Information processing apparatus, distance measuring device, distance measuring system, and information processing method

Abstract

To accurately measure a distance to an object even in an environment where there is fog or rain.SOLUTION: An information processing apparatus comprises: a histogram generation unit that generates a histogram indicating a relation between a light reception time and a light reception frequency on the basis of a plurality of light reception signals including reflected light from an object; a first peak detection unit that detects a peak of the light reception frequency in the histogram; a determination unit that determines whether or not a light propagation disturbance factor is present including at least one of fog, haze, mist, rain, or snow, on the basis of the histogram and the light reception time at the peak; a removal unit that, when the determination unit determines that the light propagation disturbance factor is present, removes light reception frequency information according to the light propagation disturbance factor included in the histogram, and extracts the light reception frequency information after the removal; a second peak detection unit that detects a peak of the light reception frequency information after the removal; and a distance measuring unit that measures the distance to the object on the basis of the peak detected by the second peak detection unit.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] FIELD Embodiments of the present invention relate to an information processing device, a distance measuring device, a distance measuring system, and an information processing method. [Background technology]

[0002] With the evolution of LiDAR (Light Detection & Ranging) technology, it is expected that the importance of 3D data recognition and classification technology will increase in the future, just as it does for 2D images.

[0003] Fog or rain is a major factor in degrading the performance of systems that use cameras or sensors such as LiDAR for monitoring, assist or automate various manual tasks, etc. In order to change the control of the system depending on the weather, it is essential to instantly and easily determine the environment such as fog or rain at the lowest possible cost. In addition, fog or rain itself is a factor that significantly degrades the performance of LiDAR. LiDAR often uses infrared light, but infrared light is easily absorbed or scattered by moisture. Therefore, in situations where fog or rain is present, the distance that LiDAR can measure is limited.

[0004] Many existing LiDAR devices have a multi-echo function that selects the true reflected light peak from multiple reflected light peaks. However, when the light intensity of light reflected by particles such as fog or rain is high, the multi-echo function does not work properly and the distance measurement accuracy decreases. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2021-511556 [Patent Document 2] International Publication No. 2020 / 179065 [Patent Document 3] Patent Publication No. 2021-099698 [Non-patent literature]

[0006] [Non-Patent Document 1] https: / / web.media.mit.edu / ~guysatat / fog / Summary of the Invention [Problem to be solved by the invention]

[0007] The embodiments of the present invention provide an information processing device, a distance measuring device, a distance measuring system, and an information processing method that can easily and instantly determine an environment such as fog or rain without incurring any costs. [Means for solving the problem]

[0008] In order to solve the above problems, according to one embodiment of the present invention, there is provided a histogram generating unit that generates a histogram indicating a relationship between a light reception time and a light reception frequency based on a plurality of light reception signals including reflected light from an object; a first peak detection unit that detects a peak of the light reception frequency of the histogram; a determination unit that determines whether or not a light propagation obstruction factor including at least one of fog, mist, haze, rain, or snow is present based on the histogram and the light receiving time of the peak, The determination unit determines whether or not the light propagation disturbance factor exists based on the peak light reception time and a degree of change in the light reception frequency of the histogram before and after the peak light reception time. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram of a distance measuring system including an information processing device according to an embodiment. [Diagram 2] FIG. 2 is a block diagram showing the internal configuration of an information processing unit included in the information processing apparatus according to an embodiment. [Diagram 3] FIG. 2 is a diagram illustrating a schematic view of a state in which a light scanning unit scans an object with light projected thereon. [Figure 4]FIG. 2 is a block diagram showing a schematic configuration of a light receiving section for one pixel of the light detection unit. [Diagram 5] 1 is a flowchart showing a processing operation of an information processing device according to an embodiment. [Figure 6] FIG. 13 is a diagram showing an example of a curve generated by the light reception frequency of each bin of a histogram. [Figure 7] 7 is a diagram showing an example in which a threshold comparison unit detects a first time and a second time using a threshold having a lower signal level than the threshold in FIG. 6; [Figure 8] 5A to 5C are diagrams for explaining the processing of a fitting unit. [Figure 9] 13 is a diagram showing the shape of a curve generated by the light reception frequency of each bin of a histogram when a light propagation obstruction factor exists. [Figure 10A] 13 shows the experimental results of the first experiment in which distance measurement was performed with fog removal switched on and off in a foggy environment with a visibility of 40 m. [Figure 10B] This figure shows the results of an experiment in which distance measurement was performed by switching the rain removal function on and off in a rainy environment with a rainfall of 50 mm / h. [Figure 11] External view of the second experiment. [Figure 12] FIG. 11 shows the results of a second experiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of an information processing device, a distance measuring device, a distance measuring system, and an information processing method will be described with reference to the drawings. The following description will focus on the main components of the information processing device, the distance measuring device, and the distance measuring system, but the information processing device, the distance measuring device, and the distance measuring system may include components and functions that are not shown or described. The following description does not exclude components and functions that are not shown or described.

[0011] Fig. 1 is a block diagram of a distance measuring system 2 including an information processing device 1 according to an embodiment. The distance measuring system 2 in Fig. 1 includes the information processing device 1, a light projecting unit 3, and a light detecting unit 4. In this specification, the information processing device 1 and the light detecting unit 4 are collectively referred to as a distance measuring device 10.

[0012] The light projecting section 3 includes a light source unit 5 and a light scanning section 6. The light source unit 5 intermittently emits a light pulse signal. The light source unit 5 emits a plurality of light pulse signals in a line or a plane.

[0013] The optical scanning unit 6 scans the propagation direction of the optical pulse signal emitted from the light source unit 5 in a one-dimensional or two-dimensional direction. This allows the optical pulse signal to be irradiated onto an object 20 existing in a three-dimensional space. The object 20 may be a stationary object or a moving object. When the light source unit 5 is a surface light-emitting object, the optical scanning unit 6 can be omitted.

[0014] The light detection unit 4 receives a reflected light signal of the light pulse signal irradiated to the object 20. The light detection unit 4 has a plurality of light receiving units 7. The light detection unit 4 receives a reflected light signal incident, for example, within a two-dimensional area. In this specification, the smallest unit within the two-dimensional area where the light detection unit 4 receives a reflected light signal is called a pixel. The light detection unit 4 has a plurality of light receiving units 7 that receive a reflected light signal for each pixel.

[0015] The information processing device 1 measures the distance to the object 20 based on the reflected light signal received by the light detection unit 4, and generates three-dimensional data including distance information of the object 20. The information processing device 1 may generate a two-dimensional image including luminance information of the periphery of the object 20. The information processing device 1 has an information processing unit 8 that measures the distance to the object 20, and an image processing unit 9 that generates three-dimensional data including the distance information of the object 20.

[0016] Fig. 2 is a block diagram showing an internal configuration of an information processing unit 8 included in the information processing device 1 according to an embodiment. As shown in Fig. 2, the information processing unit 8 according to an embodiment includes a histogram generating unit 11, a first peak detecting unit 12, a determining unit 13, a removing unit 14, a second peak detecting unit 15, and a distance measuring unit 16.

[0017] The histogram generating unit 11 generates a histogram indicating the relationship between the light receiving time and the light receiving frequency based on a plurality of light receiving signals including the reflected light from the object 20. The histogram is a graph of the light receiving frequency for each of a plurality of bins each representing a different time. The histogram generating unit 11 generates a histogram for each pixel that receives light by the light receiving unit 7, for example. Alternatively, the histogram generating unit 11 may generate a histogram for each of a plurality of pixels.

[0018] The first peak detection unit 12 detects a peak of the light reception frequency of the histogram generated by the histogram generation unit 11. More specifically, the first peak detection unit 12 detects, as the peak, the light reception frequency in the bin with the maximum light reception frequency of the histogram.

[0019] The determination unit 13 determines whether or not there is a light propagation obstruction factor including at least one of fog, mist, haze, rain, or snow, based on the histogram generated by the histogram generation unit 11 and the light receiving time of the peak detected by the first peak detection unit 12. Fog is a meteorological term that refers to a state in which the visibility is less than 1 km. Mist is a meteorological term that refers to a state in which the visibility is 1 km or more and less than 10 km. Haze is not a meteorological term, but refers to a state in which the visibility is limited by water droplets, dust, dirt, smoke, or the like. The light propagation obstruction factors determined by the determination unit 13 include not only moisture in the atmosphere, but also various particles that make up dust and dirt. Particles such as moisture that can be a light propagation obstruction factor may absorb the light emitted by the light projection unit 3, or may reflect or scatter the light.

[0020] When the determination unit 13 determines that a light propagation disturbance factor exists, the removal unit 14 removes the light reception frequency information due to the light propagation disturbance factor included in the histogram generated by the histogram generation unit 11, and extracts the light reception frequency information after the removal. The histogram generated by the histogram generation unit 11 includes the light reception frequency information of the light reflected by the object 20, the light reception frequency information of the light reflected or scattered by particles or the like that are the light propagation disturbance factor, and the light reception frequency information due to the ambient light. The removal unit 14 performs a process of removing the light reception frequency information of the light reflected or scattered by particles or the like that are the light propagation disturbance factor and the light reception frequency information due to the ambient light from the histogram. The removal unit 14 generates a light reception frequency curve that does not include the light reception frequency information due to the light propagation disturbance factor.

[0021] The second peak detection unit 15 detects peaks of the light-receiving frequency curve after removal by the removal unit 14. That is, the second peak detection unit 15 detects peaks of the light-receiving frequency curve that does not include light-receiving frequency information due to light propagation disturbance factors. When the determination unit 13 determines that no light propagation disturbance factors exist, the second peak detection unit 15 detects the same peak as the peak detected by the first peak detection unit 12.

[0022] Distance measurement unit 16 measures the distance to object 20 based on the peak detected by second peak detection unit 15. This makes it possible to detect peaks without being affected by factors that impede light propagation, such as fog or rain, and therefore makes it possible to accurately measure the distance to object 20 based on the detected peak.

[0023] The image processing unit 9 generates three-dimensional data including the object 20 based on the distance of the object 20 measured by the distance measuring unit 16. The three-dimensional data may be expressed as three-dimensional point cloud data that shows the positions of the distance-measured points in a three-dimensional space, or may be expressed as a distance image that shows the distance by color. The more the number of light projections by the light projection unit 3, the more the number of point clouds included in the three-dimensional data will be, and the less the number of light projections, the fewer the number of point clouds will be. In addition, when the time interval of light projection is constant, the horizontal or vertical interval of the point clouds is determined by the interval at which the viewing angle seen from the light detection unit 4 is divided into a constant angular width. When the angular width of the viewing angle is constant, the number of point clouds included in the object 20 will be greater the closer the object 20 is to the object, and will be smaller the farther the object 20 is to the object.

[0024] The determination unit 13 determines whether or not a factor of optical propagation disturbance exists based on the peak light receiving time and the degree of change in the light receiving frequency of the histogram before and after the peak light receiving time. As a specific example, the determination unit 13 has a threshold comparison unit 17 and a peak time determination unit 18. The threshold comparison unit 17 detects a period during which the light receiving frequency of the histogram is equal to or greater than a predetermined threshold. The peak time determination unit 18 determines whether or not a factor of optical propagation disturbance exists based on the period detected by the threshold comparison unit 17 and the peak light receiving time detected by the first peak detection unit 12.

[0025] In a more specific example, threshold comparison unit 17 detects a first time when the light receiving frequency of the histogram generated by histogram generation unit 11 matches a predetermined threshold, and a second time after the period detected by threshold comparison unit 17 has elapsed since the first time. Peak time determination unit 18 compares a first period from the first time to the peak time with a second period from the peak time to the second time, and determines that a light propagation disturbance factor exists when the second period is longer than the first period by at least a predetermined period.

[0026] The above-mentioned threshold is, for example, a fixed value set based on the average value of the sum of the light reception frequencies of all bins of the histogram. Alternatively, the threshold may be a value that changes according to the light reception frequency of the peak detected by the first peak detection unit 12. Furthermore, the threshold comparison unit 17 may change the threshold in a plurality of ways to change the time length of the period from the first time to the second time. In this case, the determination unit 13 may determine whether or not the second period is longer than the first period by a predetermined period or more for each of the plurality of thresholds, and may finally determine whether or not a light propagation disturbance factor exists based on these determination results.

[0027] Additionally, the information processing device 1 according to an embodiment may include a fitting unit 19. The fitting unit 19 generates a function that fits a curve generated by the light reception frequency of each bin of the histogram generated by the histogram generating unit 11. More specifically, the fitting unit 19 generates a curve of a first function that fits a first curve generated by the light reception frequency of each bin of the histogram from the first time to the peak time detected by the threshold comparing unit 17, and generates a curve of a second function that fits a second curve generated by the light reception frequency of each bin of the histogram from the peak time to the second time.

[0028] The removal unit 14 generates a third curve including the light reception frequency information after the removal by calculating the difference between the first and second curves generated based on the light reception frequency of each bin of the histogram and the curve of the first function and the curve of the second function generated by the fitting unit 19.

[0029] FIG. 3 is a diagram showing a schematic diagram of the manner in which the optical scanning unit 6 scans the object 20 with light projected thereon. The optical scanning unit 6 scans while simultaneously projecting a plurality of light beams from a light source unit 5 having a plurality of laser light sources arranged in one or two dimensions. Each circle in FIG. 3 is a diagram showing a schematic diagram of a beam spot bs of the laser light. The laser light irradiated to the object 20 is reflected by the object 20 and received by the optical detection unit 4. The optical detection unit 4 receives the reflected light from the object 20 in pixel units. The optical detection unit 4 has a light receiving unit 7 for a plurality of pixels.

[0030] 4 is a block diagram showing a schematic configuration of the light receiving section 7 for one pixel of the light detection unit 4. The light receiving section 7 has a silicon photomultiplier (SiPM) 23 having a plurality of single photon avalanche diodes (SPADs) 22, an analog digital converter (ADC) 24, and a memory unit 25.

[0031] The SPAD22 can detect light in units of one photon, and when a photon is detected, the output voltage drops. The detection of light by the SPAD22 is called firing. The SiPM23 has multiple SPAD22, and the greater the amount of light received by the light receiving unit 7, the more SPAD22 fires, and the lower the output voltage of the SiPM23 becomes. Therefore, the ADC24 can output a multi-value digital signal according to the amount of light received by performing AD conversion on the output voltage of the SiPM23. In this specification, the digital signal output by the ADC24 may be called RAW data.

[0032] Fig. 5 is a flowchart showing the processing operation of the information processing device 1 according to an embodiment. The flowchart in Fig. 5 starts after the light receiving unit 7 starts the operation of detecting light in synchronization with the light projecting unit 3 intermittently emitting a light pulse signal.

[0033] First, the histogram generating unit 11 generates a histogram based on the light receiving signal of the light receiving unit 7 (step S1). Next, the first peak detecting unit 12 detects the peak of the light receiving frequency of the histogram (step S2). FIG. 6 is a diagram showing an example of a curve w0 generated by the light receiving frequency of each bin of the histogram. The curve w0 in FIG. 6 shows an example where the light receiving frequency is maximum (peak) in the bin at the light receiving time tp. In the example of FIG. 6, the first peak detecting unit 12 detects the light receiving time tp corresponding to the peak of the curve w0.

[0034] Next, the threshold comparator 17 compares the light reception frequency of the histogram with a threshold and detects a first time and a second time at which the light reception frequency matches the threshold (step S3). In the example of Fig. 6, the threshold comparator 17 detects a first time t1 and a second time t2.

[0035] The first time t1 and the second time t2 change depending on the signal level of the threshold. Fig. 7 is a diagram showing an example in which the threshold comparator 17 detects the first time t1' and the second time t2' using a threshold whose signal level is smaller than the threshold in Fig. 6. The first time t1' in Fig. 7 is earlier than the first time t1, and the second time t2' is later than the second time t2. Therefore, the period T between the first time t1 and the second time t2 is shorter than the period T' between the first time t1' and the second time t2'.

[0036] Next, the peak time determination unit 18 compares a first period LL between the first time t1 and the peak time tp with a second period LR between the peak time tp and the second time t2, and determines whether the second period LR is longer than the first period LL by a predetermined period or more (step S4). That is, it determines whether a factor of optical propagation disturbance exists.

[0037] If it is determined that the second period LR is longer than the first period LL by at least a predetermined period, it is determined that a factor of optical propagation disturbance exists. In the examples of Fig. 6 and Fig. 7, the peak time determination unit 18 determines that the second period LR is longer than the first period LL by at least a predetermined period. The specific length of the predetermined period, which is the difference between the second period LR and the first period LL, can be any length. For example, the predetermined period may be set to a value of at least 10% of the first period LL or the second period LR.

[0038] According to the inventor's verification, the curve shape of the light reception frequency of light reflected or scattered by atmospheric moisture, which is a factor of light propagation obstruction, or particles other than moisture constituting dust and dirt, has the same curve shape as a gamma distribution. If the second period LR is longer than the first period LL by a predetermined period or more, it indicates the presence of a factor of light propagation obstruction, and the curve shape after the peak time of the curve generated by the light reception frequency of each bin of the histogram has the same curve shape as a gamma distribution.

[0039] On the other hand, when no light propagation obstruction factor exists, the shape of the curve generated by the light reception frequency of each bin of the histogram after the peak time becomes the same as that of a Gaussian distribution.

[0040] In this way, the peak time determination unit 18 can determine that a light propagation obstruction factor exists if the curve in the second period LR is a gamma distribution curve, and can determine that a light propagation obstruction factor does not exist if the curve in the second period LR is a Gaussian distribution curve.

[0041] When it is determined in step S4 that a light propagation disturbance factor exists, the fitting unit 19 generates a curve of a function to be fitted to the curve generated by the light reception frequency of each bin of the histogram (step S5). FIG. 8 is a diagram for explaining the processing of the fitting unit 19. The fitting unit 19 performs fitting processing separately for a first period LL before the light reception time tp of the peak and a second period LR after the light reception time of the peak. The reason for performing fitting processing separately for the first period LL and the second period LR is that the curve shapes of the first curve w1 generated by the light reception frequency of each bin of the histogram in the first period LL and the second curve w2 generated by the light reception frequency of each bin of the histogram in the second period LR are different.

[0042] 9 is a diagram showing the shape of a curve w0 generated by the light reception frequency of each bin of a histogram when a light propagation disturbance factor is present. As shown in FIG. 9, the maximum peak of the curve w0 is a peak caused by the light propagation disturbance factor, and the second largest peak is a peak based on the reflected light from the object 20.

[0043] 8, the fitting unit 19 generates a curve w3 of a first function consisting of a linear or quadratic function that passes through two points, the intersection point with the threshold (first time t1) and the peak position (time tp), during the first period LL and matches the shape of the first curve w1 as closely as possible. Similarly, the fitting unit 19 generates a curve w4 of a second function consisting of a linear or quadratic function that passes through two points, the intersection point with the threshold (second time t2) and the peak position (time tp), during the second period LR and matches the shape of the second curve w2 as closely as possible.

[0044] In this way, the fitting unit 19 generates the curve w3 of the first function in the first period LL, and generates the curve w4 of the second function in the second period LR through fitting processing. As can be seen from Fig. 8, there is a large difference between the curve w0 generated based on the light reception frequency of each bin in the original histogram and the curves w3 and w4 generated by the fitting unit 19 around the time when reflected light from the object 20 is received (near time t3).

[0045] Next, the removal unit 14 detects a difference curve between a curve generated by the light reception frequency of each bin of the histogram and the curves of the first and second functions (step S6). The detected difference curve is, for example, a curve (third curve) w5 as shown in Fig. 8, which is a light reception frequency curve that includes reflected light from the object 20 and does not include light due to light propagation obstruction factors.

[0046] Next, the second peak detector 15 detects the peak of the third curve w5 based on the difference in step S5 as a second peak (step S7). The second peak is used to measure the distance to the object 20.

[0047] On the other hand, if it is determined in step S4 that no light propagation obstruction factor is present, the second peak detection unit 15 detects the first peak detected by the first peak detection unit 12 as the second peak without performing processing by the fitting unit 19 and the removal unit 14 (step S8).

[0048] Next, the distance measurement unit 16 measures the distance to the object 20 based on the second peak (step S9).

[0049] (First experiment) The present inventor conducted an experiment (hereinafter referred to as the first experiment) to compare the success rate of distance measurement when the processing of the determination unit 13 and the removal unit 14 was performed and when it was not performed. Hereinafter, performing the processing of the determination unit 13, the fitting unit 19, and the removal unit 14 is referred to as "fog (rain) removal on," and not performing the processing of the determination unit 13, the fitting unit 19, and the removal unit 14 is referred to as "fog (rain) removal off."

[0050] FIG. 10A shows the results of a first experiment in which distance measurement was performed with fog removal switched on and off in a foggy environment with a visibility of 40 m, and FIG. 10B shows the results of an experiment in which distance measurement was performed with rain removal switched on and off in a rainy environment with a rainfall of 50 mm / h.

[0051] 10A and 10B, the horizontal axis is the distance [m] to the object 20, and the vertical axis is the distance measurement success rate [%]. Fig. 10A shows a curve w11 when fog removal is on and a curve w12 when fog removal is off. Fig. 10B shows a curve w13 when rain removal is on and a curve w14 when rain removal is off.

[0052] 10A and 10B, in both a foggy environment and a rainy environment, the success rate of distance measurement of an object 20 located at a distance of more than 15 m can be significantly improved by performing the processing of the determination unit 13, the fitting unit 19, and the removal unit 14. In a foggy environment, the success rate of distance measurement at a distance of more than 40 m decreases even if the processing of the determination unit 13, the fitting unit 19, and the removal unit 14 is performed, but in a rainy environment, the success rate of distance measurement can be maintained high even at a distance of more than 40 m by performing the processing of the determination unit 13, the fitting unit 19, and the removal unit 14.

[0053] (Second experiment) The inventor conducted an experiment (hereinafter referred to as the second experiment) in which multiple objects 20 were placed at equal intervals from the distance measuring device 10 and fog removal was switched on and off to see to which object 20 a distance image could be generated.

[0054] Fig. 11 is an external view of the second experiment. A distance measuring device 10 is placed in the foreground of Fig. 11, and multiple objects 20 are placed at regular intervals from the distance measuring device 10 to a distance far away. The objects 20 are reflectors that reflect light emitted from the light projecting unit 3 of the distance measuring device 10. The second experiment was conducted in a foggy environment with a visibility of 40 m.

[0055] Fig. 12 shows the results of the second experiment. The left side of Fig. 12 shows a group of three-dimensional data showing the results of the experiment when defog is off, and the right side of Fig. 12 shows a group of three-dimensional data showing the results of the experiment when defog is on. As shown in the figure, when defog is on, light from a more distant object 20 can be received stably compared to when defog is off, and the measurable distance can be extended.

[0056] In this manner, in this embodiment, a histogram is generated based on the light reception signal at the light receiving unit 7, and it is determined whether or not a light propagation disturbance factor exists based on the peak position of the histogram and the shape of the curve generated by the light reception frequency of the histogram. If it is determined that a light propagation disturbance factor exists, a curve including the light reception frequency due to the reflected light from the object 20 is generated by removing the light reception frequency due to the light propagation disturbance factor from the light reception frequency of each bin of the histogram, and the distance to the object 20 is measured by detecting the peak of this curve. This allows for highly accurate distance measurement even in an environment where a light propagation disturbance factor exists. The curve including the light reception frequency due to the reflected light from the object 20 can be easily detected by taking the difference between the curve generated by the light reception frequency of each bin of the histogram and the linear or quadratic function curve that is fitted to this curve.

[0057] At least a part of the information processing device 1, the distance measuring device 10, and the distance measuring system 2 described in the above-mentioned embodiment may be configured with hardware or software. When configured with software, a program that realizes at least a part of the functions of the information processing device 1, the distance measuring device 10, and the distance measuring system 2 may be stored in a recording medium such as a flexible disk or a CD-ROM, and may be read and executed by a computer. The recording medium is not limited to a removable one such as a magnetic disk or an optical disk, and may be a fixed recording medium such as a hard disk device or a memory.

[0058] In addition, the programs for realizing at least some of the functions of the information processing device 1, the distance measuring device 10, and the distance measuring system 2 may be distributed via a communication line (including wireless communication) such as the Internet. Furthermore, the programs may be encrypted, modulated, or compressed and distributed via a wired line or wireless line such as the Internet, or stored in a recording medium.

[0059] [Note] [Item 1] a histogram generating unit that generates a histogram indicating a relationship between a light receiving time and a light receiving frequency based on a plurality of light receiving signals including reflected light from an object; a first peak detection unit that detects a peak of the light reception frequency of the histogram; a determination unit that determines whether or not a light propagation obstruction factor including at least one of fog, mist, haze, rain, or snow is present based on the histogram and the light receiving time of the peak, the determination unit determines whether or not the light propagation disturbance factor exists based on the peak light reception time and a degree of change in the light reception frequency of the histogram before and after the peak light reception time. Information processing device. [Item 2] a removal unit that removes light-reception frequency information due to the light-propagation disturbance factor included in the histogram when the determination unit determines that the light-propagation disturbance factor exists, and extracts light-reception frequency information after the removal; a second peak detection unit that detects a peak in the light reception frequency information after the removal; a distance measurement unit that measures a distance to the object based on the peak detected by the second peak detection unit, The information processing device according to claim 1. [Item 3] an image processing unit that generates three-dimensional data including the object based on the distance to the object measured by the distance measuring unit; Item 3. An information processing device according to item 2. [Item 4] The determination unit is a threshold comparison unit that detects a period during which the light reception frequency of the histogram is equal to or greater than a predetermined threshold; and a peak time determination unit that determines whether or not the light propagation disturbance factor exists based on the period and the light receiving time of the peak. Item 2. The information processing device according to item 2 or 3. [Item 5] the threshold comparison unit detects a first time when the light reception frequency of the histogram matches the predetermined threshold and a second time after the first time by the period of time; the peak time determination unit compares a first period from the first time to the peak time with a second period from the peak time to the second time, and determines that the optical propagation disturbance factor exists when the second period is longer than the first period by at least a predetermined period. Item 5. An information processing device according to item 4. [Item 6] a fitting unit that generates a curve of a first function that is fitted to a first curve that is generated by the light reception frequency of each bin of the histogram from the first time to the peak time, and generates a curve of a second function that is fitted to a second curve that is generated by the light reception frequency of each bin of the histogram from the peak time to the second time, the removal unit generates a third curve including the light-reception frequency information after the removal based on a difference between the first curve and the second curve and the curve of the first function and the curve of the second function. Item 5. An information processing device according to item 5. [Item 7] each of the first function and the second function is a linear function or a quadratic function; the fitting unit generates the first function that passes through a first intersection point between the first curve and the threshold value at the first time and the peak, and approximates a shape of the first curve between the first intersection point and the peak, and generates the second function that passes through a second intersection point between the second curve and the threshold value at the second time and the peak, and approximates a shape of the second curve between the second intersection point and the peak. Item 7. An information processing device according to item 6. [Item 8] The second peak detection unit detects a peak of the third curve. Item 8. An information processing device according to item 7. [Item 9] the predetermined threshold is a fixed value that is set based on an average value of the sum of the light reception frequencies of all bins of the histogram; Item 9. An information processing device according to any one of items 4 to 8. [Item 10] The predetermined threshold value varies depending on the frequency of light reception of the peak detected by the first peak detection unit. Item 9. An information processing device according to any one of items 4 to 8. [Item 11] the threshold comparison unit detects a plurality of the periods by changing the threshold in a plurality of ways, the peak time determination unit determines whether or not the optical propagation disturbance factor exists based on each of the plurality of periods and the time of the peak. Item 9. An information processing device according to any one of items 4 to 8. [Item 12] When the determination unit determines that the light propagation disturbance factor does not exist, the second peak detection unit detects the same peak as the peak detected by the first peak detection unit. 12. The information processing device according to any one of items 2 to 11. [Item 13] the determination unit determines that the light propagation disturbance factor exists when a curve generated by the light reception frequency of each bin of the histogram after the time of the peak becomes a gamma distribution curve. 13. The information processing device according to any one of items 2 to 12. [Item 14] the determination unit determines that the light propagation obstruction factor does not exist when a curve generated by the light reception frequency of each bin of the histogram after the time of the peak becomes a Gaussian distribution curve. 13. The information processing device according to any one of items 2 to 12. [Item 15] the removal unit removes the light reception frequency information due to the light propagation disturbance factor and the light reception frequency information due to the ambient light, which are included in the histogram. 15. An information processing device according to any one of items 2 to 14. [Item 16] the histogram generation unit generates the histogram including a light reception frequency due to ambient light, a light reception frequency due to reflected light from the object, and a light reception frequency due to the light propagation obstruction factor when the determination unit determines that the light propagation obstruction factor exists. Item 16. An information processing device according to any one of items 2 to 15. [Item 17] A light receiving unit that repeatedly receives light reflected by an object; The information processing device according to any one of items 2 to 16, Ranging device. [Item 18] A light emitting unit that repeatedly projects light onto the object; A distance measuring device according to item 17, The distance measurement unit measures the distance to the object based on a time difference between a time when the light emitting unit emits light and a time of the peak detected by the second peak detection unit. Ranging system. [Item 19] generating a histogram showing a relationship between a light reception time and a light reception frequency based on a plurality of light reception signals including reflected light from an object; Detecting a peak in the frequency of light reception in the histogram; determining whether or not a light propagation obstruction factor including at least one of fog, mist, or haze is present based on the histogram and the light receiving time of the peak; determining whether or not the light propagation disturbance factor exists based on the peak light reception time and a degree of change in the light reception frequency of the histogram before and after the peak light reception time; Information processing methods.

[0060] The aspects of the present disclosure are not limited to the above-mentioned individual embodiments, but include various modifications that may be conceived by a person skilled in the art, and the effects of the present disclosure are not limited to the above-mentioned contents. In other words, various additions, modifications, and partial deletions are possible within the scope of the conceptual idea and intent of the present disclosure derived from the contents defined in the claims and their equivalents. [Explanation of symbols]

[0061] REFERENCE SIGNS LIST 1 Information processing device, 2 Distance measuring system, 3 Light projection section, 4 Light detection section, 5 Light source unit, 6 Light scanning section, 7 Light receiving section, 8 Information processing section, 9 Image processing section, 10 Distance measuring device, 11 Histogram generation section, 12 First peak detection section, 13 Judgment section, 14 Removal section, 15 Second peak detection section, 16 Distance measurement section, 17 Threshold comparison section, 18 Peak time judgment section, 19 Fitting section, 20 Object, 25 Memory section

Claims

1. a histogram generating unit that generates a histogram indicating a relationship between a light receiving time and a light receiving frequency based on a plurality of light receiving signals including reflected light from an object; a first peak detector for detecting a peak of the light reception frequency of the histogram; a determination unit that determines whether or not a light propagation obstruction factor including at least one of fog, mist, haze, rain, or snow is present based on the histogram and the light receiving time of the peak, the determination unit determines whether or not the light propagation disturbance factor exists based on the peak light reception time and a degree of change in the light reception frequency of the histogram before and after the peak light reception time. Information processing device.

2. a removal unit that removes light-reception frequency information due to the light-propagation disturbance factor included in the histogram when the determination unit determines that the light-propagation disturbance factor exists, and extracts light-reception frequency information after the removal; a second peak detection unit that detects a peak in the light reception frequency information after the removal; a distance measurement unit that measures a distance to the object based on the peak detected by the second peak detection unit. The information processing device according to claim 1 .

3. an image processing unit that generates three-dimensional data including the object based on the distance to the object measured by the distance measuring unit; The information processing device according to claim 2 .

4. The determination unit is a threshold comparison unit that detects a period during which the light reception frequency of the histogram is equal to or greater than a predetermined threshold; and a peak time determination unit that determines whether or not the light propagation disturbance factor exists based on the period and the light receiving time of the peak. The information processing device according to claim 2 .

5. the threshold comparison unit detects a first time when the light reception frequency of the histogram matches the predetermined threshold and a second time after the first time by the period of time; the peak time determination unit compares a first period from the first time to the peak time with a second period from the peak time to the second time, and determines that the optical propagation disturbance factor exists when the second period is longer than the first period by a predetermined period or more. The information processing device according to claim 4.

6. a fitting unit that generates a curve of a first function that is fitted to a first curve that is generated by the light reception frequency of each bin of the histogram from the first time to the peak time, and generates a curve of a second function that is fitted to a second curve that is generated by the light reception frequency of each bin of the histogram from the peak time to the second time, the removal unit generates a third curve including the light-reception frequency information after the removal based on a difference between the first curve and the second curve and a curve of the first function and a curve of the second function. The information processing device according to claim 5 .

7. each of the first function and the second function is a linear function or a quadratic function; the fitting unit generates the first function that passes through a first intersection point between the first curve and the threshold value at the first time and the peak, and approximates a shape of the first curve between the first intersection point and the peak, and generates the second function that passes through a second intersection point between the second curve and the threshold value at the second time and the peak, and approximates a shape of the second curve between the second intersection point and the peak. The information processing device according to claim 6.

8. The second peak detection unit detects a peak of the third curve. The information processing device according to claim 7.

9. the predetermined threshold is a fixed value that is set based on an average value of the sum of the light reception frequencies of all bins of the histogram; The information processing device according to claim 4.

10. the predetermined threshold value varies depending on the frequency of light reception of the peak detected by the first peak detection unit. The information processing device according to claim 4.

11. the threshold comparison unit detects a plurality of the periods by changing the threshold in a plurality of ways, the peak time determination unit determines whether or not the optical propagation disturbance factor exists based on each of the plurality of periods and the time of the peak. The information processing device according to claim 4.

12. When the determination unit determines that the light propagation disturbance factor does not exist, the second peak detection unit detects the same peak as the peak detected by the first peak detection unit. The information processing device according to claim 2 .

13. the determination unit determines that the light propagation disturbance factor exists when a curve generated by the light reception frequency of each bin of the histogram after the time of the peak becomes a gamma distribution curve. The information processing device according to claim 2 .

14. the determination unit determines that the light propagation obstruction factor does not exist when a curve generated by the light reception frequency of each bin of the histogram after the time of the peak becomes a Gaussian distribution curve. The information processing device according to claim 2 .

15. the removal unit removes the light reception frequency information due to the light propagation disturbance factor and the light reception frequency information due to the ambient light, which are included in the histogram. The information processing device according to claim 2 .

16. the histogram generation unit generates the histogram including a light reception frequency due to ambient light, a light reception frequency due to reflected light from the object, and a light reception frequency due to the light propagation obstruction factor when the determination unit determines that the light propagation obstruction factor exists. The information processing device according to claim 2 .

17. A light receiving unit that repeatedly receives light reflected by an object; The information processing device according to claim 2, Ranging device.

18. A light emitting unit that repeatedly projects light onto the object; A distance measuring device according to claim 17, the distance measurement unit measures the distance to the object based on a time difference between a time when the light emitting unit emits light and a time of the peak detected by the second peak detection unit. Ranging system.

19. generating a histogram showing a relationship between a light reception time and a light reception frequency based on a plurality of light reception signals including reflected light from an object; Detecting a peak in the frequency of light reception in the histogram; determining whether or not a light propagation obstruction factor including at least one of fog, mist, or haze is present based on the histogram and the light receiving time of the peak; determining whether or not the light propagation disturbance factor exists based on the peak light reception time and a degree of change in the light reception frequency of the histogram before and after the peak light reception time; Information processing methods.

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