Light detection device, and control method

Abstract

[Problem] To allow suppression of signal saturation. [Solution] A light detection device is provided with: a pixel array unit having a plurality of pixels that output a detection signal in response to detection of light; a light-emitting unit having a plurality of light-emitting element portions that irradiate a detection target with light in correspondence to the plurality of pixels; a measurement unit that measures, for each of the plurality of pixels, the number of times the detection signal has been output while a measurement period from a measurement start time point to a measurement end time point is repeated a predetermined number of times; and a control unit that controls a light detection unit, the light-emitting unit, and the measurement unit. The control unit causes the number of times to be measured in a first period, and controls, in a second period, at least any of a light emission intensity, the number of light emissions, and the length of the second period for each of the plurality of light-emitting element portions on the basis of the number of times for each of the plurality of pixels in the first period.

Description

Photodetection device and control method

[0001] The present disclosure relates to a light detection device and a control method.

[0002] The ToF (Time of Flight) method is often used to measure the distance to a detection target. In this ToF method, light is emitted and the reflected light reflected by the detection target is detected. The ToF method measures the distance to the detection target by measuring the time difference between the timing at which the light is emitted and the timing at which the reflected light is detected (see Patent Document 1).

[0003] JP 2023-10253 A

[0004] However, there is a risk that the signal will saturate at close range or when an object has high reflectivity, resulting in a deterioration in distance accuracy.

[0005] The present disclosure provides a photodetector capable of suppressing signal saturation and a control method thereof.

[0006] In order to solve the above problems, according to the present disclosure, there is provided a light detection device comprising: a pixel array section having a plurality of pixels that output a detection signal in response to the detection of light; a light emitting section having a plurality of light emitting element sections that irradiate a detection target with light corresponding to the plurality of pixels; a measurement section that measures the number of times that the detection signal is output for each of the plurality of pixels while a measurement period from the start of measurement to the end of measurement is repeated a predetermined number of times; and a control section that controls the pixel array section, the light emitting section, and the measurement section, wherein the control section measures the number of times in a first period, and in a second period, controls at least one of the light emission intensity, the number of lights emitted, and the length of the second period for each of the plurality of light emitting element sections based on the number of times for each of the plurality of pixels in the first period.

[0007] The control unit may stop the emission of light from the light-emitting unit during an eleventh period of the first period and measure the number of times, and may shorten the second period as the number of times during the eleventh period increases.

[0008] The control unit may, during a twelfth period of the first period, which is different from the eleventh period, cause the plurality of light-emitting element units to emit light at the start of the measurement and measure the number of times, cause the measurement unit to measure the number of times for each of the plurality of pixels relative to the elapsed time since the measurement started and output of the detection signal during the twelfth period, and during the second period, control at least one of the light-emitting intensity and the number of times for each of the plurality of light-emitting element units based also on the number of times for each of the plurality of pixels during the twelfth period.

[0009] The measurement unit may add the number of times as an integrated value for each elapsed time of the twelfth period, and the control unit may reduce the light-emitting intensity of the corresponding light-emitting element unit during the second period as the maximum value of the integrated value increases.

[0010] The control unit may control the light-emitting intensity of each of the plurality of light-emitting element units according to a subtraction value obtained by subtracting the time average of the number of times in the 11th period from the cumulative value of the number of times for each elapsed time in the 12th period.

[0011] The control unit may decrease the light emission intensity of the corresponding light emitting element unit as the maximum value of the subtraction value increases.

[0012] When the subtraction value does not exceed a predetermined value, the control unit may stop the light emission of the corresponding light-emitting element unit during the second period.

[0013] The eleventh period may be executed before the second period and the twelfth period, and the control unit may stop the light emission of the corresponding light-emitting element unit during the twelfth period and the second period if the number of times during the eleventh period exceeds a predetermined value.

[0014] The control unit may further include a ranging processing unit that, during the second period, causes the measurement unit to add up the number of times the detection signal has been output over the elapsed time from the start of measurement during the measurement period, which is repeated at a predetermined cycle, as an integrated value for each of the plurality of pixels, and generates a distance value for each of the plurality of pixels based on the period from the start of measurement corresponding to the maximum value of the integrated value.

[0015] The control unit may stop light emission of a light-emitting element unit corresponding to a pixel for which the integrated value exceeds a predetermined value during the second period.

[0016] The length of the second period and the number of lights emitted in the second period may be linked, and the number of lights emitted may increase as the second period becomes longer.

[0017] The image pickup device may further include an imaging section having a plurality of imaging pixels for capturing visible light, the imaging range of which corresponds to each of the plurality of pixels.

[0018] The control unit may execute control over the light-emitting element unit and the pixel corresponding to a designated area of ​​the image captured by the imaging unit during the first period and the second period.

[0019] When the value related to the light amount of the instruction area exceeds a predetermined value, the control unit may not execute the control of the first period, but may execute the control of the second period with a predetermined light emission intensity and number of light emissions.

[0020] The control unit may further include an image processing unit that designates the designated area.

[0021] The control unit may change at least one of the number of repetitions and the light emission intensity in the twelfth period according to an algorithm for extracting the designated area in the image processing unit.

[0022] The image processing unit may specify an area to be detected for a particular category.

[0023] The image processor may indicate a region of a particular spatial frequency.

[0024] The image processing unit may specify an area in which a specific image is to be synthesized.

[0025] The control unit may stop irradiation by the light-emitting unit during an eleventh period of the first period and measure the number of times, and during a twelfth period of the first period, which is different from the eleventh period, cause the plurality of light-emitting element units to emit light at the start of the measurement and measure the number of times, and cause the measurement unit to measure the number of times for each of the plurality of pixels during the twelfth period relative to the elapsed time since the start of the measurement when the detection signal was output, and the control unit may control the light-emitting intensity of each of the plurality of light-emitting element units according to a subtraction value obtained by subtracting the time average of the number of times during the eleventh period from the integrated value of the number of times for each elapsed time during the twelfth period, and may lengthen the second period as the number of times during the eleventh period increases.

[0026] In order to solve the above problems, the present disclosure provides a control method for a photodetector including a pixel array unit having a plurality of pixels that output detection signals in response to light detection, and a light-emitting unit having a plurality of light-emitting element units that irradiate a detection target with light corresponding to the plurality of pixels, the control method measuring the number of times the detection signal is output for each of the plurality of pixels during a first period in which a measurement period from a measurement start point to a measurement end point is repeated a predetermined number of times, and controlling at least one of the light emission intensity, the number of lights emitted, and the length of the second period for each of the plurality of light-emitting element units based on the number of times for each of the plurality of pixels during the first period during a second period.

[0027] 1 is a block diagram showing an example of the configuration of a photodetector 1 according to a first embodiment. A diagram showing the correspondence between a plurality of light-emitting element units and a plurality of pixels. A diagram showing the correspondence between another plurality of light-emitting element units and a plurality of pixels. A block diagram showing an example of the configuration of a photodetector. A block diagram showing an example of the configuration of a control unit. A diagram showing an example of a control mode of a drive control unit. A flowchart showing an example of control of a photodetector according to the present embodiment. A block diagram showing an example of the configuration of a photodetector according to a second embodiment. A block diagram showing an example of the configuration of a control unit according to the second embodiment. A schematic diagram showing a designated area in a first algorithm. A schematic diagram showing distance measurement of a designated area and reflecting the distance measurement in autofocus. A schematic diagram showing a designated area in a second algorithm. A schematic diagram showing distance measurement of a designated area and reflecting the distance measurement in the second algorithm. A schematic diagram showing a designated area in a third algorithm. A flowchart showing an example of control of a photodetector according to the second embodiment. A block diagram showing an example of the general configuration of a vehicle control system. An explanatory diagram showing an example of the installation positions of an outside vehicle information detection unit and an imaging unit.

[0028] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0029] First Embodiment [Configuration Example] FIG. 1 is a block diagram showing a configuration example of a photodetector 1 according to a first embodiment. The photodetector 1 is an example of a ToF sensor, and is configured to emit light toward a detection target and detect light reflected by the detection target. The photodetector 1 includes a light emitter 11, an optical system 12, a photodetector 20, and a controller 30. FIG. 1 also shows a main controller (host) 5. For example, if the photodetector 1 is mounted on a vehicle, the main controller 5 may be a monitoring device on the vehicle. For example, the main controller 5 outputs an instruction signal to the photodetector 1 to start imaging, etc. The main controller also executes monitoring processing using a distance image output by the photodetector 1.

[0030] The light emitting unit 11 is configured to emit a light pulse L0 toward the detection target based on an instruction from the control unit 30. The light emitting unit 11 emits the light pulse L0 by performing a light emitting operation that alternately repeats light emission and non-emission based on an instruction from the control unit 30. The light emitting unit 11 has a light source that emits, for example, infrared light. This light source is configured using, for example, a laser light source.

[0031] 2 is a diagram showing the correspondence relationship between the multiple light-emitting element units Lp of the light-emitting unit 11 and the multiple pixels P of the pixel array unit 21 (see FIG. 4) in the light-detecting unit 20. As shown in FIG. 2, the light-emitting unit 11 has multiple light-emitting element units Lp that irradiate light onto the detection target in correspondence with the multiple pixels P. As a result, the light-emitting unit 11 emits a light pulse L0 in a light pattern including multiple spot lights. Return light L1 of the multiple spot lights corresponds to the corresponding multiple pixels P.

[0032] 3 is a diagram showing the correspondence relationship between a plurality of light-emitting element units Lp of another light-emitting unit 11 and a plurality of pixels P of a pixel array unit 21 (see FIG. 4) in the light-detecting unit 20. As shown in FIG. 3, the number of light-emitting element units Lp and the number of pixels P do not have to be the same. As shown in FIG. 3, it is also possible to have a plurality of pixels Pa correspond to a light-emitting element unit La.

[0033] 1 again, the optical system 12 is configured to include a lens that forms an image on the light receiving surface S of the light detection unit 20. Return light L1 that is emitted from the light emitting unit 11 and reflected by the detection target enters the corresponding pixel P in this optical system 12.

[0034] The light detection unit 20 is configured to detect the returning light L1 based on instructions from the control unit 30. The light detection unit 20 then generates a distance image based on the detection result and outputs image data of the generated distance image to the main control unit (Host) 5 as a distance image DT.

[0035] The control unit 30 is configured to supply control signals to the light emitting unit 11 and the light detecting unit 20 and control their operations to thereby control the operation of the light detecting device 1. The control unit 30 has a CPU (Central Processing Unit). Some or all of the functional units of the control unit 30 may be realized by hardware such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), or an FPGA (Field Programmable Gate Array). The control unit 30 will be described in detail later.

[0036] With this configuration, the control unit 30 causes the light emitter 11 and the light detector 20 to perform a measurement in which the measurement period from the start of measurement to the end of measurement is repeated a predetermined number of times. During normal measurement, the control unit 30 causes the light emitter 11 to irradiate a light pulse L0 at the start of measurement. The control unit 30 also causes the light detector 20 to measure the number of times that the returning light L1 is detected during each measurement period. In this case, the light detector 20 can generate a histogram that adds up the number of detections for each elapsed time from the start of measurement to the time that the returning light L1 is detected. The light detector 1 then generates a distance to the detection target for each pixel P based on the histogram.

[0037] 4 is a block diagram showing an example configuration of the light detection unit 20. The light detection unit 20 has a pixel array unit 21, a measurement unit 24, and a distance calculation unit 25. The pixel array unit 21 has a plurality of pixels P that output a pulse detection signal PLS in response to detection of the return light L1.

[0038] The pixel array unit 21 has a plurality of pixels P arranged in a matrix. Each of the plurality of pixels P is configured to generate a pulse detection signal PLS by detecting the return light L1. The pixel P has a photoelectric conversion element that converts light into an electric charge. For example, a single photon avalanche diode (SPAD) can be used as the photoelectric conversion element. These configurations can be general configurations.

[0039] The measurement unit 24 measures the number of times that the pixel P outputs the detection signal PLS while the measurement period from the start of measurement to the end of measurement is repeated a predetermined number of times for each of the plurality of pixels P. The measurement unit 24 can generate a histogram HG for each of the plurality of pixels P, in which the number of detections is added for each elapsed time from the start of measurement to the time when the returning light L1 is detected.

[0040] Based on instructions from the control unit 30, the distance calculation unit 25 calculates the distance value between the light detection device 1 and the measurement target using each of the multiple histograms HG. The distance calculation unit 25 calculates the distance value based on, for example, the elapsed time from the start of measurement of the peak value of the histogram HG. In this way, the distance calculation unit 25 generates a distance image and outputs image data of the generated distance image to the main control unit 5 as data DT.

[0041] The control unit 30 will now be described in detail with reference to Figures 5 and 6. Figure 5 is a block diagram showing an example configuration of the control unit 30. The control unit 30 has a drive control unit 32, a determination unit 34, and a storage unit 36. The control unit 30 configures each unit by, for example, executing a program stored in the storage unit 36. The storage unit 36 ​​stores the program and various data.

[0042] As described above, the drive control unit 32 controls the light emitter 11 and the light detector 20. The drive control unit 32 has a plurality of control modes. The first mode is a preliminary measurement mode, and the second mode is a normal measurement mode. The second mode is a measurement mode based on the measurement result in the first mode.

[0043] 6 is a diagram showing examples of control modes of the drive control unit 32. The horizontal axis indicates measurement time, and from top to bottom, measurement examples are shown for the pixels MP_A to MP_D in each mode. Note that, for simplicity of explanation, the example will be described using the pixels MP_A to MP_D, but similar control is executed for all pixels P of the pixel array unit 21 and for each of the corresponding light-emitting element units Lp of the light-emitting unit 11.

[0044] The first mode period is a first period t1 (preliminary measurement period) from time t10 to time t30, and the second mode period is a second period t2a-t2d (main light emission period) from time t30 to time t40. The first mode period further includes an eleventh period t11 (dummy exposure period) from time t10 to time t20, and a twelfth period t12 (pre-light emission period) from time t20 to time t30.

[0045] In graphs ga11 to gd2, the horizontal axis represents the elapsed time from the start of measurement, and the vertical axis represents the number of times the detection signal PLS is detected for each elapsed time from the start of measurement to the time when the return light L1 is detected. In other words, graphs ga11 to gd2 are histograms in which the number of times the detection signal PLS is detected is added up for each elapsed time.

[0046] Graph ga11 shows the measurement results for pixel MP_A during the eleventh period t11, graph ga12 shows the measurement results for pixel MP_A during the twelfth period t12, and graph ga2 shows the measurement results for pixel MP_A during the second period t2a. Similarly, graph gb11 shows the measurement results for pixel MP_B during the eleventh period t11, graph gb12 shows the measurement results for pixel MP_B during the twelfth period t12, and graph gb2 shows the measurement results for pixel MP_B during the second period t2b. Similarly, graph gc11 shows the measurement results for pixel MP_C during the eleventh period t11, graph gc12 shows the measurement results for pixel MP_C during the twelfth period t12, and graph gc2 shows the measurement results for pixel MP_C during the second period t2c. Similarly, graph gd11 is the measurement result of pixel MP_D in an eleventh period t11, graph gd12 is the measurement result of pixel MP_D in a twelfth period t12, and graph gd2 is the measurement result of pixel MP_D in a second period t2d.

[0047] More specifically, the drive control unit 32 causes the measurement unit 24 to measure the number of times that the detection signal PLS is output for each of the plurality of pixels P while the measurement period from the start to the end of measurement is repeated a predetermined number of times (e.g., 100 times) in the first period t1. Based on the number of times that the detection signal PLS is output for each of the plurality of pixels P, the drive control unit 32 sets the intensity of the light-emitting element unit PL corresponding to each of the pixels MP_A to MP_D and the length of the second periods t2a to t2d. Note that the number of times that the light-emitting element unit PL emits light is linked to the length of the second periods t2a to t2d, and the number of times that the light-emitting element unit PL emits light is calculated by dividing the second periods t2a to t2d by the measurement period.

[0048] Furthermore, during an eleventh period t11 of the first period t1, the drive control unit 32 stops the light emission of the light emitter 11 and causes the light detection unit 20 to perform measurement. As a result, during the eleventh period t11, the light detection unit 20 can measure the intensity of ambient light up to the measurement target.

[0049] Graph gd11 shows the least ambient light, followed by graph ga11. Graphs gb11 and gc11 have almost the same values. As can be seen, the ambient light is least for the measurement of pixel MP_D, followed by the least for the measurement of pixel MP_A. On the other hand, the ambient light is greater for the measurements of pixels MP_B and MP_C. Note that it is not necessary to generate a histogram during the 11th period t11, and the total number of additions of the detection signal PLS may be divided by the 11th period t11.

[0050] Furthermore, during a twelfth period t12 of the first period t1, the drive control unit 32 causes the light emitter 11 to emit light at the start of measurement, causing the light detection unit 20 to perform measurement. This enables the light detection unit 20 to measure the intensity of the return light L1 from the measurement object during the twelfth period t12. The return light L tends to increase as the reflection intensity of the measurement object increases, and also increases as the distance decreases.

[0051] The intensity of the return light L1 is strong in graphs g11 and gb12, and weak in graphs gc12 and gd12. On the other hand, the ambient light is strong for measurements of pixels MP_B and MP_C. As can be seen from this, the intensity of the return light L1 is strong for measurements of pixels MP_A and MP_B, and weak for measurements of pixels MP_C and MP_D.

[0052] Based on the measurement results of the first period t1, the judgment unit 34 judges and sets the second periods t2a to t2d for the pixels MP_A to MP_D and the intensity of the corresponding light-emitting element units Lp so that the measurement accuracy is higher within a range where the histogram does not saturate.

[0053] More specifically, the determination unit 34 shortens the length of the second periods t2a to t2d as the number of detections of the detection signal PLS increases during the eleventh period t11. This reduces the effects of ambient light. Furthermore, during the twelfth period t12, as described above, the drive control unit 32 causes the measurement unit 24 to generate a histogram by adding up the number of detections of the detection signal PL as an integrated value for each elapsed time from the start of measurement. As the maximum integrated value increases, the determination unit 34 reduces the light-emitting intensity of the corresponding light-emitting element unit Lp. This prevents the histogram from saturating even when the reflectivity of the object being measured is high or when the object is close.

[0054] Furthermore, the determination unit 34 determines the light emission intensity of each light-emitting element unit Lp according to a subtraction value obtained by subtracting the time average of the number of detections in the eleventh period t11 from the integrated value of the number of detections for each elapsed time in the twelfth period t12, and sets the intensity for the second period t2a to t2d. This makes it possible to further improve the accuracy of determining the measured intensity. That is, the determination unit 34 determines and sets the light emission intensity of the corresponding light-emitting element unit Lp to be reduced as the maximum value of the subtraction value increases.

[0055] Furthermore, as the number of detections in the eleventh time period t11 increases, the determination unit 34 can lengthen the second time periods t2a to t2d and increase the emission intensity of each light-emitting element unit Lp within a range that does not cause saturation. This makes it possible to increase the number of measurements in the second time periods t2a to t2d. That is, the determination unit 34 determines the emission intensity of each light-emitting element unit Lp according to the subtraction value obtained by subtracting the time average of the number of detections in the eleventh time period t11 from the integrated value of the number of detections for each elapsed time in the twelfth time period t12, and sets the emission intensity of each light-emitting element unit Lp for the second time periods t2a to t2d, which are longer within a range that does not cause saturation.

[0056] Furthermore, the determination by the determination unit 34 includes a determination to stop measurement itself during the second period t2a to t2d. More specifically, if the number of times the detection signal PLS is detected during the eleventh period t11 exceeds a predetermined value, the determination unit 34 stops the light emission of the corresponding light-emitting element unit Lp during the twelfth period t12 and the second periods t2a to t2d. This makes it possible to stop measurement of pixels MP_A to MP_D that are likely to become saturated even if measurement is performed during the second periods t2a to t2d, thereby reducing power consumption.

[0057] Furthermore, if the maximum value of the subtraction value in the twelfth time period t12 exceeds a predetermined value, the determination unit 34 stops the light emission of the corresponding light-emitting element unit Lp in the second time periods t2a to t2d. This makes it possible to stop the measurement of pixels MP_A to MP_D that are likely to become saturated even if measurements are performed in the second time periods t2a to t2d, thereby reducing power consumption.

[0058] The drive control unit 32 performs measurements during the second periods t2a to t2d and at the light emission intensities of the light-emitting element units Lp that are determined by the determination unit 34. This allows the drive control unit 32 to converge the maximum values ​​of the histogram to approximately the same value that is lower than the saturation value, as shown in graphs ga2 to gd2. In this way, saturation can be suppressed while harmonizing the intensities of the ambient light and the return light L1 from the measurement object, thereby further improving measurement accuracy.

[0059] The drive control unit 32 causes the measurement unit to generate a histogram during measurement of the second period t2a to t2d. This enables the determination unit 34 to determine the saturation state of the histogram. Therefore, if a change in the situation during measurement of the second period t2a to t2d causes the maximum value of the histogram to exceed a predetermined value, the drive of the corresponding pixels MP_A to MP_D and light-emitting element unit Lp is stopped. This makes it possible to output a histogram signal Hg before saturation.

[0060] The above is a description of the configuration of the photodetector 1 according to this embodiment, and a control example will be described below. Fig. 7 is a flowchart showing a control example of the photodetector 1 according to this embodiment. In Fig. 7, the left side of line L10 mainly shows an example of control for the light-emitting unit 11, and the area between line L10 and line L20 mainly shows an example of control for the photodetector 20.

[0061] First, a measurement start instruction signal is input from the main control unit 5 to the control unit 30 of the photodetector 1 (step S10), and the drive control unit 32 of the control unit 30 starts pre-driving (step S12). Next, the drive control unit 32 causes each pixel P of the photodetector 20 to detect the detection signal PLS during an eleventh period t11, and causes the measurement unit 24 to measure the number of times the detection signal PLS is detected (step S14). At this time, the drive control unit 32 causes the light emitter 11 to enter a standby state in which light emission is stopped during the eleventh period t11 (step S16).

[0062] Next, the determination unit 34 determines whether there is a pixel P whose number of detections of the detection signal PLS during the eleventh period t11 exceeds a predetermined value (step S18). If the determination unit 34 determines that there is a pixel P whose number of detections is equal to or less than the predetermined value (Y in step S18), the drive control unit 32 causes each pixel P of the light detection unit 20 to detect the detection signal PLS during the twelfth period t12 for that pixel P and causes the measurement unit 24 to measure the number of detections of the detection signal PLS (step S20). At this time, the drive control unit 32 causes the light-emitting element unit Lp corresponding to the pixel P to be measured to perform pre-emission for the twelfth period t12 (step S22).

[0063] Next, the determination unit 34 determines whether the maximum value of the subtraction value in the twelfth period t12 exceeds a predetermined value (step S24). If the determination unit 34 determines that there is a pixel P whose subtraction value is equal to or less than the predetermined value (Y in step S24), the drive control unit 32 sets a second period t2 for that pixel P (step S26) and causes the pixel P to be driven for the second period t2. At this time, the drive control unit 32 sets the second period t2 and a light-emitting intensity for the light-emitting element unit Lp corresponding to the pixel P to be measured (step S30), and causes the light-emitting element unit Lp to emit light for the second period t2 (step S32).

[0064] When the second period t2 for all pixels P ends, the drive control unit 32 outputs the histogram HG generated by the measurement unit 24 to the distance calculation unit 25, calculates the distance value, and outputs it to the main control unit 5 (step S34).

[0065] On the other hand, if the determination unit 34 determines that a pixel P larger than the predetermined value exists (N in step S18), it stops driving the pixel P and puts it into a standby state (step S36). Similarly, if the determination unit 34 determines that a pixel P larger than the predetermined value does not exist (N in step S24), it stops driving the pixel P and puts it into a standby state (step S36).

[0066] The main control unit 5 determines whether or not to end the process (step S38), and if not (N in step S38), repeats the process from step S10. On the other hand, if to end (Y in step S38), the entire process ends.

[0067] As described above, according to this embodiment, the control unit 30 causes the measurement unit 24 to measure the number of times that the detection signal PLS is output for each of the plurality of pixels P during the first period t1 while the measurement period from the start of measurement to the end of measurement is repeated a predetermined number of times. Then, during the second period t2, the control unit 30 controls at least one of the light emission intensity, the number of lights emitted, and the length of the second period t2 for each of the plurality of light-emitting element components P, based on the number of detections for each of the plurality of pixels during the first period t1. This makes it possible to suppress saturation of the histogram in the measurement unit 24, thereby further improving measurement accuracy.

[0068] Furthermore, the first period t1 is divided into an eleventh period t11 and a twelfth period t12, and during the eleventh period t11, the light emission of the light-emitting unit 11 is stopped. This makes it possible to measure the intensity of the ambient light during the eleventh period t11, and during the second period t2, it is possible to harmonize the intensity of the ambient light and the intensity of the return light L1 from the object to be measured, while suppressing saturation of the histogram, thereby enabling further improvement in measurement accuracy.

[0069] Second Embodiment The photodetection device 1 according to the second embodiment differs from the photodetection device 1 according to the first embodiment in that it further includes an imaging unit capable of capturing color images and performs distance measurement within a designated area within an image captured by the imaging unit. The differences from the photodetection device 1 according to the first embodiment will be described below.

[0070] 8 is a block diagram showing an example of the configuration of the photodetector 1 according to the second embodiment. The photodetector 1 according to the second embodiment further includes an imaging unit 40 capable of capturing color images. The imaging unit 40 is, for example, a camera having RGB pixels, and the imaging range of each RGB pixel corresponds to the measurement range of each pixel p of the photodetector 20. Therefore, the drive control unit 32 can match the measurement range of each pixel p of the photodetector 20 to a designated area of ​​the image captured by the imaging unit 40.

[0071] FIG. 9 is a block diagram showing an example configuration of the control unit 30 according to the second embodiment. As shown in FIG. 9 , the control unit 30 according to the second embodiment further includes an image processing unit 38. The image processing unit 38 extracts a designated area from an image captured by the imaging unit 40. For example, the image processing unit 38 has a first algorithm for extracting an area for autofocus as the designated area. The image processing unit 38 also has a second algorithm for extracting a range in which the image is not blurred as the designated area. The image processing unit 38 also has a third algorithm for extracting a range in which a virtual object is to be placed as the designated area. The drive control unit 32 can change at least one of the number of repetitions of the measurement period in the first period t1 and the light emission intensity in the twelfth period t12, depending on the algorithm used by the image processing unit 38.

[0072] FIG. 10 is a schematic diagram showing the designated area Af11 in the first algorithm. This is an example of an error in autofocus in the designated area Af11 in the captured image g130. FIG. 11 is a schematic diagram showing the drive control unit 32 measuring the distance to the designated area Af11 using mode 1 and mode 2, and reflecting the distance image DT in the autofocus of the imaging unit 40. In this way, the imaging unit 40 performs autofocus that reflects the distance image DT, thereby improving the autofocus accuracy in the designated area Af11. Furthermore, because the drive control unit 32 drives only the pixels p within the range corresponding to the designated area Af11, rather than all pixels p, power consumption can be reduced.

[0073] FIG. 12 is a schematic diagram showing the designated area Ar12b in the second algorithm. This shows an example in which blurring of the designated area Ar12b in the captured image g130 other than the area Ar12a on the near side is not performed properly. FIG. 13 is a schematic diagram showing the drive control unit 32 performing distance measurement of the designated area Ar12b using mode 1 and mode 2 and reflecting the distance image DT in the blurring process of the designated area Ar12b by the imaging unit 40. In this way, the imaging unit 40 performs blurring of the designated area Ar12b reflecting the distance image DT, thereby improving the accuracy of the blurring process within the designated area Ar12b. Furthermore, the drive control unit 32 drives only the pixels p within the range corresponding to the designated area Ar12b, rather than all pixels p, thereby reducing power consumption.

[0074] FIG. 14 is a schematic diagram showing the designated area Ar14 in the third algorithm. This is an example in which a virtual object Vr17 is positioned by reflecting the distance image DT of the designated area Ar14 in the captured image g130. In this way, the image capture unit 40 positions the virtual object Vr17 in the designated area Ar14, reflecting the distance image DT, enabling high-performance placement of the virtual object Vr17 that is consistent with perspective. Furthermore, the drive control unit 32 drives only the pixels p within the range corresponding to the designated area Ar14, rather than all of the pixels p, thereby reducing power consumption.

[0075] Fig. 15 is a flowchart showing an example of control of the photodetector 1 according to the second embodiment. Fig. 5 shows the area between lines L20 and L30 as an example of control of the image capture unit 40. As shown in Fig. 15, first, a measurement start instruction signal is input from the main controller 5 to the controller 30 of the photodetector 1 (step S10), and the drive controller 32 of the controller 30 executes image capture by the image capture unit 40 (step S40). Next, the drive controller 32 causes the image processor 38 to extract the designated area (step S42).

[0076] Thereafter, the control example of the photodetector 1 according to the first embodiment differs in that the pixels p in the designated area extracted by the image processing unit 38 and the corresponding light-emitting element units Lp are driven from step S12 to step S34. As described above, according to the present embodiment, only the pixels p and the light-emitting element units Lp in the range corresponding to the designated area Ar14 in the captured image g130 are driven, thereby further reducing power consumption.

[0077] At least a part of the photodetector 1 described in the above embodiment may be configured with hardware or software. In the case of a software configuration, a program that realizes at least a part of the functions of the photodetector 1 may be stored on 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 removable recording media such as magnetic disks and optical disks, but may also be fixed recording media such as hard disk drives and memories.

[0078] In addition, a program that realizes at least a part of the functions of the photodetector 1 may be distributed via a communication line (including wireless communication) such as the Internet. Furthermore, the program may be encrypted, modulated, or compressed and distributed via a wired line or wireless line such as the Internet, or stored on a recording medium.

[0079] <Application Examples of the Technology According to the Present Disclosure> The technology according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of moving body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, a robot, construction machinery, or agricultural machinery (tractor).

[0080] 16 is a block diagram showing a schematic configuration example of a vehicle control system 7000, which is an example of a mobile object control system to which the technology according to the present disclosure can be applied. The vehicle control system 7000 includes a plurality of electronic control units connected via a communication network 7010. In the example shown in FIG. 16, the vehicle control system 7000 includes a drive system control unit 7100, a body system control unit 7200, a battery control unit 7300, an outside-vehicle information detection unit 7400, an inside-vehicle information detection unit 7500, and an integrated control unit 7600. The communication network 7010 connecting these multiple control units may be an in-vehicle communication network conforming to any standard, such as a Controller Area Network (CAN), a Local Interconnect Network (LIN), a Local Area Network (LAN), or FlexRay (registered trademark).

[0081] Each control unit includes a microcomputer that performs arithmetic processing according to various programs, a memory unit that stores the programs executed by the microcomputer or parameters used in various calculations, and a drive circuit that drives various controlled devices. Each control unit includes a network I / F for communicating with other control units via a communication network 7010, and a communication I / F for communicating with devices or sensors inside and outside the vehicle via wired or wireless communication. Figure 16 illustrates the functional configuration of the integrated control unit 7600, including a microcomputer 7610, a general-purpose communication I / F 7620, a dedicated communication I / F 7630, a positioning unit 7640, a beacon receiving unit 7650, an in-vehicle device I / F 7660, an audio / video output unit 7670, an in-vehicle network I / F 7680, and a memory unit 7690. The other control units also include a microcomputer, a communication I / F, a memory unit, and the like.

[0082] The drivetrain control unit 7100 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 7100 functions as a control device for a drive force generating device for generating drive force for the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating braking force for the vehicle. The drivetrain control unit 7100 may also function as a control device for an ABS (Antilock Brake System) or an ESC (Electronic Stability Control), etc.

[0083] A vehicle state detection unit 7110 is connected to the drivetrain control unit 7100. The vehicle state detection unit 7110 includes at least one of a gyro sensor that detects the angular velocity of the axial rotational motion of the vehicle body, an acceleration sensor that detects the acceleration of the vehicle, or a sensor that detects the amount of operation of the accelerator pedal, the amount of operation of the brake pedal, the steering angle of the steering wheel, the engine rotation speed, the rotation speed of the wheels, etc. The drivetrain control unit 7100 performs arithmetic processing using signals input from the vehicle state detection unit 7110, and controls the internal combustion engine, the drive motor, the electric power steering device, the brake device, etc.

[0084] The body system control unit 7200 controls the operation of various devices equipped in the vehicle body according to various programs. For example, the body system control unit 7200 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches can be input to the body system control unit 7200. The body system control unit 7200 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0085] The battery control unit 7300 controls the secondary battery 7310, which is the power supply source for the drive motor, in accordance with various programs. For example, information such as battery temperature, battery output voltage, or remaining battery capacity is input to the battery control unit 7300 from a battery device equipped with the secondary battery 7310. The battery control unit 7300 performs arithmetic processing using these signals, and controls the temperature regulation of the secondary battery 7310 or a cooling device or the like equipped in the battery device.

[0086] The outside vehicle information detection unit 7400 detects information outside the vehicle equipped with the vehicle control system 7000. For example, at least one of an imaging unit 7410 and an outside vehicle information detection unit 7420 is connected to the outside vehicle information detection unit 7400. The imaging unit 7410 includes at least one of a time-of-flight (ToF) camera, a stereo camera, a monocular camera, an infrared camera, and other cameras. The outside vehicle information detection unit 7420 includes at least one of an environmental sensor for detecting the current weather or climate, or a surrounding information detection sensor for detecting other vehicles, obstacles, pedestrians, etc. around the vehicle equipped with the vehicle control system 7000.

[0087] The environmental sensor may be, for example, at least one of a raindrop sensor that detects rain, a fog sensor that detects fog, a sunshine sensor that detects the degree of sunshine, and a snow sensor that detects snowfall. The surrounding information detection sensor may be at least one of an ultrasonic sensor, a radar device, and a LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) device. The imaging unit 7410 and the outside vehicle information detection unit 7420 may each be provided as an independent sensor or device, or may be provided as a device in which multiple sensors or devices are integrated.

[0088] 17 shows an example of the installation positions of the imaging unit 7410 and the vehicle exterior information detection unit 7420. The imaging units 7910, 7912, 7914, 7916, and 7918 are provided, for example, at least one of the front nose, side mirrors, rear bumper, back door, and upper part of the windshield inside the vehicle cabin of the vehicle 7900. The imaging unit 7910 provided on the front nose and the imaging unit 7918 provided on the upper part of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 7900. The imaging units 7912 and 7914 provided on the side mirrors mainly acquire images of the sides of the vehicle 7900. The imaging unit 7916 provided on the rear bumper or back door mainly acquires images of the rear of the vehicle 7900. The imaging unit 7918 provided on the upper part of the windshield inside the vehicle cabin is mainly used to detect leading vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0089] 17 shows an example of the imaging ranges of the imaging units 7910, 7912, 7914, and 7916. Imaging range a indicates the imaging range of the imaging unit 7910 provided on the front nose, imaging ranges b and c indicate the imaging ranges of the imaging units 7912 and 7914 provided on the side mirrors, respectively, and imaging range d indicates the imaging range of the imaging unit 7916 provided on the rear bumper or back door. For example, by overlaying the image data captured by the imaging units 7910, 7912, 7914, and 7916, a bird's-eye view image of the vehicle 7900 viewed from above can be obtained.

[0090] The outside vehicle information detection units 7920, 7922, 7924, 7926, 7928, and 7930 provided on the front, rear, sides, corners, and above the windshield inside the vehicle cabin of the vehicle 7900 may be, for example, ultrasonic sensors or radar devices. The outside vehicle information detection units 7920, 7926, and 7930 provided on the front nose, rear bumper, back door, and above the windshield inside the vehicle cabin of the vehicle 7900 may be, for example, LIDAR devices. These outside vehicle information detection units 7920 to 7930 are mainly used to detect preceding vehicles, pedestrians, obstacles, etc.

[0091] Returning to FIG. 16 , the explanation will be continued. The outside-vehicle information detection unit 7400 causes the imaging unit 7410 to capture an image outside the vehicle and receives the captured image data. The outside-vehicle information detection unit 7400 also receives detection information from the connected outside-vehicle information detection unit 7420. If the outside-vehicle information detection unit 7420 is an ultrasonic sensor, a radar device, or a LIDAR device, the outside-vehicle information detection unit 7400 emits ultrasonic waves or electromagnetic waves and receives information on the received reflected waves. Based on the received information, the outside-vehicle information detection unit 7400 may perform object detection processing or distance detection processing for people, vehicles, obstacles, signs, text on the road, etc. Based on the received information, the outside-vehicle information detection unit 7400 may also perform environmental recognition processing for recognizing rainfall, fog, road conditions, etc. Based on the received information, the outside-vehicle information detection unit 7400 may also calculate the distance to an object outside the vehicle.

[0092] The outside vehicle information detection unit 7400 may also perform image recognition processing or distance detection processing to recognize people, vehicles, obstacles, signs, or characters on the road surface based on the received image data. The outside vehicle information detection unit 7400 may perform processing such as distortion correction or alignment on the received image data, and may also generate an overhead image or a panoramic image by combining image data captured by different image capturing units 7410. The outside vehicle information detection unit 7400 may also perform viewpoint conversion processing using image data captured by different image capturing units 7410.

[0093] The interior information detection unit 7500 detects information inside the vehicle. A driver state detection unit 7510 that detects the driver's state is connected to the interior information detection unit 7500, for example. The driver state detection unit 7510 may include a camera that captures an image of the driver, a biosensor that detects the driver's biometric information, or a microphone that collects sound from within the vehicle cabin. The biosensor is provided, for example, on the seat or steering wheel, and detects the biometric information of a passenger sitting in the seat or the driver gripping the steering wheel. The interior information detection unit 7500 may calculate the driver's level of fatigue or concentration based on the detection information input from the driver state detection unit 7510, or may determine whether the driver is dozing off. The interior information detection unit 7500 may perform processing such as noise canceling on the collected audio signal.

[0094] The integrated control unit 7600 controls the overall operation of the vehicle control system 7000 according to various programs. An input unit 7800 is connected to the integrated control unit 7600. The input unit 7800 may be implemented by a device that can be operated by a passenger, such as a touch panel, a button, a microphone, a switch, or a lever. Data obtained by voice recognition of a voice input through a microphone may be input to the integrated control unit 7600. The input unit 7800 may be, for example, a remote control device using infrared or other radio waves, or an externally connected device such as a mobile phone or a personal digital assistant (PDA) that can operate the vehicle control system 7000. The input unit 7800 may be, for example, a camera, in which case the passenger can input information using gestures. Alternatively, data obtained by detecting the movement of a wearable device worn by the passenger may be input. Furthermore, the input unit 7800 may include, for example, an input control circuit that generates an input signal based on information input by the passenger using the input unit 7800 and outputs the input signal to the integrated control unit 7600. Passengers and the like operate this input unit 7800 to input various data to the vehicle control system 7000 and to instruct processing operations.

[0095] The storage unit 7690 may include a ROM (Read Only Memory) that stores various programs executed by the microcomputer, and a RAM (Random Access Memory) that stores various parameters, calculation results, sensor values, etc. The storage unit 7690 may also be realized by a magnetic storage device such as an HDD (Hard Disc Drive), a semiconductor storage device, an optical storage device, a magneto-optical storage device, or the like.

[0096] The general-purpose communication I / F 7620 is a general-purpose communication I / F that mediates communication with various devices present in the external environment 7750. The general-purpose communication I / F 7620 may implement a cellular communication protocol such as GSM (Global System of Mobile communications), WiMAX (registered trademark), LTE (Long Term Evolution), or LTE-Advanced (LTE-A), or other wireless communication protocols such as a wireless LAN (also referred to as Wi-Fi (registered trademark)) or Bluetooth (registered trademark). The general-purpose communication I / F 7620 may connect to a device (e.g., an application server or a control server) present on an external network (e.g., the Internet, a cloud network, or an operator-specific network) via, for example, a base station or an access point. In addition, the general-purpose communication I / F 7620 may connect to a terminal located near the vehicle (e.g., a terminal of a driver, pedestrian, or store, or an MTC (Machine Type Communication) terminal) using, for example, P2P (Peer To Peer) technology.

[0097] The dedicated communication I / F 7630 is a communication I / F that supports a communication protocol designed for use in vehicles. The dedicated communication I / F 7630 may implement a standard protocol such as WAVE (Wireless Access in Vehicle Environment), which is a combination of a lower layer IEEE 802.11p and an upper layer IEEE 1609, DSRC (Dedicated Short Range Communications), or a cellular communication protocol. The dedicated communication I / F 7630 typically performs V2X communication, which is a concept including one or more of vehicle-to-vehicle communication, vehicle-to-infrastructure communication, vehicle-to-home communication, and vehicle-to-pedestrian communication.

[0098] The positioning unit 7640 performs positioning by receiving, for example, GNSS signals from GNSS (Global Navigation Satellite System) satellites (for example, GPS signals from GPS (Global Positioning System) satellites), and generates position information including the latitude, longitude, and altitude of the vehicle. Note that the positioning unit 7640 may identify the current position by exchanging signals with a wireless access point, or may obtain position information from a terminal such as a mobile phone, PHS, or smartphone that has a positioning function.

[0099] The beacon receiving unit 7650 receives, for example, radio waves or electromagnetic waves transmitted from radio stations or the like installed on the road, and acquires information such as the current location, congestion, road closures, required travel time, etc. The function of the beacon receiving unit 7650 may be included in the dedicated communication I / F 7630 described above.

[0100] The in-vehicle device I / F 7660 is a communication interface that mediates connections between the microcomputer 7610 and various in-vehicle devices 7760 present in the vehicle. The in-vehicle device I / F 7660 may establish wireless connections using wireless communication protocols such as wireless LAN, Bluetooth (registered trademark), NFC (Near Field Communication), or WUSB (Wireless USB). Furthermore, the in-vehicle device I / F 7660 may establish a wired connection such as USB (Universal Serial Bus), HDMI (High-Definition Multimedia Interface), or MHL (Mobile High-Definition Link) via a connection terminal (and a cable, if necessary) not shown. The in-vehicle device 7760 may include, for example, at least one of a mobile device or a wearable device owned by a passenger, or an information device carried into or attached to the vehicle. The in-vehicle device 7760 may also include a navigation device that searches for a route to an arbitrary destination. The in-vehicle device I / F 7660 exchanges control signals or data signals with these in-vehicle devices 7760.

[0101] The in-vehicle network I / F 7680 is an interface that mediates communication between the microcomputer 7610 and the communication network 7010. The in-vehicle network I / F 7680 transmits and receives signals in accordance with a predetermined protocol supported by the communication network 7010.

[0102] The microcomputer 7610 of the integrated control unit 7600 controls the vehicle control system 7000 in accordance with various programs based on information acquired via at least one of the general-purpose communication I / F 7620, the dedicated communication I / F 7630, the positioning unit 7640, the beacon receiving unit 7650, the in-vehicle device I / F 7660, and the in-vehicle network I / F 7680. For example, the microcomputer 7610 may calculate control target values ​​for the driving force generating device, the steering mechanism, or the braking device based on the acquired information inside and outside the vehicle, and output control commands to the drivetrain control unit 7100. For example, the microcomputer 7610 may perform cooperative control aimed at realizing functions of an Advanced Driver Assistance System (ADAS), including vehicle collision avoidance or impact mitigation, following driving based on the following distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane departure warning, etc. In addition, the microcomputer 7610 may perform cooperative control for the purpose of autonomous driving, in which the vehicle travels autonomously without relying on driver operation, by controlling a driving force generating device, steering mechanism, braking device, etc. based on information acquired about the vehicle's surroundings.

[0103] The microcomputer 7610 may generate three-dimensional distance information between the vehicle and objects such as surrounding structures and people, and create local map information including information about the vicinity of the vehicle's current location, based on information acquired via at least one of the general-purpose communication I / F 7620, the dedicated communication I / F 7630, the positioning unit 7640, the beacon receiving unit 7650, the in-vehicle device I / F 7660, and the in-vehicle network I / F 7680. Furthermore, the microcomputer 7610 may predict dangers, such as a vehicle collision, the approach of a pedestrian, or entry into a closed road, based on the acquired information, and generate a warning signal. The warning signal may be, for example, a signal for generating a warning sound or turning on a warning lamp.

[0104] The audio / image output unit 7670 transmits at least one audio and / or image output signal to an output device capable of visually or audibly notifying the vehicle occupants or the outside of the vehicle. In the example of FIG. 16 , an audio speaker 7710, a display unit 7720, and an instrument panel 7730 are illustrated as examples of the output devices. The display unit 7720 may include, for example, at least one of an on-board display and a head-up display. The display unit 7720 may have an AR (Augmented Reality) display function. The output device may also be other devices, such as headphones, a wearable device such as an eyeglass-type display worn by the occupant, a projector, or a lamp. When the output device is a display device, the display device visually displays results obtained by various processes performed by the microcomputer 7610 or information received from other control units in various formats, such as text, images, tables, and graphs. When the output device is an audio output device, the audio output device converts audio signals, such as reproduced audio data or acoustic data, into analog signals and audibly outputs the analog signals.

[0105] In the example shown in FIG. 16 , at least two control units connected via the communication network 7010 may be integrated into a single control unit. Alternatively, each control unit may be composed of multiple control units. Furthermore, the vehicle control system 7000 may include another control unit not shown. In the above description, some or all of the functions performed by one of the control units may be assigned to another control unit. In other words, as long as information is transmitted and received via the communication network 7010, predetermined arithmetic processing may be performed by one of the control units. Similarly, a sensor or device connected to one of the control units may be connected to another control unit, and multiple control units may transmit and receive detection information to and from each other via the communication network 7010.

[0106] A computer program for realizing each function of the photodetector 1 according to this embodiment described with reference to FIG. 1 can be implemented in any control unit or the like. A computer-readable recording medium storing such a computer program can also be provided. Examples of the recording medium include a magnetic disk, an optical disk, a magneto-optical disk, and a flash memory. The computer program may also be distributed, for example, via a network without using a recording medium.

[0107] In the vehicle control system 7000 described above, the light detection device 1 according to this embodiment described with reference to FIG. 1 can be applied to the integrated control unit 7600 of the application example shown in FIG. 16 . For example, the light detection device 1 corresponds to a LIDAR device in the outside-vehicle information detection unit 7420. For example, the outside-vehicle information detection unit 7400 may perform object detection processing or distance detection processing for people, vehicles, obstacles, signs, or text on the road surface based on information received from the light detection device 1. The outside-vehicle information detection unit 7400 may perform environment recognition processing for recognizing rainfall, fog, road conditions, etc. based on the received information. The outside-vehicle information detection unit 7400 may calculate the distance to an object outside the vehicle based on the received information. In this case, since the signal is not saturated, object detection processing, distance detection processing, environment recognition processing, etc. can be performed with higher accuracy.

[0108] 1 may be realized in a module (for example, an integrated circuit module configured on a single die) for the integrated control unit 7600 shown in Fig. 16. Alternatively, the light detection device 1 described using the light detection device 1 shown in Fig. 16 may be realized by a plurality of control units of the vehicle control system 7000 shown in Fig. 16.

[0109] The present technology can be configured as follows:

[0110] (1) A photodetector comprising: a pixel array unit having a plurality of pixels that output a detection signal in response to the detection of light; a light-emitting unit having a plurality of light-emitting element units that irradiate a detection target with light corresponding to the plurality of pixels; a measurement unit that measures the number of times the detection signal is output for each of the plurality of pixels during a measurement period from the start of measurement to the end of measurement, the number of times being repeated a predetermined number of times; and a control unit that controls the pixel array unit, the light-emitting unit, and the measurement unit, wherein the control unit measures the number of times during a first period, and during a second period, controls at least one of the light emission intensity, the number of lights emitted, and the length of the second period for each of the plurality of light-emitting element units based on the number of times for each of the plurality of pixels during the first period.

[0111] (2) The light detection device according to (1), wherein the control unit stops irradiation of the light-emitting unit during an eleventh period of the first period and measures the number of times, and shortens the second period as the number of times during the eleventh period increases.

[0112] (3) The photodetector according to (2), wherein the control unit, during a twelfth period of the first period different from the eleventh period, causes the plurality of light-emitting element units to emit light at the start of measurement and measures the number of times; causes the measurement unit to measure the number of times for each of the plurality of pixels relative to the elapsed time since the start of measurement when the detection signal was output during the twelfth period; and during the second period, controls at least one of the light emission intensity and the number of times of light emission for each of the plurality of light-emitting element units based also on the number of times for each of the plurality of pixels during the twelfth period.

[0113] (4) The photodetector according to (3), wherein the measurement unit adds up the number of times as an integrated value for each elapsed time of the twelfth period, and the control unit reduces the light emission intensity of the corresponding light-emitting element unit as the maximum value of the integrated value increases during the second period.

[0114] (5) The light detection device according to (3) or (4), wherein the control unit controls the light emission intensity of each of the plurality of light-emitting element units according to a subtraction value obtained by subtracting a time average of the number of times in the eleventh time period from an integrated value of the number of times for each elapsed time in the twelfth time period.

[0115] (6) The photodetector according to (5), wherein the control unit reduces the light emission intensity of the corresponding light-emitting element unit as the maximum value of the subtraction value increases.

[0116] (7) The photodetector according to (5) or (6), wherein the control unit stops the light emission of the corresponding light-emitting element unit during the second period when the subtraction value does not exceed a predetermined value.

[0117] (8) The photodetector according to any one of (3) to (7), wherein the eleventh period is executed before the second period and the twelfth period, and the control unit stops the light emission of the corresponding light-emitting element unit during the twelfth period and the second period when the number of times during the eleventh period exceeds a predetermined value.

[0118] (9) The control unit, during the second period, causes the measurement unit to add up the number of times the detection signal has been output over the elapsed time from the start of measurement during the measurement period, which is repeated at a predetermined cycle, as an integrated value for each of the plurality of pixels, and the optical detection device described in any one of (3) to (8) further includes a ranging processing unit that generates a distance value for each of the plurality of pixels based on the period from the start of measurement corresponding to the maximum value of the integrated value.

[0119] (10) The photodetector according to (9), wherein the control unit stops light emission of a light-emitting element unit corresponding to a pixel for which the integrated value exceeds a predetermined value during the second period.

[0120] (11) The photodetector according to any one of (3) to (10), wherein the length of the second period and the number of emissions in the second period are linked, and the number of emissions increases as the second period becomes longer.

[0121] (12) The light detection device according to any one of (3) to (11), further including an imaging unit having a plurality of imaging pixels that capture visible light and whose imaging ranges correspond to the plurality of pixels, respectively.

[0122] (13) The light detection device according to (12), wherein the control unit executes control of the light-emitting element unit and the pixel corresponding to a designated area of ​​the image captured by the imaging unit during the first period and the second period.

[0123] (14) The light detection device according to (13), wherein, when a value relating to the light amount of the indication area exceeds a predetermined value, the control unit does not execute the control for the first period, but executes the control for the second period with a predetermined value of light emission intensity and number of light emissions.

[0124] (15) The light detection device according to (13) or (14), wherein the control unit further includes an image processing unit that designates the designated area.

[0125] (16) The light detection device according to (15), wherein the control unit changes at least one of the number of repetitions and the light emission intensity in the twelfth period according to an algorithm for extracting the designated area of ​​the image processing unit.

[0126] (17) The light detection device according to (16), wherein the image processing unit indicates a region to be detected that is a specific category.

[0127] (18) The light detection device according to (16) or (17), wherein the image processing unit indicates a region of a specific spatial frequency.

[0128] (19) The light detection device according to any one of (16) to (18), wherein the image processing unit indicates an area in which a specific image is to be synthesized.

[0129] (20) The control unit, during an eleventh period of the first period, stops irradiation by the light-emitting unit and measures the number of times, and during a twelfth period of the first period, which is different from the eleventh period, causes the plurality of light-emitting element units to emit light at the start of the measurement and measures the number of times, and causes the measurement unit to measure the number of times for each of the plurality of pixels relative to the elapsed time since the start of the measurement when the detection signal was output during the twelfth period, and the control unit controls the light-emitting intensity for each of the plurality of light-emitting element units in accordance with a subtraction value obtained by subtracting the time average of the number of times during the eleventh period from the integrated value of the number of times for each elapsed time during the twelfth period, and lengthens the second period as the number of times during the eleventh period increases.

[0130] (21) A method for controlling a photodetector including a pixel array unit having a plurality of pixels that output detection signals in response to light detection, and a light-emitting unit having a plurality of light-emitting element units that irradiate a detection target with light corresponding to the plurality of pixels, the method measuring the number of times the detection signal is output for each of the plurality of pixels during a first period in which a measurement period from a measurement start point to a measurement end point is repeated a predetermined number of times, and controlling at least one of the light-emitting intensity, the number of lights emitted, and the length of the second period for each of the plurality of light-emitting element units based on the number of times for each of the plurality of pixels during the first period during a second period.

[0131] The aspects of the present disclosure are not limited to the individual embodiments described above, but include various modifications that may be conceived by those skilled in the art, and the effects of the present disclosure are not limited to the above-described contents. In other words, various additions, modifications, and partial deletions are possible within the scope of the conceptual idea and spirit of the present disclosure, which is derived from the contents defined in the claims and their equivalents.

[0132] 1: photodetector, 11: light-emitting unit, 12: optical system, 20: photodetector, 21: pixel array, 24: measurement unit, 25: distance calculation unit, 30: control unit, 21: pixel array, Lp: light-emitting element unit, P: pixel, t1: first period, t11: eleventh period, t12: thirteenth period, t2: second period

Claims

1. A photodetection device comprising: a pixel array unit having a plurality of pixels that output detection signals in response to the detection of light; a light-emitting unit having a plurality of light-emitting element units that irradiate a detection target with light corresponding to the plurality of pixels; a measurement unit that measures the number of times the detection signal is output for each of the plurality of pixels during a measurement period from the start of measurement to the end of measurement, which is repeated a predetermined number of times; and a control unit that controls the pixel array unit, the light-emitting unit, and the measurement unit, wherein the control unit measures the number of times during a first period, and during a second period, controls at least one of the light emission intensity, the number of lights emitted, and the length of the second period for each of the plurality of light-emitting element units based on the number of times for each of the plurality of pixels during the first period.

2. The optical detection device of claim 1, wherein the control unit stops the emission of the light emitting unit during an eleventh period of the first period and measures the number of times, and shortens the second period as the number of times during the eleventh period increases.

3. The photodetector device of claim 2, wherein the control unit, during a twelfth period of the first period different from the eleventh period, causes the plurality of light-emitting element units to emit light at the start of the measurement and measures the number of times, causes the measurement unit to measure the number of times for each of the plurality of pixels relative to the elapsed time since the start of the measurement when the detection signal was output during the twelfth period, and during the second period, controls at least one of the light emission intensity and the number of times of light emission for each of the plurality of light-emitting element units based also on the number of times for each of the plurality of pixels during the twelfth period.

4. The photodetector according to claim 3, wherein the measurement unit adds up the number of times as an integrated value for each elapsed time of the twelfth period, and the control unit reduces the light emission intensity of the corresponding light-emitting element unit as the maximum value of the integrated value increases during the second period.

5. The optical detection device described in claim 3, wherein the control unit controls the light emission intensity of each of the plurality of light-emitting element units according to a subtraction value obtained by subtracting the time average of the number of times in the 11th period from the integrated value of the number of times for each elapsed time in the 12th period.

6. The photodetector according to claim 5, wherein the control unit reduces the light emission intensity of the corresponding light emitting element unit as the maximum value of the subtraction value increases.

7. The photodetector according to claim 5, wherein the control unit stops the light emission of the corresponding light-emitting element unit during the second period if the subtraction value does not exceed a predetermined value.

8. The photodetector device of claim 3, wherein the 11th period is executed before the second period and the 12th period, and the control unit stops the light emission of the corresponding light-emitting element unit during the 12th period and the second period if the number of times during the 11th period exceeds a predetermined value.

9. The optical detection device described in claim 3, further comprising a distance measurement processing unit that, during the second period, causes the measurement unit to add up the number of times the detection signal has been output over the elapsed time from the start of measurement during the measurement period, which is repeated at a predetermined cycle, as an integrated value for each of the plurality of pixels, and generates a distance value for each of the plurality of pixels based on the period from the start of measurement corresponding to the maximum value of the integrated value.

10. The photodetector according to claim 9, wherein the control unit stops light emission of the light-emitting element units corresponding to pixels for which the integrated value exceeds a predetermined value during the second period.

11. A photodetector according to claim 3, wherein the length of the second period and the number of emissions in the second period are linked, and the number of emissions increases as the second period becomes longer.

12. The light detection device according to claim 3, further comprising an imaging section having a plurality of imaging pixels for capturing visible light, the imaging range of which corresponds to each of the plurality of pixels.

13. The light detection device according to claim 12, wherein the control unit executes control during the first period and the second period for the light emitting element unit and the pixel corresponding to a designated area of ​​the image captured by the imaging unit.

14. The light detection device described in claim 13, wherein the control unit does not execute the control for the first period when the value related to the light amount of the indication area exceeds a predetermined value, but executes the control for the second period with a predetermined value of light emission intensity and number of times of light emission.

15. The light detection device according to claim 13, wherein the control unit further comprises an image processing unit that indicates the designated area.

16. The photodetector according to claim 15, wherein the control unit changes at least one of the number of repetitions and the light emission intensity during the twelfth period in accordance with an algorithm for extracting the designated area in the image processing unit.

17. The light detection device according to claim 16, wherein the image processing unit indicates a region to be detected that is a specific category.

18. The light detection device according to claim 16, wherein the image processing section indicates a region of a particular spatial frequency.

19. The photodetection device according to claim 16, wherein the image processing unit indicates an area in which a particular image is to be synthesized.

20. The photodetector device of claim 1, wherein the control unit stops irradiation of the light-emitting unit during an eleventh period of the first period and measures the number of times, and during a twelfth period of the first period, which is different from the eleventh period, causes the plurality of light-emitting element units to emit light at the start of the measurement and measures the number of times, and causes the measurement unit to measure the number of times for each of the plurality of pixels relative to the elapsed time from the start of the measurement when the detection signal is output during the twelfth period, and the control unit controls the light emission intensity of each of the plurality of light-emitting element units in accordance with a subtraction value obtained by subtracting the time average of the number of times during the eleventh period from the integrated value of the number of times for each elapsed time during the twelfth period, while lengthening the second period as the number of times during the eleventh period increases.

21. A control method for a photodetector comprising: a pixel array unit having a plurality of pixels that output detection signals in response to light detection; and a light-emitting unit having a plurality of light-emitting element units that irradiate a detection target with light corresponding to the plurality of pixels, wherein the number of times the detection signal is output during a first period, in which a measurement period from the start of measurement to the end of measurement is repeated a predetermined number of times, is measured for each of the plurality of pixels; and during a second period, the light-emitting intensity, the number of lights emitted, and / or the length of the second period for each of the plurality of light-emitting element units are controlled based on the number of times for each of the plurality of pixels during the first period.

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