JPH1194520A - Real-time range finder - Google Patents

Abstract

(57) [Summary] [Problem] To easily measure a distance in real time using an existing technology without using a special sensor having each photosensor provided with a time measurement function. Light having different wavelength characteristics is incident on a first light modulator having a different light transmittance depending on a position and a second light modulator having a different light transmittance from the light modulator. Then, the light outputs are combined to produce the same object OB.
, And images are taken using the optical filters 31 that respectively extract the wavelength components of the first and second light sources 30. The values of each pixel of the obtained plurality of image data, the imaging elements 18 and 20, and the light source 30 Has a distance calculation unit 24 that calculates the distance to the object OB from the geometrical arrangement of.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a range finder for measuring a three-dimensional position (distance image) of a subject.

[0002]

2. Description of the Related Art A range finder is a device for measuring a distance image of a subject, and various measurement principles have been developed. For example, as shown in FIG. 14, a vertically long linear light (slit light) is radiated to an object to be a subject, the light is swept in a horizontal direction, and the reflected light is captured by a camera, and 3 Measure the dimensional position.

FIG. 15 shows a configuration example of a range finder employing the above measurement principle. In the range finder shown in FIG. 1, light from a light source 1 is converted into a vertically long linear light by a slit 2, and a projection direction of the light is swept in a horizontal direction with respect to a subject 4 by a rotating mirror 3. The reflected light from the subject 4 is received by the photosensor 6 through the lens 5, and the light receiving timing of each photosensor 6 is determined by the timing measuring unit 7 to the distance calculating unit 8.
To measure the elapsed time from the sweep start time until the light reaches each photosensor 6. Thereby, the projection direction θ of the slit light when the light reaches each photosensor 6 can be known. Then, the three-dimensional position of the point P of the subject 4 is measured from the projection direction θ and the position of the photosensor 6 by the principle of triangulation. By calculating this for each photosensor 6, the three-dimensional position of each point of the subject 4 can be measured.

[0004]

However, since the above-described range finder measures the time at which light arrives at each photo sensor in the photo sensor portion, each of the photo sensors has a time measurement function for measuring time. I had to have it. Also, in order to obtain the resolution of a general range image, it is necessary to increase the resolution of the photo sensor. For this purpose, a considerably large integration is required, in which the photosensor array is formed into an IC and a time measurement circuit is provided around each photosensor. Therefore, in order to realize the system, a dedicated IC has to be manufactured, which is difficult to realize.

[0005] The present invention has been made in view of the above circumstances, and can be easily performed by using existing technology without using a special sensor having a time measurement function in each photosensor. It is an object of the present invention to provide a range finder capable of measuring a distance in real time.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention has a first light emitting device having different light transmittances depending on positions.
The light modulator and the light modulator, light having different wavelength characteristics are incident on a second light modulator having a different light transmittance, and the light outputs are combined and projected on the same subject, 1st, 2nd
A distance calculating unit that calculates the distance to the subject from the value of each pixel of the obtained image data and the geometrical arrangement of the image sensor and the light source, using the optical filter that extracts the wavelength component of the light source. Is a real-time range finder.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, a first optical modulator that generates an optical pattern having a different light transmittance depending on a position is different from the first optical modulator. A second optical modulator that generates an optical pattern; first and second light sources that emit light having different wavelength characteristics to the first and second optical modulators; A plurality of optical filters, each of which receives light from a subject on which an optical pattern output from the optical modulator is projected and extracts wavelength components corresponding to wavelength characteristics of the first and second light sources; and A plurality of image sensors arranged corresponding to the optical filter, and the value of each pixel of the image data obtained from each image sensor and the geometric arrangement of the image sensor and the light source, the distance to the subject Real-time range file comprising a distance calculator for calculating A da, by the light irradiating the subject into a plurality of patterns light, without preparing the sensor as to have a time measurement function to each photosensor, performing an operation that can easily measure the distance in real time.

According to a second aspect of the present invention, there is provided a first optical modulator for generating an optical pattern having a different light transmittance depending on a position;
A second optical modulator that generates an optical pattern different from the optical modulator, and first and second light sources that input light having different wavelength characteristics to the first and second optical modulators, respectively. A pattern light operation of projecting the light patterns of the first and second optical modulators onto a subject, and a diffuse light operation of projecting a plurality of lights having different wavelength characteristics onto the subject with a uniform light intensity distribution. And light source control means for performing time-sharing alternately, and light from a subject on which light is projected by the pattern light operation and the diffuse light operation is respectively incident and matched with the wavelength characteristics of the first and second light sources. A plurality of optical filters for respectively extracting wavelength components, a plurality of image sensors arranged corresponding to the plurality of optical filters, and a value of each pixel of image data obtained from each image sensor during the diffused light operation Calculate the surface reflectance correction coefficient of the subject from A distance calculation for calculating a distance to a subject from a value of each pixel of image data obtained from each image sensor at the time of a tan light operation, a geometric arrangement between the image sensor and the light source, and the reflectance correction coefficient. This is a real-time range finder including a unit and an effect that distance measurement can be performed even when the reflectance characteristic of the subject surface depends on the wavelength.

According to a third aspect of the present invention, there is provided a first optical modulator for generating an optical pattern having a different light transmittance depending on a position,
A second optical modulator that generates an optical pattern different from the optical modulator, and first and second light sources that input light having different wavelength characteristics to the first and second optical modulators, respectively. An image sensor for receiving light from a subject on which an optical pattern output from the first and second optical modulators is projected; and a wavelength characteristic adapted to wavelength characteristics of the first and second light sources. A plurality of optical filters, each having a plurality of optical filters arranged so as to be spatially multiplexed on the image sensor, and a value of each pixel of image data in a light region of each of a plurality of wavelengths acquired by the image sensor. A real-time range finder including a distance calculation unit that calculates a distance to an object from a geometric arrangement of an image sensor and the light source, wherein a distance image of the object can be obtained by providing only one image sensor. To play.

According to a fourth aspect of the present invention, there is provided a first optical modulator for generating an optical pattern having a different light transmittance depending on a position,
A second optical modulator that generates an optical pattern different from the optical modulator, and first and second light sources that input light having different wavelength characteristics to the first and second optical modulators, respectively. A pattern light operation for projecting light patterns from the first and second optical modulators to a subject, and a diffused light for projecting a plurality of lights having different wavelength characteristics to the subject with a uniform light intensity distribution. Light source control means for alternately performing the operation in a time-division manner, an image sensor for receiving light from a subject on which light is projected by the pattern light operation and the diffuse light operation, and a wavelength of the first and second light sources. A plurality of optical filters each having a wavelength characteristic matched to the characteristic and arranged so as to be spatially multiplexed on the image sensor, and a subject based on a value of each pixel of image data obtained from the image sensor during the diffused light operation. Calculate the surface reflectance correction coefficient of the A distance calculating unit that calculates a distance to a subject from a value of each pixel of the image data obtained from the image sensor, a geometric arrangement of the image sensor and the light source, and the surface reflectance correction coefficient. This is a real-time range finder that performs distance measurement with one image sensor even when the reflectance characteristic of the subject surface depends on the wavelength.

According to a fifth aspect of the present invention, there is provided a light source unit for spatially sweeping slit light projected onto a subject, and light from the subject swept by the slit light is adjusted to the wavelength characteristic of the slit light. An optical filter for extracting a wavelength component, an image sensor arranged corresponding to the optical filter, and a light source control unit for changing a light intensity change pattern of a light source in the first sweep and the second sweep using slit light. Calculating the exit angle of the slit light at each position of the image from the output of the image sensor for the first sweep and the output of the image sensor for the second sweep, thereby calculating the distance to the subject at each position of the image It is a real-time range finder that includes a distance calculator and can measure distance without measuring the light receiving timing of a plurality of photo sensors. It was performing an operation.

According to a sixth aspect of the present invention, in the real-time range finder according to the fifth aspect, the light source unit uses a light modulator having a different light transmittance depending on a position, and a specific light pattern on a subject is used. By emitting light at once,
In place of the slit light sweep operation,
An effect is obtained that distance measurement can be performed by one light emitting operation.

An embodiment of the present invention will be specifically described below with reference to the drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
1 is a configuration diagram of a real-time range finder according to an embodiment of the present invention. In the real-time range finder according to the first embodiment, optical patterns having different light intensity distributions and wavelength characteristics are generated by an optical pattern generator (A) 11 and an optical pattern generator (B) 12 and synthesized by a half mirror 13. To irradiate the object OB. In addition, the configuration is such that the reflected light from the subject OB is condensed by the lens 14 and the respective reflected lights corresponding to the optical outputs of the optical pattern generator (A) 11 and the optical pattern generator (B) 12 are separated and received. doing. Specifically, the reflected light from the subject OB incident on the lens 14 is converted into a half mirror (A) 1
5 and further, the reflected component at the half mirror (A) 15 is guided to another half mirror (B) 16. An optical filter (A) 17 and an image sensor (A) 18 are arranged on the optical axis on the transmission side of the half mirror (A) 15, and an optical filter (B) is arranged on the optical axis on the reflection side of the half mirror (B) 16. ) 19, and an image sensor (B) 20.

An image sensor (C) 21 is arranged on the optical axis on the transmission side of the half mirror (B) 16 so as to receive light in the visible light region and output a video signal of the object OB. .

An optical pattern A signal processing circuit 22 is connected to a video output terminal of the image pickup device (A) 18, and an image pickup device (B) 20
Is connected to the optical pattern B signal processing circuit 23. The distance image is measured by inputting the output signals of the optical pattern A signal processing circuit 22 and the optical pattern B signal processing circuit 23 to the distance calculation unit 24.

A color camera signal processing circuit 25 is connected to a video output terminal of the image pickup device (C) 21 so as to obtain a texture image.

Image sensors (A) 18 and (B) 20, optical pattern A signal processing circuit 22, optical pattern B signal processing circuit 23,
The operation timing of the distance calculation unit 24 is controlled by the control unit 26. The control unit 26 further instructs the light source controller 27 to execute the light pattern generation units (A) 11 and (B) 1
2 is controlled.

FIG. 2 shows the configuration of the optical pattern generator (A) 11. An optical filter 31 is arranged in front of the light source 30, and an optical modulator 32 is
And an exit lens 33. Optical filter 31
Has a transmittance property of transmitting only a component in the vicinity of the wavelength lambda _A. The light modulator 32 is formed of, for example, a liquid crystal filter, and is set to have a transmittance characteristic in which the light transmittance continuously increases from the left side to the right side in the horizontal direction as shown in FIG. . Note that another optical pattern generation unit (B) 1
2 has the same configuration as the optical pattern generator (A) 11, but differs in the transmission wavelength band of the optical filter. Optical filter provided in the optical pattern generator (B) 12 has the transmittance characteristic as the peak of the transmittance is at the different wavelengths lambda _B from the wavelength lambda _A. Also, the optical pattern generation unit (B) 12
In the optical modulator of No. 1, the light transmittance distribution is obtained by inverting the distribution state of the optical modulator 32.

The operation of the real-time range finder according to the present embodiment configured as described above will be described.

First, the operation of the optical pattern generators (A) and (B) will be described. The light pattern generation unit (A) 11 includes a light source 30
4 passes through the optical filter 31, and
Only the light near the wavelength λ _A as shown in FIG. Then, an optical pattern having a wavelength characteristic on the wavelength λ _A side shown in FIG. 4A and having a light intensity distribution as shown by a solid line in FIG. Lights having different intensities are emitted from the half mirror 13 by the exit lens 33.
Incident on. On the other hand, the optical pattern generation unit (B) 12 also has a wavelength characteristic on the wavelength λ _B side shown in FIG. 4A and has a light intensity distribution as shown by a broken line in FIG. An optical pattern is generated by the optical filter and the optical modulator, and enters the half mirror 13 through the exit lens.

These two optical pattern generators (A) and (B)
The light emitted from the light is combined by the half mirror 13 and one of the combined light is horizontally inverted by the half mirror 13, so that each wavelength λ is represented by a solid line and a broken line as shown in FIG. _A and λ _B are projected onto the subject OB.

The emitted light hits the object OB, and the reflected light is reflected by the lens 14, the half mirror (A) 15, and the half mirror (B) 16 to the image pickup devices (A) 18 and (B) 2.
0, and enters (C) 21. As shown in FIG. 4B, the optical filter (A) 17 disposed on the front surface of the imaging element (A) 18 transmits a component in a predetermined area including the wavelength λ _A but a predetermined area including the wavelength λ _B. Are set to have such characteristics as to cut. Further, as shown in FIG. 4B, the optical filter (B) 19 disposed on the front surface of the imaging element (B) 20 transmits components in a predetermined region including the wavelength λ _B but includes the wavelength λ _A. The components of the region are set to have such characteristics as to cut. Therefore, the optical pattern generation unit (A) 11,
The light of the optical pattern generation unit (B) 12 is converted to an image sensor (A) 18,
(B) The light can be received separately from the light from the light source 20.

Here, the ratio f of the light intensity at each pixel of the output of the image sensor (A) 18 and the image sensor (B) 20 changes as shown in FIG. 5 with respect to the horizontal angle position θ of the light pattern. . The light intensity ratio is measured by the imaging devices (A) 18 and (B) 20, and the light emission angle θ0 is measured. FIG. 5 shows that the horizontal angle θ0 of the emitted light having the light intensity ratio Ia / Ib can be measured. Assuming that the function of Ia / Ib is f, θ0 =
f-1 (Ia / Ib)).

Next, the distance calculator 24 calculates the light intensity ratio of each pixel position from the outputs of the optical pattern A signal processor 22 and the optical pattern B signal processor 23 based on the signal intensity of each pixel. Then, the angle of incidence of light is calculated from the characteristics shown in FIG. The direction of the light emitted from the optical pattern generators (A) and (B) is calculated from this angle and the geometrical positional relationship between the image sensors (A) and (B) and the optical pattern generators (A) and (B). Then, based on the principle of triangulation, the three-dimensional position of the part of the object OB which is shown at the position of each pixel is calculated. Thus, a distance image of the subject OB is obtained. At the same time, a texture image of the subject OB corresponding to the obtained distance image is obtained by the outputs of the image sensor (C) 21 and the color camera signal processing unit 25.

Up to this point, when the reflectance characteristic of the object surface does not depend on the wavelength of light, that is, when the object has a uniform color, or when the two wavelengths λ _A and λ _{B in} FIG. 4 are sufficiently close values. This is the operation of the real-time range finder when the reflectance characteristics of the object are considered to be substantially the same at two wavelengths.

However, in general, the light reflectance characteristic of the surface reflectance of the subject changes depending on the location. Therefore, as shown in FIG. 6, the operation when the light of the optical pattern generation units (A) and (B) described in the first embodiment is pattern light (pattern light operation) and the diffused light operation are alternately performed. The distance measurement can be performed even when the surface reflectance of the subject depends on the light wavelength. Basically, the operation of the pattern light measurement is the same as the operation described above.

However, in the above description, a different calculation is performed when obtaining the angle θ0. That is, in the case of the diffused light operation, the light modulator 32 of the light pattern generation units (A) and (B)
Is set to project uniform light (set so as to have uniform transmittance), and the light pattern generation unit (A) at this time is set.
(B) The subject reflected light of each emitted light is imaged, and the ratio of the outputs of the optical pattern A signal processing unit 22 and the optical pattern B signal processing unit 23 is determined by each photo sensor (each pixel sensor on the image sensor).
The calculation is made for each of them, and the ratio of the surface reflectivity of each light source of the subject at the time of light irradiation is prepared, and this is used as a correction coefficient. Next, when calculating the angle θ0, the light intensity ratio Ia / Ib
Is multiplied by a correction coefficient, and f ^-1 (Ia / Ib
X correction coefficient) is calculated for each photosensor output, and the correct light receiving angle is measured. This corrects the error due to the light wavelength dependence of the surface reflectance of the subject, and calculates the three-dimensional position of the subject based on the principle of triangulation based on this and the geometric positional relationship between the image sensor and the optical pattern generator. I do.

In the first embodiment, as shown in FIG. 3B, the optical filters disposed on the front surfaces of the image pickup devices (A) 18 and (B) 20 are different depending on the light wavelength.
The two lights may be separated. Generally, the light emitted from the optical pattern generation units (A) 11 and (B) 12 is set to infrared light, thereby performing distance measurement and using the image sensor (C) 21.
Receives light in the visible region, and captures the texture of the subject by the color camera signal processing unit 25. However, the image pickup devices (A) 18 and (B) 20 set the optical filter characteristics in the visible region, do not take an image simultaneously with the image pickup device (C) 21, and operate the optical pattern generation units (A) 11 and (B) 12. The operation is performed in a time-division manner, and the image pickup device (A) 18,
If (B) 20 and (C) 21 operate, it is not necessary to set the light source in the infrared region. Further, the light modulator for creating the light pattern can be replaced with a light projector for projecting a pattern image such as a video projector.

In the first embodiment, if light in the infrared region is used as the pattern light, the image pickup device (C) 21 can be used.
The color camera signal processing circuit 23 can capture the texture image at the same time as the distance image measurement. However, the pattern light is set in the visible region, and the texture image is captured by time-division processing at a timing other than when slit light is projected. Is also good.

In the first embodiment, the light source 3
Although 0 has been described as a lamp, a light source having wavelength selection characteristics, such as an LED, may be used. In this case, the wavelengths of the two LED lights are set to different values, and an optical filter corresponding to these wavelengths is mounted on the image sensor. The optical filter in the light source unit can be omitted.

If the wavelengths of the two types of light are set to be very close, if the surface reflectivity of the object does not change rapidly with the light wavelength, the distance between the two types of light can be accurately measured without performing diffused light measurement. Images can be measured.

Further, in the first embodiment, two types of light sources are used. However, two or more types of light sources are used to independently receive the respective lights, and each photo sensor combines the respective light intensities. May be used to calculate the angle at which the light is emitted.

As described above, according to the present embodiment, by using existing technology, the emitted light is converted into a plurality of pattern lights, so that each photosensor has a time measurement function. It is possible to realize a range finder that can easily measure a distance in real time without preparing a finder.

(Second Embodiment) FIG. 7 shows a configuration diagram of a real-time range finder according to a second embodiment of the present invention. Note that, in FIG. 7, portions having the same functions as those in the above-described first embodiment are denoted by the same reference numerals.

In the real-time range finder according to the present embodiment, an optical filter (C) 42 is arranged in front of a light source (C) 41, and a slit 43 is arranged on the emission side of the optical filter (C) 42. The vertical slit light generated by the slit 43 is emitted to the subject OB via the rotating mirror 44. The light source (C) 41 is controlled by a light source controller 45, and the slit 43 is controlled by a slit control unit 46. The rotation mirror 44 is controlled by a rotation control unit 47. On the other hand, the reflected light from the subject OB is
The light is received at 8 and is incident on the half mirror (A) 15 to be branched. An optical filter (C) 49 and an image sensor (A) 50 are arranged on the optical axis on the transmission side of the half mirror (A) 15. Further, an image sensor (C) 21 is arranged on the optical axis on the reflection side of the half mirror (A) 15.

An image processing unit 51 is connected to a video output terminal of the image pickup device (A) 50, and a memory 52 is attached to the image processing unit 51. The control unit 53 controls the distance calculation unit 24, the light source controller 45, the slit control unit 46, and the rotation control unit 47.

The operation of the real-time range finder according to the present embodiment configured as described above will be described below.

First, light emitted from the light source (C) 41 passes through the optical filter (C) 42, becomes light having a certain infrared wavelength characteristic, and becomes slit light in the vertical direction by the slit 43. This is swept in the horizontal direction by the rotating mirror 44 to project slit light on the subject OB.

The sweep of the slit light by the rotating mirror 44 is performed once in the horizontal direction in one field, as shown in FIG. In the case where the image pickup by the image pickup device is non-interlaced, it is performed once in one frame in the horizontal direction.

At this time, as shown in FIG. 8B, the light source controller 45 increases the light intensity in the first sweep and gradually reduces the light intensity in the second sweep. (C) The light intensity of 41 is controlled.

The light generated in this way is used for the object OB.
And the reflected light is captured by the image sensor (A) 50. In this case, the exposure is performed without a shutter operation, and the reflected light of the light scanned in each field (frame) is accumulated in the image sensor, and the captured image is transferred to the image processing unit 51.

The image processing section 51 stores the image captured in the field (1) shown in FIG. 8B in the memory 52, and simultaneously stores this image and the image captured in the field (2). And refer to the luminance value at the same coordinates of each image. The specific angle θ is determined by the combination of the luminance value of the image obtained by the first sweep and the luminance value of the image obtained by the second sweep.
Is determined (FIG. 8C). That is, one range image can be obtained in two fields (frames). For example, assuming that the coordinate at time t1 is equal to the x coordinate of the image at t2, the luminance (magnitude of the image signal) is measured and L
When L1 and L2 are obtained, the value of L1 / L2 is calculated and FIG.
According to (c), the angle θ is specified. At this time, L1 / L2
The value of the ratio does not depend on the presence of a texture pattern (color distribution) on the surface of the subject, since the reflected light of the subject from the same light source is captured although the intensity is different. This makes it possible to estimate the angle θ with high accuracy.

Thereafter, the distance calculator 24 calculates the angle θ at each coordinate, calculates the distance from the distance (base line length) between the rotating mirror 44 and the lens 48 to the object OB by triangulation, and calculates the distance of the entire screen. Obtain information and output it as a distance image.

The texture image is captured by the image sensor (C) 2
1 and is converted into an image signal by the color camera signal processing unit 25 and output as a texture image. At this time, two texture images can be obtained for one distance image. However, one or both of them may be calculated and output as an average value or an intermediate value for each pixel.

As described above, according to the present embodiment, the obtained two sweeps (two fields or two frames) are performed by sweeping the slit light twice and changing the light intensity at that time. ) Can be uniquely determined without depending on the surface reflectivity of the subject, and the distance calculation can be easily performed by two parts of the two images.
It becomes possible once in the field (frame).

In the second embodiment, the light source (C) 41 has a lamp shape. However, if the light source (C) 41 is constituted by an infrared LED or an infrared laser, the optical filter (C) 42 is omitted. Can also.

Further, in the second embodiment, the slit pattern is swept in the horizontal direction to generate an optical pattern. However, even if the sweep operation is eliminated by using an optical pattern generator as shown in FIG. Good. In this case, instead of the first and second sweeps, the first and second light patterns are irradiated in a time-division manner, and the image pickup device (A) 18 sequentially captures the reflected light of the subject according to the timing. Will be.

(Third Embodiment) FIG. 9 shows a configuration diagram of a real-time range finder according to a third embodiment of the present invention. The same parts as those in the second embodiment are denoted by the same reference numerals.

In the third embodiment, the half mirror (B) 60 is positioned on the optical axis on the reflection side of the half mirror (A) 15 on which light is incident from the lens 48 on which the reflected light of the object OB is incident.
Is arranged. An optical filter (B) 61 and an image sensor (B) 62 are arranged on the optical axis on the reflection side of the half mirror (B) 60. Two image sensors (A) 5
0 and the output of the image sensor (B) 62 are input to the image signal processing unit 63. The light source is one type of light source (C) 41, and an optical filter (C) 42 having a wavelength passing characteristic according to the light source (C) 41 is used.

The operation of the real-time range finder according to the present embodiment configured as described above will be described below.

First, the light source (C) 41 is swept in FIG.
As shown in (a), the operation is performed twice in one field in the horizontal direction. In the case where the image pickup by the image pickup device is non-interlaced, it is performed twice in one frame in the horizontal direction. At this time, the light intensity of the light source (C) 41 is gradually increased by the light source controller 45 in the first sweep, and
In the first sweep, the light intensity is controlled so as to gradually decrease (FIG. 10B).

The light generated in this way is used for the object OB.
And the reflected light is applied to the image pickup devices (A) 50 and (B) 6
2 to catch. Exposure to the image sensor in this case,
Exposure in a shutter operation is performed, and reflected light of light scanned in each sweep is used as an image sensor (A) 50, (B)
The stored image is transferred to the image signal processing unit 63. That is, as shown in FIG.
The exposure time of the sweeping image sensor (A) 50 is T1, and the exposure time of the second sweeping image sensor (B) 62 is T2. At this time, the image signal processing unit 63 processes the image captured in the area (1) shown in FIG. 10C and the image captured in the area (2) shown in FIG. Is referred to. Subsequent operations are the same as in the second embodiment of the present invention.

The specific angle θ is determined by the combination of the luminance value of the image obtained by the first sweep and the luminance value of the image obtained by the second sweep (FIG. 10D). In other words, two types of images for two sweeps in one field (frame) are acquired by the shutter operation of the image sensor, and one image is acquired from these two types.
Two range images can be obtained. For example, assuming that the coordinates at time t3 are equal to the x-coordinate of the image at t4, the luminance (magnitude of the image signal) is measured. By 10 (c),
Specify the angle θ. At this time, the value of the ratio L3 / L4 does not depend on the texture pattern on the surface of the subject even if the texture pattern exists on the surface of the subject since the reflected light of the subject to the same light source is captured though the intensity is different.

Thus, also in this embodiment, highly accurate estimation of the angle θ can be performed. After that, the distance calculation unit 24 calculates the angle θ at each coordinate, calculates the distance from the distance (base line length) between the rotating mirror 44 and the lens 48 to the subject OB by triangulation, and obtains distance information of the entire screen. ,
Output as a distance image.

The texture image is captured by the image sensor (C) 2
2, the image is converted into an image signal by the color camera signal processing unit 25, and is output as a texture image.

In FIG. 10, two slit light sweeps are finished just twice in one field (frame) period. However, as shown in FIGS. The sweep may be performed at high speed using a part of the period. Other operations are the same as in the third embodiment.

As described above, according to the present embodiment, the slit light is swept twice so that the change in the light intensity at that time is made different, so that each part of the two images for the obtained two sweeps is obtained. Can be uniquely determined without depending on the surface reflectivity of the subject, whereby the distance can be easily calculated once in one field.

In this embodiment, the light source has a lamp shape. However, if the light source is constituted by an infrared LED or an infrared laser, the optical filter (C) 42 can be omitted.

Further, in this embodiment, the slit pattern is swept in the horizontal direction to generate an optical pattern. However, the sweep operation may be eliminated by using an optical pattern generator as shown in FIG. In this case, instead of the first and second sweeps,
The first and second optical pattern light modulators prepare and irradiate time-division pattern light.

In the first to third embodiments, the change of the optical pattern is performed linearly, but any change pattern may be used. Further, a change in the optical pattern may be changed for each distance measurement, and a measurement strong against noise may be performed.
In this case, a highly accurate distance measurement result may be output by using an optical filter technique such as averaging processing and median processing using a plurality of continuous distance measurement results.

In the first to third embodiments,
A plurality of image pickup devices are combined using a half mirror so that the same field of view can be picked up. However, as shown in FIG.
(B) It may be provided before 20. Also, as shown in FIG. 12B, the half mirror 73 is arranged in an X-shape, so that three image sensors (A) 18, (B) 20, and (C) 22 are provided.
May be divided into incident light. Further, light may be divided into three imaging element cameras by a structure using a dichroic mirror applied to a three-chip imaging element camera or the like. That is,
Any method can be applied as long as it is a method of optically obtaining an image of the same visual field.

In the first embodiment, instead of using a plurality of image sensors to separate light of two different wavelengths, a single image sensor (D) 74 as shown in FIG. Light of two wavelengths is received, and two types of optical filters A and B are alternately arranged in a stripe pattern on the surface as shown in FIG. 13B to multiplex images for the two wavelengths into one image. May be detected. In this case, the stripe is vertical,
It can be either sideways. Also, as shown in FIG.
The optical filters A and B may be arranged in a checkered pattern. However, in these cases, the resolution of the image for light of each wavelength is reduced.

[0064]

As described in detail above, according to the present invention, it is possible to easily perform real-time operation using existing technology without using a special sensor having a time measurement function for each photosensor. A range finder capable of measuring distance can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a real-time range finder according to a first embodiment of the present invention;

FIG. 2 is a configuration diagram of an optical pattern generation unit provided in the first embodiment.

FIG. 3A is a characteristic diagram of an optical modulator provided in an optical pattern generation unit. FIG. 3B is a light intensity distribution diagram of an optical pattern coming out of the optical pattern generation unit.

4A is a transmittance characteristic diagram of an optical filter provided in an optical pattern generation unit. FIG. 4B is a transmittance characteristic diagram of an optical filter provided in a light reception unit.

FIG. 5 is a diagram illustrating a relationship between a pattern light emission angle and a pixel intensity ratio according to the first embodiment.

FIG. 6 is an explanatory diagram of a time-sharing operation in the first embodiment.

FIG. 7 is a configuration diagram of a real-time range finder according to a second embodiment of the present invention.

8A is a diagram showing a sweep operation in a light source unit according to a second embodiment. FIG. 8B is a diagram showing a relationship between sweep and light intensity in the light source unit according to the second embodiment. Of Light Intensity Ratio and Light Projection Angle in First Embodiment

FIG. 9 is a configuration diagram of a real-time range finder according to a third embodiment of the present invention.

10A is a diagram showing a sweep operation of slit light in a light source unit according to the third embodiment. FIG. 10B is a diagram showing a relationship between sweeping and light intensity in the light source unit according to the third embodiment. ) Relationship between exposure time and captured image in the third embodiment. (D) Relationship between light intensity ratio and light projection angle in the third embodiment.

FIG. 11A is a diagram showing a sweeping operation of slit light in a light source unit in the case of high-speed scanning according to the third embodiment; Relationship between sweep and light intensity (c) Exposure timing diagram in case of high-speed scanning in the third embodiment

12A is a diagram illustrating a modified example of the light receiving unit side in each embodiment of the present invention. FIG. 12B is a diagram illustrating another modified example of the light receiving unit side in each embodiment of the present invention.

13A is a diagram illustrating a modified example of the light receiving unit side in each embodiment of the present invention. FIG. 13B is a diagram illustrating an example of arrangement of an optical filter in the light receiving unit according to each embodiment of the present invention. 14 shows another example of the arrangement of the optical filter in the light receiving unit according to each embodiment of the present invention.

FIG. 14 is a conceptual diagram of a conventional range finder.

FIG. 15 is a configuration diagram of a conventional range finder.

[Explanation of symbols]

 Reference Signs List 11 optical pattern generation unit (A) 12 optical pattern generation unit (B) 13 half mirror 14 lens 15 half mirror (A) 16 half mirror (B) 17 optical filter (A) 18 image sensor (A) 19 optical filter (B) 20) Image sensor (B) 21 Image sensor (C) 22 Optical pattern A signal processing circuit 23 Optical pattern B signal processing circuit 24 Distance calculator 30 Light source 31 Optical filter 32 Optical modulator 33 Emitting lens

Claims (6)

[Claims] A first optical modulator that generates an optical pattern having a different light transmittance depending on a position; a second optical modulator that generates an optical pattern different from the first optical modulator; First and second light sources for inputting light having different wavelength characteristics to each of the first and second optical modulators, and optical patterns output from the first and second optical modulators are projected. A plurality of optical filters, each of which receives light from a subject and extracts wavelength components corresponding to the wavelength characteristics of the first and second light sources; and a plurality of image sensors arranged corresponding to the plurality of optical filters. A real-time range finder comprising: a distance calculating unit that calculates a distance to a subject from a value of each pixel of image data obtained from each image sensor and a geometric arrangement between the image sensor and the light source. 2. A first optical modulator for generating an optical pattern having a different light transmittance depending on a position, a second optical modulator for generating an optical pattern different from the optical modulator, and the first and second optical modulators. First and second light sources for inputting light having different wavelength characteristics to each of the second light modulators, and a pattern light operation for projecting light patterns from the first and second light modulators to a subject And a diffused light operation for projecting a plurality of lights having different wavelength characteristics to the subject with a uniform light intensity distribution in a time-division manner. The light from the projected subject is incident on the first,
A plurality of optical filters for extracting wavelength components corresponding to the wavelength characteristics of the second light source; a plurality of image sensors arranged corresponding to the plurality of optical filters; and The surface reflectance correction coefficient of the subject is calculated from the value of each pixel of the obtained image data, and the value of each pixel of the image data obtained from each image sensor during the pattern light operation, the image sensor, and the light source. A real-time range finder, comprising: a distance calculator for calculating a distance to a subject from the geometrical arrangement of (1) and the reflectance correction coefficient. 3. A first optical modulator for generating an optical pattern having a different light transmittance depending on a position, a second optical modulator for generating an optical pattern different from the optical modulator, and the first and second optical modulators. First and second light sources for inputting light having different wavelength characteristics to each of the second light modulators, and light from the subject on which the light patterns output from the first and second light modulators are projected. An image sensor that receives light, a plurality of optical filters each having a wavelength characteristic corresponding to the wavelength characteristics of the first and second light sources and arranged so as to be spatially multiplexed on the image sensor; And a distance calculation unit that calculates the distance to the subject from the value of each pixel of the image data in the light region of each type of wavelength obtained in and the geometrical arrangement between the image sensor and the light source. Real-time range finder. 4. A first optical modulator for generating an optical pattern having a different light transmittance depending on a position, a second optical modulator for generating an optical pattern different from the optical modulator, and the first and second optical modulators. First and second light sources for inputting light having different wavelength characteristics to each of the second light modulators, and a pattern light operation for projecting light patterns from the first and second light modulators to a subject And a diffused light operation for projecting a plurality of lights having different wavelength characteristics to the subject with a uniform light intensity distribution in a time-division manner. An image sensor that receives light from the projected object, and a plurality of image sensors each having a wavelength characteristic corresponding to the wavelength characteristic of the first and second light sources and arranged so as to be spatially multiplexed on the image sensor. An optical filter and an image obtained from the image sensor during the diffused light operation The surface reflectance correction coefficient of the subject is calculated from the value of each pixel of the data, and the value of each pixel of the image data obtained from the image sensor during the pattern light operation and the geometrical arrangement of the image sensor and the light source A real-time range finder, comprising: a distance calculation unit that calculates a distance to a subject from the surface reflectance correction coefficient and the surface reflectance correction coefficient. 5. A light source unit for spatially sweeping slit light projected on a subject, and an optical filter for extracting light from the subject swept into the slit light and extracting a wavelength component matched to the wavelength characteristic of the slit light. An image sensor arranged corresponding to the optical filter; a light source unit control means for changing a light intensity change pattern of the light source in the first sweep and the second sweep by the slit light; Calculating the emission angle of the slit light at each position of the image from the output of the image sensor and the output of the image sensor for the second sweep;
A real-time range finder including a distance calculation unit that calculates a distance to a subject at each position of an image. 6. The light source unit emits a specific light pattern on a subject at a time by using an optical modulator having a different light transmittance depending on a position, instead of the slit light sweeping operation. The real-time range finder according to claim 5, wherein