JPH06118088A - Optical speed detector - Google Patents

Abstract

PURPOSE:To realize a compact, light-weight, and inexpensive optical speed detector which can detect speed in a non-contact condition with an object to be measured. CONSTITUTION:Light reflected from a moving object 1 which is an object to be measured is converged in a light receiving section 22 by a cylindrical lens 21. It is possible for the cylindrical lens 21 to converge incident light in the array-shape light receiving section 22 in the shape of slit. It is possible to obtain speed in the same way as the conventional optical speed detector which has a space filter. Further, it is possible to obtain a bright optical system. Consequently, it is possible to obtain a bright optical system by deepening depth so that effect of fluctuation of distance from the object 1 is reduced. Consequently, it is possible to omit a space filter and eliminate a powerful projector. Thus, a compact, light-weight, and inexpensive speed detector can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an optical speed detecting device capable of detecting the speed of a moving object in a non-contact state.

[0002]

2. Description of the Related Art Conventionally, a spatial filter composed of a plurality of slits has been used as a speed measuring device capable of measuring a ground speed of a moving object such as a vehicle in a completely non-contact state on the vehicle. Optical speed measuring devices are known. FIG. 21 shows the measurement principle. That is, the spatial filters 3 such as slits arranged at a constant pitch P
Looking through the object 1 moving at velocity V through, a signal of light intensity at frequency V / P is obtained.

For this reason, the reflected light from the object 1 is condensed through the imaging lens 2, decomposed in a certain direction by the spatial filter 3, and then collected by the condenser lens 4 in the light receiver 5. As for the signal from, the intensity signal centered on the frequency of αV / P is obtained, where α is the magnification of the imaging lens. Therefore, when the signal of this light intensity is analyzed by the frequency analyzer 6 and the center frequency f is obtained, the velocity V is obtained because the pitch P and the magnification α are known.

FIG. 22 shows a schematic configuration of a measuring instrument actually constructed based on the above measuring method. This speed measuring device 10 detects light passing through one slit 11 by two series of photosensors 12. In this device 10, the light projected from the projector 14 and reflected by the object 1 is collected by the objective lens 13, and the slit 11
And is detected by the photo sensor 12. As the two series of photosensors 12, a special one having a filter characteristic as a spatial grating and a function of canceling a large unevenness from an image forming field is used. The signal from the photo sensor 12 is amplified by the amplifier 16 that constitutes the waveform shaping circuit 15, and the active filter 17 further removes high-frequency components that become noise. Then, the velocity V is calculated from the center frequency by the arithmetic circuit 17, and the obtained velocity is displayed on the display device 19.

[0005]

Such a non-contact type speed detecting device not only detects the speed of an automobile,
It is suitable for various moving objects, for example, sports such as skiing and skating, watching races such as motorcycles and automobiles, and measuring the speed of the head of a golf club. Since the configuration is simple, an inexpensive device can be configured. Is expected to be.

In the apparatus shown in FIG. 22, in order to detect a constant velocity regardless of the distance between the object 1 to be measured and the apparatus 10, it is necessary to deepen the depth of focus of the optical system. There is. It is known that this depth of focus is proportional to f / (S × α) where S is the width of the slit, f is the focal length of the objective lens, and α is the magnification of the optical system. However, if the focal length f is lengthened, the apparatus becomes long, and it is difficult to reduce the magnification α because the lens diameter is limited. Therefore, the width S of the slit remains to be reduced, but if the width S of the slit is reduced, the amount of light passing through the slit is significantly reduced, and thus a powerful projector is required. When the F number of the optical system is increased as described above, the depth of focus becomes deeper, but the brightness is lowered, and therefore the entire device including the projector becomes large.

On the other hand, in order to improve the accuracy of the detected speed, it is necessary to secure the number of slits acting as a spatial filter, but simply increasing the number of slits causes the size of the entire apparatus to increase. On the other hand, when the pitch of the slits is made small, the effective area of the photosensor, which is the light receiving section, becomes small and the amount of light decreases. For this reason, even in this case, a powerful floodlight is required, and the device becomes large. As described above, if it is attempted to give the optical speed detecting device practical performance, the device is likely to be large and expensive.

In view of the above problems, it is an object of the present invention to realize an inexpensive and compact optical velocity measuring device.

[0009]

In the present invention, in order to solve the above problems, a cylindrical lens, a lenticular lens, and a linear Fresnel lens are used to collect light from a subject in a slit shape. . That is, the optical velocity detecting device according to the present invention is capable of condensing the light from the object to be measured in a slit shape in at least a one-dimensional direction. It is characterized in that it has a slit-shaped image forming system capable of forming an image and a speed detection system for detecting the speed from the center frequency of the output signal from the arrayed light receiving section. This slit-shaped imaging system can be constructed using one selected from the group including a cylindrical lens, a lenticular lens, a linear Fresnel lens and an echelette.

Further, it is desirable that two or more light receiving groups are formed into an array light receiving section by the light receiving portion, and the light receiving groups are arranged mutually along the one-dimensional direction. Further, it is also effective to have an irradiation means for irradiating the object to be measured with pulsed light of a predetermined cycle, and a synchronous detection means for synchronously processing the signals from the arrayed light receiving section at a predetermined cycle. Further, the influence of noise can be reduced by forming the sensitivity adjusting means for controlling the sum of the synchronization components of the signals output from each of the light receiving parts to be constant. Further, by inserting a slit means having two or more slit portions corresponding to each lens in the vicinity of the focal length of each lens of the slit-shaped imaging system, it is possible to configure a device having a deeper depth. is there.

[0011]

[Function] A cylindrical lens as described above, a lenticular lens composed of a plurality of cylindrical lenses,
A single linear Fresnel lens, a plurality of linear Fresnel lenses, and the like can condense light from a subject on a light receiving portion in a slit shape without reducing the amount of light. Therefore, without using a slit or the like, the reflected light from the subject illuminated on the entire lens can be used to condense in a one-dimensional slit shape to form an image on the light receiving portion, and at the same time a bright optical system can be formed. be able to. Therefore, it is possible to make the optical system sufficiently bright even if the depth is increased. Especially, the cylindrical lens is used as a lenticular lens,
Since a linear Fresnel lens can also have a plurality of lenses arranged side by side, a plurality of optical axes can be configured from a plurality of lenses and the like, and even if the F number of each lens is large in order to obtain a deep optical system. A bright imaging system as a whole can be obtained. Therefore, a powerful floodlight or the like is unnecessary. In this way, by adopting the slit-shaped imaging system as described above, it is possible to realize a small-sized and inexpensive optical speed detection device that does not require a slit and has a simple structure, without using a slit. be able to.

When such a slit-shaped image forming system is used, a slit-shaped image formed by a cylindrical lens or the like is used as a light receiving portion to form an array by a plurality of light receiving elements which can be detected as a spatial filter. It suffices to configure the light receiving portion, and it is also possible to form an array light receiving portion by arranging ordinary photodiodes, phototransistors and the like in an array. Therefore, the light receiving section can also be composed of a light receiving element which is inexpensive and has good performance and which is commercially available.

Further, when the array-shaped light receiving section is divided into two or more light receiving groups, the movement direction corresponding to the direction divided by the slit image forming system is discriminated from the phase difference of the signals obtained from the respective light receiving groups. Is possible. Therefore, not only the velocity value but also the vector amount including the direction can be detected. For this reason, it becomes possible to perform arithmetic processing such as the moving distance and the acceleration.

As a method of reducing noise in the signal from the light receiving section, the irradiation means for irradiating the object to be measured with pulsed light of a predetermined cycle and the signal from the arrayed light receiving section are synchronously processed in a predetermined cycle. It is conceivable to install a synchronous detection means for doing so. As described above, in the present speed detection device, since the amount of light projected is small, the irradiation means can be easily configured by using a semiconductor laser or the like that easily oscillates the pulse. The light is not limited to light and may be infrared light.

Further, in order to remove the noise from the reflected light whose intensity of the fluorescent lamp changes periodically, the sensitivity adjusting means for controlling the sum of the synchronous components of the signals output from the respective light receiving parts to be constant. The sensitivity of the light receiving portion may be feedback-controlled by using.

Further, by inserting a slit means having two or more slit portions corresponding to each lens in the vicinity of the focal length of each lens of the slit-shaped image forming system, an apparatus having a deeper depth can be constructed, It is possible to realize a highly accurate optical speed detection device, which is very little affected by the distance to the object to be measured.

[0017]

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

[Embodiment 1] FIG. 1 shows an outline of an optical velocity detecting device 20 according to Embodiment 1. This device
It is composed of a cylindrical lens 21 desired in the direction of the object 1 to be measured, an array-shaped light receiving section 22 for detecting the light formed by the cylindrical lens 21, and a detection section hood 23 for covering these. Further, it is provided with a waveform shaping circuit 15 for processing the optical signal from the light receiving section 22, a calculation section 18 for calculating and outputting the detected speed, and a display section 19 for displaying the speed. 2 and 3
Shows a state in which the cylindrical lens 21 collects light in a slit shape on the light receiving unit 22, and as shown in FIG. 3, when collecting the reflected light from the object 1, it is opposite to the moving direction of the object 1. The light receiving portion 22 that is condensed in a slit shape on the side
The image of moves.

FIG. 4 shows an outline of the light receiving section 22 of this example. The light receiving unit 22 of this example is in the form of an array in which eight phototransistors 30 are arranged vertically and horizontally. Then, the columns arranged in the direction in which the light is condensed in the slit shape by the cylindrical lens, that is, in the direction orthogonal to the X direction are electrically connected to form one light receiving portion 31.

Therefore, in this example, the light receiving section 22 is
Eight light receiving portions 31.1 to 31.8 are formed in the X direction.

FIG. 5 shows these light receiving portions 31.1 to 31.1.
1.8 shows that a signal is output in response to the light condensed by the cylindrical lens 21. The light condensed by the cylindrical lens 21 reflects the uneven pattern existing on the surface of the object 1 moving at the speed V. That is, light having an intensity corresponding to the uneven pattern is formed on the light receiving portion 22 by the cylindrical lens 21, and the light receiving portions 31.1 to 31.8 correspond to the velocity V of the moving object 1 depending on the intensity of the light. To move. That is,
As shown in FIG. 3, when the object 1 moves in the order of A, B, and C, the slit-shaped image is formed on the light receiving unit 22 by A ′,
Move in the order of B'and C '. Then, each light receiving portion 31.
1 to 31.8 output a signal corresponding to the intensity of the light with which the light receiving portion is irradiated. Therefore, for example, when strong light is reflected, a high level optical signal corresponding thereto is received. From 31.8 to 31.8 in sequence. During the period T which is the interval of the high level signal, each light receiving portion 3
When the distance of 1 is the pitch P, it is expressed by the following equation.

T = 1 / f = P / (V × α) (1) where f is the frequency, and α is the magnification of the optical system by the cylindrical lens 21.

Therefore, the velocity V of the object 1 can be obtained by obtaining the center frequency f of the signal output from the light receiving portion 31.

FIG. 6 shows a schematic configuration of the waveform shaping circuit 15 of this example. In this example, in order to obtain the center frequency f, the signals from the adjacent light receiving portions 31 are A1 and A2, and the photocurrent generated from the light receiving portions 31 is taken out as a voltage signal and the difference is taken to obtain a sine wave. I am trying to get a close narrow band random signal. That is, the odd-numbered light receiving portions 31.1, 31.3, 31.
Photocurrent from 5, 31.7 is supplied to the detection resistor 32,
The voltage generated in the resistor 32 is supplied to the non-inverting output of the operational amplifier 41 of the waveform shaping circuit 15. On the other hand, the photocurrents from the even-numbered light receiving portions 31.2, 31.4, 31.6, and 31.8 are supplied to the detection resistor 33, and the voltage generated in this resistor 33 is supplied to the inverting output of the operational amplifier 41. It Therefore, the operational amplifier 41 outputs a sinusoidal signal corresponding to the photocurrent from each of the light receiving portions 31.1 to 31.8. Only the AC component of the signal from the operational amplifier 41 is amplified by the buffer 43 via the pass capacitor 42. Further, after a high frequency component, which is noise, is removed via the low pass filter 44, the high frequency component is supplied to the calculation unit 18, the center frequency f is obtained, and the speed V is obtained.

Incidentally, as shown in FIG. 7, it is of course possible to configure the light receiving portion 22 by using the photodiode 34 as a light receiving element, and the photocurrent from the photodiode 34 is detected by the detecting resistor 32, as in the above. Processing with 33,
If it is introduced into the waveform shaping circuit 15, the velocity V can be obtained by obtaining the center frequency f. In addition, the configuration of the light receiving unit 22 is also
As shown in FIG. 8, it is also possible to increase the number of light receiving portions, which is a combination of light receiving elements, by connecting every other light receiving element such as a phototransistor arranged in a column direction that is a direction orthogonal to the X direction. Is.

FIG. 9 shows a lenticular lens 29 composed of a plurality of cylindrical lenses. Instead of the cylindrical lens 21 shown in FIG. 1, this lenticular 29 may be used to configure an optical system. As shown in FIG. 9, lenticular lens 29 includes cylindrical lenses 25.1 to 25. n are arranged in parallel in the X direction. Therefore, the light 26 incident on the lenticular lens 29 receives the respective cylindrical lenses 25.1 to 25. It is divided into n pieces in the X direction by n, and can be condensed in a slit shape on the corresponding light receiving element of the light receiving section 22. Thus, unlike the spherical lens, the cylindrical lens can have a plurality of lenses arranged in a plane. Therefore, the lenticular lens 29 has a function of condensing light so as to form a plurality of optical axes, and even if the optical system of each lens is dark, a bright optical system as a whole can be obtained. it can.

Instead of the lenticular lens 29, a linear Fresnel lens 27 as shown in FIG. 10 can be used. The linear Fresnel lens 27 shown in FIG.
Is a lens in which a plurality of linear Fresnel lenses are arranged in parallel in the X direction similarly to the lenticular lens, and can simultaneously function as a spatial filter at the same time as condensing. Further, since the linear Fresnel lens can image incident light in a slit shape, it is a bright lens in spite of its deep depth, and constitutes a slit-shaped image forming system of the optical velocity detecting device as in this example. A lens suitable for. Of course, a slit-shaped image can be obtained also by a single linear Fresnel lens. For this reason, it is possible to construct an optical system similar to the cylindrical lens 21 shown in FIG. 1 with only a single linear Fresnel lens. Similar to the lenticular lens and the linear Fresnel lens, the echelette grating prism 28 shown in FIG. 11 can be used to obtain an image divided in the X direction, and a spatial filter such as a slit can be omitted to simplify the configuration. The optical speed detection device can be configured.

As described above, the optical velocity detecting device of this embodiment is a device using a slit-shaped optical system such as a cylindrical lens and a lenticular lens, and is capable of collecting light in a slit-like manner using a conventional slit. It is a compact, inexpensive device with a simple structure that is achieved by a single slit-shaped optical system.
Furthermore, since a deep and bright optical system can be obtained, a floodlight or the like is not necessary, and in this respect, downsizing and cost reduction are possible.

[Second Embodiment] FIG. 12 shows a second embodiment of the present invention.
The structure of the light-receiving unit 22 of the optical speed detection device according to FIG. The other parts of the apparatus of this example, such as the slit-shaped optical system, are the same as those in the first embodiment, and the description thereof is omitted. The light-receiving unit 22 of this example is an array-shaped light-receiving unit in which light-receiving elements 30 such as phototransistors are arranged in an array as in the first embodiment, but in this example, two light-receiving systems A and B are configured. Has been done. That is, the light receiving unit of this example is set to 1 in the X direction.
Six, eight light receiving elements are arranged in a column direction orthogonal to the six light receiving elements. Further, in order to reduce the area of the light receiving section 22 and improve the sensitivity, the light receiving elements forming the adjacent rows are arranged in a staggered pattern. Has been done. Then, the light receiving elements 30 forming the row
Are connected to each other to form the light receiving portions 31.1 to 3.16, and the four light receiving portions 31 form one pitch P. Therefore, the light receiving portions 31.1, 31.5, 3
The group A1 is composed of 1.9 and 31.13, and the photocurrent from this group A1 is input to the non-inverting input of the operational amplifier 41a of the waveform shaping circuit 15a via the detection resistor (not shown) as in the first embodiment. Be led to. Similarly, the light receiving portion 3
A group A2 is composed of 1.3, 31.7, 31.11, and 31.15, and the photocurrent from this group A2 passes through the detection resistor (not shown) as in the first embodiment, and the waveform shaping circuit. It is led to the inverting input of the operational amplifier 41a of 15a.
Further, the light receiving portions 31.2, 31.6, 31.10, 3
Group B1 is composed of 1.14, and this group B1
The photocurrent from is detected by a detection resistor (not shown) as in the first embodiment.
Through the non-inverting input of the operational amplifier 41b of the waveform shaping circuit 15b. Further, the light receiving portions 31.4, 3
The group B2 is composed of 1.8, 31.12, and 31.16, and the photocurrent from this group B2 passes through the detection resistor (not shown) as in the first embodiment, and the waveform shaping circuit 15b.
Of the operational amplifier 41b.

Other processes in the waveform shaping circuits 15a and 15b, such as a pass capacitor, are the same as those in the first embodiment, and the description thereof will be omitted. Then, the waveform shaping circuits 15a and 15b
The optical signals A and B processed in 1 are input to the calculation unit 18, and the calculation unit 18 determines the speed value and the direction.
That is, as shown in FIG. 13, the optical signals A and B are both signals of the frequency f that reflects the reflected light from the moving object 1 moving at the speed V, but they are generated at the light receiving portion deviated by ¼ pitch. Since it is an optical signal that has been converted, it becomes a signal whose phase is shifted by π / 4. Therefore, if the signal A lags the signal B, it can be seen that the object 1 is moving in the direction X, and conversely, if the signal B lags the signal A, the object 1
Is moving in the direction opposite to the direction X. As described above, in the optical velocity detecting device of this example, not only the velocity of the object 1 can be detected in a non-contact state, but also the moving direction thereof can be detected. Since the moving direction can be determined in this way, various data such as the moving distance or the acceleration direction can be derived as well as the speed. Further, by installing such an optical velocity detecting device in two or more directions and processing the obtained optical signal in the same manner as described above, not only the one-dimensional direction but also the two-dimensional and three-dimensional directions are obtained. It is possible to obtain data such as speed, moving distance, and acceleration.

[Third Embodiment] FIG. 14 shows an outline of an optical velocity detecting device according to a third embodiment. The device of this example also
An imaging system including a lenticular lens 29 desired in the direction of the object 1 to be measured, an array-shaped light receiving section 22 for detecting the light imaged by the lenticular lens 29, and a detection section hood 23 covering these. And the light receiving section 22
It has a waveform shaping circuit 15 for processing the optical signal from, a detection system including a calculation unit 18 for calculating and outputting the detected speed and a display unit 19 for displaying the speed. The same parts as those of the above-mentioned embodiments are designated by the same reference numerals and the description thereof will be omitted.

The point to be noticed in the apparatus of this example is that, in addition to the above-mentioned imaging system and detection system, an irradiation device 50 capable of irradiating pulsed light is provided. This irradiation device 50
Is a pulse control unit 51 that oscillates a pulse having a predetermined cycle.
And an irradiation unit 52 that emits pulsed light according to the oscillated pulse. Then, the light receiving section 2 of the imaging system
The optical signal obtained from 2 is detected by the synchronous detection circuit 45 added to the waveform shaping circuit 15 and is supplied to the arithmetic unit 18 in a state where noise is removed.

FIG. 15 shows the structure of the irradiation device 50 so that it can be compared with the waveform shaping circuit 15. In this example, the pulse control unit 51 generates an oscillator 53 that generates a predetermined pulse such as a crystal oscillator, and divides the pulse from the oscillator 53 to generate a timing signal having a preset cycle. The timing signal generated by the timing generation circuit 54 is supplied to both the light emitting element drive circuit 55 that drives the light emitting element and the synchronous detection circuit 45 that performs synchronous detection in the waveform shaping circuit 15. Supplied. The light emitting element drive circuit 55 causes the irradiation unit 5 to follow the timing signal.
A light emitting element such as a semiconductor laser or LED forming 2 is made to emit light. Then, the light emitted from the irradiation unit 52 is reflected by the object 1 moving at the speed V, and converted into an optical signal by the image forming system including the lenticular lens 29 and the like.

FIG. 16 shows how the noise is removed by the detection by this device. Under continuous light, the object 1
The optical signal detected by the light receiving unit 22 due to the movement of
As shown by the waveform W1, it is amplified in a form mixed with a noise component. On the other hand, in the device of the present example, the timing generation circuit 54 generates a pulse signal having a high frequency (about several kHz) as shown by the waveform W2, and the same pulsed light is emitted in synchronization with this. Is irradiated from. This pulsed irradiation light is reflected by the object 1, and the light receiving unit 22
Detected in. Therefore, if it is continuous light, the waveform W1
Although an optical signal as shown in FIG. 3 is obtained, an optical signal having a waveform W3 modulated into pulsed irradiation light is obtained from the light receiving unit 22 of this example.

When the optical signal modulated by such pulsed irradiation light is rectified (detected) by the synchronous detection circuit 45 in synchronization with the timing signal, a pulsating flow signal waveform as shown by the waveform W4 is obtained. To be And this waveform W
By passing 4 through the low-pass filter 44, high frequency components including the timing signal are removed, and an output with a high S / N ratio such as a waveform W5 showing a low frequency f corresponding to the speed V can be obtained.

As described above, in the optical velocity detecting apparatus of this embodiment, the high-frequency timing signal is generated and the light reception signal obtained by the irradiation light irradiated in synchronization with the timing signal is synchronously detected. Therefore, the signal obtained after detection has a very high S / N ratio, and it is possible to arithmetically output the stable and highly accurate speed V. Further, in the apparatus of this example, since the slit-shaped image forming system for forming the image of the light reflected from the object is very bright, the light emitted for performing the synchronous detection may be weak. Therefore, LE
An irradiation device that has a simple structure such as D or a semiconductor laser and is inexpensive, and that consumes less energy can be adopted. As a whole speed detection device, a small and inexpensive device with high accuracy can be provided. Can be realized.

In this example, the irradiation unit such as an LED is intermittently caused to emit light, but the irradiation unit that continuously emits light is intermittently caused by a rotating slit or the like, and the modulated optical signal is obtained as a result. Of course, it is also possible to perform synchronous detection by using it. Further, the light to be applied is not limited to visible light and may be infrared light.

[Fourth Embodiment] FIG. 17 schematically shows an optical velocity detecting device according to a fourth embodiment. The light receiving unit 2
The cylindrical lens and the like for forming an image on 2 are the same as those in the first embodiment, and illustration and description thereof will be omitted. The device of this example is a device that removes noise due to irradiation light from the outside and enables stable speed measurement. That is, road lights or indoor fluorescent lights are lit at a constant cycle, for example, 60 or 50 Hz. Therefore, object 1
These lights reflected from the light receiving section 22 also have the same AC intensity component, and each of the light receiving sections 31.1 and 31.
The voltage signals v1 and v2 from 2 are also as shown in FIG.
There are intensity components of the same frequency, and these become noise. Such noise components v1 and v2 have the same phase, but the same voltage v is applied to each of the light receiving portions 31.1 and 31.2.
Even if the noise component v is supplied, the noise components v are different because the sensitivities of the light receiving portions 31.1 and 31.2 vary.
A difference occurs between the amplitudes of 1 and v2. As a result, the light receiving portion 3
When a noise component due to a difference in amplitude is output from the operational amplifier 41 to which the voltage signal corresponding to the photocurrent from 1.1 and 31.2 is input, and the frequency of this noise is close to the frequency indicating the speed of the object May be erroneously recognized as a signal indicating speed.

Therefore, in the apparatus of this example, attention is paid to the fact that the noise components due to such external light have the same phase, and the sensitivities of the respective light receiving portions are controlled so as to cancel the noise components having the same phase. I am trying. As a result, as shown in FIG. 19, the light receiving portions 31.1 and 3
The periodic amplitude difference between the noise components v1 and v2 output from 1.2 disappears, and it is possible to prevent the output from the operational amplifier 41 from being affected. Specifically, the operational amplifier 6
1 is added to the sensitivity adjusting circuit, that is, the AGC circuit 60, and the voltage obtained by subtracting the values of the noise components v1 and v2 from the constant voltage V0 is input to the operational amplifier 61.
As a result, the output voltage v of the operational amplifier 61 applied to the light receiving portions 31.1 and 31.2 fluctuates so that the sum of the noise components v1 and v2 becomes the constant voltage V0, and therefore the light receiving portions 31.1 and 31. .2 is the noise component v1
Feedback control can be performed in the direction in which there is no fluctuation in v2 and v2.

As described above, in the optical velocity detecting device of this example, the noise component from the external light can be removed, and a stable and highly reliable velocity value can be obtained.
Of course, since the phase of the optical signal from the moving object is inverted if the light receiving part is different, it is not affected by this sensitivity adjustment circuit, is amplified without being canceled, and can be detected with an accurate value. .

[Embodiment 5] FIG. 20 shows a linear Fresnel lens 27 and a light receiving portion 2 which constitute an optical velocity detecting device of this embodiment.
2, a slit group 70 inserted near the focal length of each lens of the linear Fresnel lens 27 is shown. Since the processing of the optical signal detected by the light receiving unit 22 is the same as that of the above-described embodiment, illustration and description thereof will be omitted.

The apparatus of this example is a linear Fresnel lens 27.
For each lens, a slit group 70 having one slit 71 is inserted near its focal length. As a result, the slit 71 plays the same role as the diaphragm of the camera, and when it is installed in the vicinity of the focal length of the lens, only parallel rays are allowed to pass. Thereby, the depth of the slit-shaped imaging system using the linear Fresnel lens 27 becomes deeper, and even if the distance to the object to be measured changes considerably, the influence on the detection speed can be minimized. .
Therefore, it is possible to realize a device which is excellent in detecting the speed when the distance to the object changes significantly.

In general, if the slit 71 is installed and the depth is increased, the brightness becomes insufficient, and highly accurate measurement is impossible. However, in the apparatus of this example, unlike the conventional apparatus using a spherical lens or the like which is difficult to arrange in parallel, a slit-shaped image forming system including a plurality of linear Fresnel lenses 27 is used, and A plurality of slits 71 can be installed on the optical axis. Therefore, it is possible to obtain brightness as the entire device. Therefore, even if the depth is deep, it is bright, the measurement accuracy can be maintained, and the device can be made small and inexpensive. Of course, not only the linear Fresnel lens but also when using a lenticular lens, slits 7 are provided at positions corresponding to the focal lengths of the individual cylindrical lenses.
The same effect as described above can be obtained by inserting the slit group 70 in which 1 can be installed.

Various applications are conceivable as application examples of the optical velocity detecting device described in each of the above embodiments.
For example, as an application example as a speed measuring device, a measuring device such as a head speed of a golf club, a passing speed measuring device of a moving object (sports / bikes such as skis and skates,
For watching a car race or other leisure activities), a ground speed measuring device for cars and other moving objects, a speed measuring camera (which records the speed of a subject on a film by incorporating it in the camera), the flow velocity of mucus or powder, etc. There is a flow meter. In addition, as an application example as a distance measuring device, a moving amount can be detected by installing the coordinate measuring device for an automobile or other moving object (installed on both sides of a vehicle etc.). The rotation angle can be calculated from the difference in the amount, and as a result, the moving coordinates can be measured.), The winding amount (moving length) measuring device for cloth or paper, and the application as a linear encoder (currently used). Since the linear encoder that is used has a finite length component such as a slit plate in the detection unit, the measurement distance is limited. Since the distance can be measured without limitation, it is possible to detect the movement amount of a long-axis object, such as a long-axis cylinder, which has been conventionally difficult in terms of cost or technology.

[0045]

As described above, according to the present invention, a cylindrical lens capable of condensing the light incident on the lens in a slit shape, a lenticular lens in which the cylindrical lenses are arranged in parallel, a linear Fresnel lens, or the like. Is used to obtain a bright slit-shaped imaging system even if the optical system has a deep depth of focus. Therefore, the light from the DUT moving at a certain speed is imaged in a slit shape on the array-shaped light receiving unit by such a slit-shaped imaging system, and is similar to the conventional optical speed detection device using a spatial filter. Moreover, the speed of the measured object can be calculated. Furthermore, the cylindrical lens and the linear Fresnel lens allow multiple lenses to be arranged in parallel, which also makes it possible to easily obtain a large number of optical axes. The system can be used, and the projector and the like can be omitted. Therefore, the optical velocity detection device according to the present invention,
It has a simple structure, is small and lightweight, and can be manufactured at low cost. Of course, in terms of accuracy, it is possible to obtain a high value in spite of being small in size, because a function equivalent to that of the spatial filter can be obtained by the slit-shaped image formation obtained in the array-shaped light receiving unit.

In addition to such an optical velocity detecting device, in the present invention, two or more light receiving groups are formed so that the moving direction of the object to be measured can be determined. Therefore, it is possible to calculate various data such as distance or acceleration. Further, as a measure against noise, a synchronous detection means is realized to enable output with a high S / N ratio.

Furthermore, by installing a sensitivity adjusting circuit also for disturbance noise light, erroneous detection is prevented,
We have realized a speed detection device that can perform highly accurate and stable functions. Further, by inserting the slit means having the slit portion, it is possible to realize a speed detecting device having a deeper depth and capable of highly accurate measurement without being affected by the distance to the object to be measured.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an outline of an optical speed detection device according to a first embodiment of the invention.

FIG. 2 is an explanatory diagram showing an optical system of the optical velocity detection device shown in FIG.

FIG. 3 is an explanatory diagram showing an operation of the optical velocity detection device shown in FIG.

FIG. 4 is an explanatory diagram showing a light receiving portion of the speed detection device shown in FIG.

5 is a timing chart showing an optical signal detected by a light receiving unit shown in FIG.

6 is a block diagram showing a configuration of a detection system that processes an optical signal from the light receiving unit shown in FIG.

FIG. 7 is an explanatory diagram showing a configuration when the light receiving unit shown in FIG. 6 is replaced with a photodiode.

FIG. 8 is an explanatory diagram showing another arrangement of the light receiving units shown in FIG.

9 is a perspective view showing a lenticular lens adopted in place of the cylindrical lens in the speed detecting device shown in FIG.

10 is a perspective view showing a linear Fresnel lens that can be used instead of the lenticular lens shown in FIG.

11 is a perspective view showing an echelette lattice prism that can be used instead of the lenticular lens shown in FIG.

FIG. 12 is an explanatory diagram showing a configuration of a light receiving unit and a waveform shaping circuit of an optical velocity detecting device according to a second embodiment of the invention.

13 is an explanatory diagram showing waveforms obtained from the waveform shaping circuit shown in FIG.

FIG. 14 is an explanatory diagram showing an outline of an optical speed detection device according to a third embodiment of the invention.

15 is a block diagram showing an outline of a detection system and an irradiation device of the speed detection device shown in FIG.

FIG. 16 is an explanatory diagram showing waveforms obtained in each part of the speed detection device shown in FIG.

FIG. 17 is a block diagram showing an outline of an optical speed detection device according to a fourth embodiment of the invention.

FIG. 18 is a graph diagram illustrating a noise state generated in the speed detection device shown in FIG.

19 is a graph showing a state in which the noise state is eliminated by the speed detection device shown in FIG.

FIG. 20 is an explanatory diagram showing a slit-shaped imaging system of an optical velocity detection device according to a fifth embodiment of the invention.

FIG. 21 is an explanatory diagram showing the principle of an optical velocity detection device using a spatial filter.

FIG. 22 is an explanatory diagram showing a configuration of a conventional optical velocity detecting device.

[Explanation of symbols]

 1 ·· Moving object 2 · · Imaging lens 3 · · Spatial filter 4 · · Condenser lens 5 · · Light receiver 6 · · Frequency analyzer 15 · · Waveform shaping circuit 18 · · Calculation unit 19 · · Display unit 20 · ·・ Optical speed detection device 21 ・ ・ Cylindrical lens 22 ・ ・ Light receiving part 23 ・ ・ Detection part hood 27 ・ ・ Linear Fresnel lens 28 ・ ・ Echlet grating prism 29 ・ ・ Lenticular lens 30 ・ ・ Light receiving element 31 ・ ・ Light receiving Part 32, 33 Detection resistor 34 Photodiode 41 61 Operational amplifier 42 Pass capacitor 43 Buffer 44 Lowbus filter 45 Periodic detection circuit 50 Irradiator 51 Pulse control 52 .. Irradiator 53 .. Oscillator 54 .. Timing generation circuit 55 .. Light emitting element drive circuit 60 .. Sensitivity adjustment Circuit (AGC circuit) 70 ・ ・ Slit group 71 ・ ・ Slit

Claims (6)

[Claims] 1. A slit shape capable of condensing light from an object to be measured into a slit shape in at least a one-dimensional direction and capable of forming an image on each of the light receiving portions of an array light receiving portion in which two or more light receiving portions are arranged. An optical speed detecting device comprising an image forming system and a speed detecting system for detecting a speed from a center frequency of an output signal from the arrayed light receiving section. 2. The slit-shaped imaging system according to claim 1, wherein the slit-shaped imaging system is a cylindrical lens, a lenticular lens,
An optical velocity sensing device comprising one selected from the group comprising a linear Fresnel lens and an echelette. 3. The array-shaped light receiving section according to claim 1, wherein two or more light receiving groups of light receiving portions are formed.
An optical velocity detecting device characterized in that the light receiving groups are mutually arranged along the one-dimensional direction. 4. The method according to any one of claims 1 to 3,
An optical velocity detection device, comprising: an irradiation unit that irradiates the measured object with pulsed light having a predetermined cycle; and a synchronous detection unit that synchronously processes signals from the arrayed light receiving unit at the predetermined cycle. apparatus. 5. The method according to any one of claims 1 to 4,
An optical velocity detecting device comprising a sensitivity adjusting means for controlling a sum of synchronous components of signals output from each of the light receiving parts to be constant. 6. The method according to any one of claims 1 to 5,
An optical velocity detecting device comprising slit means having two or more slit portions corresponding to each lens near the focal length of each lens of the slit-shaped imaging system.