JP2002366885A - Information reproduction system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reproduce information through adequate binarization. SOLUTION: A threshold detection part 20 computes a threshold for binarization in a vertical blanking period according to a maximum value and a minimum value obtained from a video signal of a previous field. When the threshold computation result is not more than a prescribed value, the means that an image is very dark, so proper binarization can not be performed through image pickup operation with the current quantity of light. Accordingly, a system control part performs control for increasing the quantity of irradiation light of an LED as a light source.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to so-called multimedia including audio information such as audio and music, video information obtained from cameras and video equipment, and digital code data obtained from personal computers and word processors. The present invention relates to an information reproducing system that optically reads the above code pattern from an information recording medium such as paper on which information is recorded as an optically readable two-dimensional code pattern and reproduces the original multimedia information.

[0002]

2. Description of the Related Art Conventionally, various media such as magnetic tapes and optical disks have been known as media for recording voice, music and the like. However, even if these media are made in large quantities, the unit price is somewhat expensive, and a large space is required for storage. Furthermore, if it is necessary to hand over the recorded audio medium to another person at a remote location, it takes time and effort to mail it or take it directly. There was also. Also, other than audio information, video information obtained from cameras, video equipment, etc., and digital code data obtained from personal computers, word processors, etc.
The same applies to the so-called multimedia information as a whole including the above.

To cope with such a problem, Japanese Patent Laid-Open Publication No. Hei 6-231466 discloses that multimedia information including at least one of audio information, video information, and digital code data can be transmitted by facsimile. In addition, a plurality of dots are two-dimensionally arranged as image information that can be copied in large quantities at low cost, that is, encoded information.
A system for recording on an information recording medium such as paper in the form of a dimensional code pattern and a system for reproducing the same are disclosed.

The two-dimensional code pattern disclosed in this publication is as shown in FIG. That is, this figure corresponds to FIG.
A dot code 170 is shown as a dimensional code pattern. In the data format of the dot code 170, one block 172 includes a marker 174, a block address 176, address error detection and error correction data 178, and a data area 180 in which actual data is entered. And this block 172
Are vertically, horizontally, and two-dimensionally arranged, and are collected to form a dot code 170.

FIG. 10 corresponds to FIG. 15 of the above-mentioned publication, and is a diagram showing a configuration of a multimedia information reproducing apparatus. This information reproducing apparatus has a dot code 170
, A scanning unit 186 for recognizing the image data supplied from the detecting unit 184 as a dot code and normalizing the dot data, and a binarizing unit for converting multi-valued data into binary. Value processing section 188, demodulation section 190, adjustment section 192 for adjusting the data string, data error correction section 194 for correcting a read error and data error during reproduction, and data separation section 196 for separating data according to the respective attributes. , A decompression processing unit for data compression processing according to each attribute, a display unit or a reproduction unit, or another input device.

In the detecting section 184, the dot code 170 on the sheet 182 is illuminated by the light source 198, and the reflected light is converted into an image forming optical system 200 such as a lens and a spatial filter 202 for removing moire and the like. The information is detected as an image signal by an imaging unit 204 such as a CCD or CMD that converts light information into an electric signal, and is amplified by a preamplifier 206 and output. The light source 198, the imaging optical system 200, the spatial filter 202, the imaging unit 204, and the preamplifier 20
Reference numeral 6 denotes an external light shielding unit 208 for preventing disturbance to external light.
Is configured within. The image signal amplified by the preamplifier 206 is converted into digital information by the A / D converter 210 and supplied to the next-stage scan converter 186.

[0007] The imaging section 204 is controlled by an imaging section control section 212. For example, when an interline transfer type CCD is used as the imaging unit 204,
The imaging unit control unit 212 stores a V blank signal for vertical synchronization, an imaging device reset pulse signal for resetting information charges, and a two-dimensionally arranged charge transfer accumulation unit as control signals for the imaging unit 204. Charge transfer gate pulse signal for sending the transferred charges to a plurality of vertical shift registers, and a horizontal charge transfer CLK which is a transfer clock signal for a horizontal shift register for transferring charges in the horizontal direction and outputting the charges to the outside.
And a vertical charge transfer pulse signal for transferring the plurality of vertical shift register charges in the vertical direction and sending the signals to the horizontal shift register.

Then, the imaging section control section 212 gives a light emitting cell control pulse to the light source for setting the light emission timing of the light source 198 in accordance with this timing.

The image data is read between the V blank of this one field and the V blank. Light source 19
Reference numeral 8 denotes that pulse lighting is performed instead of continuous lighting, and subsequent pulse lighting is performed while synchronizing in field units. In this case, the timing is controlled such that exposure is performed during the V blanking period, that is, while no image charge is output, so that clock noise during pulse lighting does not enter the signal output. That is, since the light emitting cell control pulse is a very thin digital clock pulse generated instantaneously and gives a large power to the light source, it is necessary to prevent noise due to the light from entering the analog image signal. Required,
As a measure for this, the light source is pulsed during the V blanking period. By doing so, the S / N is improved. In addition, the pulse lighting means that the light emission time is shortened, and thus has a great effect of eliminating the influence of blurring due to the fluctuation and movement of the manual scanning. This enables high-speed scanning.

Further, even if the reproducing apparatus is tilted and disturbance such as external light enters for some reason in spite of the presence of the external light shielding section 208, the S / N deterioration is minimized. , Once before the light source 198 emits light during the V blanking period, an image sensor reset pulse is output to reset an image signal, and light emission is performed immediately thereafter.
Reading is performed.

Next, the scan converter 186 will be described. The scan conversion unit 186 is a unit that recognizes image data supplied from the detection unit 184 as a dot code and performs normalization. As a method, image data from the detection unit 184 is first stored in the image memory 214, read out therefrom once, and sent to the marker detection unit 216. The marker detector 216 detects a marker for each block. Then, the data array direction detection unit 218 detects the rotation or tilt and the data array direction using the marker.
The address control unit 220 reads out image data from the image memory 214 based on the result so as to correct the image data and supplies it to the interpolation circuit 222. At this time, lens aberration information is read from the memory 224 for correcting distortion of the lens in the imaging optical system 200 of the detection unit 184, and the lens is also corrected. Then, the interpolation circuit 222
Performs an interpolation process on the image data to convert the image data into an original dot code pattern.

The output of the interpolation circuit 222 is output to the binarization processing unit 1
88. Basically, the dot code 170
Is a white and black pattern, that is, binary information, and is therefore binarized by the binarization processing unit 188. At this time, the threshold value determination circuit 226 adaptively performs binarization while determining the threshold value in consideration of the influence of disturbance, the influence of signal amplitude, and the like.

[0013] Since the modulation is performed at the time of recording, the demodulation section 190 first demodulates the data, and then inputs the data to the data string adjustment section 192.

In the data string adjusting section 192, first, the block address detecting section 228 detects the block address of the above-described two-dimensional block, and then the block address error detecting / correcting section 230 detects and corrects the block address error. After performing, the address control unit 23
2, the data is stored in the data memory unit 234 in block units. By storing data in units of block addresses in this way, data can be stored without waste even when data is lost or entered halfway.

Thereafter, the data read from the data memory unit 234 is subjected to error correction by the data error correction unit 194. The output of the error correction unit 194 is branched into two, one of which is sent to a personal computer, a word processor, an electronic organizer, or the like via the I / F 236 as digital data. The other is supplied to a data separation unit 196, where images, handwritten characters and graphs, characters and line drawings,
Sound (2 for the sound as it is and for the voice synthesized)
Types).

The image corresponds to a natural image and is a multi-valued image. This is performed by the decompression processing section 238 to perform decompression processing corresponding to, for example, JPEG when compressed, and further, the data interpolation circuit 240 interpolates data that cannot be corrected.

For binary image information such as handwritten characters and graphs, a decompression processing section 242 performs decompression processing on MR / MH / MMR and the like performed by compression, and a data interpolation circuit 244. Interpolation of data for which error correction is not possible is performed.

Characters and line drawings are converted to another display pattern through a PDL (page description language) processing unit 246. Note that, in this case, if the line drawing and the character are subjected to the code compression processing after being coded, they are subjected to decompression (Huffman, Jiblempel, etc.) processing by the corresponding decompression processing unit 248, and then PD
The data is supplied to the L processing unit 246.

The data interpolation circuits 240, 244 and P
The output of the DL processing unit 246 is
According to 0, the data is synthesized or selected, converted into an analog signal by the D / A converter 252, and displayed on a display device 254 such as a CRT (television monitor) or FMD (face mounted display). Note that the FMD is a spectacle-type monitor (handy monitor) for wearing on the face, and is effective, for example, for applications such as virtual reality or when viewing a large screen in a small place.

For audio information, the decompression processing unit 2
A decompression process for ADPCM or the like is performed at 56, and a data interpolation circuit 258 interpolates data for which error correction cannot be performed. Alternatively, in the case of speech synthesis, the speech synthesis unit 260 receives the speech synthesis code and actually synthesizes the speech from the code and outputs the synthesized speech. In this case, when the code itself is compressed, as in the case of the characters and line drawings, the decompression processing unit 262 performs decompression processing such as Huffman or Jibrempel, and then performs speech synthesis.

Data interpolator 258 and speech synthesizer 26
The output of 0 is synthesized or selected by a synthesizing or switching circuit 264, converted into an analog signal by a D / A converter 266, and then output to a speaker, headphones, or other audio output device 268 equivalent thereto.

Also, characters and line drawings are output directly from the data separation unit 196 to a page printer or plotter 270, and the characters or the like are printed on paper as word processing characters. It can be done.

Of course, for images, CRT and FM
In addition to D, it is possible to print with a video printer or the like, and it is also possible to take a picture of the image.

In such an information reproducing apparatus, for example, the detection unit 184 and the scan conversion unit 186 are housed in a pen-shaped housing, and the dot code 170 on the sheet 182 is optically read. As a reading unit, the reading unit is held by hand, and the recorded dot code 170 is read.
The code is read by manually scanning over the sheet 182 along the line.

[0025]

The binarization processing unit 188 for adaptively binarizing while making a threshold determination by the threshold determination circuit 226 as described above is disclosed in, for example, A binarization circuit as disclosed in Japanese Patent No. 61383 is known. This binarization circuit has A
The maximum value and the minimum value of the previous frame are obtained from the digital data converted by the / D converter, a threshold value is calculated from the maximum value and the minimum value, and binarization is performed using the calculated threshold value as the threshold value of the current frame.

In the above-described dot code 170 reproducing system, since the distance from the sheet 182 to the imaging unit 204 is short, the effect of regular reflection is great, and the video signal obtained from the imaging unit 204 contains noise. It will be something. Also, when there is a pixel defect in the imaging unit 204, it becomes noise. Due to such noise, in the configuration of the binarization circuit disclosed in the above publication, the maximum value and the minimum value cannot be obtained accurately, and as a result, the binarization at an appropriate threshold cannot be performed. Would.

The present invention has been made in view of the above points, and has as its object to provide an information reproducing system for reproducing information by appropriately binarizing.

[0028]

In order to achieve the above object, an information reproducing system according to the present invention optically converts a code pattern from a recording medium in which information is recorded as an optically readable code pattern. An information reproducing system that reads and reproduces the information, a light source that illuminates the code pattern, an imaging unit that captures the code pattern illuminated by the light source and outputs a corresponding image signal, and an image from the imaging unit A threshold detection unit that calculates a threshold for binarizing the signal based on the image signal; a system control unit that controls the amount of illumination of the light source based on the threshold calculated by the threshold detection unit; and the threshold detection unit And a binarizing unit for binarizing the image signal from the imaging unit with the threshold value calculated in (1).

That is, according to the information reproducing system of the present invention, the threshold value detecting section calculates the threshold value for binarizing the image signal based on the image signal from the imaging section, and the system control section calculates the threshold value. The illumination light amount of the light source that illuminates the code pattern is controlled by the set threshold value.

[0030]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1A is a diagram showing a configuration of a binarizing circuit according to the first embodiment of the present invention which can be used as the binarizing section 188 and the threshold value judging section 226 shown in FIG. is there.

The image signal input from the input terminal 10 is
The period is supplied to a period extracting unit 12 that extracts a specific period in the image. The cycle extracting unit 12 may extract, for example, the cycle of the marker 174 that is periodically arranged in the dot code as shown in FIG. That is, when the pattern of the marker 174 and the data dot 174A as shown at the top of the drawing is imaged, the image actually obtained from the imaging unit is as shown in the middle of the drawing. In order to extract only the period of the marker 174 from such an image signal, the period extracting unit 12 is configured as a low-pass filter. As a result, as shown at the bottom of the drawing, a fine pattern such as the data dot 174A is removed, and a signal in which only the white portion where the dot code is not recorded and the amplitude of only the marker 174 are stored is obtained. Can be

When a dot code having the same size as the data dot 174A and having a pattern matching dot composed of a predetermined position and pattern is used, the period extracting unit 12
May extract the cycle of the pattern matching dots. In this case, the cycle extracting unit 12 is configured as a bandpass filter that extracts the cycle of the pattern matching code.

FIGS. 1C and 1D show the characteristics of the filter constituting the period extracting unit 12 when extracting the marker 174 and when extracting the pattern matching dot (data dot 174A), respectively. These examples show a case where the frequency of the data of one pixel of the CCD constituting the imaging unit is 10 MHz, the minimum dot size of the data dot 174A is 3 pixels, and the dot size of the marker 174 is 21 pixels.

The image signal output from the period extracting unit 12 is supplied to the maximum value detecting unit 16 via the detecting gate 14.
And the minimum value detector 18. Here, the detection gate 14 converts the output signal of the cycle extraction unit 12 into a predetermined unit,
For example, the image is divided into fields or frames, and the following description will be made assuming that the image is divided into fields. Therefore, the maximum value detection unit 16 and the minimum value detection unit 18 detect the maximum value and the minimum value of the image signal within the range of one field.

The detected maximum value and minimum value are supplied to the threshold value detecting section 20. The threshold value detected by the threshold value detection unit 20 is held in the data holding unit 22 for the predetermined unit, that is, for one field. In addition, the threshold value detecting unit 20 determines, for example, the threshold value th as the maximum value max and the minimum value m
Calculated by the following equation (1) using in.

Th = min + k (max−min) (1) Here, k is an internal division ratio for determining a threshold value, and may be a fixed value or an image of a dot whose size is known in advance. It may be set adaptively based on the binarized result.

On the other hand, the image signal input to the input terminal 10 is also supplied to the signal processing circuit 24. The signal processing circuit 24 is, for example, a waveform equalizing circuit, and functions as a filter for raising a dot cycle.

The output of the signal processing circuit 24 and the output of the data holding unit 22 are compared by a comparator 26, and the result is output from an output terminal 28 as a binary signal.

The system control unit 30 controls each of the above units, and also detects the maximum value max and the minimum value m detected by the maximum value detection unit 16 and the minimum value detection unit 18.
In is constantly monitored to detect an error or the like.

The signal processing circuit 24 has a configuration as shown in FIG. That is, the input signal is supplied to the adder 24C via the two delay circuits 24A and 24B.
, And directly to the adder 24C. Here, the data is delayed by one dot by the two delay circuits 24A and 24B. Therefore, the adder 24C adds both sides of the period for one dot. The result of this addition is supplied to the subtractor 24E after being multiplied by the coefficient from the system control unit 30 by the multiplier 24D. The other input of the subtractor 24E is provided with a result obtained by multiplying the output of the delay circuit 24A, that is, the middle period of one dot by the coefficient from the system control unit 30 by the multiplier 24F. The multiplier 24G multiplies the difference between these multiplication results by a coefficient from the system control unit 30, and outputs the result to the comparator 26 as an output of the signal processing circuit 24. .

In practice, the system control unit 3
Instead of giving each coefficient from 0, a configuration in which one coefficient is finally multiplied by hardware may be adopted.

As described above, in the first embodiment,
Since a specific period in the code, for example, the period of the marker is extracted, unnecessary noise can be removed. That is, erroneous detection due to noise can be prevented, so that an appropriate threshold can be obtained.

The direction of delay in the delay circuits 24A and 24B is the same one-dimensional direction as the modulation direction of the dot code. That is, the reading direction of the image memory 214 and the modulation direction in FIG. 10 are the same. Therefore, effective waveform equalization can be performed with such a simple circuit configuration. Further, since the dot cycle is emphasized by the waveform equalizing circuit, the amplitude of the signal of the dot cycle is amplified, and the binarization can be surely performed.

Since the image signal input to the input terminal 10 has been read from the image memory 214 of the scan converter in the data arrangement direction, the reading direction, the modulation direction, and the delay direction have been described as being the same. However, when this is directly input from the imaging unit 204, the imaging unit 20
The scanning direction of the pixels of CCD No. 4 is the same as the modulation direction and the delay direction.

Next, a second embodiment of the present invention will be described.

FIG. 3A is a diagram showing the configuration, and FIG.
The same reference numerals as in FIG. 1A of the embodiment denote the same parts, and a description thereof will not be repeated.

That is, in the second embodiment, the LED 34 is connected to the system control unit 30 via the LED driver 32. That is, the system control unit 30 basically controls the amount of light of the LED 34 to be variable according to the maximum value detected by the maximum value detection unit 16. Here, the LED 34 corresponds to the light source 198 in the configuration of FIG. 10 and illuminates the dot code 170 recorded on the sheet 182 surface.

As shown in FIG. 3B, the LED driver 32 is composed of a transistor and a resistor, and its driving pulse is applied from the system control unit 30. In this case, the system control unit 30
As shown in FIG. 3C, the maximum value detected by the maximum value detection unit 16 is input to the saturation detection comparator 30A and the dark detection comparator 30B, and the maximum value is saturated or darkened. Are compared to determine whether they have been output. Then, the width or height (amplitude) of the drive pulse generated by the pulse generator 30C is changed according to the comparison result.

For example, when the amount of light currently being emitted is dark, it can be still bright unless it is saturated when it is in a state where the illuminance is not applied most. Change the pulse width to increase the amount of light, and conversely, if it is saturated at the high maximum value, that is, the exposure amount in a bright state, it can still be darkened, so it will be darker The width of the pulse.

Here, since only two detection comparators are used, two-stage light quantity control is performed. However, by increasing the number of detection comparators, the light quantity is discretely increased by the number. It becomes possible to control. As described above, by controlling the light amount discretely based on the maximum value, the dynamic range of the signal can be secured, and the binarization can be surely performed.

Next, this light amount control will be described with reference to the timing charts of FIGS.

In these drawings, the waveform shown at the top is a video signal supplied to the input terminal 10. Here, the row period is a vertical blanking period.

The second waveform from the top is a signal detection gate pulse supplied from the system control unit 30 for opening and closing the detection gate 14.
This is a signal for determining a frame in which part in the video signal to detect, and becomes high in field units. The detection gate 14 supplies the output signal of the cycle detection unit 12 to the maximum value / minimum value detection circuits 16 and 18 at the subsequent stage only during the high period.

The third waveform shown below is a threshold value calculation signal for controlling the threshold value calculation timing in the threshold value detection section 20, and the calculation is performed when the threshold value is high. The system control unit 30 sets this signal to a high state at a timing during the vertical blanking period.

The fourth waveform is a sample-and-hold (S / S) for controlling the timing of holding the threshold given from the system control unit 30 to the data holding unit 22.
H) It is a pulse. When the S / H pulse becomes high, the data holding unit 22 samples the result of the threshold operation, and holds the result during a low period, that is, a period of one field.

The fifth waveform is a reset (RES) pulse to the threshold detector 20. This is because if the threshold calculation result in the threshold detection unit 20 is held in the data holding unit 22, the threshold calculation result is stored in the threshold detection unit 2
Since it is no longer necessary to hold the value at 0, it is reset here.

The sixth shows the result of the threshold calculation calculated by the threshold detector 20 and stored in the data storage 22. For example, there are three types of states: within a preset regulation, below the regulation (low), or above the regulation (high).

The seventh shows the state of the set coefficient L. The setting coefficient L is as follows. That is, in the present embodiment, the threshold value th is calculated by the following equation (2) in the threshold value detection unit 20.

Th = {min + k (max−min)} L (2) This set coefficient L is normally “1” when the light quantity of the LED 34 is not changed,
Is set to “1” or more, or “1” or less, only for the field in which the light amount is changed.

Eighth is the irradiation light amount of the LED 34, where low means dark and high means bright.

[0062] The last ninth waveform indicates the exposure timing in the imaging unit (not shown).

First, the case where the light quantity is insufficient will be described with reference to FIG.

The threshold value calculation in the threshold value detecting section 20 is performed during a vertical blanking period between the field shown as the previous field and the field shown as the first field. This threshold value calculation is obtained from the video signal of the previous field. This is performed by the above equation (2) based on the maximum and minimum values. If the threshold calculation result obtained in this way is a value equal to or less than the specified value, this means that the image is considerably dark, and if image capturing is continued with this light amount, appropriate binarization will not be performed. . Therefore, control is performed to increase the irradiation light amount of the LED 34. In the present embodiment, since the irradiation is performed in units of fields, the light amount is kept low in the first field and the irradiation is performed before the start of the second field. Increase the light intensity.

However, the threshold value calculation performed during the vertical blanking period between the first field and the second field is based on the video signal of the first field exposed during the vertical blanking period between the previous field and the first field. It is based on. On the other hand, the signal that is actually binarized by the comparator 26 is the signal that was exposed during the vertical blanking period between the first field and the second field, that is, the second field that was exposed when the irradiation light amount was high. Video signal. That is, although the video signal is high, the threshold value remains as it is, and appropriate binarization is not performed. Therefore, for the second field, the value of the setting coefficient L is set to “1” or more. By doing so, it becomes possible to detect the light quantity shortage and also take in the data of the field where the irradiation light quantity has changed from low to high.

The value of the setting coefficient L is set to "1" or more only in the field in which the light amount is changed from low to high. Here, as the value of the set coefficient L of “1” or more, for example, if the irradiation light amount is increased by 15%,
A value such as “1.15” is set. Of course, it is necessary to set this value to an appropriate value corresponding to the applied device configuration.

Since the light quantity does not change in the next second to third fields, the value of the set coefficient L is returned to "1".

FIG. 5 is a timing chart showing a case where the light amount is excessive, and is basically the same as FIG.

In this example, when the illumination of the LED 34 is dimmed because it is too bright, the control is performed such that the set coefficient L of the second field is set to "1" or less, and when the third field is entered, it is returned to "1". ing.

The amount of light of the LED 34 can be changed by changing the amplitude or width of the pulse generated by the pulse generator 30C as described above.
When changing the pulse width, due to the characteristics of the dot code,
Darkness does not mean that the width, that is, the light emission time, can be extended.

That is, when an image is picked up by manually scanning the dot code, the positional relationship between each dot of the dot code and the image pickup unit changes every moment during the one exposure period. For example,
Now, consider a case where the state shown in FIG. 6A is as shown in FIG. 6A, but the state shown in FIG. 6A becomes as shown in FIG. 6A during one exposure period. Where a, b, c, d,
e, f, and g indicate pixels of, for example, a CCD of the imaging unit.

First, when the state changes from the state (a) to the state (a) during one exposure period, the state is stationary, and the integrated output of each pixel in this case is represented by ( B)
, As shown as the first waveform, pixels a and b and f and g
Is a value (amplitude) corresponding to black, pixels d and e are values (amplitude) corresponding to white, and pixel c is an intermediate value (amplitude). That is, the dot cycle is stored in the pixels a to e.

Next, when the state changes from the state (a) to the state (b), as shown in the middle waveform in FIG. 6B, the pixel a almost only passes through a black portion. Therefore, the pixel b moves from the center of the black dot to the center of the white portion, so that the integrated output is an intermediate value between black and white. Accordingly, as in the case of the stationary state, since the period from the pixel a to the pixel e is almost one period, the period is preserved. Therefore, even if the manual scanning is performed such that the state moves from the state (a) to the state (b) during one exposure period, the amplitude is reduced but the period is preserved, so that the detection is performed. There is a possibility.

However, if the pixel moves from the state (a) to the state (c) during one exposure period, all the pixels similarly pass between black and white. As shown in the last waveform in B), the integrated output potential becomes a flat value of the intermediate value. That is, if the movement amount becomes too large within one exposure period, the movement becomes blurred and cannot be detected.

Therefore, the length of one exposure period, that is, LED3
It is necessary to control the light emission time of the light emission time of the exposure light within a range in which dots can be detected when manual scanning is performed at a maximum scanning speed which does not cause block omission and is predetermined by the apparatus. That is, as shown in FIG. 6B, the amplitude decreases as the moving amount increases, the contrast ratio is lost, the noise is buried in noise, and detection becomes impossible. It is necessary to define the light emission time of the LED 34 within the allowable movement amount range. It has been experimentally confirmed that the maximum allowable movement amount range is about ／ of one dot.

Next, a third embodiment of the present invention will be described.

FIG. 7 is a diagram showing the configuration. The same components as those in FIG. 1A of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

That is, in the third embodiment, the system control unit 30 is provided with the error detection circuit 30D. The error detection circuit 30D captures the maximum value and the minimum value of the video signal detected by the maximum value detection unit 16 and the minimum value detection unit 18 and detects whether or not it reads the dot code correctly. If it is found that the code has not been read correctly, an error signal is sent to the threshold detection unit 20 or the fact that the dot code is not scanned indicates that the multimedia information reproduced by the subsequent processing of the binarization circuit is used. This is a circuit for displaying on a monitor 36 for output or outputting an error sound to notify the occurrence of an error.

For example, if the minimum value is larger than expected, it means that a blank image has been scanned. In this case, the threshold value detection unit 20 outputs a fixed threshold value. , The monitor 36 displays a message that this is not a dot code.

On the other hand, when the maximum value is smaller than the specified value, it means that a black portion is being scanned, or
This is a state where the light emitted from the light source is not returned, that is, a case where the imaging unit is not imaging the medium. Also in such a case, similarly, it is displayed that the dot code is not scanned, or a certain fixed threshold is forcibly output from the threshold detection unit 20.

That is, even if only white or black is imaged, the maximum value and the minimum value always exist in the image, and if the threshold value is calculated by the threshold value detection unit 20 using these, for example, white Despite shooting,
The irregularities on the surface of the medium will be output as a binary signal, and in order to eliminate such a thing,
A fixed threshold is output.

Next, a fourth embodiment of the present invention will be described.

FIG. 8A is a diagram showing the structure of the first embodiment.
The same reference numerals as in FIG. 1A of the embodiment denote the same parts, and a description thereof will not be repeated.

That is, in the fourth embodiment, a non-linear processing unit 38 is provided at a stage preceding the period extracting unit 12 and the signal processing circuit 24.

The non-linear processing unit 38 does not always detect the dot code recorded by ink on the paper surface of the medium with ink, and the ink is not always black in the video signal. Since the base is floating as shown in (), processing for suppressing the base to a certain black level is performed as shown in FIG. As a result, the contrast ratio between white and black increases, and binarization is easily performed.

The binarization circuits described in the first to fourth embodiments can be constituted by analog circuits, or can be constituted as digital processing circuits. Needless to say, it can be appropriately selected according to the device to be applied.

Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments, and various modifications and applications are possible within the scope of the present invention. . Here, the summary of the present invention is as follows.

(1) The dot code is optically scanned from a recording medium in which multimedia information including at least one of audio information, image information and digital code data is recorded as an optically readable dot code. Reading means for reading, a binarizing circuit for binarizing an image signal corresponding to the dot code read by the reading means, and performing predetermined processing on the binarized data from the binarizing circuit The binarizing circuit in the information reproducing system, comprising: processing means for restoring the original multimedia information; and output means for reproducing and outputting each piece of multimedia information based on an output signal from the processing means. To extract a specific period from the dot code in the image signal corresponding to the dot code read by the reading means. , A maximum value and a minimum value detecting means for detecting a maximum value and a minimum value in a predetermined unit of a specific cycle extracted by the filter, and a maximum value and a maximum value detected by the maximum value and the minimum value detecting means. Threshold calculation means for calculating a binarization threshold from the minimum value,
A binarization circuit for binarizing an image signal corresponding to the dot code read by the reading unit with a threshold value calculated by the threshold value calculation unit.

That is, since a specific period in the dot code is extracted, erroneous detection due to noise can be prevented, and a reliable threshold can be obtained.

(2) To receive an image signal corresponding to a dot code read by the reading means and to binarize a signal resulting from performing one-dimensional waveform equalization processing in the same direction as the modulation direction of the dot code. The binarization circuit according to (1), further comprising a signal processing circuit that supplies the signal of (1) to the binarization means.

That is, since the scanning direction and the modulation direction of the two-dimensional image sensor of the reading means are the same, small-sized and effective waveform equalization can be performed by one-dimensional waveform equalization processing.

(3) The dot code is a data code corresponding to the content of the multimedia information to be reproduced, and a marker arranged at a predetermined position with respect to the data code for determining the reading reference point. And the filter is a filter for extracting the period of the marker. The binarization circuit according to (1), wherein

That is, since the period of the marker is extracted, unnecessary noise can be removed, and a reliable threshold can be obtained.

(4) The binarization circuit according to (2), wherein the waveform equalization processing in the signal processing circuit emphasizes the dot period of the data code.

That is, the amplitude of the signal of the dot cycle is amplified, and the binarization can be performed reliably.

(5) A light quantity control means for discretely controlling the light quantity of the light source provided in the reading means based on the maximum value detected by the maximum value and the minimum value detection means, is further provided. The binarization circuit according to the above (1).

That is, the dynamic range of the signal can be ensured, and the binarization can be reliably performed.

(6) The binarization circuit according to (5), wherein the light quantity control means controls the light quantity in two stages.

That is, the circuit configuration is simplified, and a dynamic range can be secured with a small-scale circuit.

(7) The binarizing circuit according to (5), further comprising means for changing a threshold value calculated by the threshold value calculating means based on a change in light quantity by the light quantity control means.

That is, the input signal immediately after the light quantity control operation can be accurately binarized.

(8) The binarization according to (1), further comprising means for detecting an error based on a relationship between the maximum value and the minimum value detected by the maximum value and minimum value detection means. circuit.

That is, it is possible to detect that the obtained input signal is not the one of the two-dimensional data to be detected (all black, all white, or intermediate thereof). Further, it is possible to detect whether the controlled light amount is appropriate.

(9) Provided before the filter,
The binarizing circuit according to (1), further comprising means for performing a non-linear process on an image signal corresponding to the dot code read by the reading means.

That is, by compressing the black level, the contrast is improved, and the binarization can be reliably performed.

(10) The binarization circuit according to (1), wherein the threshold value calculating means performs a threshold value calculation during a vertical blanking period.

That is, the operation for obtaining the threshold value required for binarization can be completed during the blanking period of the scanning operation for reproducing the two-dimensional data.

(11) The light quantity control means includes an exposure time control means for controlling the light quantity according to the exposure time. The exposure time control means sets the exposure time in consideration of the movement blur at the maximum scanning speed, (5) wherein the exposure control time range is defined within the maximum allowable movement amount.
2. The binarization circuit according to 1.

That is, since the movement blur is reduced and the influence of the blur is eliminated, the binarization can be surely performed.

[0110]

As described in detail above, according to the present invention,
It is possible to provide an information reproducing system that reproduces information by appropriately performing binarization.

[Brief description of the drawings]

FIG. 1A is a block diagram of a binarizing circuit according to a first embodiment, and FIGS. 1B to 1D are diagrams for explaining the operation of a period extracting unit in FIG. 1A; FIG.

FIG. 2A is a block diagram of a signal processing circuit in FIG. 1A, and FIG. 2B is a diagram for explaining a delay direction.

3A is a block diagram of a binarization circuit according to a second embodiment, FIG. 3B is a circuit diagram of an LED driver in FIG. 3A, and FIG. 3C is a diagram of FIG. FIG. 3 is a block diagram of a system control unit.

FIG. 4 is a timing chart for explaining an example of field-by-field control of the amount of light when there is insufficient light.

FIG. 5 is a timing chart for describing an example of field-based control of the amount of light in the case of light over.

FIG. 6A is a diagram showing various positional relationships between each dot and an image sensor when an image is captured while scanning a dot code, and FIG. 6B is a diagram for explaining the relationship between a scanning speed and an image output signal. FIG.

FIG. 7 is a block diagram of a binarizing circuit according to a third embodiment;

FIG. 8A is a block diagram of a binarizing circuit according to a fourth embodiment, and FIGS. 8B and 8C are diagrams for explaining the operation of the nonlinear processing unit in FIG. FIG.

FIG. 9 is a diagram illustrating a format of a dot code.

FIG. 10 is a diagram showing a configuration of a conventional multimedia information reproducing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Input terminal, 12 ... Period extraction part, 14 ... Detection gate, 16 ... Maximum value detection part, 18 ... Minimum value detection part, 20 ...
Threshold detection unit, 22: data holding unit, 24: signal processing circuit, 24A, 24B: delay circuit, 24C: adder, 24
D, 24F, 24G: multiplier, 24E: subtractor, 26 ...
Comparator, 28 output terminal, 30 system control unit, 30A saturation detection comparator, 30B dark detection comparator, 30C pulse generation unit, 30D error detection circuit, 32 LED driver, 34 LED, 36 Monitor 38: Non-linear processing unit.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) G06K 19/00 GF Term (Reference) 5B035 BB00 BB03 BB11 BB12 BC05 5B057 AA11 CA08 CA12 CB06 CB12 CE12 CH01 5B072 AA02 CC21 DD02 DD21 EE12 FF02 FF03 FF08 JJ07 LL13 LL15 LL18

Claims (5)

[Claims] 1. An information reproducing system for optically reading a code pattern from a recording medium on which information is recorded as an optically readable code pattern and reproducing the information, a light source illuminating the code pattern, An imaging unit that captures a code pattern illuminated by the light source and outputs a corresponding image signal; and a threshold detection unit that calculates a threshold for binarizing the image signal from the imaging unit based on the image signal. A system control unit that controls the illumination light amount of the light source according to a threshold value calculated by the threshold value detection unit; and a binarization method that binarizes an image signal from the imaging unit with the threshold value calculated by the threshold value detection unit. Means, comprising: an information reproducing system comprising: 2. The light source is configured to perform pulse lighting in synchronization with a predetermined unit of the image signal, and the threshold detection unit is configured to calculate the threshold for each of the predetermined units. The system control unit is configured to control the amount of illumination of the light source for each of the predetermined units, and the binarization unit is configured to binarize the image signal for each of the predetermined units. The information reproducing system according to claim 1, wherein: 3. The information reproducing system according to claim 2, wherein the system control unit changes a width or a height of the pulse in order to control an illumination light amount of the light source. 4. The code pattern comprises a plurality of blocks, each block comprising a plurality of dots corresponding to the content of information to be reproduced.
A data area arranged in a dimension, a marker arranged at a predetermined position with respect to the data area for determining a reading reference point of the data area, and a block address. When the dot code is possible, the width of the pulse as one exposure period changed by the system control unit is determined when the dot code is manually scanned at a predetermined maximum scanning speed that does not cause block omission. 4. The information reproducing system according to claim 3, wherein the information is controlled within a range where the dots can be detected. 5. The method according to claim 1, wherein the threshold detecting unit calculates the threshold.
2. The information reproducing system according to claim 1, wherein the information reproduction is performed within a vertical blanking period of the image signal.