the coordinate input points can be determined.

  At this time, as described above, for example, the shadow detected by the sensor unit closer to the coordinate input position due to the influence of the coordinate input position or the like is large in both width and depth, and the sensor unit on the side far from the coordinate input position. When the shadow detected in (2) becomes smaller in both width and depth, and any of the shadows cannot be detected, an erroneous coordinate candidate point is detected.

  An example of such a case will be described below.

  5 and 6 show a plurality of input examples in the case where accurate coordinates cannot be detected because the shadows indicating θL2 and θR2 do not exceed the threshold thsh0.

  In this case, as shown in FIGS. 5 and 6, each sensor unit cannot detect a shadow in the direction of the broken line (that is, P12, P21, P22). Therefore, in practice, one input is made only at the position of P11 even though a plurality of inputs are made at the positions of Pa (for example, P12 in FIG. 5) and Pb (for example, P21 in FIG. 5). False positive.

  Furthermore, another example will be described.

  7 and 8 show a plurality of input examples when accurate coordinate detection cannot be performed because only θR2 does not exceed the threshold value thsh0.

  In this case, as shown in FIGS. 7 and 8, the sensor unit 1R cannot detect a shadow in the direction of the broken line (that is, P12, P12). Therefore, in practice, although two or more inputs are performed at positions Pa (for example, P12 in FIG. 5) and Pb (for example, P21 in FIG. 5), two input points are set to P11 and P21. They are present and erroneously detected as overlapping when viewed from the sensor unit 1R.

  As described above, even in a plurality of simultaneous coordinate input operations (hereinafter also abbreviated as “multiple inputs”), as in the case of a single input, the shadow to be detected by each sensor unit is between the input positions of each sensor unit and the indicator. When the pointing device enters or exits the coordinate input effective area, it may not be detected by one of the sensor units due to a difference in the distance between them. In this case, coordinate calculation cannot be executed. In addition, if multiple inputs are allowed, an incorrect coordinate or coordinate candidate is calculated, rather than calculating the coordinate.

  Therefore, the present invention proposes a configuration that solves these problems. In particular, in the present invention, two thresholds for detecting the presence of shadows due to light shielding are set from the relative light intensity distribution. The two threshold values are set based on the maximum ratio of the shadow intensity (the depth of the valley in the relative light intensity distribution) assumed from the optical characteristics of the sensor unit.

Here, assuming that the maximum value of the assumed shadow intensity is dpth_max and the maximum value dpth_min, the maximum ratio M of shadow intensity is M = dpth_max / dpth_min (Formula 1_1)
It becomes. And at this time,
thsh1 / thsh2> M (Formula 1_2)
A threshold value that satisfies the above is set. If these two thresholds are applied to the relative light intensity distribution, when the larger shadow exceeds the second threshold (thsh2), the smaller shadow necessarily exceeds the first threshold (thsh1). That is, the configuration is such that the presence of the larger shadow is determined by the second threshold (thsh2), and the smaller shadow is determined by the first threshold (thsh1). As a result, it is possible to avoid calculating the wrong coordinates because the smaller shadow cannot be detected even though the larger shadow is detected as described above.

  According to such a configuration, in the case of a single input, it can be avoided that coordinate calculation cannot be performed when the pointing tool enters and exits the coordinate input effective area. Further, in the case of a plurality of inputs, by recognizing an incorrect coordinate candidate, it is possible to avoid the problem of erroneously recognizing the presence or absence of overlapping shadows and, as a result, calculating an incorrect coordinate.

  Thus, the effect obtained by the present invention is very large, and it can be said that it is essential in the coordinate input device in this field.

  Next, the structure in Embodiment 1 of this invention is demonstrated.

  9 to 11 show the relationship between the number of shadows in the relative light intensity distribution obtained from the two sensor units 1L and 1R and the threshold value to be set when all the inputs shown in FIG. 3 are performed. (It is omitted for the case where only the order is changed).

  In addition, in FIGS. 9-11, the shadow in relative light intensity distribution is shown by s1, s2, s3, s4.

  In each of FIGS. 9 to 11, the diagrams on the left side show the configuration of shadows detected by the sensor unit having the larger number of shadows exceeding the first threshold thsh1. Further, the right diagram shows the configuration of the shadow detected by the sensor unit with the smaller number of shadows exceeding the first threshold thsh1.

  For convenience, the description will be made assuming that the number of shadows detected by the sensor unit 1L is larger. Further, in each of FIGS. 9 to 11, the position of the shadow has no meaning, and only the relationship among the number of shadows, the intensity (depth) of the shadow, and the threshold values (thsh1, thsh2) is meaningful.

  In a plurality of inputs to the configuration shown in FIG. 3, for example, two effective coordinate candidate points are determined by two sensor units 1L and 1R, and a final coordinate input point is determined from the two sets. Or it is good also as a structure which comprises a 3rd sensor unit and final coordinate input point is determined by the information obtained from the 3rd sensor unit, and one set of coordinate candidate points.

  In the first embodiment, since multiple inputs are assumed, it is determined whether there is a single input, multiple inputs, or overlap of shadows associated with multiple inputs, the state of the detected shadow, that is, whether the shadow exceeds two thresholds. Execute with confirmation, depending on whether or not. Thereby, it is possible to determine only coordinate candidate points with a certainty without error and prevent erroneous coordinate calculation.

  Hereinafter, FIGS. 9 to 11 will be described.

[[A classification (Fig. 9)]]
The A classification shown in FIG. 9 shows a case where the number of shadows exceeding at least the first threshold thsh1 is one for each of the sensor units 1L and 1R.

[In the case of FIG. 9A]
Since the shadows detected by the sensor units 1L and 1R both exceed the second threshold thsh2, the shadow detected by the sensor unit 1R accompanying the same input should also exceed at least the first threshold thsh1. Here, in the sensor unit 1R, only s3 exceeds the first threshold thsh1.

  Of the shadows on the sensor unit 1R side, the shadow corresponding to the shadow s1 on the sensor unit 1L side is either the shadow s3 or the shadow S4 (broken line) overlapping at the same position as the shadow s3.

On the other hand, the same argument can be made for the shadow s3. That is, among the shadows of the sensor units 1L side, the shadow corresponding to the shadow s3, shadow s1, or a shadow s2 (dashed line) Nodochi Raka which overlap at substantially the same position as the shadow s1.

  Here, in both the sensor units 1L and 1R, the fact that the shadows overlap is a state that can be regarded as an input indicating the same position, that is, a single input or a single input.

  Thereby, it can be determined that the shadow s1 and the shadow s3 correspond as shadows, that is, one input of (s1, s3).

[In the case of FIG. 9B]
The shadow on the sensor unit 1R side corresponding to the shadow s1 on the sensor unit 1L side is the shadow s3 or the shadow s4 (broken line) overlapping the shadow s3. On the other hand, the shadow on the sensor unit 1L side corresponding to the shadow s3 on the sensor unit 1R side is the shadow s2 (dashed line) that overlaps with the shadow s1 or the shadow s1 because the shadow s3 does not exceed the second threshold thsh1. Alternatively, it is unknown which of the shadows s2 ′ is in a different position and has not been detected yet (even the first threshold thsh1 is not exceeded).

  In this case, it is determined that at least one input defined by (s1, s3) exists.

  However, it cannot be denied that the second input exists. That is, there may be another input defined by (s2, s3) or (s2, s4).

[In the case of FIG. 9C]
This is a case where the shadow s1 does not correspond to the shadow s3. In this case, there is a high possibility that (s1, s3) exists, but the two inputs defined by (s1, s4) and (s2, s3) are incomplete (ie, the second second threshold thsh2 is set). It may be detected (without exceeding). Therefore, no input can be determined.

[[B classification (FIG. 10)]]
The B classification shown in FIG. 10 shows a case where the number of shadows exceeding the first threshold thsh1 is two for one sensor unit (here, described as the sensor unit 1L side) and one for the other sensor unit. ing.

[In the case of FIGS. 10A and 10B]
Both the shadow s1 and the shadow s2 on the sensor unit 1L side exceed the second threshold thsh2. For this reason, the shadow on the sensor unit 1R side corresponding to these must surely exceed the first threshold thsh1. Here, only the shadow s3 exceeds the first threshold thsh1 on the sensor unit 1R side. Since the shadow s4 overlaps with the shadow s3, the shadow s4 is identified here as the shadow s3.

  Therefore, it can be said that the shadow of the sensor unit 1R corresponding to the shadow s1 and the shadow s2 exists at least overlapping the position of the shadow s3. That is, it can be determined that there are two inputs (s1, s3) and (s2, s3).

[FIGS. 10C and 10D]
The shadow s1 on the sensor unit 1L side exceeds the second threshold thsh2. For this reason, the shadow on the sensor unit 1R side corresponding to this is at least exceeding the first threshold thsh1. Here, only the shadow s3 exceeds the first threshold thsh1 on the sensor unit 1R side. Therefore, the shadow corresponding to the shadow s1 is the shadow s3 or the shadow s4 overlapping the shadow s3.

  On the other hand, the shadow s2 exceeds the first threshold thsh1, but does not exceed the second threshold thsh2. Accordingly, the corresponding shadow on the sensor unit 1R side does not necessarily exceed the first threshold thsh1, and cannot be said to be the shadow s3 or the shadow s4 overlapping the shadow s3.

  Therefore, in this case, it can be determined that the input of (s1, s3) exists. It is also certain that there is another input, but it is unclear whether it is (s2, s3) or (s2, s4), and cannot be determined (here, a shadow s4 'may exist) Have sex).

[In the case of FIGS. 10E and 10F]
The shadow s3 on the sensor unit 1R side exceeds the second threshold thsh2. For this reason, the shadow on the sensor unit 1L side corresponding to this should at least exceed the first threshold thsh1.

  However, there are two shadows s1 and s2 as shadows that exceed the first threshold thsh1 on the sensor unit L side, and none of them exceeds the second second threshold thsh2. Therefore, the shadow corresponding to these corresponds to the shadow s3 on the sensor unit R side, or the shadow s4 overlapping with the shadow s3, or corresponds to the shadow s4 ′ that is not yet detected at another position. Is not clear.

  Therefore, in this case, it is certain that there are two inputs, but there is no input (that is, a combination of shadows) that can be determined as a result.

[[C classification] (FIG. 11)]
In the C classification shown in FIG. 11, the positions of two shadows can be specified for both the sensor units 1L and 1R. Here, it is certain that the third input is prohibited and the input is at least two inputs. Therefore, the positions of all the shadows can be specified, and it can be said that there is no shadow that has been detected yet in another position.

  Accordingly, in this case, the coordinate positions of the two actual inputs cannot be specified in any of the cases of FIGS. 11A to 11F, regardless of whether each shadow exceeds the second threshold thsh2. Four coordinate candidate points including one actual input point can be determined.

  As described above, in the first embodiment, input coordinates, four coordinate candidate points, or two overlapping points can be determined based on the classifications illustrated in FIGS. 9 to 11.

  As described above, in FIG. 9 to FIG. 11, a set of coordinate candidate point determination states based on the detection state of the number of shadows detected by the sensor units 1L and 1R can be defined as follows. Here, the combination of the number of shadows is expressed as [XY] (X = 1, 2, Y = 1, 2).

Determining state (1) ([1-1] a): Determining a single input point Determining state (2) ([1-1] b): Determining one input point out of two input points Determining state (3) ([2-1]): Confirmation that two input points overlap when viewed from one sensor unit (one sensor unit) Confirmation state (4) ([2-2]): Two actual input points Confirmation of four coordinate candidate points including “Confirmed state (5)” ([0-0]): No confirmation of input point and coordinate candidate point Note that the confirmed states (1) to (5) expressed here are only sensors. Based on the relationship between the above two thresholds rather than the simple number of shadows detected by the units 1L and 1R, the coordinate candidate point determination process described below ensures the certainty of the input point or coordinate candidate point. This is the number of shadows for indicating a definite state determined to be present. Therefore, in some cases, the number of shadows actually detected is different and may be smaller.

  The above is the principle of determining input points or coordinate candidate points in the first embodiment. Further, by combining this determination principle with true / false determination, a light-shielding input type coordinate input device corresponding to a plurality of inputs can be configured.

  Hereinafter, the coordinate candidate point determination process according to the first embodiment will be described with reference to FIG.

  FIG. 12 is a flowchart showing coordinate candidate point determination processing according to the first embodiment of the present invention.

  First, in step S1, the number of shadows exceeding the first threshold (thsh1) is determined from the relative light intensity distribution detected by the sensor units 1L and 1R. And based on this determination result, it branches to each process.

  If the combination of the number of shadows is [1-1] in step S1, the process proceeds to step S2, and it is determined whether or not 1 is included in the number of shadows exceeding the second threshold (thsh2) among the shadows to be processed. To do. If 1 is included (YES in step S2), the process proceeds to step S3, and it is determined that the state is the final state (1). On the other hand, when 1 is not included (NO in step S2), the process proceeds to step S4, and it is determined that the state is the finalized state (5).

  If the combination of shadow numbers is [2-1] in step S1, the process proceeds to step S7, and one of the sensor unit blocks in the shadow number exceeding the second threshold (thsh2) among the shadows to be processed. It is determined whether or not 2 is included in the number of shadows on the side of (sensor unit 1L or 1R) (in this case, the other is sensor unit B (sensor unit 1R or 1L)). When 2 is included, it progresses to step S8 and determines with it being a definite state (3). When 1 is included, it progresses to step S9 and determines with it being a definite state (2). When 0 is included, it progresses to step S10 and it determines with it being a definite state (5).

  If the combination of the number of shadows is [2-2] in step S1, the process proceeds to step S5 and is determined to be in the finalized state (4).

  If the combination of the number of shadows is [2-0] or [1-0] in step S1, the process proceeds to step S6 and it is determined that the state is the finalized state (5).

  Then, based on these finalized states, coordinate calculation processing suitable for each finalized state is executed, so that coordinate calculation related to a plurality of inputs can be performed with high accuracy. A specific example of this coordinate calculation process will be described in the second embodiment.

  As described above, in the light-shielding coordinate input device according to the configuration of the first embodiment, a shadow detected by input in an arbitrary set of sensor units among a plurality of sensor units that observe input to the coordinate input effective area is input. While determining the number of input points that can determine the existence of the input from the shadow intensity and the number of shadows of one sensor unit with a large number, the number of shadows detected by one sensor unit (sensor unit A), The number of shadows detected by the other sensor unit (sensor unit B) is compared to determine whether there is a shadow overlap.

  Here, with respect to the relative light intensity distribution obtained from the sensor unit, a threshold value for determining the presence of a shadow at the sensor unit B is a first threshold value, and a threshold value for determining the presence of a shadow at the sensor unit A is a second threshold value. Then, the second threshold value is set to a higher level than the first threshold value (the degree of light shielding by the relative light intensity distribution).

  With this configuration, for example, when N shadows are detected by the sensor unit A, the shadows should be detected from the sensor unit B as long as the shadows do not overlap. Then, when the number of shadows detected by the sensor unit B is the same as the number of shadows of the sensor unit A, it can be determined that there is no overlap of shadows, and when the number of shadows is small, there are as many overlaps as there are.

  Here, when the number of shadows detected by both is N, N × N coordinate candidate points can be determined, and when the number of shadows detected by the sensor unit B is 1, N coordinate candidates The determination that the point can be confirmed is established.

  When this is applied to N = 2, the present invention can realize the following determination.

  If the sensor unit A has two shadows exceeding the second threshold and the sensor unit B has two shadows exceeding the first threshold, the existence of four coordinate candidate points is determined.

  When the number of shadows exceeding the second threshold is 2 on the sensor unit A and the number of shadows exceeding the first threshold is 1 on the sensor unit B, the two coordinate input points are omitted when viewed from the sensor unit B. It is confirmed that they are arranged in a straight line (overlapping).

  When the number of shadows exceeding the second threshold is 1 in the sensor unit A and the number of shadows exceeding the first threshold is 1 in the sensor unit B, it is determined that one coordinate input point exists.

  With the configuration described above, in Embodiment 1, coordinate input is effective even when a shadow (light-shielding range) detected with the same input is detected with a difference in level between different sensor units. By determining the instruction state in the region (the confirmation state and the detection state described above), it is possible to prevent the input coordinates from being missed by a single input, and to prevent detecting wrong coordinates different from the input coordinates by a plurality of inputs. .

  Further, in the configuration of the first embodiment, it is possible to avoid problems such as false detections that occur when the pointing tool enters and exits the coordinate input effective area with input, and stable coordinate input can be realized.

<Embodiment 2>
FIG. 13 is a diagram showing a configuration of a light shielding type coordinate input apparatus according to the second embodiment of the present invention.

  The basic configuration of the coordinate input device shown in FIG. 13 is the same as the coordinate input device of FIG. 1A. In the first embodiment, the detailed configuration of the sensor units 1L and 1R has not been specifically described. However, this will be collectively described in the second embodiment.

  Moreover, while the sensor units 1L and 1R of the first embodiment show a case where each of the built-in light projecting unit and light receiving unit is one set, in FIG. 13 of the second embodiment, the sensor units 1L and 1R are The case where it comprises 2 sets of each is shown. In other words, the first embodiment has a monocular configuration in which one optical unit is built in one sensor unit, whereas in the second embodiment, a compound eye (two optical units are built in one sensor unit ( Binocular) configuration.

<Detailed description of sensor unit 1>
Next, the configuration in the sensor units 1L and 1R will be described with reference to FIG. As described above, the sensor units 1L and 1R are roughly composed of a light projecting unit and a light receiving unit.

  FIG. 14 is a diagram showing a detailed configuration of the sensor unit according to the second embodiment of the present invention.

  In FIG. 14, 101A and 101B are infrared LEDs that emit infrared light, and project light in a range of approximately 90 ° toward the retroreflective portion 4 by the light projecting lenses 102A and 102B, respectively. Here, the light projecting units in the sensor units 1L and 1R are realized by the infrared LEDs 101A and 101B and the light projecting lenses 102A and 102B. Thereby, each of the sensor units 1L and 1R includes two light projecting units.

  Then, the infrared light projected from the light projecting unit is retroreflected in the arrival direction by the retroreflecting unit 4, and the light is detected by the light receiving units in the sensor units 1L and 1R.

  The light receiving unit includes a one-dimensional line CCD 104 provided with a shield member 105 that restricts the field of view of the light and provides an electrical shield, light receiving lenses (for example, fθ lenses) 106A and 106B as a condensing optical system, It comprises diaphragms 108A and 108B that roughly limit the incident direction of incident light, and infrared filters 107A and 107B that prevent the incidence of extraneous light (disturbance light) such as visible light.

  The light reflected by the retroreflecting unit 4 passes through the infrared filters 107A and 107B and the stops 108A and 108B, and is collected on the detection element 110 surface of the line CCD 104 by the light receiving lenses 106A and 106B. Thereby, each of the sensor units 1L and 1R includes two light receiving units.

  The member 103 and the member 109 are arranged to dispose the optical components constituting the light projecting unit and the light receiving unit, and prevent light projected by the light projecting unit from directly entering the light receiving unit, or to cut off external light. It functions as an upper hood 103 and a lower hood 109.

  In the second embodiment, the throttles 108A and 108B are formed integrally with the lower hood 109. However, it goes without saying that the diaphragms 108A and 108B may be separate parts, and further, on the upper hood 103 side. And 108B and the light receiving lenses 106A and 106B are provided to facilitate positioning of the light receiving portion with respect to the light emission center of the light projecting portion (that is, all the main optical components are arranged only by the upper hood 103). Can also be realized.

  FIG. 15A is a view of the assembled state of the sensor unit 1L (1R) in the state of FIG. 14 as viewed from the front direction (perpendicular to the coordinate input surface). As shown in FIG. 15A, the two light projecting units in the sensor unit 1L (1R) are arranged so that their principal ray directions are substantially parallel to each other with a predetermined distance d therebetween. Each of 102A and 102B is configured to project light in a range of approximately 90 °.

  FIG. 15B is a cross-sectional view of the portion indicated by the thick arrow in FIG. 14A. The light from the infrared LED 101A (101B) is a light beam that is limited to be approximately parallel to the coordinate input surface by the light projection lens 102A (102B). As described above, the light is projected mainly on the retroreflective portion 4.

  On the other hand, FIG. 15C is a view of the state in which the infrared LEDs 101A and 101B, the projection lenses 102A and 102B, and the upper hood 103 in FIG. 15A are removed as viewed from the front direction (perpendicular to the coordinate input surface).

  Here, in the case of Embodiment 2, the light projecting unit and the light receiving unit have an arrangement configuration (see FIG. 15B) that is superimposed on the vertical direction of the coordinate input effective area 3 that is the coordinate input surface, and the front direction (coordinates). When viewed from the direction perpendicular to the input surface, this corresponds to the light emission center of the light projecting unit and the reference position of the light receiving unit (that is, the reference point position for measuring the angle. In the second embodiment, the diaphragm 108A (108B). ), Which is the point where the light rays intersect in the figure).

  Therefore, as described above, since the two light projecting portions are arranged so as to be substantially parallel to each other in the principal ray direction with a predetermined distance d apart, the two light receiving portions are similarly separated by the predetermined distance d. And each optical axis (optical symmetry axis) is configured to be substantially parallel.

  In addition, light that is approximately parallel to the coordinate input surface projected by the light projecting unit and is projected in a direction of approximately 90 ° in the in-plane direction is recursed in the light arrival direction by the retroreflecting unit 4. The light is reflected, passes through the infrared filter 107A (107B), the stop 108A (108B), and the condenser lens 106A (106B), and is condensed and imaged on the detection element 110 surface of the line CCD 104.

  Therefore, since the output signal of the line CCD 104 outputs a light intensity distribution according to the incident angle of the reflected light, the pixel number of each pixel constituting the line CCD 104 indicates angle information.

  Note that the distance L between the light projecting unit and the light receiving unit shown in FIG. 15B is sufficiently smaller than the distance from the light projecting unit to the retroreflective unit 4. The light can be detected by the light receiving unit.

  As described above, the sensor unit 1L (1R) includes at least two light projecting units and two light receiving units that detect the light projected by the respective light projecting units (in the case of the second embodiment, the light projecting). Part has two sets and the light receiving part has two sets).

  In the second embodiment, the left part of the detection elements 110 arranged in a line in the line CCD 104 which is a part of the light receiving unit is the light condensing region of the first light receiving unit, and the right part is the second light receiving unit. Although the light condensing region is used to share components, the present invention is not limited to this, and it goes without saying that a line CCD may be provided for each light receiving unit.

<Description of control / arithmetic unit>
Between the control / arithmetic unit 2 and the sensor units 1L and 1R, the CCD control signal for the line CCD 104 in the light receiving unit, the CCD clock signal and output signal, and the drive signals for the infrared LEDs 101A and 101B in the light projecting unit are mainly used. Are being exchanged.

  Here, a detailed configuration of the control / arithmetic unit 2 will be described with reference to FIG.

  FIG. 16 is a block diagram showing a detailed configuration of a control / arithmetic unit according to the second embodiment of the present invention.

  The CCD control signal is output from an arithmetic control circuit (CPU) 21 constituted by a one-chip microcomputer or the like, and shutter timing of the line CCD 104, data output control, and the like are performed.

  The arithmetic control circuit 21 operates in accordance with the clock signal from the clock generation circuit (CLK) 22. The clock signal for the CCD is transmitted from the clock generation circuit (CLK) 22 to the sensor units 1L and 1R, and arithmetic control is performed to perform various controls in synchronization with the line CCD 104 in each sensor unit. It is also input to the circuit 21.

  The LED drive signal for driving the infrared LEDs 101A and 101B of the light projecting unit is sent from the arithmetic control circuit 21 via the LED drive circuit (not shown) to the infrared LEDs 101A in the light projecting units of the corresponding sensor units 1L and 1R. And 101B.

  Detection signals from the line CCDs 104 in the light receiving portions of the sensor units 1L and 1R are input to the A / D converter 23 and converted into digital values under the control of the arithmetic control circuit 21. The converted digital value is stored in the memory 132 and used for calculating the angle of the pointing tool. Then, a coordinate value is calculated from the calculated angle, and is output to the external terminal via the serial interface 7 (for example, USB, IEEE1394, RS232C interface, etc.).

  When a pen is used as the pointing tool, a digital signal obtained by demodulating the pen signal is output from the pen signal receiving unit 5 that receives the pen signal from the pen, and is input to the sub CPU 24 as a pen signal detection circuit. After the signal is analyzed, the analysis result is output to the arithmetic control circuit 21.

<Detailed description regarding optical arrangement of sensor unit 1>
FIG. 17 is an explanatory diagram for explaining an optical arrangement of the coordinate input device according to the second embodiment of the present invention.

  In FIG. 17, in particular, the arrangement of the left sensor unit 1L will be described. The right sensor unit 1R has the same characteristics except for the symmetrical relationship with the left sensor unit 1L with respect to the Y-axis in the drawing, and thus the description thereof is omitted.

  As described above, the sensor unit 1L has two sets of light projecting units and light receiving units (optical units L1 and L2), and their optical axes (optical symmetry axes, the light beam 151, and (Corresponding to the light beam 161) are arranged substantially parallel and separated by a predetermined distance d. Further, the sensor unit 1L is arranged such that its sensor surface is inclined by θs with respect to one side of the coordinate input effective area 3.

  Further, the light projecting range (or the detection angle range of the light receiving unit) of one light projecting unit in the sensor unit 1L is defined as a light beam 152 and a light beam 153, and the other is defined as a light beam 162 and a light beam 163.

  The sensor unit 1R has two sets of light projecting units and light receiving units (optical units R1 and R2).

  The effective visual field range of the two sets of optical units (the light projecting unit and the light receiving unit) defined by the light beam 152 and the light beam 153 or the light beam 162 and the light beam 163 is approximately 90 °, and of course the range is, for example, 100 °. Although it is possible to set and design the effective visual field range to be larger, for example, the optical distortion of optical components (for example, lenses) constituting the optical unit increases, and the optical system is configured at low cost. This is disadvantageous.

  Accordingly, in order to obtain the pointing position information of the pointing tool that blocks the projected light at each light receiving unit, it is necessary to set the coordinate input effective area within the area defined by the light beam 152 and the light beam 163. This is a preferred form. Therefore, if the coordinate input effective area is set to the area 171 as shown in the figure, the light shielding position of the pointing tool (light shielding object) in the area 171 can be detected by the two sets of light receiving units in the sensor unit 1L. .

  However, by setting in this way, for example, the housing frame determined by the relationship between the housing 172 of the coordinate input device incorporating each component and the area 171 where the coordinates can be input becomes larger, and the coordinates are larger than the operable area. The subject that the magnitude | size of the whole input device will become large arises. In order to solve this problem, it is needless to say that the shape of the sensor unit 1L (1R) is reduced, and furthermore, two sets of optical units (light projecting unit and light receiving unit) defined by the light beam 151 and the light beam 161 are used. It is preferable to make the predetermined distance d of the part) smaller.

  In the coordinate input device according to the second embodiment, in order to make the casing frame determined by the coordinate input effective area 3 and the casing 172 as small as possible, one light receiving unit in the sensor unit 1L (1R) All areas of the effective area 3 are stored in the effective field of view, but the other light receiving unit is set so that the area defined by the area 173 in the figure is outside the effective field of view.

  The distance d is determined by the projection component viewed from the direction of the pointing tool when the pointing tool is at the left or right end or upper end of the coordinate input effective area 3, that is, d * cos (θL−θs). It is comprised so that it may become substantially equal to the radius of.

  In this way, in FIG. 17, the pointing tool behind is configured not to completely enter the region between the light beam 151 and the light beam 161 in the drawing.

  In the second embodiment, for example, the light intensity distribution obtained from each of the optical units L1, L1, R2, and R1 in FIG. 17 is acquired. Then, the number of shadows and the shadow position (angle) obtained by each optical unit are calculated from the light intensity distribution, and the optical unit L1 or L2 constituting the sensor unit 1L and the optical unit constituting the sensor unit 1R. Four types of combinations obtained from R1 or R2, that is, (L1, R1), (L1, R2), (L2, R1) and (L2, R2) are selected in order.

  Next, in each combination, the coordinate candidate points are determined or the overlapping situation of the coordinate candidate points is determined, and an appropriate combination of the optical units is selected from them. Thereby, an actual input point is determined from so-called coordinate candidate points (so-called true / false determination), and finally two input coordinates are determined.

Hereinafter, the four combinations (L1, R1), (L1, R2), (L2, R1), and (L2, R2) are expressed as “LR optical unit combinations” or “LR combinations”.
Next, the coordinate calculation process in Embodiment 2 is demonstrated using FIG.

  FIG. 18 is a flowchart showing coordinate calculation processing executed by the coordinate input device according to the second embodiment of the present invention.

  First, in step S101, light intensity distribution data in each optical unit of the optical units L1, L2, R1, and R2 is acquired. Next, in step S102, the light intensity distribution data for the LR combination is sequentially selected from the acquired light intensity distribution data, and the coordinate candidate point determination process of FIG. 12 of the first embodiment is executed for the selected light intensity distribution data. (Steps S102 to S109).

  Next, a coordinate calculation process (steps S110 to S123) is executed based on the processing result of the coordinate candidate point determination process.

  Then, by the coordinate candidate point determination process for each LR combination, as shown in the first embodiment, one of the following fixed states is obtained.

Determining state (1) ([1-1] a): Determining a single input point Determining state (2) ([1-1] b): Determining one input point out of two input points Determining state (3) ([2-1]): Confirmation that two input points overlap when viewed from one sensor unit Confirmation state (4) ([2-2]): Four coordinate candidates including two actual input points Determination of points Determination state (5) ([0-0]): No determination of input points and coordinate candidate points As described in the first embodiment, the determination states (1) to (5) expressed here are However, it is not a simple number of shadows detected by the sensor units 1L and 1R, but a determined state in which it is determined that there is a certainty of existence of an input point or a coordinate candidate point based on the relationship between the two threshold values. Is the number of shadows to indicate Therefore, in some cases, the number of shadows actually detected is different and may be smaller.

  In the second embodiment, each LR combination is determined to be one of the above defined states (1) to (5), and based on the determination result, each optical unit in the sensor units 1L and 1R. Determine the detection state of the number of shadows in the unit.

  Detection state [1]: [1-1] a or [1-1] b in all LR combinations.

  Detection state [2]: There are two or more LR combinations of [2-2].

  Detection state [3]: There is an LR combination of [2-2] and an LR combination of [2-1].

  Detection state [4]: There is an LR combination of [2-2] and an LR combination of [1-1].

  Detection state [5]: There is one or more LR combinations of [2-1].

  In the second embodiment, the detection state of the number of shadows in each optical unit is determined (steps S110 to S112 and steps S114 to S116), and a coordinate calculation method [1 defined in advance according to the determined detection state [1. ] To [5] to calculate coordinates (steps S118 to S122). Then, the coordinate calculation result is output (step S123). On the other hand, if none of the above detection states is determined, it is determined that coordinate detection is impossible, and the process is terminated (step S113 or step S117).

  In FIG. 18, regarding the detection states [1] to [5], the detection states are determined in order from the top. For example, when the detection states [3] and [4] are satisfied, the detection state [3] is preferentially determined.

  Hereinafter, the details of each of the coordinate calculation methods [1] to [5] will be described.

Coordinate calculation method [1] (in the case of step S118: detection state [1])
In the case of the detection state [1], the case of [1-1] a in all LR combinations is a case where a single input is made. In the case of [1-1] b in all LR combinations, two inputs are made, but one input is not correctly detected.

  Here, the latter case is mainly a state when the pointing tool enters or exits the coordinate input effective area. In such a case, calculation of incorrect coordinates is prevented by ignoring inputs that are not correctly detected. Therefore, in the detection state [1], coordinate calculation is executed as a single input in both cases of [1-1] a and [1-1] b.

  In this case, the coordinate calculation can be executed by any LR combination. For example, in the optical unit combination (L1, R1), the coordinate calculation is executed by <coordinate calculation processing (1)> described later. .

Coordinate calculation method [2] (in the case of step S119: detection state [2])
The detection state [2] is a case where two or more pairs [2-2] are present from the LR combinations (L1, R1), (L1, R2), (L2, R1), and (L2, R2). .

  Two sets are selected from these, and the four coordinate candidate points obtained from each are compared.

  Here, as a specific example, the case where (L1, R1) and (L2, R1) are [2-2] will be described with reference to FIGS.

  In FIG. 19, P11, P12, P21, and P22 are determined from the combination of (L1, R1) based on <coordinate calculation processing (1)> described later. Similarly, in FIG. 20, P′11, P′12, P′21, and P′22 are determined from the combination of (L2, R1) based on <coordinate calculation processing (2)> described later.

  Here, the values of the four coordinate candidate points obtained from the respective LR combinations are compared.

  Among them, the coordinate candidate points based on the actually input coordinates are the same in principle in both LR combinations. On the other hand, coordinates that are not based on the actually input coordinates (so-called coordinate candidate points as virtual images) are different in each combination due to the offset of the optical unit position.

  Therefore, by comparing the values of the four coordinate candidate points obtained from the respective LR combinations, it is possible to determine that the coordinate candidate point whose comparison result substantially matches is the true coordinate value of the two input points. .

  In the examples of FIGS. 19 and 20, P11 and P22 are determined as two input points based on actual inputs.

Coordinate calculation method [3] (in the case of step S120: detection state [3])
The detection state [3] is a case where the LR combination [2-2] and the LR combination [2-1] exist.

  Here, as a specific example, the case where (L1, R2) is [2-2] and (L1, R1) is [2-1] will be described with reference to FIGS.

In FIG. 21, P11, P12, P21, and P22 are determined from the combination of (L1, R2) based on <coordinate calculation processing (2)> described later. Similarly, FIG. 22 determines PP1 and PP2 from the combination of (L1, R1) based on <coordinate calculation process (1)> described later.
Here, among P11, P12, P21, and P22 in FIG. 21, one of (P11, P22) and (P12, P21), which is a coordinate candidate point relatively close to (PP1, PP2) in FIG. And determine them as a set of coordinate values of two input points.

  In the example of FIGS. 21 and 22, P12 and P21 are determined as two input points based on actual inputs.

Coordinate calculation method [4] (in the case of step S121: detection state [4])
The detection state [4] is a case where the LR combination [2-2] and the LR combination [1-1] exist.

  Here, as a specific example, the case where (L1, R2) is [2-2] and (L1, R1) is [1-1] will be described with reference to FIGS.

  Here, it seems strange that the [2-2] LR combination and the [1-1] LR combination occur simultaneously. That is, if one is an LR combination of [2-2], the other is an LR combination of [2-1], or if one is an LR combination of [1-1], the other is an LR combination of [2-1]. It is a normal feeling.

  However, in reality, the shadow detection timing for each optical unit is slightly shifted, especially at timings when the intensity change of the shadow is severe, such as when the pointing device enters or exits the coordinate input effective area. The impact cannot be ignored. That is, due to this detection timing shift, a shadow that should originally be detected in both of the optical units may be detected only in one side.

  In the present invention, for example, in order to avoid instability (specifically, erroneous coordinates are detected for a moment) caused by such an event, the detection state [4] is defined. Consider all combinations.

Specifically, FIG. 23 determines P11, P12, P21, and P22 from the combination of (L1, R2) based on <Coordinate calculation processing (2)> described later. Similarly, in FIG. 24, PP1 is determined from the combination of (L1, R1) based on <coordinate calculation processing (1)> described later.
Here, it is determined whether or not any of P11, P12, P21, and P22 in FIG. 23 substantially matches PP1 in FIG. In the example of FIGS. 23 and 24, P22 substantially coincides with PP1.

  Therefore, P22 is a coordinate based on an actual input. When P22 is an actual input, P11 is also an actual input. Therefore, in the examples of FIGS. 23 and 24, P11 and P22 are determined as two input points based on the actual input.

Coordinate calculation method [5] (in the case of step S122: detection state [5])
The detection state [5] is a case where one or more LR combinations of [2-1] exist.

  Here, as a specific example, the case where (L1, R1) is [2-1] and (L2, R2) is [1-1] will be described with reference to FIGS.

  In FIG. 25, PP1 and PP2 are determined from the combination of (L1, R1) based on <coordinate calculation processing (1)> described later. In addition, for the combination of (L2, R2) in FIG. 26, the coordinates that are overlapped on one side at (L1, R1) are determined, so that coordinate calculation is not necessary.

  That is, regarding the detection state [5], the coordinates of the two input points are determined by only one set of [2-1] LR combinations, regardless of other LR combinations.

  In FIG. 26, approximately central portions at both ends of one overlapping shadow detected from the optical unit R2 are approximately treated as one angle θR, and PP1 is determined based on <coordinate calculation process (3)>. You may do it.

  The coordinate calculation result of one or two input points calculated by any one of the coordinate calculation methods [1] to [5] as described above is output to the external terminal via the serial interface 7, and the image display device Displayed on the output device as a cursor movement or locus.

  Next, details of the processing contents of the coordinate calculation processes (1) to (3) will be described.

<Coordinate calculation process (1)>
Here, a coordinate calculation process (1) for calculating coordinates by a combination of the optical units L1 and R1 will be described with reference to FIG.

  In the sensor units 1L and 1R of FIG. 27, the optical units on the left and right outer sides with respect to the coordinate input effective area 3 are optical units (L1, R1). The left and right inner optical units are optical units (L2, R2).

  The angle data obtained from each optical unit is defined so that the Y axis downward direction is 0 ° when viewed from the corresponding sensor unit, and the angle increases inward and in the left and right target directions. In addition, the coordinate positions where each optical unit exists are P (L1), P (L2), P (R1), and P (R2).

  For example, when calculating coordinates based on the angle data obtained from the optical unit (L1, R1), the following function Xt, which determines the X and Y directions as shown, with the point O as the origin, Define Yt.

Xt (θL-45, θR-45)
= (tan (θL-45) -tan (θR-45)) / [2 * (1-tan (θL-45) * tan (θR-45))] (120)
Yt (θL-45, B-45)
= (-1) * [(1-tan (θL-45)) * (1-tan (θR-45))
/(2*(1-tan(θL-45)*tan(θR-45)))-0.5] (121)
If defined in this way, the coordinates of the point P (X, Y) when the point O in FIG.
X = DLR * Xt (θL-45, θR-45) (122)
Y = DLR * Yt (θL-45, θR-45) (123)
It becomes.

<Coordinate calculation process (2)>
Here, a coordinate calculation process (2) for calculating coordinates by a combination of the optical units L2 and R1 will be described with reference to FIG.

  In FIG. 28, the designated position of the pointing tool is P ′. Further, an intersection of the straight line P (L1) -P (R1) and the straight line P (L2) -P 'is defined as S'.

In FIG. 28, the calculation of the coordinates of P ′ from the positional relationship of the three points S ′, P (R1), O ′ is shown in FIG. 27 from the three points P (L1), P (R1), O to P Equivalent to calculating coordinates. Here, the vector O′P ′ is expressed as O ′ → P ′, the X component is expressed as (O ′ → P ′) x, the Y component is expressed as (O ′ → P ′) y, and the equations (120) and (121) are expressed. )
(O '→ P') x = (DLR-ΔD) * Xt (θL-45, θR-45) (130)
(O '→ P') y = (DLR-ΔD) * Yt (θL-45, θR-45) (131)
It becomes. From FIG. 28, ΔD = Sx + Sy * tan (θL) (132)
However, Sx = d * cos (θs), Sy = d * sin (θs) (133)
Furthermore, as is clear from FIG.
(O → O ') x = ΔD / 2 (134)
(O → O ') y = (-1) * ΔD / 2 (135)
It becomes. Thus, the coordinates of P ′ with the point O as the origin can be calculated as the X component and the Y component of (O → P ′) = (O → O ′) + (O → P ′).

  Here, similarly, when the coordinates are calculated by the combination of the optical unit L1 and the optical unit R2, the calculation can be similarly performed by changing only the above-mentioned X component.

<Coordinate calculation process (3)>
Here, a coordinate calculation process (3) for calculating coordinates by a combination of the optical units L2 and R2 will be described with reference to FIG.

In FIG. 29, calculating the coordinates of P ″ from the positional relationship of the three points P (L2), P (R2), and O ″ is shown in FIG. 27 as three points P (L1), P (R1), It is equivalent to calculating the coordinates of P from O. Here, the vector O ″ P ″ is expressed as O ″ → P ″, the X component is expressed as (O ″ → P ″) x, and the Y component is expressed as (O ″ → P ″) y. Using the equations (120) and (121),
(O '' → P '') x = (DLR-2 * Sx) * Xt (θL-45, θR-45) (141)
(O '' → P '') y = (DLR-2 * Sx) * Yt (θL-45, θR-45) (142)
It becomes. As is clear from FIG.
(O → O ″) x = 0 (143)
(O → O ″) y = (-1) * (Sx + Sy) (144)
It becomes. As a result, the coordinates of P ″ with the point O as the origin can be calculated as the X and Y components of (O → P ″) = (O → O ″) + (O → P ″). it can.

  As described above, in the second embodiment, coordinates can be calculated for all LR combinations.

  As described above, according to the second embodiment, similarly to the first embodiment, the input coordinates are prevented from being missed at the time of single input, and the wrong coordinates different from the input coordinates are detected at the time of multiple inputs. It is possible to prevent an erroneous number of input coordinates.

<Embodiment 3>
In the third embodiment, a configuration in which a sensor unit 1C is newly added as shown in FIG. 30 to the configuration shown in FIG. 1 of the first embodiment will be described.

  FIG. 30 shows a case where a plurality of inputs are performed at points P12 and P21.

  In this case, as shown in FIG. 31A, a shadow is detected at the positions of θL1 and θL2 in the sensor unit 1L. Further, as shown in FIG. 31B, in the sensor unit 1R, shadows are detected at the positions of θR1 and θR2. Further, as shown in FIG. 31C, shadows are detected at the positions of θC1 and θC4 in the sensor unit 1C. Based on these three sets of angle data, four coordinate candidate points P11, P12, P21 and P22 are calculated. Then, from these coordinate candidate points, by determining whether the coordinates are true by some means, for example, it is determined that P11 and P22 are real images and P12 and P21 are virtual images, and the coordinate input points are determined. Become.

  The sensor unit 1C shown in FIG. 30 has substantially the same configuration as the sensor units 1L and 1R, but the structure of the built-in optical unit (light receiving unit and light projecting unit) is different, and the field of view of the sensor units 1L and 1R Is approximately 90 degrees, whereas the field of view of the sensor unit 1C is approximately 180 degrees.

  In the second embodiment, the coordinate candidate points are detected by the sensor units 1L and 1R, and the actual input point is determined from the coordinate candidate points based on the positional relationship with the shadow detected by the sensor unit 1C (so-called true / false determination). Finally, two input coordinates are determined.

  For example, in FIG. 30, four coordinate candidate points P11, P12, P21, and P22 are observed by the sensor units 1L and 1R. Among these coordinate candidate points, the coordinate candidate points observed in the predetermined direction by the sensor unit 1C are the coordinate candidate points of the actual input points, and these are finally output as two input coordinates. . In particular, in the case of FIG. 30, only the shadows of θC1 and θC4 are observed in the sensor unit 1C, so P11 and P22 are the coordinates of the actual input points.

  In the third embodiment, the same coordinate candidate point determination process as that in the first embodiment is performed on the detection results obtained from the sensor units 1L and 1R.

However, in the third embodiment, if the maximum value of the assumed shadow intensity is dpth_max and the maximum value dpth_min, including the shadow intensity detected by the sensor unit 1C, the maximum ratio M of the shadow intensity is M = dpth_max / dpth_min (Formula 3_1)
It becomes. And at this time,
thsh1 ′ / thsh2 ′> M (Formula 3_2)
A threshold value that satisfies the above is set. If these two threshold values are applied to the relative light intensity distribution, when the larger shadow exceeds the second threshold value (thsh_2 ′), the smaller shadow always exceeds the first threshold value (thsh_1 ′). Will be.

  That is, by determining the presence of the larger shadow using the second threshold (thsh_2 ′) and determining the smaller shadow using the first threshold (thsh_1 ′), the larger shadow as described above is used. In spite of being detected, it is possible to avoid calculating the wrong coordinates because the smaller shadow cannot be detected.

  Hereinafter, coordinate calculation processing according to the third embodiment will be described with reference to FIG.

  FIG. 32 is a flowchart showing a coordinate calculation process executed by the coordinate input device according to the third embodiment of the present invention.

  First, in step S201, light intensity distribution data in the sensor units 1L, 1R, and 1C is acquired. Next, in step S202, the light intensity distribution data for the LR combination is sequentially selected from the acquired light intensity distribution data, and the coordinate candidate point determination process of FIG. 12 of the first embodiment is executed for the selected light intensity distribution data. To do.

  Next, a coordinate calculation process (step S203 to step S209) is executed based on the processing result of the coordinate candidate point determination process.

  In particular, in the third embodiment, three types of detection states [1] to [3] among the detection states described in the second embodiment are considered as detection states of the number of shadows in each sensor unit.

  In the third embodiment, the detection state of the number of shadows in the sensor unit 1L and the sensor unit 1R is determined (steps S203 to S205), and the coordinate calculation methods [6a] to [6c defined in advance according to the determined detection state. ] To calculate coordinates (steps S206 to S208). Then, the coordinate calculation result is output (step S209). On the other hand, if none of the above detection states is determined, it is determined that coordinate detection is impossible, and the process is terminated (step S210).

  Hereinafter, the details of each of the coordinate calculation methods [6a] to [6c] will be described.

Coordinate calculation method [6a] (in the case of step S206: detection state [1])
The case of the detection state [1] or [2] is a case where a single input is made. In this case, coordinate calculation is executed by the <coordinate calculation process (1)> described in the second embodiment.

Coordinate calculation method [6b] (step S207: detection state [2])
The detection state [2] means that there are two or more pairs [2-2] from among the LR combinations (L1, R1), (L1, R2), (L2, R1), and (L2, R2). It is.

  In this case, the coordinate values of the obtained four coordinate candidate points are calculated by the <coordinate calculation process (1)> described in the second embodiment. Further, the angle when each coordinate candidate point is observed from the sensor unit 1C is calculated in advance.

  Among these, what is substantially positioned with the shadow angle actually observed by the sensor unit 1C is adopted as two input coordinates. At this time, the presence or absence of a shadow observed by the sensor unit 1C is performed using the first threshold (thsh1 '). That is, here, it is based on the premise that a shadow exceeding thsh1 'is always detected by the sensor unit 1C at the actual coordinate candidate points.

Coordinate calculation method [6c] (step S208: detection state [3])
The case of the detection state [3] is a case where the sensor units 1L and 1R are [2-1].

  In this case, it is approximated that there are two input coordinates on the substantially central angle at both ends of the overlapping shadow, and each of them is combined with the other two shadows in the <coordinate calculation described in the first embodiment. Coordinates are determined based on processing (1)>. The light intensity distribution data detected by the sensor unit 1C is not used for true / false determination but is used for verification to improve the accuracy of the determined coordinate value.

  As described above, according to the third embodiment, in addition to the effects described in the first embodiment, by configuring the sensor unit 1C, it is possible to realize the true / false determination related to coordinate calculation more efficiently and accurately. Can do.

  Although the embodiments have been described in detail above, the present invention can take an embodiment as, for example, a system, an apparatus, a method, a program, or a storage medium, and specifically includes a plurality of devices. The present invention may be applied to a system that is configured, or may be applied to an apparatus that includes a single device.

  In the present invention, a software program (in the embodiment, a program corresponding to the flowchart shown in the drawing) that realizes the functions of the above-described embodiment is directly or remotely supplied to the system or apparatus, and the computer of the system or apparatus Is also achieved by reading and executing the supplied program code.

  Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. In other words, the present invention includes a computer program itself for realizing the functional processing of the present invention.

  In that case, as long as it has the function of a program, it may be in the form of object code, a program executed by an interpreter, script data supplied to the OS, or the like.

  As a recording medium for supplying the program, for example, floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card ROM, DVD (DVD-ROM, DVD-R) and the like.

  As another program supply method, a client computer browser is used to connect to an Internet homepage, and the computer program of the present invention itself or a compressed file including an automatic installation function is downloaded from the homepage to a recording medium such as a hard disk. Can also be supplied. It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, the present invention includes a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer.

  In addition, the program of the present invention is encrypted, stored in a storage medium such as a CD-ROM, distributed to users, and key information for decryption is downloaded from a homepage via the Internet to users who have cleared predetermined conditions. It is also possible to execute the encrypted program by using the key information and install the program on a computer.

  In addition to the functions of the above-described embodiments being realized by the computer executing the read program, the OS running on the computer based on an instruction of the program is a part of the actual processing. Alternatively, the functions of the above-described embodiment can be realized by performing all of them and performing the processing.

  Furthermore, after the program read from the recording medium is written to a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion board or The CPU or the like provided in the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are also realized by the processing.

It is a figure which shows the structure of the coordinate input device of the light-shielding system of Embodiment 1 of this invention. It is a figure for demonstrating the characteristic of Embodiment 1 of this invention. It is a figure for demonstrating the subject in this invention. It is a figure for demonstrating multiple input operation. It is a figure which shows the light intensity distribution obtained from the sensor unit in input operation of FIG. It is a figure for demonstrating multiple input operation. It is a figure which shows the light intensity distribution obtained from the sensor unit in input operation of FIG. It is a figure for demonstrating multiple input operation. It is a figure which shows the light intensity distribution obtained from the sensor unit in input operation of FIG. It is a figure for demonstrating the structure of Embodiment 1 of this invention. It is a figure for demonstrating the structure of Embodiment 1 of this invention. It is a figure for demonstrating the structure of Embodiment 1 of this invention. It is a flowchart which shows the coordinate candidate point confirmation process of Embodiment 1 of this invention. It is a figure which shows the structure of the coordinate input device of the light-shielding system of Embodiment 2 of this invention. It is a figure which shows the detailed structure of the sensor unit of Embodiment 2 of this invention. It is an optical layout of the sensor unit according to the second embodiment of the present invention. It is an optical layout of the sensor unit according to the second embodiment of the present invention. It is an optical layout of the sensor unit according to the second embodiment of the present invention. It is a block diagram which shows the detailed structure of the control and arithmetic unit of Embodiment 2 of this invention. It is explanatory drawing for demonstrating the optical arrangement | positioning of the coordinate input device of Embodiment 2 of this invention. It is a flowchart which shows the coordinate calculation process which the coordinate input device of Embodiment 2 of this invention performs. It is a figure for demonstrating the coordinate calculation method of Embodiment 2 of this invention. It is a figure for demonstrating the coordinate calculation method of Embodiment 2 of this invention. It is a figure for demonstrating the coordinate calculation method of Embodiment 2 of this invention. It is a figure for demonstrating the coordinate calculation method of Embodiment 2 of this invention. It is a figure for demonstrating the coordinate calculation method of Embodiment 2 of this invention. It is a figure for demonstrating the coordinate calculation method of Embodiment 2 of this invention. It is a figure for demonstrating the coordinate calculation process of Embodiment 2 of this invention. It is a figure for demonstrating the coordinate calculation process of Embodiment 2 of this invention. It is a figure for demonstrating the coordinate calculation process of Embodiment 2 of this invention. It is a figure for demonstrating the coordinate calculation process of Embodiment 2 of this invention. It is a figure for demonstrating the coordinate calculation process of Embodiment 2 of this invention. It is a figure which shows the structure of the coordinate input device of Embodiment 3 of this invention. It is a figure which shows the light intensity distribution obtained from the sensor unit in input operation of FIG. It is a flowchart which shows the coordinate calculation process which the coordinate input device of Embodiment 3 of this invention performs.

Explanation of symbols

1L, 1R Sensor unit 2 Arithmetic / control unit 3 Coordinate input effective area 4 Retroreflecting unit 5 Pen signal receiving unit

Claims (13)

A coordinate input device for detecting a designated position on a coordinate input area,
A plurality of sensor means provided around the coordinate input area, comprising: a light projecting unit that projects light to the coordinate input area; and a light receiving unit that receives incoming light;
Reflecting means provided around the coordinate input area and recursively reflects incident light;
The coordinate input based on the number of shadows that are in the range exceeding the first threshold and the number of shadows in the range that exceeds the second threshold in the light intensity distribution obtained from each of the plurality of sensor units by the instruction from the instruction unit Determination means for determining whether the instruction input by the instruction means in the region is singular, plural, or multiple shadows are overlapped , and
The first threshold value is a threshold value for detecting, as the shadow, a range of a relatively low level of light intensity from the light intensity distribution,
The second threshold value is a threshold value for detecting a range of a relatively high light intensity level as the shadow from the light intensity distribution,
The determination means includes
In the set of sensor means selected from the plurality of sensor means, the number of shadows of the shadow exceeding the second threshold in the light intensity distribution with respect to one sensor means is 1, and the other sensor means of the set of sensor means When the number of shadows of the shadow exceeding the first threshold in the light intensity distribution for is 1, it is determined that the instruction input by the instruction means is singular,
The number of shadows of the shadow exceeding the second threshold in the light intensity distribution obtained from the one sensor means is 2, and the number of shadows of the shadow exceeding the first threshold in the light intensity distribution for the other sensor means is In the case of 1, the coordinate input device is characterized in that a plurality of instructions are input by the instruction means, and the shadow obtained from the other sensor means determines that a plurality of shadows overlap . From the determination result of whether the input of the instruction by the instruction means in the coordinate input area determined by the determination means is singular, plural, or multiple shadows, and each of the plurality of sensor means The coordinate input device according to claim 1 , further comprising a calculation unit that calculates the designated position coordinates on the coordinate input region based on the obtained light intensity distribution. In both of the sensor means selected from the plurality of sensor means, when the number of shadows exceeding the first threshold is 2, the determination means determines that there are four coordinate candidate points. The coordinate input device according to claim 1 . The ratio of the first threshold and the second threshold value, to claim 1, wherein the greater than the ratio of the maximum and minimum values of the shadow to be expected in the light intensity distribution for a set of sensor means which is the selected The coordinate input device described. The coordinate input device according to claim 1, wherein the sensor unit includes one optical unit including the light projecting unit and the light receiving unit. The coordinate input device according to claim 1, wherein the sensor unit includes two optical units including the light projecting unit and the light receiving unit. A plurality of sensor means provided around the coordinate input area, including a light projecting unit that projects light to the coordinate input area and a light receiving unit that receives incoming light, A method for controlling a coordinate input device that detects a designated position,
An acquisition step of acquiring a light intensity distribution obtained from the plurality of sensor means according to an instruction by the instruction means;
Based on the number of shadows that are a range exceeding the first threshold and the number of shadows that is a range exceeding the second threshold in the light intensity distribution obtained from each of the plurality of sensor means acquired by the acquisition step, A determination step of determining whether the instruction input by the instruction means in the coordinate input area is singular, plural, or a plurality of shadows are overlapped , and
The first threshold value is a threshold value for detecting, as the shadow, a range of a relatively low level of light intensity from the light intensity distribution,
The second threshold value is a threshold value for detecting a range of a relatively high light intensity level as the shadow from the light intensity distribution,
The determination step includes
In the set of sensor means selected from the plurality of sensor means, the number of shadows of the shadow exceeding the second threshold in the light intensity distribution with respect to one sensor means is 1, and the other sensor means of the set of sensor means When the number of shadows of the shadow exceeding the first threshold in the light intensity distribution for is 1, it is determined that the instruction input by the instruction means is singular,
The number of shadows of the shadow exceeding the second threshold in the light intensity distribution obtained from the one sensor means is 2, and the number of shadows of the shadow exceeding the first threshold in the light intensity distribution for the other sensor means is In the case of 1, there is a plurality of instructions input by the instruction means, and the shadow obtained from the other sensor means determines that a plurality of shadows overlap . When the number of shadows exceeding the first threshold is 2 in both of the sensor means selected from the plurality of sensor means, the determination step determines that there are four coordinate candidate points.
The control method of the coordinate input device according to claim 7. The ratio between the first threshold value and the second threshold value is larger than the ratio between the maximum value and the minimum value of the shadow assumed in the light intensity distribution for the selected set of sensor means.
The control method of the coordinate input device according to claim 7. A plurality of sensor means provided around the coordinate input area, including a light projecting unit that projects light to the coordinate input area and a light receiving unit that receives incoming light, A program for causing a computer to execute control of a coordinate input device that detects a designated position,
An acquisition procedure for acquiring a light intensity distribution obtained from the plurality of sensor means according to an instruction by the instruction means;
Based on the number of shadows that are a range exceeding the first threshold and the number of shadows that are a range exceeding the second threshold in the light intensity distribution obtained from each of the plurality of sensor means acquired by the acquisition procedure, Causing the computer to execute a determination procedure for determining whether the instruction input by the instruction means in the coordinate input area is singular, plural, or plural shadows ,
The first threshold value is a threshold value for detecting, as the shadow, a range of a relatively low level of light intensity from the light intensity distribution,
The second threshold value is a threshold value for detecting a range of a relatively high light intensity level as the shadow from the light intensity distribution,
The determination procedure is as follows:
In the set of sensor means selected from the plurality of sensor means, the number of shadows of the shadow exceeding the second threshold in the light intensity distribution with respect to one sensor means is 1, and the other sensor means of the set of sensor means When the number of shadows of the shadow exceeding the first threshold in the light intensity distribution for is 1, it is determined that the instruction input by the instruction means is singular,
The number of shadows of the shadow exceeding the second threshold in the light intensity distribution obtained from the one sensor means is 2, and the number of shadows of the shadow exceeding the first threshold in the light intensity distribution for the other sensor means is When the number is 1, a plurality of instructions are input by the instruction means, and a shadow obtained from the other sensor means is determined to be a plurality of overlapping shadows . A coordinate input device for detecting a designated position on a coordinate input area,
A plurality of sensor means;
Based on the light intensity distribution obtained from each of the plurality of sensor means and the first threshold value and the second threshold value by the instruction by the instruction means , the instruction input by the instruction means in the coordinate input area is singular or plural. Or a determination means for determining whether a plurality of shadows overlap .
The first threshold value is a threshold value for detecting, as the shadow, a range of a relatively low level of light intensity from the light intensity distribution,
The second threshold value is a threshold value for detecting a range of a relatively high light intensity level as the shadow from the light intensity distribution,
The determination means includes
In the set of sensor means selected from the plurality of sensor means, the number of shadows of the shadow exceeding the second threshold in the light intensity distribution with respect to one sensor means is 1, and the other sensor means of the set of sensor means When the number of shadows of the shadow exceeding the first threshold in the light intensity distribution for is 1, it is determined that the instruction input by the instruction means is singular,
The number of shadows of the shadow exceeding the second threshold in the light intensity distribution obtained from the one sensor means is 2, and the number of shadows of the shadow exceeding the first threshold in the light intensity distribution for the other sensor means is In the case of 1, the coordinate input device is characterized in that a plurality of instructions are input by the instruction means, and the shadow obtained from the other sensor means determines that a plurality of shadows overlap . In both of the sensor means selected from the plurality of sensor means, when the number of shadows exceeding the first threshold is 2, the determination means determines that there are four coordinate candidate points.
The coordinate input device according to claim 1. The ratio between the first threshold value and the second threshold value is larger than the ratio between the maximum value and the minimum value of the shadow assumed in the light intensity distribution for the selected set of sensor means.
  The coordinate input device according to claim 1.

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