JP2014021017A - Information acquisition device and object detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information acquisition device capable of appropriately acquiring distance information, and an object detection device.SOLUTION: The information acquisition device has a first processing route for searching for a displacement position on an actual measurement dot pattern, of an entire segment area S to acquire distance information for the entire segment area S (S108 to S112). Further, the information acquisition device has a second processing route for searching for displacement positions on the actual measurement dot pattern, of divided segment areas Sa and Sb to acquire distance information for the divided segment areas Sa and Sb (S104 to S107). The information acquisition device determines whether dots reflected from positions at different distances are included in a comparison area on the actual measurement dot pattern, which is to be collated with the entire segment area S, or not on the basis of a difference between pixel displacement amounts Na and Nb to select one of the first processing route and the second processing route (S103).

Description

  The present invention relates to an object detection apparatus that detects an object in a target area based on the state of reflected light when light is projected onto the target area, and an information acquisition apparatus suitable for use in the object detection apparatus.

  Conventionally, object detection devices using light have been developed in various fields. An object detection apparatus using a so-called distance image sensor can detect not only a planar image on a two-dimensional plane but also the shape and movement of the detection target object in the depth direction. In such an object detection apparatus, light in a predetermined wavelength band is projected from a laser light source or an LED (Light Emitting Diode) onto a target area, and the reflected light is received by a light receiving element such as a CMOS image sensor. Various types of distance image sensors are known.

  In a distance image sensor of a type that irradiates a target region with laser light having a predetermined dot pattern, reflected light from the target region of laser light having a dot pattern is received by a light receiving element. Then, based on the light receiving position of the dot on the light receiving element, the distance to each part of the detection target object (irradiation position of each dot on the detection target object) is detected using triangulation (for example, Patent Literature 1, Non-Patent Document 1).

JP 2012-32379 A

19th Annual Conference of the Robotics Society of Japan (September 18-20, 2001) Proceedings, P1279-1280

  In the object detection apparatus, a reflection plane is set in advance at a predetermined distance of the target area, and a reference dot pattern obtained by imaging the dot pattern irradiated on the reflection plane is held in the memory. This reference dot pattern is collated with the actually measured dot pattern captured during actual operation. Specifically, the reference dot pattern is divided into segment areas of a predetermined size, and the positions of the dots included in the segment areas on the measured dot pattern are searched. In this search, the degree of matching between the dots in the segment area and the dots in the measured dot pattern is obtained.

  However, the actually measured dot pattern captured during actual operation may include dots reflected by a surface such as a room floor or wall whose distance from the object detection device continuously changes. In this case, since the actually measured dot pattern includes dots reflected by the surfaces at a plurality of distances, dots from different distances can be included in an area corresponding to one segment area. If this happens, matching between the dots in the segment area and the dots in the measured dot pattern becomes unstable, and there is a possibility that distance acquisition cannot be performed stably.

  The present invention has been made in view of this point, and provides an information acquisition device and an object detection device capable of stably performing distance detection.

  A first aspect of the present invention relates to an information acquisition device. The information acquisition apparatus according to this aspect is configured to project a laser beam emitted from a laser light source onto a target area with a predetermined dot pattern, and to be arranged laterally apart from the projection optical system by a predetermined distance. A light receiving optical system that images the target area with an image sensor, a reference dot pattern that is imaged by the light receiving optical system when the laser beam is irradiated onto a reference surface, and an image that is captured by the image sensor during measurement. A distance acquisition unit that acquires distance information related to a distance to an object included in the target area based on the measured dot pattern. The distance acquisition unit searches for a displacement position of the segment area set in the reference dot pattern on the measured dot pattern, and acquires the distance information for the segment area based on the searched displacement position. A displacement position on the measured dot pattern of the divided segment area obtained by dividing the first processing route and the segment area is searched, and the distance information with respect to the segment area is acquired based on the searched displacement position. And a second processing route. The distance acquisition unit is a predetermined unit for determining whether or not a dot reflected from a position at a different distance is included in a comparison area on the actual measurement dot pattern that is collated with the segment area during the search. The distance information is acquired by selecting either the first processing route or the second processing route based on whether or not the determination condition is satisfied.

  A 2nd aspect of this invention is related with an object detection apparatus. The object detection device according to this aspect includes the information acquisition device according to the first aspect and an object detection unit that detects a predetermined target object based on the distance information.

  ADVANTAGE OF THE INVENTION According to this invention, the information acquisition apparatus and object detection apparatus which can acquire distance information appropriately can be provided.

  The effects and significance of the present invention will become more apparent from the following description of embodiments. However, the embodiment described below is merely an example when the present invention is implemented, and the present invention is not limited to the following embodiment.

It is a figure which shows the structure of the object detection apparatus which concerns on embodiment. It is a figure which shows the structure of the information acquisition apparatus and information processing apparatus which concern on embodiment. It is a figure which shows the irradiation state of the laser beam with respect to the target area | region which concerns on embodiment, and the light reception state of the laser beam on an image sensor. It is a figure explaining the production | generation method of the reference pattern which concerns on embodiment. It is a figure explaining the distance detection method which concerns on embodiment. It is a figure explaining the situation where multiple parallaxes concerning an embodiment are included. It is a figure which shows the example of the distance acquisition result which concerns on a comparative example. It is a figure which shows the example of a division | segmentation of the functional block and segment area | region of the distance acquisition part which concerns on embodiment. It is a flowchart concerning the presence determination of multiple parallax and the process of distance acquisition which concern on embodiment. It is a figure which shows the example of the distance acquisition result which concerns on embodiment. It is a figure which shows the circuit block of distance acquisition which concerns on embodiment. It is a flowchart concerning the presence determination and distance acquisition processing of multiple parallaxes according to a modified example. It is a figure which shows the example of a division | segmentation of the segment area | region which concerns on the example of a change. It is a flowchart concerning the presence determination and distance acquisition processing of multiple parallaxes according to a modified example. It is a flowchart concerning the presence determination and distance acquisition processing of multiple parallaxes according to a modified example.

  Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the present invention is applied to an information acquisition apparatus of a type that irradiates a target area with laser light having a predetermined dot pattern.

  First, FIG. 1 shows a schematic configuration of an object detection apparatus 1 according to the present embodiment. As shown in the figure, the object detection device 1 includes an information acquisition device 2 and an information processing device 3. The television 4 is controlled by a signal from the information processing device 3.

  The information acquisition device 2 projects infrared light over the entire target area, and receives the reflected light with a CMOS image sensor, whereby the distance between each part of the object in the target area (hereinafter referred to as “three-dimensional distance information”). To get. The acquired three-dimensional distance information is sent to the information processing apparatus 3 via the cable 5.

  The information processing device 3 is, for example, a television control controller, a game machine, a personal computer, or the like. The information processing device 3 detects an object in the target area based on the three-dimensional distance information received from the information acquisition device 2, and controls the television 4 based on the detection result.

  For example, the information processing device 3 detects a person based on the received three-dimensional distance information and detects the movement of the person from the change in the three-dimensional distance information. For example, when the information processing device 3 is a television control controller, the information processing device 3 detects the person's gesture from the received three-dimensional distance information and outputs a control signal to the television 4 in accordance with the gesture. The application program to be installed is installed.

  For example, when the information processing device 3 is a game machine, the information processing device 3 detects the person's movement from the received three-dimensional distance information, and displays a character on the television screen according to the detected movement. An application program that operates and changes the game battle situation is installed.

  FIG. 2 is a diagram illustrating the configuration of the information acquisition device 2 and the information processing device 3.

  The information acquisition apparatus 2 includes a projection optical system 100 and a light receiving optical system 200 as a configuration of the optical unit. The projection optical system 100 and the light receiving optical system 200 are arranged in the information acquisition device 2 so as to be aligned in the X-axis direction.

  The projection optical system 100 includes a laser light source 110, a collimator lens 120, a mirror 130, and a diffractive optical element (DOE) 140. The light receiving optical system 200 includes an aperture 210, an imaging lens 220, a filter 230, and a CMOS image sensor 240. In addition, the information acquisition apparatus 2 includes a CPU (Central Processing Unit) 21, a laser driving circuit 22, an imaging signal processing circuit 23, an input / output circuit 24, and a memory 25 as a circuit unit.

  The laser light source 110 outputs laser light in a narrow wavelength band having a wavelength of about 830 nm in a direction away from the light receiving optical system 200 (X-axis negative direction). The collimator lens 120 converts the laser light emitted from the laser light source 110 into substantially parallel light.

  The mirror 130 reflects the laser light incident from the collimator lens 120 side in the direction toward the DOE 140 (Z-axis direction).

  The DOE 140 has a diffraction pattern on the incident surface. Due to the diffractive action of this diffraction pattern, the laser light incident on the DOE 140 is converted into laser light having a predetermined dot pattern and irradiated onto the target area.

  The diffraction pattern of the DOE 140 has, for example, a structure in which a step type diffraction hologram is formed in a predetermined pattern. The diffraction hologram is adjusted in pattern and pitch so as to convert the laser light that has been made substantially parallel light by the collimator lens 120 into a laser light having a dot pattern. The DOE 140 irradiates the target region with the laser beam incident from the mirror 130 as a laser beam having a dot pattern that spreads radially.

  The laser light reflected from the target area enters the imaging lens 220 via the aperture 210.

  The aperture 210 stops the light from the outside so as to match the F number of the imaging lens 220. The imaging lens 220 collects the light incident through the aperture 210 on the CMOS image sensor 240. The filter 230 is a band-pass filter that transmits light in the infrared wavelength band including the emission wavelength (about 830 nm) of the laser light source 110 and cuts the wavelength band of visible light.

  The CMOS image sensor 240 receives the light collected by the imaging lens 220 and outputs a signal (charge) corresponding to the amount of received light to the imaging signal processing circuit 23 for each pixel. Here, in the CMOS image sensor 240, the output speed of the signal is increased so that the signal (charge) of the pixel can be output to the imaging signal processing circuit 23 with high response from the light reception in each pixel.

  The CPU 21 controls each unit according to a control program stored in the memory 25. With this control program, the CPU 21 is provided with the functions of a laser control unit 21a for controlling the laser light source 110 and a distance acquisition unit 21b for generating three-dimensional distance information.

  The laser drive circuit 22 drives the laser light source 110 according to a control signal from the CPU 21.

  The imaging signal processing circuit 23 controls the CMOS image sensor 240 to sequentially take in the signal (charge) of each pixel generated by the CMOS image sensor 240 for each line at a predetermined imaging interval. Then, the captured signals are sequentially output to the CPU 21. Based on the signal (imaging signal) supplied from the imaging signal processing circuit 23, the CPU 21 calculates the distance from the information acquisition device 2 to each part of the detection target by processing by the distance acquisition unit 21b. The input / output circuit 24 controls data communication with the information processing device 3.

  The information processing apparatus 3 includes a CPU 31, an input / output circuit 32, and a memory 33. In addition to the configuration shown in the figure, the information processing apparatus 3 is configured to communicate with the television 4 and to read information stored in an external memory such as a CD-ROM and install it in the memory 33. However, the configuration of these peripheral circuits is not shown for the sake of convenience.

The CPU 31 controls each unit according to a control program (application program) stored in the memory 33. With this control program, the CPU 31 is provided with the functions of an object detection unit 31a for detecting an object in the image and a function control unit 31b for controlling the function of the television 4 according to the movement of the object. . Such a control program is, for example,
It is read from the CD-ROM by a drive device (not shown) and installed in the memory 33.

  The object detection unit 31a extracts the shape of the object in the image from the three-dimensional distance information supplied from the information acquisition device 2, and detects the movement of the extracted object shape. Here, the object detection unit 31a generates a binarized image in order to extract only the planar shape of the object from the three-dimensional distance information supplied from the information acquisition device 2 based on the threshold regarding the distance. Thereafter, the generated binarized image is compared with the object shape extraction template for extracting the object shape stored in the memory 33, and the object shape to be extracted from the motion and the object shape in the three-dimensional distance information are compared. Specify the center position of. In this way, the object detection unit 31a detects the movement of the object by tracking the distance information of the center position of the specified object shape every predetermined time.

  For example, when the control program is a game program, the function control unit 31b executes a process for operating a character on the television screen in accordance with a human movement (gesture) detected by the object detection unit 31a. When the control program is a program for controlling the function of the television 4, the function control unit 31 b performs the function (channel switching) of the television 4 based on a signal from the object detection unit 31 a according to a person's movement (gesture). And volume adjustment, etc.) are executed.

  The input / output circuit 32 controls data communication with the information acquisition device 2.

  The projection optical system 100 and the light receiving optical system 200 are installed side by side with a predetermined distance in the X axis direction so that the projection center of the projection optical system 100 and the imaging center of the light receiving optical system 200 are aligned on a straight line parallel to the X axis. Is done. The installation interval between the projection optical system 100 and the light receiving optical system 200 is set according to the distance between the information acquisition device 2 and the reference plane of the target area.

  Next, a method for acquiring three-dimensional distance information by the information acquisition device 2 will be described.

  FIG. 3A is a diagram schematically showing the irradiation state of the laser light on the target region, and FIG. 3B is a diagram schematically showing the light receiving state of the laser light in the CMOS image sensor 240. For convenience, FIG. 3B shows a flat surface (screen) in the target area and a light receiving state when a person is present in front of the screen.

  As shown in FIG. 3A, the projection optical system 100 irradiates a target region with laser light having a dot pattern (hereinafter, the entire laser light having this pattern is referred to as “DP light”). . In FIG. 3A, the light flux region of DP light is indicated by a solid line frame. In the light flux of DP light, dot regions (hereinafter simply referred to as “dots”) generated by the diffraction action by the DOE 140 are scattered according to the dot pattern by the diffraction action by the DOE 140.

  When a flat surface (screen) exists in the target area, DP light reflected thereby is distributed on the CMOS image sensor 240 as shown in FIG.

In FIG. 3B, the entire DP light receiving area on the CMOS image sensor 240 is indicated by a broken line frame, and the DP light receiving area incident on the imaging effective area of the CMOS image sensor 240 is indicated by a solid line frame. Has been. The effective imaging area of the CMOS image sensor 240 is an area where the CMOS image sensor 240 receives a DP light and outputs a signal as a sensor, and has a size of, for example, VGA (horizontal 640 pixels × vertical 480 pixels). . In addition, the light of Dt0 on the target area shown in FIG. 9A enters the position of Dt′0 shown in FIG. The figure of the person in front of the screen is C
On the MOS image sensor 240, imaging is performed with the top, bottom, left and right reversed.

  Here, the distance detection method will be described with reference to FIGS.

  FIG. 4 is a diagram for explaining a reference pattern setting method used in the distance detection method.

  As shown in FIG. 4A, a flat reflection plane RS perpendicular to the Z-axis direction is disposed at a position at a predetermined distance Ls from the projection optical system 100. The emitted DP light is reflected by the reflection plane RS and enters the CMOS image sensor 240 of the light receiving optical system 200. Thereby, an electrical signal for each pixel in the effective imaging area is output from the CMOS image sensor 240. The output electric signal value (pixel value) for each pixel is developed on the memory 25 of FIG.

  Hereinafter, an image including all pixel values obtained by reflection from the reflection surface RS is referred to as a “reference image”, and the reflection surface RS is referred to as a “reference surface”. Then, as shown in FIG. 4B, a “reference pattern region” is set on the standard image. FIG. 4B shows a state in which the light receiving surface is seen through in the positive direction of the Z axis from the back side of the CMOS image sensor 240. The same applies to the drawings after FIG.

  A plurality of segment areas having a predetermined size are set for the reference pattern area set in this way. The size of the segment area is determined in consideration of the contour extraction accuracy of the object based on the obtained distance information, the load of the calculation amount of distance detection for the CPU 21, and the error occurrence rate by the distance detection method described later.

  With reference to FIG.4 (c), the segment area | region set to a reference pattern area | region is demonstrated. In FIG. 4C, for the sake of convenience, the size of each segment area is indicated by 9 pixels wide × 9 pixels high, and the center pixel of each segment area is indicated by a cross.

  As shown in FIG. 4C, the segment areas are set such that adjacent segment areas are arranged at intervals of one pixel in the X-axis direction and the Y-axis direction with respect to the reference pattern area. That is, a certain segment area is set at a position shifted by one pixel with respect to a segment area adjacent to the segment area in the X-axis direction and the Y-axis direction. At this time, each segment area is dotted with dots in a unique pattern. Therefore, the pattern of pixel values in the segment area is different for each segment area. The narrower the interval between adjacent segment areas, the greater the number of segment areas included in the reference pattern area, and the resolution of distance detection in the in-plane direction (XY plane direction) of the target area is enhanced.

  Thus, information on the position of the reference pattern area on the CMOS image sensor 240, pixel values (reference patterns) of all pixels included in the reference pattern area, and segment area information set for the reference pattern area are shown in FIG. 2 memory 25. These pieces of information stored in the memory 25 are hereinafter referred to as “reference templates”.

  The CPU 21 in FIG. 2 refers to the reference template when calculating the distance from the projection optical system 100 to each part of the detection target object. When calculating the distance, the CPU 21 calculates the distance to each part of the object based on the shift amount of the dot pattern in each segment area obtained from the reference template.

For example, as shown in FIG. 4A, when an object is present at a position closer than the distance Ls, DP light (DPn) corresponding to a predetermined segment area Sn on the reference pattern is reflected by the object, and the segment area Sn. It is incident on a different region Sn ′. Since the projection optical system 100 and the light receiving optical system 200 are adjacent to each other in the X-axis direction, the displacement direction of the region Sn ′ with respect to the segment region Sn is parallel to the X-axis. In the case of FIG. 4A, since the object is at a position closer than the distance Ls, the region Sn ′ is displaced in the positive direction of the X axis with respect to the segment region Sn. If the object is at a position farther than the distance Ls, the region Sn ′ is displaced in the negative X-axis direction with respect to the segment region Sn.

  Based on the displacement direction and displacement amount of the region Sn ′ with respect to the segment region Sn, the distance Lr from the projection optical system 100 to the part of the object irradiated with DP light (DPn) is triangulated using the distance Ls. Calculated based on Similarly, the distance from the projection optical system 100 is calculated for the part of the object corresponding to another segment area. The details of this calculation method are described in, for example, Non-Patent Document 1 (The 19th Annual Conference of the Robotics Society of Japan (September 18-20, 2001) Proceedings, P1279-1280).

  In this distance calculation, it is detected to which position the segment area Sn of the reference template has been displaced during actual measurement. This detection is performed by collating the dot pattern obtained from the DP light irradiated onto the CMOS image sensor 240 at the time of actual measurement with the dot pattern included in the segment region Sn. Hereinafter, an image made up of all the pixel values obtained from the DP light irradiated to the imaging effective area on the CMOS image sensor 240 at the time of actual measurement will be referred to as “measured image”. The effective imaging area of the CMOS image sensor 240 at the time of actual measurement is, for example, the size of VGA (horizontal 640 pixels × vertical 480 pixels), as in the case of acquiring the reference image.

  FIGS. 5A to 5E are diagrams for explaining such a distance detection method. FIG. 5A is a diagram showing a reference pattern area set in a standard image on the CMOS image sensor 240, and FIG. 5B is a diagram showing an actually measured image on the CMOS image sensor 240 at the time of actual measurement. FIG. 5C to FIG. 5E are diagrams for explaining a collation method between the DP light dot pattern included in the actual measurement image and the dot pattern included in the segment area of the reference template. For convenience, FIGS. 5 (a) and 5 (b) show only a part of the segment areas, and FIGS. 5 (c) to 5 (e) show the size of each segment area. It is shown by pixel × 9 pixels vertically. 5B, for the sake of convenience, as shown in FIG. 4B, there is a person in front of the reference plane as a detection target object, and an image of the person is reflected. It is shown.

  When searching for the displacement position at the time of actual measurement of the segment area Si in FIG. 5A, as shown in FIG. 5B, the search area Ri is set for the segment area Si on the actual measurement image. The search area Ri has a predetermined width in the X-axis direction. The segment area Si is sent one pixel at a time in the search area Ri in the X-axis direction, and the dot pattern of the segment area Si is compared with the dot pattern on the measured image at each feed position. Hereinafter, a region corresponding to each feed position on the actually measured image is referred to as a “comparison region”. A plurality of comparison areas having the same size as the segment area Si are set in the search area Ri, and the comparison areas adjacent in the X-axis direction are shifted by one pixel from each other.

  In FIG. 5D, the pixel position (center pixel position) on the measured image corresponding to the pixel position of the segment region Si on the reference image is shifted from the position shifted by x pixels in the X axis negative direction to x in the X axis positive direction. The search area Ri is set so that the segment area Si is sent in a pixel shifted range (hereinafter referred to as “search range L0”).

  At the time of distance detection, the segment area Si is fed one pixel at a time in the X-axis direction in the search area Ri, and at each feed position, the dot pattern of the segment area Si stored in the reference template and the dot pattern of the DP light of the measured image The degree of matching is required. As described above, the segment area Si is sent only in the X-axis direction in the search area Ri as described above. Normally, the dot pattern of the segment area set by the reference template is a predetermined value in the X-axis direction at the time of actual measurement. This is because the displacement occurs only within the range.

  At the time of actual measurement, depending on the position of the detection target object, the dot pattern corresponding to the segment area may protrude from the actual measurement image in the X-axis direction. In this case, since the dot pattern corresponding to the segment area is not within the effective imaging area of the CMOS image sensor 240, the segment area cannot be properly matched. However, since it is possible to perform matching appropriately in areas other than the end segment areas, there is little influence on object distance detection.

  In addition, when matching is performed appropriately for the end region, the effective imaging region of the CMOS image sensor 240 at the time of actual measurement may be made larger than the effective imaging region of the CMOS image sensor 240 at the time of acquiring the reference image. What can be used should be used. As a result, the actually measured image becomes larger than the reference image, but matching can be appropriately performed for the end segment area.

  When detecting the matching degree, first, the number of gradations of the pixel value of each pixel in the reference pattern area and the pixel value of each pixel in each segment area of the actually measured image is reduced. For example, when the pixel values of the reference image and the actually measured image are 8-bit gradation, the pixel values of 0 to 255 are converted into the pixel values of 0 to 12. Then, the converted pixel value is held in the memory 25. Thereafter, the similarity between the comparison region and the segment region Si is obtained. That is, the difference between the pixel value of each pixel in the segment area Si and the pixel value of the corresponding pixel in the comparison area is obtained. A value Rsad obtained by adding the obtained difference to all the pixels in the comparison region is acquired as a value indicating the similarity.

  For example, as shown in FIG. 5C, when pixels in n columns × m rows are included in one segment area, the pixel values T (i, j) of the pixels in i columns and j rows in the segment area. ) And the pixel value I (i, j) of the pixel in the comparison area i column and j row. Then, the difference is obtained for all the pixels in the segment area, and the value Rsad of the equation shown in FIG. 5C is obtained from the sum of the differences. The smaller the value Rsad, the higher the degree of similarity between the segment area and the comparison area.

  Thus, as shown in FIG. 5D, the value Rsad is obtained for all the comparison regions of the search region Ri for the segment region Si.

  FIG. 5E is a graph schematically showing the value Rsad at each feed position in the search area Ri. When the value Rsad is obtained for all the comparison regions of the search region Ri for the segment region Si, first, the minimum value B1 is referred to from the obtained value Rsad. Next, the second smallest value B2 of the obtained value Rsad is referred to. If the ratio between the second smallest value B2 and the minimum value B1 is equal to or smaller than a predetermined threshold value, the search for the segment region Si is considered as an error. On the other hand, when the ratio of the second smallest value B2 and the minimum value B1 exceeds the threshold value, the comparison area Ci corresponding to the minimum value B1 is determined as the movement area of the segment area Si.

  For example, as shown in FIG. 5D, the comparison area Ci corresponding to the segment area Si is in the positive direction of the X axis with respect to the pixel position Si0 on the measured image at the same position as the pixel position of the segment area Si on the reference image. It is detected at a position shifted by α pixels. This is because the dot pattern of the DP light on the measured image is displaced in the X-axis positive direction from the segment area Si0 on the reference image by a detection target object (person) that is present at a position closer to the reference plane.

  Thus, when the displacement position of each segment region is searched from the dot pattern of DP light acquired at the time of actual measurement, detection corresponding to each segment region is performed by triangulation based on the displacement position as described above. The distance to the part of the target object is obtained.

  In this manner, the same segment area search is performed for all the segment areas from the segment area S1 to the segment area Sn.

  The information acquisition device 2 provides the information processing device 3 as an image in which the distance to the detection target object corresponding to each segment area acquired as described above is assigned to pixel values expressed in white to black gradations. Output. Hereinafter, an image in which a distance corresponding to each segment area is expressed by a pixel value is referred to as a “distance image”. As described above, in the present embodiment, since the segment area is set at an interval of one pixel with respect to the reference pattern area of the standard image, the distance image has a resolution (substantially approximately the same VGA size as the standard image). 640 × approximately 480).

  Note that the above matching degree detection method is an example, and the present invention is not limited to this. For example, in the above description, as the error detection method for the segment region Si, the ratio of the second smallest value B2 and the minimum value B1 of the value Rsad is used, but the average of the values Rsad obtained for all the comparison regions is used. A method may be used in which an error is determined when the ratio (B1 / Ba) between the value Ba and the minimum value B1 is equal to or smaller than a predetermined threshold value, or when the size of the minimum value B1 is equal to or smaller than a predetermined threshold value. A technique for determining an error may be used.

  FIG. 6A is a schematic diagram showing an actually measured image captured indoors, and FIG. 6B is a schematic diagram of the projection optical system 100 and the light receiving optical system 200 viewed from the X-axis direction. FIG. 6A shows a comparison region Cg of the floor position at a shorter distance than the reference surface and a comparison region Cw of the wall position at a shorter distance than the reference surface. FIG. 6B shows a floor area Cg ′ corresponding to the comparison area Cg. In the comparison areas Cg and Cw, the positions of the dots in the reference image are indicated by broken white circles, and the positions of the dots in the measured image are indicated by black circles. Note that the projection optical system 100 and the light receiving optical system 200 in FIG. 6B are shown as being shifted in the Y-axis direction and the Z-axis direction for convenience, but are actually arranged in a straight line in the X-axis direction.

  In the actual measurement image of FIG. 6A, the ceiling of the room, the floor, and the wall are reflected together with the person. The upper half of the comparison area Cg is an image of the upper half (back side) of the area Cg ′ in FIG. 6B, and the lower half of the comparison area Cg is the lower half (front side) of the area Cg ′. It is what was imaged. Here, the front side (Z-axis negative side) of the region Cg ′ is farther from the reference plane than the back side (Z-axis positive side). As described above, the displacement of the dot in the left-right direction (X-axis direction) increases as the object moves away from the reference plane. For this reason, in the actually measured image of FIG. 6A, the displacement amount D2 of the dot Dt2 included in the lower half of the comparison region Cg is larger than the displacement amount D1 of the dot Dt1 included in the upper half of the comparison region Cg. . Similarly, the displacement amount D4 of the dot Dt4 included in the right half of the comparison region Cw is larger than the displacement amount D3 of the dot Dt3 included in the left half of the comparison region Cw.

  Hereinafter, the amount of displacement of the dot acquired during actual measurement from the corresponding position in the reference image is referred to as parallax. Further, when the difference in parallax exceeds one pixel in the comparison area, it is referred to as a plurality of parallaxes.

  As described above, the amount of displacement of the dots included in the comparison region Cg of the floor position is smaller on the upper side (Y-axis negative side) in FIG. 6A and larger on the lower side (Y-axis positive side). . Further, in FIG. 6A, the displacement amount of dots included in the wall position comparison region Cw is smaller on the left side (X-axis negative side) and larger on the right side (X-axis positive side).

The comparison area corresponding to the position of a surface that is inclined with respect to the reference surface (XY plane), such as a floor or a wall, includes dots reflected from positions at different distances. Therefore, in this case, among the comparison areas in the search range, the comparison area corresponding to the segment area may include a plurality of parallaxes.

  FIGS. 7A to 7C are diagrams illustrating a comparative example in the case where dot patterns are matched in a segment area having a predetermined size when a plurality of parallaxes are included in one comparison area. is there. FIG. 7A is a graph showing an example of the distribution of the value Rsad in the case of the comparative example, and FIGS. 7B and 7C schematically show examples of distance information obtained in the case of the comparative example. FIG. In FIG. 7A, for the sake of convenience, only the horizontal axis in the positive range is shown, but actually, as shown in FIG. 5E, the horizontal axis in the negative range also exists. 7B and 7C show a part of the distance image, and one cell corresponds to one pixel of the distance image. In each cell, black indicates an error, dark hatching indicates a long distance, and light hatching indicates a short distance.

  When a value Rsad is calculated in a segment area having a predetermined size when a plurality of parallaxes are included in the comparison area, the value Rsad is reduced at a plurality of positions N1 and N2, as shown in FIG. For example, in the example of FIG. 7A, the dot reflected by the floor on the near side in FIG. 6A matches the dot in the measured image with a pixel shift amount of 8, and is reflected by the floor on the back side. Matches the dot of the measured image at the position of the pixel shift amount 10. Therefore, in the graph of FIG. 7A, the value Rsad obtained by each matching is superimposed, and therefore the value Rsad is small at two positions of the pixel shift amounts 8 and 10. In the example of FIG. 7A, the value Rsad is the smallest at the position N1, but in some cases, the value Rsad may be the smallest at the position N2.

  In this case, in fact, even if the floor is continuous at the same distance in the search direction (X-axis direction), as shown in FIG. It is possible that distance information on the near floor (short distance) is mixed in the search direction.

  In addition, when a plurality of parallaxes are included in one comparison area, the relative positions of the dots in the comparison area are displaced, so that it is difficult for the dots in the comparison area to match the dots in the segment area. For example, in the example of FIG. 7A, among the dots in the segment area, the dot that matches the dot of the actually measured image at the position of the value B2 (pixel shift 8) is usually the position of the minimum value B1 (pixel shift 10). ) Does not match the dots in the measured image. For this reason, the minimum value B1 is relatively large, and the ratio between the second smallest value B2 and the minimum value B1 is considerably small.

  In this case, it is easy to meet the above-described error condition, and as shown in FIG.

  As described above, when the single distance information cannot be obtained on the surface of the object having the same distance in the search direction (X-axis direction), the object shape extraction by the object detection unit 31a in FIG. There is a possibility that it cannot be done. The same applies to the case where many distance acquisition errors occur.

  Therefore, in the present embodiment, when a plurality of parallaxes are included in the comparison area, a search for the measured image is performed using an area obtained by dividing the segment area.

  FIG. 8A is a diagram illustrating functional blocks of the distance acquisition unit 21b. FIG. 8B is a diagram illustrating an example of segment area division.

  The divided segment area Sa shown in FIG. 8B is an example of the first divided segment area described in claim 2. Further, the divided segment area Sb is an example of a second divided segment area described in claim 2.

  Referring to FIG. 8A, the distance acquisition unit 21b has the functions of two Rsad calculation blocks 211a and 211b and the function of a parallax determination / distance calculation block 212. The Rsad calculation blocks 211 a and 211 b are supplied with a reference template from the memory 25 and a measured image from the imaging signal processing circuit 23. Here, the segment area S is set to a size of 15 pixels × 15 pixels and is held in the reference template.

  Similarly to the above, the segment area S is collated with each comparison area in a predetermined search range. At the time of this search, as shown in FIG. 8 (b), the Rsad calculation block 211a includes pixel information included in the upper half area (divided segment area Sa) of 15 pixels × 8 pixels in the segment area S, The value Rsad is calculated by matching the pixel information in the measured image. In the above search, the Rsad calculation block 211b uses the pixel information included in the lower half area (divided segment area Sb) of the 15 pixels × 7 pixels in the segment area S and the pixel information in the measured image. The value Rsad is calculated by matching. Hereinafter, the value Rsad calculated from the divided segment area Sa is referred to as Rsa, and the value Rsad calculated from the divided segment area Sb is referred to as Rsb.

  The parallax determination / distance calculation block 212 determines whether or not a plurality of parallaxes are included in the comparison area corresponding to the segment area S from the values Rsa and Rsb calculated by the Rsad calculation blocks 211a and 211b. The necessity of dividing S is determined. Then, the parallax determination / distance calculation block 212 selects a value Rsad calculated by a segment area of an appropriate size according to whether or not division is necessary. When the entire segment area S is selected, the parallax determination / distance calculation block 212 adds the value Rsa and the value Rsb. The sum of the value Rsa and the value Rsb corresponds to the value Rsad acquired for the entire segment area S. Hereinafter, a value obtained by adding the value Rsa and the value Rsb is referred to as a value Rs. Then, the parallax determination / distance calculation block 212 acquires the distance information based on the value Rsad calculated by the segment area of an appropriate size. The distance information acquired in this way is output to the information processing apparatus 3 via the input / output circuit 24 as the above-described distance image.

  FIG. 9 is a flowchart illustrating processing for determining the presence / absence of multiple parallaxes and obtaining a distance. This process is performed by a function in the distance acquisition unit 21b of the CPU 21 in FIG.

  The processing flow shown in FIG. 9 is an example of the configuration described in claims 2 and 4.

  Referring to FIG. 9, when a measured image is input from imaging signal processing circuit 23, CPU 21 first refers to a reference template from memory 25 and calculates values Rsa and Rsb for divided segment areas Sa and Sb. (S101). Then, the CPU 21 acquires the pixel shift amount Na of the minimum value Ba1 in the value Rsa and the pixel shift amount Nb of the minimum value Bb1 in the value Rsb (S102).

  FIG. 10A is a graph showing a distribution example of the value Rsa calculated by the divided segment area Sa, and FIG. 10B is a graph showing a distribution example of the value Rsb calculated by the divided segment area Sb. FIG. 10C is a graph showing a distribution example of values obtained by adding the value Rsa and the value Rsb. FIG. 10D is a diagram schematically illustrating an example of distance information obtained in the case of the present embodiment. FIG. 10 (d) corresponds to FIGS. 7 (b) and (c) in the comparative example. In FIG. 10D, dark hatching indicates a long distance, and thin hatching indicates a short distance.

Referring to FIG. 10A, the divided segment area Sa is smaller than the segment area S shown in FIG. 8B, so the value Rsa obtained by the divided segment area Sa is smaller than that in FIG. The overall size is getting smaller. In FIG. 7A, the value Rsad is small at a plurality of positions N1 and N2. In FIG. 10A, the value Rsa is small only at the position Na (pixel shift amount) of the minimum value Ba1. It has become.

  Referring to FIG. 10B, the value Rsb obtained by the divided segment area Sb is also generally smaller than that in FIG. In the case of FIG. 10B, the value Rsb is small only at the position Nb (pixel shift amount) of the minimum value Bb1. As shown in FIG. 8B, the segment segment area Sb is set slightly smaller than the segment segment area Sa, so that the value Rsb in FIG. 10B is the value Rsa in FIG. Slightly smaller than.

  Therefore, as shown in FIGS. 10A and 10B, the minimum values Ba1 and Bb1 of the divided segment areas Sa and Sb are the second smallest values Ba2 and Bb2 compared to FIG. 7A. Since the ratio tends to be large, it is easy to be appropriately matched. As shown in FIG. 6A, the difference between the displacement amounts D1 and D2 in the comparison region Cg is relatively large. However, in the present embodiment, since the segment area S is divided vertically as described above, the difference in the displacement amount (parallax) of the dots in the comparison area corresponding to the divided segment areas Sa and Sb is the segment area S. Is a few steps smaller than the difference in the displacement (parallax) of the dots in the comparison region corresponding to, and is at most about 0 to 1 pixel. Accordingly, in the calculation of the values Rsa and Rsb for the divided segments Sa and Sb, the influence due to the difference in the displacement amount (parallax) of the dots is slight.

  Returning to FIG. 9, the CPU 21 determines whether or not the absolute value of the difference between the pixel shift amounts Na and Nb exceeds the predetermined threshold Th1 and is lower than the predetermined threshold Th2 (S103). By this step S103, it is determined whether or not a plurality of parallaxes are included in the comparison region by planes having the same distance in the search direction (X-axis direction) such as the floor. That is, when the determination in step S103 is YES, it is determined that a plurality of parallaxes due to a floor or the like are included in the comparison region.

  When the comparison area is an area that captures a surface such as a floor, as described above, the difference between the parallax in the upper half and the parallax in the lower half may exceed one pixel. In this case, the difference between the position where the upper half divided segment area Sa matches the measured image and the position where the lower half divided segment Sb matches the measured image also exceeds one pixel. Therefore, when the absolute value of the difference between the pixel shift amounts Na and Nb exceeds 1, it can be assumed that a plurality of parallaxes are generated in the comparison region. Therefore, the threshold value Th1 is set to 1, for example.

  Further, when the comparison area is an area that captures a surface having the same distance in the search direction (X-axis direction) such as a floor, the difference between the parallax in the upper half and the lower half in the comparison area is at most several. It is assumed that the pixel is about a pixel, and the absolute value of the difference between the pixel shift amounts Na and Nb is also assumed to be at most about a few pixels. When the absolute value of the difference between the pixel shift amounts Na and Nb is relatively large, the comparison area may be an area for imaging the boundary between the object and the background, or the quality of the value Rsad is assumed to be poor. Can be done. Therefore, when the absolute value of the difference between the pixel shift amounts Na and Nb is relatively large, it is considered that the same processing as that for a surface such as a floor should not be applied. Therefore, the threshold value Th2 is set to 5, for example.

  When the absolute value of the difference between the pixel shift amounts Na and Nb exceeds the threshold Th1 and is less than the threshold Th2 (S103: YES), the CPU 21 determines that 2 out of the values Rsa obtained by the divided segment area Sa in the upper half. It is determined whether or not the ratio (Ba2 / Ba1) between the second smallest value Ba2 and the minimum value Ba1 exceeds a predetermined threshold value Tα (S104). Thereby, it is determined whether or not the distance value obtained from the value Rsa is an error.

When this ratio (Ba2 / Ba1) exceeds the threshold value Tα (S104: YES), the CPU 21 gives the information processing device 3 a distance value corresponding to the pixel shift amount Na obtained by the search for the upper half divided segment area Sa. Output (S105). Thus, if a plurality of parallaxes are included in the comparison area corresponding to the entire segment area S and the search result of the upper half segment area Sa is not an error, the upper half segment area Sa is always searched. The distance by is acquired.

  When the search result of the upper half segment area Sa is determined to be an error (S104: NO), the CPU 21 minimizes the second smallest value Bb2 among the values Rsb obtained by the lower half segment area Sb. It is determined whether or not the ratio of the value Bb1 (Bb2 / Bb1) exceeds the threshold value Tα (S106). Thereby, it is determined whether or not the distance value obtained from the value Rsb is an error.

  When this ratio (Bb2 / Bb1) exceeds the threshold value Tα (S106: YES), the CPU 21 gives the information processing device 3 a distance value corresponding to the pixel shift amount Nb obtained by searching the lower half of the segment segment area Sb. Output (S107). Thereby, when a plurality of parallaxes are included in the comparison area corresponding to the entire segment area S and the search for the upper half segment area Sa results in an error, the search for the lower half segment area Sb is performed. The distance is obtained.

  When the ratio (Bb2 / Bb1) is equal to or less than the threshold value Tα (S106: NO), the CPU 21 adds the value Rsa and the value Rsb to obtain the value Rs (S108). Then, the CPU 21 determines whether or not the ratio (B2 / B1) between the second smallest value B2 and the minimum value B1 among the values Rs exceeds the threshold value Tα (S109). The value Rs is a value equivalent to the value Rsd obtained for the entire segment region S in FIG. That is, the value Rsa shown in FIG. 10C is equivalent to the value Rsad shown in FIG. Even if the search results of the divided segment areas Sa and Sb are errors, the search results of the entire segment area S may not be an error. Therefore, when both the search results of the divided segment areas Sa and Sb are errors (S105: NO), the CPU 21 further performs a distance acquisition process using the value Rs corresponding to the entire segment area S.

  When the ratio between the second smallest value B2 and the minimum value B1 exceeds the threshold value Tα (S109: YES), the CPU 21 acquires the pixel shift amount N1 of the minimum value B1 in the value Rs (S110). Then, the CPU 21 outputs a distance value corresponding to the pixel shift amount N1 obtained from the value Rs to the information processing apparatus 3 (S111).

  When the ratio between the second smallest value B2 and the minimum value B1 is equal to or less than the threshold value Tα (S109: NO), the CPU 21 outputs an error value to the information processing device 3 (S112). The error value is normally a value that cannot be acquired as a distance value (for example, 0).

  When the absolute value of the difference between the pixel shift amounts Na and Nb is equal to or less than the threshold value Th1 or greater than or equal to the threshold value Th2 (S103: NO), the CPU 21 advances the process to S109 and searches for the entire segment area S as described above. A corresponding distance acquisition process is performed (S109 to S112). As described above, when the determination in S103 is NO, it is assumed that the comparison region is not a region for imaging a surface having the same distance in the search direction (X-axis direction) such as the floor. Therefore, in this case, a search equivalent to the search using the normal segment region S is performed, and the distance value is acquired.

  As described above, it is determined whether or not the comparison region of the search range of the segment region S includes a plurality of parallaxes, and the divided segment regions Sa and Sb or the entire segment region S depending on the determination result. The distance is acquired by either of the above. Thereafter, the CPU 21 advances the process to step S113 and performs the process for the next segment area. In this way, the CPU 21 repeats the determination of the presence / absence of a plurality of parallaxes and the distance acquisition process for all segment areas.

  According to the processing flow of FIG. 9, as schematically shown in FIG. 10D, the segment area S searches for an area on the measured image, such as a floor or a ceiling, that captures a surface of the same distance in the search direction. Even in the case, distance information of the same distance can be acquired.

  That is, when such a region is searched, the determination in S103 of FIG. 9 is YES, and distance acquisition is performed by the divided segment regions Sa and Sb. When the divided segment areas Sa and Sb are used, the ratio between the minimum value of Rsad and the second smallest value increases as described with reference to FIGS. It is hard to become an error. Further, since the distance acquisition by the divided segment area Sa is performed in preference to the distance acquisition by the divided segment area Sb in the determination step of S104, the obtained distance information is aligned with the distance value acquired by the divided segment area Sa. It becomes easy. Accordingly, as schematically shown in FIG. 10D, distance information of the same distance can be acquired even in a region where a surface of the same distance in the search direction is imaged, such as a floor or a ceiling.

  If the segment area S searches for an area other than the surface such as the floor or ceiling on the measured image, the determination in S103 of FIG. 9 is NO, and the search using the segment area S is performed as usual. . The segment area S has a larger number of dots and higher dot uniqueness than the divided segment areas Sa and Sb. For this reason, when the segment area S is used, the displacement position search accuracy is higher and the distance acquisition accuracy is higher than when the segmented segment areas Sa and Sb are used. Therefore, when searching for a region other than a surface such as a floor or a ceiling, the search using the segment region S is performed as usual, so that the accuracy of distance information of an object other than the floor or the ceiling can be improved.

  If the search range comparison area includes a plurality of parallaxes and an error occurs in the search for the upper half segment segment area Sa, the processes of S106 and S107 are performed, and the lower half segment segment area Sb is used. Since distance acquisition is performed, the distance value may be somewhat discontinuous. Therefore, in order to suppress such discontinuity of distance values as much as possible, the processing of S106 and S107 is omitted, and if S104 is determined to be NO, the processing proceeds to S108, and the distance acquisition by the entire segment region S is obtained. It is better to apply On the other hand, in this case, an error is likely to occur in the processing after S108. Therefore, in order to suppress the occurrence of the error as much as possible, the processing in S106 and S107 is performed as shown in FIG. It is desirable to apply distance acquisition by the lower segment segment area Sb having a lower value.

  Moreover, although the process concerning the determination of multiple parallaxes and the distance acquisition shown in FIG. 9 is executed by the function of the CPU 21 of FIG. 2, these processes may be executed by a hardware configuration using a circuit. In this case, as shown in FIG. 11, an Rsad arithmetic circuit 26 and a parallax determination / distance arithmetic circuit 27 are provided as hardware.

  The configuration described in FIG. 11 is an example of the configuration described in claim 3. In FIG. 11, Rsad calculation blocks 26a and 26b correspond to the first and second matching calculation units according to claim 3, and an adder 26c corresponds to the addition unit according to claim 3.

  Referring to FIG. 11, the Rsad operation circuit 26 includes two Rsad operation blocks 26a and 26b and an adder 26c. The Rsad calculation blocks 26a and 26b calculate the value Rsa and the value Rsb, as in FIG. The adder 26c adds the value Rsa and the value Rsb to calculate the value Rs. In this way, the Rsad calculation circuit calculates the value Rsa, the value Rsb, and the value Rs, and outputs them to the parallax determination / distance calculation circuit 27.

The parallax determination / distance calculation circuit 27 determines whether or not a plurality of parallaxes are included by the processing of FIG. Then, the parallax determination / distance calculation circuit 27 selects the value Rsad calculated by the segment area having an appropriate size according to whether or not the division is necessary. Thereafter, the parallax determination / distance calculation circuit 27 acquires the distance information based on the value Rsad calculated by the segment area of an appropriate size. The distance information acquired in this way is output to the information processing device 3 via the input / output circuit 24 as the above-described distance image. As described above, the Rsad calculation block 26a for the divided segment area Sa and the divided segment area Sb are used. Since the Rsad calculation block 26b is provided separately, the values Rsa and Rsb of the divided segment areas Sa and Sb can be calculated in parallel. Therefore, even when the information acquisition device 2 divides the entire segment region S, the information acquisition device 2 can perform the distance acquisition process quickly.

  Since the adder 26c is provided, the value Rs when the entire segment area S is used is obtained from the value Rsa obtained from the upper half divided segment area Sa and the lower half divided segment area Sb. It can be obtained by adding the value Rsb. Therefore, the processing block for calculating the value Rs of the entire segment area S can be omitted, and the processing block can be simplified.

<Effect of Embodiment>
As described above, according to the present embodiment, when the comparison area to be searched includes a plurality of parallaxes, distance acquisition is performed using the divided segment areas. The same distance information can be stably acquired when searching for a region for imaging a surface. In addition, occurrence of errors in distance acquisition can be suppressed. Therefore, the object detection accuracy can be increased.

  Also, according to the present embodiment, after the determination of the presence or absence of a plurality of parallaxes, if the search for the upper half segment area Sa is an error, distance acquisition is performed by the lower half segment area Sb. The occurrence of acquisition errors is further suppressed.

  In addition, according to the present embodiment, after the determination of the presence or absence of a plurality of parallaxes, when the search for the segmented segment areas Sa and Sb is an error, distance acquisition is performed using the value Rs corresponding to the entire segment area S. The occurrence of distance acquisition errors is further suppressed.

  Furthermore, according to the present embodiment, the value Rsad when the entire segment area S is used is the value Rsa obtained from the upper half divided segment area Sa and the value Rsb obtained from the lower half divided segment area Sb. Therefore, the processing block for calculating the value Rsad of the entire segment area S can be omitted, and the processing block can be simplified.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made to the embodiment of the present invention in addition to the above. .

  For example, in the above embodiment, when the absolute value of the difference between the pixel shift amounts Na and Nb is within the predetermined threshold values Th1 and Th2, a plurality of parallaxes are present in the comparison region corresponding to the entire segment region S. Although determined to be included, it may be determined by other methods. As described above, when the comparison area corresponding to the entire segment area S includes a plurality of parallaxes, the ratio between the second smallest value B2 and the minimum value B1 is small. Therefore, when the ratio of the second smallest value B2 and the minimum value B1 is less than the predetermined threshold value Tα, it is assumed that a plurality of parallaxes are included, and a search is performed using the divided segment areas obtained by dividing the segment area. May be.

FIG. 12 is a flowchart showing a process for determining the presence / absence of multiple parallaxes and obtaining a distance in this case. This process is performed by a function in the distance acquisition unit 21b of the CPU 21 in FIG. Note that FIG. 12 partially changes the flowchart of FIG. 9, and the same number is assigned to a process that does not change.

  The processing flow illustrated in FIG. 9 is an example of the configuration according to claim 5.

  Referring to FIG. 12, when calculation of values Rsa and Rsb is completed by predetermined divided segment areas Sa and Sb (S101), CPU 21 first adds value Rsa and value Rsb as in S108 of FIG. Then, the value Rs corresponding to the entire segment area S is acquired (S201). Then, the CPU 21 determines whether or not the ratio (B2 / B1) between the second smallest value B2 and the minimum value B1 among the values Rs is less than a predetermined threshold value Tα (S202). Thereby, it is determined whether or not there is a possibility that the comparison area corresponding to the entire segment area S includes a plurality of parallaxes.

  When this ratio (B2 / B1) is less than the predetermined threshold value Tα (S202: YES), error determination processing is performed for the upper half divided segment area Sa and the lower half divided segment area Sb in the same manner as in FIG. (S104, S106), distance acquisition processing is performed according to the error determination result (S105, S107). In this modified example, since the pixel shift amounts Na and Nb are not acquired in advance, the pixel shift amounts Na and Nb are acquired at the timing when it is determined that the distance is acquired from the divided segment areas Sa and Sb. (S203, S204). Further, when the search results of the divided segment areas Sa and Sb are both errors (S104: NO, S106: NO), the CPU 21 outputs an error value to the information processing device 3 (S112).

  When the ratio between the second smallest value B2 and the minimum value B1 is equal to or greater than the predetermined threshold value Tα (S202: NO), the CPU 21 advances the process to S110 and performs a distance acquisition process corresponding to the search for the entire segment region S. It performs (S110-S111).

  Also in this modified example, when there is a high possibility that the comparison area corresponding to the entire segment area S includes a plurality of parallaxes, distance acquisition is performed using the divided segment areas Sa and Sb. Even if it exists, distance acquisition can be performed appropriately.

  Moreover, in the said embodiment, although segment area | region S was divided | segmented to the up-down direction, as shown to Fig.13 (a), you may divide | segment segment area S to a horizontal direction. In this case, the divided segment areas Sa and Sb in the above embodiment are replaced with the divided segment areas Sc and Sd, respectively, and the process of FIG. 9 is performed.

  Further, when the segment area S is divided into the divided segment areas Sa and Sb and the divided segment areas Sc and Sd, as shown in FIG. 14, a search using the respective divided segment areas Sa to Sd is performed. May be.

  Note that the processing flow described in FIG. 14 is an example of the configuration described in claim 6.

  In the processing flow of FIG. 14, S101 in the processing flow of FIG. 9 is replaced with S301, and S302 to S307 are added. In S301, values Rsad (Rsa to Rsd) are acquired using the divided segment regions Sa to Sd. In S302, pixel shift amounts Nc and Nd of the minimum values Bc1 and Bd1 among the values Rsc and Rsd acquired using the divided segment regions Sc and Sd are acquired.

In S103, when the absolute value of the difference between the pixel shift amounts Nc and Nd is not within the range of the threshold values Th1 and Th2 (S103: NO), the difference between the pixel shift amounts Nc and Nd acquired using the divided segment regions Sc and Sd. Is determined to be within the range of the threshold values Th3 and Th4 (S303). The threshold values Th3 and Th4 are set in the same manner as the threshold values Th1 and Th2, for example. The determination in S303 is also performed when the determination in S106 is NO.

  If the determination in S303 is YES, first, of the value Rsc obtained by the divided segment region Sc, whether or not the ratio (Bc2 / Bc1) between the second smallest value Bc2 and the minimum value Bc1 exceeds a predetermined threshold value Tα. Is determined (S304). Thereby, it is determined whether or not the distance value obtained from the value Rsc is an error. When this ratio (Bc2 / Bc1) exceeds the threshold value Tα (S304: YES), a distance value corresponding to the pixel shift amount Nc obtained by searching the segmented segment region Sc is output to the information processing device 3 (S305). .

  If the determination in S304 is NO, whether or not the ratio (Bd2 / Bd1) between the second smallest value Bd2 and the minimum value Bd1 out of the value Rsd obtained by the divided segment region Sd exceeds a predetermined threshold value Tα. It is determined (S306). Thereby, it is determined whether or not the distance value obtained from the value Rsd is an error. When this ratio (Bd2 / Bd1) exceeds the threshold value Tα (S306: YES), a distance value corresponding to the pixel shift amount Nd obtained by searching the divided segment region Sd is output to the information processing device 3 (S307). .

  If the determination in S303 is NO, or if the determination in S306 is NO, the process proceeds to S108, and distance acquisition using the entire segment region S is performed.

  According to this modified example, the distances can be appropriately acquired not only on the floor and ceiling, but also on the wall of the room, etc., by the processes of S303 to S307.

  Further, when the divided segment areas Sa to Sd are used, the modification example of FIG. 12 can be modified as shown in FIG.

  The processing flow described in FIG. 15 is another example of the processing described in claim 6.

  In the processing flow of FIG. 15, S101 in the processing flow of FIG. 12 is replaced with S401, and S402 to S407 are added. In S401, the value Rsad (Rsa to Rsd) is acquired using the divided segment areas Sa to Sd.

  When it is determined that there is a possibility that the comparison area includes a plurality of parallaxes (S202: YES), and it is determined that there is an error in the divided segment areas Sa and Sb (S104: NO, S106: NO), the divided segments It is determined whether or not the ratio (Bc2 / Bc1) between the second smallest value Bc2 and the minimum value Bc1 among the values Rsc obtained by the region Sc exceeds a predetermined threshold value Tα (S402). When this ratio (Bc2 / Bc1) exceeds the threshold value Tα (S402: YES), the pixel shift amount Nc of the minimum value Bc1 is acquired from the value Rsc (S403). Then, a distance value corresponding to the acquired pixel shift amount Nc is output to the information processing apparatus 3 (S404).

  If the determination in S402 is NO, whether or not the ratio (Bd2 / Bd1) of the second smallest value Bd2 to the minimum value Bd1 out of the value Rsd obtained by the divided segment region Sd exceeds a predetermined threshold value Tα. It is determined (S405). When this ratio (Bd2 / Bd1) exceeds the threshold value Tα (S405: YES), the pixel shift amount Nd of the minimum value Bd1 is acquired from the value Rsd (S406). Then, a distance value corresponding to the acquired pixel shift amount Nd is output to the information processing apparatus 3 (S407).

  If the determination in S405 is NO, the process proceeds to S108, and distance acquisition using the entire segment region S is performed.

  According to this modified example, similarly to the case of FIG. 14, the distance acquisition can be appropriately performed not only on the floor and ceiling, but also on the wall of the room, etc., by the processes of S402 to S407.

  In the above embodiment, the segment area S is divided into two divided segment areas Sa and Sb. However, as shown in FIG. 13B, the segment area S may be divided into four divided segment areas Se to Sh. In this case, the distance acquisition unit 21b in FIG. 8A includes four Rsad calculation blocks, and the values Rsad of the four divided segment areas Se to Sh are calculated in parallel.

  When the segment area S is thus divided into four divided segment areas Se to Sh, the values Rsa to Rsd in FIG. 14 are the values Rsad (Rse to Rsh) obtained using the divided segment areas Se to Sh. It is obtained by adding the two corresponding ones. For example, the value Rsc for the left half segment segment area Sc in FIG. 13A is obtained by adding the values Rse and Rsg obtained by the segment segment areas Se and Sg in FIG. Further, the value Rs for the entire segment region S is acquired by adding the values Rse to Rsh acquired by the divided segment regions Se to Sh. In this way, when the values Rse to Rsh are individually acquired by the four divided segment areas Se to Sh, when the arithmetic processing of the value Rsad is realized by a circuit, the circuit configuration is changed to four Rsad arithmetic blocks, An adder circuit for adding outputs from the blocks can be provided. In this case, the four Rsad calculation blocks need only perform processing on the divided segment areas Se to Sh having a small number of vertical and horizontal pixels, so that the configuration of the calculation circuit is relatively simple. Therefore, the values Rsa to Rsd in FIG. 14 and the value Rs for the entire segment region S can be acquired while reducing circuit resources.

  In addition to these, an Rsad calculation block for calculating the value Rsad of the entire segment area S may be further arranged. In this case, the value Rs can be acquired without adding the values Rsa and Rsb in S108 of FIG. In this case, as shown in FIG. 13C, the divided segment areas Se to Sh may be set so as to partially overlap so that the sizes of the areas are the same.

  Further, in the above embodiment, when a plurality of parallaxes are included, distance acquisition is performed using the divided segment areas Sa and Sb in which the segment area S is divided into two, but one of a size smaller than the segment area S is used. The distance acquisition may be performed by the segment area. For example, when a plurality of parallaxes are included, distance acquisition may be performed only by a segment area corresponding to the upper half segment area Sa.

  Further, in the above embodiment, the distance information is obtained by using the divided segment area Sa preferentially of the divided segment areas Sa and Sb, but the divided segment area Sb is preferentially used. Acquisition of distance information may be performed. Similarly, in the processing flow of FIG. 14, the distance information is obtained by using the divided segment area Sc preferentially among the divided segment areas Sc and Sd, but the divided segment area Sd is given priority. The distance information may be acquired using the information.

In the above embodiment, whether or not a plurality of parallaxes are included is determined using two threshold values Th1 and Th2 in S103 of FIG. 9, but the threshold value Th2 is omitted and the pixel shift amounts Na and Nb are determined. The determination in S103 may be made only by whether or not the absolute value of the difference exceeds the threshold value Th1. In this way, even when the comparison area is an area corresponding to the boundary of the object, distance acquisition is performed using the divided segment areas Sa and Sb, but the divided segment areas Sa and Sb are obtained.
Since the distance information acquired using b is also acquired by the matching process, it can be distance information with a certain level of accuracy.

  In the above embodiment, distance matching is performed using an image obtained by reducing the gradation of the actually measured image. However, after the filter processing for enhancing the edge of the dot is performed, the distance matching is performed. It may be broken.

  In the above embodiment, the sum of absolute values of the difference values SAD (Sum of Absolute Difference) shown in FIG. 5C is used to calculate the degree of matching of the dot pattern. A sum of squared values SSD (Sum of Squared Difference) may be used.

  In the above embodiment, the segment areas are set so that the adjacent segment areas overlap with each other. However, the segment areas adjacent to each other on the left and right may not overlap with each other, and the segment areas adjacent to each other on the upper and lower sides. However, they do not have to overlap each other. Further, the shift amount of the segment areas adjacent in the vertical and horizontal directions is not limited to one pixel, and the shift amount may be set to another number of pixels. Furthermore, in the said embodiment, although the segment area | region was set to square shape, a rectangle may be sufficient.

  In the above embodiment, the pixel values of the pixels included in the segment area and the comparison area are reduced to 0 to 12 before calculating the matching ratio between the segment area and the comparison area. It may be reduced and binarized, or matching may be performed using the pixel value obtained by the CMOS image sensor 240 as it is.

  In the above embodiment, the distance information is obtained by using the triangulation method and stored in the memory 25. However, the displacement amount (pixel displacement amount) of the segment area is used as the distance information without calculation by the triangulation method. You may acquire and distance information may be acquired by another method.

  Further, in the above embodiment, the filter 230 is disposed to remove light in a wavelength band other than the wavelength band of the laser light irradiated to the target region. For example, light other than the laser light irradiated to the target region is used. In the case where a circuit configuration for removing the signal component from the signal output from the CMOS image sensor 240 is arranged, the filter 230 may be omitted. In the above embodiment, the CMOS image sensor 240 is used as the light receiving element, but a CCD image sensor may be used instead. Furthermore, the configurations of the projection optical system 100 and the light receiving optical system 200 can be changed as appropriate. In addition, the present invention can be applied to information acquisition forms other than control input such as a television using the right hand.

  The embodiments of the present invention can be appropriately modified in various ways within the scope of the technical idea shown in the claims.

1 ... Object detection device
2 ... Information acquisition device 21b ... Distance acquisition unit 211a ... Rsad calculation block (first matching calculation unit)
211b ... Rsad calculation block (second matching calculation unit)
212 ... Parallax determination / distance calculation block (distance acquisition unit)
23 ... Imaging signal processing circuit (distance acquisition unit)
26 ... Rsad arithmetic circuit (distance acquisition unit)
26a: Rsad calculation block (first matching calculation unit)
26b Rsad calculation block (second matching calculation unit)
26c: Adder (adder)
27: Parallax determination / distance calculation circuit (distance acquisition unit)
DESCRIPTION OF SYMBOLS 3 ... Information processing apparatus 31a ... Object detection part 100 ... Projection optical system 110 ... Laser light source 200 ... Light reception optical system 240 ... CMOS image sensor (image sensor)
S: Segment area Sa: Divided segment area (first divided segment area)
Sb: Divided segment area (second divided segment area)
Sc: divided segment area (third divided segment area)
Sd: Divided segment area (fourth divided segment area)
Se to Sh: Divided segment area Cw, Cg: Comparison area

Claims (7)

A projection optical system that projects laser light emitted from a laser light source onto a target area with a predetermined dot pattern;
A light receiving optical system that is arranged so as to be laterally separated by a predetermined distance with respect to the projection optical system, and that captures the target area by an image sensor;
Based on the reference dot pattern imaged by the light receiving optical system when the laser beam is irradiated on the reference surface and the measured dot pattern imaged by the image sensor at the time of actual measurement, up to the object included in the target area A distance acquisition unit that acquires distance information about the distance,
The distance acquisition unit
A first processing route for searching for a displacement position of the segment area set in the reference dot pattern on the measured dot pattern and acquiring the distance information with respect to the segment area based on the searched displacement position; ,
A second processing route for searching for a displacement position on the measured dot pattern of the divided segment area obtained by dividing the segment area, and acquiring the distance information with respect to the segment area based on the searched displacement position; With
A predetermined determination condition for determining whether or not a dot reflected from a position at a different distance is included in the comparison region on the actual measurement dot pattern that is collated with the segment region during the search is satisfied. Based on whether or not to select the first processing route and the second processing route to obtain the distance information,
An information acquisition apparatus characterized by that. The information acquisition device according to claim 1,
The segment area is divided into a first divided segment area and a second divided segment area,
The second processing route preferentially obtains the distance information by the first divided segment area over obtaining the distance information by the second divided segment area.
An information acquisition apparatus characterized by that. The information acquisition device according to claim 2,
The distance acquisition unit
First and second matching calculation units for calculating the degree of matching between the dots in the first and second divided segment areas and the dots on the measured dot pattern, respectively;
An addition unit that obtains a matching degree between the dots on the measured dot pattern of the dots in the segment area by adding the matching degrees obtained by the first and second matching calculation units;
An information acquisition apparatus characterized by that. In the information acquisition device according to claim 2 or 3,
The distance acquisition unit has, as the determination condition, a degree of approach between a displacement position of the first divided segment region on the measured dot pattern and a displacement position of the second divided segment region on the measured dot pattern. Including a condition as to whether it is within a predetermined threshold range, and when the degree of approach is within the threshold range, select the second processing route to obtain the distance information;
An information acquisition apparatus characterized by that. In the information acquisition device according to claim 2 or 3,
The distance acquisition unit includes, as the determination condition, a condition for determining that acquisition of the distance information based on the divided segment region is not appropriate, and when the condition is satisfied, the second processing route To obtain the distance information,
An information acquisition apparatus characterized by that. In the information acquisition device according to any one of claims 2 to 5,
The segment area is divided into a third segment area and a fourth segment area in a second division direction different from a first division direction for dividing the first divided segment area and the second divided segment area. And
The second processing route sets the priority of the distance information acquisition processing in the order of the first divided segment area, the second divided segment area, the third divided segment area, and the fourth divided segment area. Set,
An information acquisition apparatus characterized by that. The information acquisition device according to any one of claims 1 to 6,
An object detection unit that detects a predetermined target object based on the distance information,
An object detection apparatus characterized by that.

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