JP2003014422A - Real time range finder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily perform a distance measurement in real time by use of a known technique without using a special sensor as time measuring function is imparted to each photosensor. SOLUTION: In this real time range finder, lights having different wavelength characteristics are incident on a first optical modulator 32 having a light transmittance varied depending on position and a second optical modulator having a light transmittance different from that of the first optical modulator 32, their optical outputs are composed and projected to the same subject OB to take the image by use of an optical filter 31 for extracting the wavelength components of first and second light source 30, respectively. This range finder comprises a distance calculation part for calculating the distance to the subject OB from the value of each pixel in two or more image data obtained by the imaging and the geometric arrangement of image pickup elements 18 and 20 with the light sources 30.

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 measuring principles have been developed. For example, as shown in FIG. 14, a vertically long linear light (slit light) is applied to an object, which is a subject, and is swept in the horizontal direction. Measure the dimensional position.

FIG. 15 shows an example of the structure of a range finder which adopts the above measurement principle. In the range finder shown in the figure, the light from the light source 1 is made into a long linear light by the slit 2, and the projection direction of this is swept horizontally with respect to the subject 4 by the 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 changed from the timing measuring unit 7 to the distance calculating unit 8
To the photosensor 6 and the elapsed time from the sweep start time until the light reaches each photosensor 6 is measured. This makes it possible to know the projection direction θ of the slit light when the light reaches each photosensor 6. 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 based on 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 range finder as described above measures the time when the light reaches each photo sensor in the photo sensor portion, it has a time measuring function for measuring the time in each photo sensor. I had to have it. Further, in order to obtain the resolution of a general range image, it is necessary to increase the resolution of the photo sensor. Therefore, it is necessary to integrate the photosensor array into an IC and to provide a time measuring circuit around each photosensor, which is a considerably large integration. Therefore, in order to realize the system, a dedicated IC must be manufactured, which is difficult to realize.

The present invention has been made in view of the above circumstances, and it is possible to easily use the existing technology without using a special sensor having a time measuring function in each photosensor. It is intended to provide a real-time range finder capable of measuring distance in real time.

[0006]

In order to achieve the above-mentioned object, the present invention provides a first light transmission device having a different light transmittance depending on the position.
Of the optical modulator and the second optical modulator having a different light transmittance from the optical modulator, light with different wavelength characteristics is made incident, and the optical outputs thereof are combined and projected to the same subject, First, second
An image is captured using an optical filter for extracting the wavelength component of each of the light sources, and a distance calculator 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. It is a real-time range finder characterized by having.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to the first aspect of the present invention is different from a first optical modulator for generating an optical pattern having a different light transmittance depending on a position, and the first optical modulator. A second optical modulator that generates an optical pattern; first and second light sources that make light having different wavelength characteristics incident on the first and second optical modulators; and the first and second optical modulators. A plurality of optical filters that respectively enter the light from the subject onto which the light pattern output from the optical modulator is projected and that extract the wavelength components that match the wavelength characteristics of the first and second light sources; A plurality of image pickup elements arranged corresponding to the optical filter, the value of each pixel of the image data obtained from each image pickup element, and the geometrical arrangement of the image pickup element and the light source, and the distance to the subject. A real-time range filter including a distance calculation unit for calculating A Sunda, 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, a first optical modulator for producing an optical pattern having a different light transmittance depending on a position and a second optical modulator for producing an optical pattern different from the optical modulator are provided. Optical modulator, first and second light sources for injecting lights having different wavelength characteristics to the first and second optical modulators, and optical patterns of the first and second optical modulators. Light source control means for alternately time-divisionally performing a pattern light operation for projecting light on a subject and a diffuse light operation for projecting a plurality of lights having different wavelength characteristics on the subject with a uniform light intensity distribution, and the pattern. A plurality of optical filters that respectively enter the light from the subject on which the light is projected by the optical operation and the diffused light operation and extract the wavelength components matched with the wavelength characteristics of the first and second light sources, and the plurality of optical filters. A plurality of imaging elements arranged corresponding to the optical filter, The surface reflectance correction coefficient of the subject is calculated from the value of each pixel of the image data obtained from each image sensor during the diffuse light operation, and each pixel of the image data obtained from each image sensor during the pattern light operation. Is a real-time range finder that includes a distance calculation unit that calculates a distance to a subject from the value of, the geometrical arrangement of the image sensor and the light source, and the reflectance correction coefficient, and the reflectance of the subject surface. Even if the characteristic depends on the wavelength, the distance can be measured.

According to a third aspect of the present invention, a first optical modulator for generating an optical pattern having a different light transmittance depending on a position and a second optical modulator for generating an optical pattern different from the optical modulator are provided. Output from the first and second light modulators, and the first and second light sources that enter light having different wavelength characteristics to the first and second light modulators, respectively. And an image pickup element for receiving light from a projected object having a light pattern and wavelength characteristics matched with the wavelength characteristics of the first and second light sources, respectively, and arranged so as to be spatially multiplexed on the image pickup element. A plurality of optical filters, the value of each pixel of the image data in the light region of each of a plurality of types of wavelengths acquired by the image sensor, and the geometrical arrangement of the image sensor and the light source to the object. A real-time range filter including a distance calculator that calculates a distance. A Sunda, performing an operation such as to obtain a distance image of the object only by providing a single image sensor.

According to a fourth aspect of the present invention, a first optical modulator for producing an optical pattern having a different light transmittance depending on a position and a second optical modulator for producing an optical pattern different from the optical modulator. Optical modulators, first and second light sources for injecting light having different wavelength characteristics to the first and second optical modulators, and light from the first and second optical modulators. Light source control means for alternately time-divisionally performing a pattern light operation for projecting a pattern on a subject and a diffuse light operation for projecting a plurality of lights having different wavelength characteristics on the subject with a uniform light intensity distribution; An image pickup device that receives light from a subject on which light is projected by a pattern light operation and a diffused light operation, and wavelength characteristics that match the wavelength characteristics of the first and second light sources, respectively, are provided on the image pickup element. A plurality of optical filters arranged so as to be spatially multiplexed, Sometimes the surface reflectance correction coefficient of the subject is calculated from the value of each pixel of the image data obtained from the image pickup device, and the value of each pixel of the image data obtained from the image pickup device at the time of the pattern light operation and the image pickup device. A real-time range finder comprising: a geometrical arrangement with the light source; and a surface reflectance correction coefficient to calculate a distance to a subject, the reflectance characteristic of the subject surface depending on wavelength. Even in such a case, there is an effect that the distance can be measured with one image sensor.

According to a fifth aspect of the present invention, there is provided a light source section for spatially sweeping slit light projected on a subject,
An optical filter that receives light from a subject swept by the slit light and extracts a wavelength component that matches the wavelength characteristic of the slit light, an image sensor arranged corresponding to the optical filter, and a first slit light Light source control means for making the change pattern of the light intensity of the light source different between the first sweep and the output of the image pickup device for the first sweep and the second sweep.
Is a real-time range finder including a distance calculator that calculates the emission angle of the slit light at each position of the image from the output of the image sensor with respect to the sweep, and thereby calculates the distance to the subject at each position of the image, It is possible to measure the distance without measuring the light receiving timings of the plurality of photosensors.

According to a sixth aspect of the present invention, in the invention according to the fifth aspect, in the real-time range finder, the light source section is located on the subject by using an optical modulator having a light transmittance different depending on the position. By projecting a specific light pattern at a time, the sweep operation of the slit light is replaced, and the distance measurement can be performed by one projecting operation.

Embodiments 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.
3 is a configuration diagram of a real-time range finder according to the embodiment of FIG. In the real-time range finder of the first embodiment, the optical pattern generation unit (A) 11 and the optical pattern generation unit (B) 12 generate optical patterns having different light intensity distributions and wavelength characteristics, and the half mirror 13 synthesizes them. And illuminates the subject OB. Further, the lens 14 condenses the reflected light from the object OB and separates and receives each reflected light corresponding to the optical output of the optical pattern generation unit (A) 11 and the optical pattern generation unit (B) 12. is doing. Specifically, the reflected light from the object OB that has entered the lens 14 is reflected by the half mirror (A) 1
5 and further guides the reflection component of the half mirror (A) 15 to another half mirror (B) 16. An optical filter (A) 17 and an image sensor (A) 18 are arranged on the transmission side optical axis of the half mirror (A) 15, and an optical filter (B) is arranged on the reflection side optical axis of the half mirror (B) 16. ) 19 and the image sensor (B) 20 are arranged.

An image pickup device (C) 21 is arranged on the transmission side optical axis of the half mirror (B) 16 so that light in the visible light region can be received and a video signal of the object OB can be output. .

An optical pattern A signal processing circuit 22 is connected to the image output terminal of the image pickup device (A) 18, and the image pickup device (B) 20 is connected.
The optical pattern B signal processing circuit 23 is connected to the video output terminal of the. 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 the video output terminal of the image pickup device (C) 21 to obtain a texture image.

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

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 provided behind the optical filter 31 when viewed from the light source 30.
And the exit lens 33 are arranged. Optical filter 31
Has a transmittance characteristic of transmitting only the component near the wavelength λ _A. The light modulator 32 is composed of, for example, a liquid crystal filter, and has 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. . In addition, another optical pattern generation unit (B) 1
2 has the same configuration as the optical pattern generation unit (A) 11, but the transmission wavelength band of the optical filter is different. The optical filter provided in the optical pattern generator (B) 12 has a transmittance characteristic such that the transmittance peaks at a wavelength λ _B different from the wavelength λ _A. In addition, the optical pattern generation unit (B) 12
The optical modulator has a light transmittance distribution obtained by inverting the distribution state of the optical modulator 32.

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

First, the operation of the optical pattern generators (A) and (B) will be described. In the light pattern generation unit (A) 11, the light source 30
The light output from the light passes through the optical filter 31 and
Only light near the wavelength λ _A as shown in (a) is extracted. Then, the optical pattern having the wavelength characteristic on the wavelength λ _A side shown in FIG. 4A and having the light intensity distribution as shown by the solid line in FIG. Light having different intensities is emitted by the emission lens 33 to the half mirror 13.
Incident on. On the other hand, similarly, the optical pattern generation unit (B) 12 similarly has the wavelength characteristic on the wavelength λ _B side shown in FIG. 4A and has the light intensity distribution as shown by the broken line in FIG. 3B. The pattern is generated by the optical filter and the optical modulator, and enters the half mirror 13 through the emission lens.

These two optical pattern generators (A) and (B)
Light emitted from the half mirror 13 is combined, and one of the combined lights is inverted in the horizontal direction by the half mirror 13. Therefore, as shown in FIG. Those of _A and λ _B are projected on the object OB.

The emitted light strikes 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, incident on (C) 21. The optical filter (A) 17 arranged in front of the image sensor (A) 18 transmits a component in a predetermined region including the wavelength λ _A but transmits a predetermined region including the wavelength λ _B as shown in FIG. 4B. The component of is set to the characteristic of cutting. Further, as shown in FIG. 4B, the optical filter (B) 19 arranged in front of the image sensor (B) 20 transmits a component in a predetermined region including the wavelength λ _B but includes the wavelength λ _A. The region components are set to have characteristics such that they are cut. Therefore, the optical pattern generation unit (A) 11,
The image sensor (A) 18, the light of the optical pattern generation unit (B) 12,
(B) 20 and 20 can separate and receive light.

Here, the light intensity ratio f at each pixel of the outputs of the image pickup device (A) 18 and the image pickup device (B) 20 changes as shown in FIG. 5 with respect to the horizontal angular position θ of the optical pattern. . The ratio of the light intensities is measured by the image pickup 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 of I _A / I _B can be measured. If the function of I _A / I _B is f, then θ ₀ = f-1
(I _A / I _B )).

Next, the distance calculation unit 24 finds the light intensity ratio of each pixel position from the outputs of the optical pattern A signal processing unit 22 and the optical pattern B signal processing unit 23 based on the signal intensity of each pixel, Then, the angle at which the light is emitted is calculated from the characteristics shown in FIG. From this angle and the geometrical positional relationship between the image pickup devices (A) and (B) and the light pattern generation units (A) and (B), the direction of the light emitted from the light pattern generation units (A) and (B) is calculated. Then, based on the principle of triangulation, the three-dimensional position of the portion of the subject OB appearing at the position of each pixel is calculated. As a result, a distance image of the subject OB is obtained. At the same time, the texture image of the subject OB corresponding to the obtained distance image is obtained by the outputs of the image pickup device (C) 21 and the color camera signal processing unit 25.

Up to this point, when the reflectance characteristic of the subject surface does not depend on the wavelength of light, that is, when the subject has a uniform color, or 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 subject are considered to be almost the same at the two wavelengths.

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

However, in the above description, the angle θ₀Ask for
Sometimes they do different calculations. That is, in the case of diffuse light operation,
The optical modulator 32 of the pattern generation units (A) and (B) is the subject OB.
Is set to project a uniform light on the
Is set so that the optical pattern generation unit (A) at this time
(B) The reflected light of the subject of each emitted light is imaged and
Output of the pattern A signal processing unit 22 and the optical pattern B signal processing unit 23.
Force ratio of each photo sensor (each pixel sensor on the image sensor)
For each of the light sources of the subject,
A surface reflectance ratio is prepared and used as a correction coefficient. Next
, The angle θ₀When calculating_A/ I_BTo
Multiply the correction factor, and then f^-1(I _A/ I_B× correction
Coefficient) is calculated for each photo sensor output, and correct light reception
Measure the angle. This allows the light of the surface reflectance of the subject
The error due to the wavelength dependence is corrected, and the
The principle of triangulation based on the geometrical positional relationship of the tongue generator
Calculate the three-dimensional position of the subject.

In the first embodiment, the optical filters arranged on the front surfaces of the image pickup devices (A) 18 and (B) 20 have different optical wavelengths depending on the level of the light wavelength, as shown in FIG. 3B.
The two lights may be separated. In general, the light emitted from the optical pattern generation units (A) 11 and (B) 12 is set to infrared, and the distance is measured by this, and the image sensor (C) 21
Receives light in the visible region, and the color camera signal processing unit 25 images the texture of the subject. However, the image pickup devices (A) 18 and (B) 20 set the optical filter characteristics in the visible region and do not pick up the image at the same time as the image pickup device (C) 21, and the optical pattern generation units (A) 11 and (B) 12 The operation is time-divided, and the imaging element (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 that creates the optical pattern may be replaced by a device that projects a pattern image such as a video projector.

In the first embodiment, if the pattern light is light in the infrared region, the image sensor (C) 21,
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 the time-division processing at the timing other than the time when the slit light is projected. Good.

Further, in the first embodiment, the light source 3
Although 0 is described as a lamp shape, a light source having a wavelength selection characteristic 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 matching them is attached to the image sensor side. The optical filter in the light source section can be omitted.

By setting the wavelengths of the two kinds of light to be very close to each other, if the surface reflectance of the subject does not change abruptly depending on the light wavelength, the diffused light measurement is not performed and the distance is accurately measured. Images can be measured.

In the first embodiment, two types of light sources are used, but two or more types of light sources are used to receive their respective lights independently, and each photosensor combines the respective light intensities. The angle at which the light is emitted may be calculated based on

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

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

In the real-time range finder of this embodiment, the optical filter (C) 42 is arranged in front of the light source (C) 41, and the slit 43 is arranged on the emission side of the optical filter (C) 42. The vertical slit light generated by the slit 43 is applied to the subject OB via the rotating mirror 44. The light source (C) 41 is controlled by the light source controller 45, and the slit 43 is controlled by the slit controller 46. The rotation mirror 44 is controlled by the rotation controller 47. On the other hand, the reflected light from the object OB is reflected by the lens 4
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 of the transmission side of the half mirror (A) 15. Further, the image pickup device (C) 21 is arranged on the optical axis of the half mirror (A) 15 on the reflection side.

An image processing section 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 section 51. Further, 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 of the present embodiment configured as described above will be described below.

First, the 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, and slit light is projected on the object OB.

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

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

The light generated in this way is used as a subject OB.
The reflected light is captured by the image sensor (A) 50. In this case, the exposure is performed without the shutter operation, 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 unit 51 stores the image captured in the field (1) portion shown in FIG. 8B in the memory 52, and simultaneously stores the image captured in the field (2) portion. And refer to the brightness value at the same coordinates in each image. The combination of the brightness value of the image from the first sweep and the brightness value of the image from the second sweep gives a specific angle θ.
Is determined (FIG. 8 (c)). That is, one range image can be obtained in two fields (frames). For example, if the coordinates at time t1 and the x-coordinate of the image at t2 are equal, the luminance (magnitude of the image signal) is measured and L
When it becomes 1 and L2, the value of L1 / L2 is calculated and the result of FIG.
The angle θ is specified by (c). At this time, L1 / L2
The value of the ratio does not depend on the texture pattern (color distribution) on the surface of the subject because the reflected light of the subject to the same light source is captured although the intensity is different. This allows highly accurate estimation of the angle θ.

After that, the distance calculation section 24 obtains the angle θ at each coordinate, calculates the distance from the distance (baseline length) between the rotary mirror 44 and the lens 48 to the object OB by triangulation, and the distance of the entire screen. Information is obtained and output as a range image.

The texture image is obtained by the image pickup device (C) 2
The color camera signal processing unit 25 forms an image signal and outputs it as a texture image. At this time, two texture images can be obtained for one distance image, but either one or both, or an average value or an intermediate value at each pixel may be calculated and output.

As described above, according to the present embodiment, the slit light is swept twice and the change in the light intensity at that time is made different, so that the two sweeps (two fields or two frames) obtained are obtained. ), The projection angle of the slit light of each part of the two images can be uniquely determined without depending on the surface reflectance of the subject, and thus the distance calculation can be easily performed.
It becomes possible once in the field (frame).

In the second embodiment, a lamp-like light source (C) 41 is used. However, if the light source (C) 41 is composed of an infrared LED or an infrared laser, the optical filter (C) 42 can be omitted. You can also

Further, in the second embodiment, the slit pattern is swept in the lateral direction to generate the optical pattern, but the optical pattern generating section as shown in FIG. 2 is used to eliminate the sweeping operation. Good. In this case, instead of the first and second sweeps, the first and second light patterns are radiated in a time division manner, and the image pickup device (A) 18 sequentially captures the reflected light of the subject at the timing. It will be.

(Third Embodiment) FIG. 9 shows a block 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 described above are designated by the same reference numerals.

In the third embodiment, a half mirror (B) 60 is placed 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.
Are 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. Further, the light source is one type of the light source (C) 41, and the optical filter (C) 42 having a wavelength passing characteristic adapted to this is used.

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

First, the sweep of the light source (C) 41 is shown in FIG.
As shown in (a), one field is performed twice in the horizontal direction. When the image pickup by the image pickup device is non-interlaced, one frame is performed twice 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 the second light intensity is increased.
During the sweep, the light intensity is controlled to be gradually weakened (FIG. 10B).

The light generated in this way is used as the subject OB.
To the image pickup device (A) 50, (B) 6
Capture by 2. In this case, the exposure to the image sensor is
The exposure is performed by the shutter operation, and the reflected light of the light scanned in each sweep is set to the image pickup device (A) 50, (B).
The image is accumulated in 62 and the captured image is transferred to the image signal processing unit 63. That is, as shown in FIG.
The exposure time of the swept image pickup device (A) 50 is T1, and the exposure time of the second swept image pickup device (B) 62 is T2. At this time, the image signal processor 63 processes the image captured in the area (1) and the image captured in the area (2) shown in FIG. Refer to the luminance value of. The subsequent operation is similar to that of the second embodiment of the present invention.

The specific angle θ is determined by the combination of the brightness value of the image obtained by the first sweep and the brightness value of the image obtained by the second sweep (FIG. 10 (d)). In other words, two sweep images in one field (frame) are acquired by the shutter operation of the image sensor,
You can get one range image. For example, if the coordinates at time t3 and the x-coordinate of the image at t4 are the same, the brightness (magnitude of the image signal) is measured, and if L3 and L4 are obtained, the value of L3 / L4 is calculated and calculated. By 10 (c),
Specify the angle θ. At this time, the value of the ratio L3 / L4 does not depend on the texture pattern existing on the surface of the subject because the reflected light of the subject to the same light source is captured although the intensity is different.

As a result, also in this embodiment, the angle θ can be estimated with high accuracy. After that, the distance calculation unit 24 obtains the angle θ at each coordinate and calculates the distance from the distance (baseline length) between the rotating mirror 44 and the lens 48 to the object OB by triangulation to obtain the distance information of the entire screen. ,
Output as a range image.

Further, the texture image is the image pickup element (C) 2
The image is picked up by 2, and the color camera signal processing unit 25 forms an image signal, which is output as a texture image.

Further, the two times of the slit light sweep are completed exactly twice in one field (frame) period in FIG. 10, but as shown in FIGS. 11A to 11C, one field (frame) ) A part of the period may be used to perform the high speed sweep. Other operations are the same as those in the third embodiment described above.

As described above, according to the present embodiment, the slit light is swept twice and the change in the light intensity at that time is made different, so that each part of the two images corresponding to the two sweeps obtained is obtained. The slit light projection angle can be uniquely determined without depending on the surface reflectance of the subject, and this makes it possible to easily calculate the distance once per field.

Further, in the present embodiment, the lamp-shaped light source is used, but the optical filter (C) 42 can be omitted if the light source is composed of an infrared LED or an infrared laser.

Further, in the present embodiment, the slit pattern is swept in the lateral direction to generate the optical pattern, but the sweeping operation may be eliminated by using the optical pattern generating section as shown in FIG. In this case, instead of the first and second sweep,
The first and second optical pattern light modulators are prepared and the pattern light is emitted in a time division manner.

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

In the first to third embodiments,
Although a plurality of image pickup devices are combined using a half mirror so that the same visual field can be picked up, as shown in FIG. 12A, the lenses 71 and 72 are connected to the respective image pickup devices (A) 18,
It may be provided in front of (B) 20. Further, as shown in FIG. 12B, the half mirror 73 is arranged in an X-shape, whereby three image pickup devices (A) 18, (B) 20, and (C) 22 are provided.
The incident light may be divided into two. Further, the light may be divided among the three image pickup device cameras by a structure using a dichroic mirror applied to a three-plate image pickup device 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.

Further, in the first embodiment, instead of dividing light of two kinds of wavelengths by using a plurality of image pickup devices, one image pickup device (D) 74 is used as shown in FIG. 13A. Upon receiving light of two types of wavelengths, two types of optical filters A and B are alternately arranged on the surface in a stripe shape as shown in FIG. 13B, and images for two types of wavelengths are multiplexed into one image. May be detected. In this case, the stripes are vertical,
Either side is fine. In addition, 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 with respect to the light of each wavelength decreases.

[0064]

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

[Brief description of 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, and FIG. 3B is a light intensity distribution diagram of an optical pattern that comes from the optical pattern generation unit.

FIG. 4A is a transmittance characteristic diagram of an optical filter included in an optical pattern generation unit, and FIG. 4B is a transmittance characteristic diagram of an optical filter included in a light receiving unit.

FIG. 5 is a relationship diagram of a pattern light emission angle and a pixel intensity ratio in the first embodiment.

FIG. 6 is an explanatory diagram of a time division operation according to the first embodiment.

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

FIG. 8A is a diagram showing a sweeping operation in the light source unit in the second embodiment. FIG. 8B is a relational diagram between sweeping and light intensity in the light source unit in the second embodiment. Of Relation between Light Intensity Ratio and Light Projection Angle in Embodiment

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

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

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

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

13A is a diagram showing a modified example of the light receiving unit side in each embodiment of the present invention. FIG. 13B is a diagram showing an arrangement example of optical filters in the light receiving unit of each embodiment of the present invention. Another example of the arrangement of the optical filter in the light receiving section of each embodiment of the invention is shown.

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

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

[Explanation of symbols] 11 Optical pattern generator (A) 12 Optical pattern generator (B) 13 Half mirror 14 lenses 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 sources 31 Optical filter 32 optical modulator 33 Output lens

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2F065 AA04 AA06 AA19 AA20 AA53                       BB05 BB18 DD02 DD03 FF01                       FF02 FF04 FF09 FF41 FF65                       GG02 GG04 GG07 GG23 HH05                       HH07 JJ03 JJ05 JJ26 LL00                       LL13 LL22 LL53 LL62 MM16                       QQ24 QQ25 QQ31 RR06                 2F112 AA09 BA06 BA11 CA12 DA09                       DA13 DA15 DA25 DA26 DA32                       EA03 FA03 FA21 FA35

Claims (2)

[Claims] 1. A light source unit for spatially sweeping slit light projected onto a subject, and an optical filter for extracting a wavelength component matched with the wavelength characteristic of the slit light by light incident from the subject swept by the slit light. An image pickup element arranged corresponding to the optical filter, a light source section control means for making the change pattern of the light intensity of the light source different between the first sweep and the second sweep by the slit light, and the first sweep The output angle of the slit light at each position of the image is calculated from the output of the image sensor and the output of the image sensor for the second sweep,
A real-time range finder having a distance calculator that calculates the distance to the subject at each position of the image. 2. The light source section, instead of the slit light sweeping operation, uses an optical modulator having a different light transmittance depending on the position to project a specific light pattern on the subject at one time. The real-time range finder according to claim 1.