Control device, optical detection system, control method, control program

Abstract

To provide a control device that enhances the distance detection accuracy of an optical sensor.SOLUTION: A processor of a control device is configured to, for each detection frame of acquiring the time distribution of output integration values by integrating a response output Os across multiple detection cycles in which the response output Os of an SPAD pixel is sampled repeatedly with the sampling cycle τs, control reference light whose irradiation timing is aligned with the starting end timing of the detection cycle and plural types of delay light whose irradiation timing is delayed from the starting end timing by the delay cycle τd less than the sampling cycle τs as irradiation light, and output data of a distance according to a specific decomposition period τpb specified from the time distribution of the output integration values as a decomposition period including the response start timing Tb of the SPAD pixel with respect to the reference light in the decomposition periods τp obtained by decomposing the sampling cycle τs by the delay cycle τd for each detection frame.SELECTED DRAWING: Figure 15

Description

Technical Field

[0001] The present disclosure relates to a technique for controlling an optical sensor.

Background Art

[0002] In recent years, optical sensors that receive reflected light from a target with respect to irradiation light irradiated by light emission using SPAD (Single Photon Avalanche Diode) pixels and detect the distance to the target have attracted attention. The disclosed technique of Patent Document 1 for controlling this type of optical sensor generates a histogram and detects the distance by repeatedly sampling and integrating the outputs of SPAD pixels that responded in one detection frame. At this time, the disclosed technique of Patent Document 1 changes the temporal resolution by adjusting the sampling frequency. Therefore, the disclosed technique of Patent Document 1 detects the distance according to the histogram obtained by the latter sampling by resampling the range specified by sampling with a low temporal resolution at a high temporal resolution.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the disclosed technique of Patent Document 1, even if the distance resolution can be ensured according to the higher temporal resolution, the frame rate is limited because two-stage sampling is repeated in a detection frame, so there is a limit to the final distance detection accuracy.

[0005] The object of this disclosure is to provide a control device that improves the accuracy of distance detection by an optical sensor. Another object of this disclosure is to provide an optical detection system that improves the accuracy of distance detection by an optical sensor. Yet another object of this disclosure is to provide a control method that improves the accuracy of distance detection by an optical sensor. Yet another object of this disclosure is to provide a control program that improves the accuracy of distance detection by an optical sensor. [Means for solving the problem]

[0006] The following describes the technical means of solving the problem described in this disclosure. Note that the claims and the reference numerals in parentheses in this section indicate the correspondence with the specific means described in the embodiments detailed later, and do not limit the technical scope of this disclosure.

[0007] The first aspect of this disclosure is, A control device for controlling an optical sensor (10) which has a processor (1b) and detects the distance (Lt) to the target by receiving reflected light from a target (Xt) to an illumination light emitted by light emission using SPAD pixels (46), The processor is, The response output (Os) of the SPAD pixel is repeatedly sampled at a sampling period (τs). The response output is integrated over multiple detection periods (τ) to obtain the time distribution (Ho) of the integrated output value (ΣOs). For each detection frame (Fτ), the irradiation timing is controlled to include a reference light (Lb) aligned with the start timing (T) of the detection period, and multiple types of delayed light (Ld) whose irradiation timing is delayed by a delay period (τd) less than the sampling period from the start timing. The system is configured to output data corresponding to a specific resolution period (τpb) identified from the time distribution of the integrated output value, which is a resolution period (τp) obtained by decomposing the sampling period into delay periods, and which includes the response start timing (Tb) of the SPAD pixel to the reference light.

[0008] A second aspect of this disclosure is, An optical sensor (10) detects the distance (Lt) to the target by receiving the reflected light from the target (Xt) in response to the illumination light emitted by the light emission using SPAD pixels (46), It comprises a control device (1) according to the first embodiment.

[0009] A third aspect of this disclosure is: A control method executed by a processor (1b) to control an optical sensor (10) that detects the distance (Lt) to a target (Xt) by receiving reflected light from a target (Xt) in response to light emitted by emission using SPAD pixels (46), The response output (Os) of the SPAD pixel is repeatedly sampled at a sampling period (τs). The response output is integrated over multiple detection periods (τ) to obtain the time distribution (Ho) of the integrated output value (ΣOs). For each detection frame (Fτ), the irradiation timing is controlled to include a reference light (Lb) aligned with the start timing (T) of the detection period, and multiple types of delayed light (Ld) whose irradiation timing is delayed by a delay period (τd) less than the sampling period from the start timing. This includes outputting data for a distance corresponding to a specific decomposition period (τpb) identified from the time distribution of the output integrated value, which is a decomposition period (τp) obtained by decomposing the sampling period into delay periods for each detection frame, and which includes the response start timing (Tb) of the SPAD pixel to the reference light.

[0010] The fourth aspect of this disclosure is: A control program including instructions executed by a processor (1b) to control an optical sensor (10) which is stored in a storage medium (1a) and detects the distance to the target (Lt) by receiving reflected light from a target (Xt) to an illumination light emitted by light emission using SPAD pixels (46), The order is, The response output (Os) of the SPAD pixel is repeatedly sampled at a sampling period (τs). The response output is integrated over multiple detection periods (τ) to obtain the time distribution (Ho) of the integrated output value (ΣOs). For each detection frame (Fτ), the irradiation timing of a reference light (Lb) aligned with the start timing (T) of the detection period, and multiple types of delayed light (Ld) whose irradiation timing is delayed by a delay period (τd) less than the sampling period from the start timing are controlled as the irradiation light. This includes outputting data for a distance corresponding to a specific decomposition period (τpb) identified from the time distribution of the output integrated value, which is a decomposition period (τp) obtained by decomposing the sampling period into delay periods for each detection frame, and which includes the response start timing (Tb) of the SPAD pixel to the reference light.

[0011] In these first to fourth embodiments, the illumination light is controlled for each detection frame in which the response output of the SPAD pixel is repeatedly sampled at the sampling period, and the response output is integrated over multiple detection cycles to obtain the time distribution of the integrated output value. At this time, a reference light whose illumination timing is aligned with the start timing of the detection cycle, and multiple types of delayed light whose illumination timing is delayed by a delay period less than the sampling period from the start timing are controlled as the illumination light. Therefore, for the reference light and each delayed light, the integrated output value at the SPAD pixel is obtained for each detection frame.

[0012] According to these first to fourth embodiments, among the resolution periods obtained by decomposing the sampling period into delay periods, the resolution period that includes the response start timing of the SPAD pixel to the reference light depends on the distance to the target. At the same time, the resolution period that includes the response start timing of the SPAD pixel to each delay light is shifted by a delay period from the resolution period that includes the response start timing of the SPAD pixel to the reference light. As a result, whether each resolution period that includes the response start timing for each delay light falls within the same sampling period as the resolution period that includes the response start timing for the reference light depends on the distance to the target, which can cause fluctuations in the time distribution of the output integrated value.

[0013] Therefore, according to the first to fourth aspects in which, for each detection frame, a distance corresponding to a specific decomposition period specified from the time distribution of the output integrated value is data-output as a decomposition period including the response start timing with respect to the reference light, the distance resolution can be increased corresponding to a decomposition period shorter than the sampling period. Moreover, since the one-stage sampling process as described above is repeated for each detection frame and the distance is data-output, the frame rate can also be increased. From the above, achieving both high distance resolution and high frame rate enables the realization of high distance detection accuracy.

Brief Description of Drawings

[0014] [Figure 1] It is a block diagram showing the overall configuration of an optical detection system according to an embodiment. [Figure 2] It is a schematic diagram showing the physical configuration of an optical sensor according to an embodiment. [Figure 3] It is a block diagram showing the functional configuration of an optical detection system according to an embodiment. [Figure 4] It is a schematic diagram showing a light projector according to an embodiment. [Figure 5] It is a graph for explaining a detection frame according to an embodiment. [Figure 6] It is a schematic diagram showing a light receiver according to an embodiment. [Figure 7] It is a block diagram showing a configuration example of a SPAD pixel according to an embodiment. [Figure 8] It is a block diagram showing another configuration example of a SPAD pixel according to an embodiment. [Figure 9] It is a graph for explaining a control flow according to an embodiment. [Figure 10] It is a graph for explaining a control flow according to an embodiment. [Figure 11] It is a graph for explaining a control flow according to an embodiment. [Figure 12] It is a graph for explaining a control flow according to an embodiment. [Figure 13] It is a graph for explaining a control flow according to an embodiment. [Figure 14] It is a flowchart showing a control flow according to an embodiment. [Figure 15] It is a graph for explaining a control flow according to an embodiment. [Figure 16] It is a graph for explaining a control flow according to an embodiment. [Figure 17] It is a graph for explaining a control flow according to an embodiment. [Figure 18] It is a graph for explaining a control flow according to an embodiment. [Figure 19] It is a graph for explaining a control flow according to an embodiment. [Figure 20] It is a graph for explaining a control flow according to an embodiment. [Figure 21] It is a graph for explaining a control flow according to an embodiment. [Figure 22] It is a graph for explaining a control flow according to an embodiment. [Figure 23] It is a graph for explaining a control flow according to an embodiment. [Figure 24] It is a graph for explaining a control flow according to an embodiment. [Figure 25] It is a graph for explaining a control flow according to an embodiment. [Figure 26] It is a graph for explaining a control flow according to an embodiment. [Figure 27] It is a graph for explaining a control flow according to an embodiment. [Figure 28] It is a graph for explaining a control flow according to an embodiment. [Figure 29] It is a graph for explaining a control flow according to an embodiment.

Mode for Carrying Out the Invention

[0015] As shown in Figure 1, one embodiment of the present disclosure relates to an optical detection system 2 comprising an optical sensor 10 and a control device 1. The optical detection system 2 is mounted on a vehicle 5, which is a mobile object. The vehicle 5 is a mobile object such as an automobile that can travel on a road with an occupant on board.

[0016] Vehicle 5 is capable of autonomous driving, either on a steady or temporary basis, in an autonomous driving control mode. Here, the autonomous driving control mode may be implemented by autonomous driving control in which the system performs all driving tasks during operation, such as conditional driving automation, advanced driving automation, or full driving automation. The autonomous driving control mode may also be implemented by advanced driving assistance control in which the occupant performs some or all of the driving tasks, such as driving assistance or partial driving automation. The autonomous driving control mode may be implemented by either one of these autonomous driving controls or advanced driving assistance controls, or by a combination of them, or by switching between them.

[0017] In the following explanation, unless otherwise specified, the forward, backward, up, down, left, and right directions are defined relative to the vehicle 5 on the horizontal plane. The horizontal direction refers to the direction parallel to the horizontal plane that serves as the direction reference for the vehicle 5. Furthermore, the vertical direction refers to the direction perpendicular to the horizontal plane that serves as the direction reference for the vehicle 5, which is also the up and down direction.

[0018] The optical sensor 10 is a so-called LiDAR (Light Detection and Ranging / Laser Imaging Detection and Ranging) for acquiring data that can be used for driving control of the vehicle 5, including automatic control driving modes. The optical sensor 10 is positioned at least one location on the vehicle 5, for example, on the front, left and right sides, rear, and roof.

[0019] As shown in Figures 2 and 3, the optical sensor 10 emits light towards a detection area DA within the external space of the vehicle 5, within a range corresponding to its placement and field of view. The optical sensor 10 receives reflected light that is incident on the sensor after the emitted light is reflected from the detection area DA. In response to the reception of the reflected light, the optical sensor 10 detects the target Xt that has reflected light within the detection area DA. In this embodiment, detection means sensing the distance Lt from the optical sensor 10 to the target Xt, as schematically shown in Figure 3.

[0020] In the optical sensor 10 applied to the vehicle 5, a typical target Xt to be detected may be at least one of the following moving objects: for example, pedestrians, cyclists, animals other than humans, and other vehicles. In the optical sensor 10 applied to the vehicle 5, a typical target Xt to be detected may be at least one of the following stationary objects: for example, guardrails, road signs, roadside structures, and objects that have fallen onto the road.

[0021] As shown in Figure 2, the optical sensor 10 comprises a housing 11, an illumination unit 21, a scanning unit 31, and a light receiving unit 41. The housing 11 is box-shaped and has light-shielding properties. The housing 11 houses the illumination unit 21, the scanning unit 31, and the light receiving unit 41 inside. The housing 11 has a light-transmitting cover panel 12. Note that in Figure 2, the portion to the left of the dashed line (cover panel 12 side) is actually a cross-section perpendicular to the portion to the right of the dashed line (units 21 and 41 side).

[0022] As shown in Figures 2 and 3, the irradiation unit 21 includes a light emitter 22 and an irradiation optical system 26. The light emitter 22 is composed of a plurality of laser diodes 24 arranged vertically, as shown in Figure 4. Each laser diode 24 may be an edge emitter laser or a vertical cavity surface-emitting laser (VCSEL). Each laser diode 24 emits light in the near-infrared region that is difficult for humans to see in the external space including the detection area DA of the vehicle 5. The emission of light from each laser diode 24 is performed as pulse emission according to a control signal from the control device 1 each time the detection period τ is repeated a set number of times (in detail, the total cumulative number Ns described later) for each detection frame Fτ shown in Figure 5.

[0023] As shown in Figure 4, the light projector 22 has a light projection window 25 formed on one side of the substrate, which is pseudo-defined by a rectangular contour with its longer side aligned with the vertical direction. The light projection window 25 is constructed as an aggregate of projection apertures in each laser diode 24. The light emitted from the projection aperture of each laser diode 24 is projected from the light projection window 25 as a longitudinal line of illumination light aligned with the vertical direction in the detection area DA. The illumination light may include non-emitting portions in the vertical direction corresponding to the spacing between the laser diodes 24. Even in this case, it is preferable that a line of illumination light is formed in the vertical direction, with the non-emitting portions macroscopically eliminated by diffraction.

[0024] As shown in Figure 2, the illumination optical system 26 guides the illumination light emitted by the light emitter 22 toward the scanning mirror 32 of the scanning unit 31. The illumination optical system 26 has one or more optical lenses to perform at least one type of optical action, such as focusing, collimating, and shaping.

[0025] As shown in Figures 2 and 3, the scanning unit 31 comprises a scanning mirror 32 and a scanning motor 35. The scanning mirror 32 is formed in the shape of a plate with a reflective film deposited on a reflective surface 33, which is one side of a substrate. The scanning mirror 32 is supported by the housing 11 so as to be rotatable around a rotation centerline along the vertical direction. The scanning mirror 32 oscillates within a finite drive range determined by a mechanical or electrical stopper. The scanning motor 35 rotates (i.e., oscillates) the scanning mirror 32 within a finite drive range. At this time, the rotation angle of the scanning mirror 32 changes sequentially with each detection frame Fτ (see Figure 5) according to a control signal from the control device 1.

[0026] The scanning mirror 32 reflects the illumination light incident from the illumination optical system 26 of the illumination unit 21 by its reflective surface 33 and illuminates the detection area DA through the cover panel 12, thereby scanning the area DA according to the rotation angle of the scanning motor 35. In this embodiment, the mechanical scanning of the detection area DA by the illumination light is substantially limited in the horizontal direction.

[0027] The scanning mirror 32 reflects the reflected light incident from the detection area DA through the cover panel 12 towards the light receiving unit 41 using its reflective surface 33, according to the rotation angle of the scanning motor 35. Here, the speed of the illuminated light and the reflected light are sufficiently large compared to the rotational speed of the scanning mirror 32. As a result, the reflected light relative to the illuminated light is further reflected towards the light receiving unit 41 so as to travel in the opposite direction to the illuminated light at the scanning mirror 32, which is rotating at approximately the same angle as the illuminated light.

[0028] The light receiving unit 41 includes a light receiving optical system 42 and a light receiver 45. The light receiving optical system 42 is positioned vertically offset from the illumination optical system 26. The light receiving optical system 42 guides the reflected light incident from the scanning mirror 32 toward the light receiver 45. The light receiving optical system 42 has one or more optical lenses to form an image of the reflected light toward the light receiver 45.

[0029] The photodetector 45 receives reflected light from the detection area DA, which is imaged by the photodetector optical system 42, and generates an output corresponding to the distance Lt to the target Xt. To this end, as shown in Figure 6, the photodetector 45 has a rectangular photodetector surface 47 formed on one side of the substrate, with its longer side aligned with the vertical direction. Reflected light from the target Xt, relative to the irradiated light, is incident on the photodetector surface 47 through the photodetector optical system 42 as a beam that spreads out in a line. The photodetector surface 47 is constructed as a collection of incident surfaces to which reflected light is incident in multiple SPAD pixels 46. Each SPAD pixel 46 is arranged along at least the vertical direction, of which it is aligned with the vertical direction and the horizontal direction.

[0030] As shown in Figures 7 and 8, each SPAD pixel 46 is composed of at least one set of SPAD element 460 and SPAD circuit 461. In the SPAD circuit 461, a bias voltage Vb is applied to the cathode of the SPAD element 460 via a switching element 462. As shown in Figure 5, the switching element 462 controls the light reception period τr, which corresponds to the reflected light, within the detection period τ that is repeated for each detection frame Fτ, according to a control signal from the control device 1. As a result, during the light reception period τr, the SPAD pixel 46 that has responded to the light reception outputs a SPAD voltage Vs that fluctuates with respect to the bias voltage Vb, as shown in Figures 9 to 12.

[0031] As shown in Figures 7 and 8, an inverter 463 is connected to the midpoint between the SPAD element 460 and the switching element 462 in the SPAD circuit 461. As shown in Figures 9 to 12, the inverter 463 outputs a pulse signal during the dead time ω from when the SPAD voltage Vs of the responding SPAD pixel 46 reverses to cross the threshold Vth and then recovers to cross the threshold Vth again. At this time, the pulse signal output from the inverter 463, which is quantized in the amplitude direction, becomes the response output Os of the SPAD pixel 46. Thus, the response start timing (Tb, Td shown in Figures 15 to 18, described later) when the response output Os of the SPAD pixel 46 begins is defined as the timing when the SPAD voltage Vs crosses the threshold Vth to the inverting side.

[0032] As shown in Figures 7 and 8, a sampling circuit 464 is connected to the output side of the inverter 463 in the SPAD circuit 461. The sampling circuit 464 further samples the response output Os as shown in Figures 9 to 12 at each detection period τ, which is repeated for each detection frame Fτ. Through this repeated sampling process, the response output Os of the SPAD pixel 46 is converted into a digital signal value discretized in the time direction.

[0033] Here, as shown in Figure 7, in the photodetector 45, where each SPAD pixel 46 is composed of one set each of SPAD element 460 and SPAD circuit 461, the digital signal value from the sampling circuit 464 is directly provided to the subsequent stage as the response output Os of the SPAD pixel 46. In particular, Figures 9 to 12 and Figures 13, 20 to 25 described later typically show the case where the number of sets of elements 460 and 461 constituting each SPAD pixel 46 is one set, as shown in Figure 7, for the sake of simplicity in explanation.

[0034] On the other hand, as shown in Figure 8, in a photodetector 45 where each SPAD pixel 46 is composed of multiple sets of SPAD elements 460 and SPAD circuits 461, the digital signal values ​​from the sampling circuit 464 of each SPAD pixel 46 are further added to each of these multiple sets by individual adders 48. Here, Figure 8 schematically shows multiple sets of elements 460 and 461 (Figure 8 shows an example of 16 sets) using multiple grids of one SPAD pixel 46. In a photodetector 45 with such a multiple set configuration as shown in Figure 8, the added value by the adder 48 is provided to the next stage as the response output Os of the SPAD pixel 46.

[0035] As shown in Figures 3, 7, and 8, the photodetector 45 is provided with a histogram memory 49 for each SPAD pixel 46. The histogram memory 49 counts the digital signal value or its sum, which is the response output Os of the corresponding SPAD pixel 46, each time the sampling period τs (the period between dashed lines in Figures 9 to 12) is repeated in each detection period τ of each detection frame Fτ, as shown in Figures 9 to 13. From the perspective of the photodetector 45 as a whole, the counted value represents the number of SPAD pixels 46 that responded within one sampling period τs, i.e., the response number Nr.

[0036] For each SPAD pixel 46, the histogram memory 49 acquires and stores an output integrated value ΣOs, which is obtained by accumulating the count value of the response output Os over a total number of integration counts Ns (see Figures 5 and 12), which is multiple times the detection period τ, for each detection frame Fτ. At this time, as shown in Figures 9 to 13, the histogram memory 49 stores the time distribution of the acquired output integrated value ΣOs as a histogram Ho, by aligning the start timing T between detection periods τ for each stacking cycle and accumulating the count value of the response output Os.

[0037] The histogram Ho of the output integrated value ΣOs, stored in the histogram memory 49 for each SPAD pixel 46, is read out by the control device 1 for each detection frame Fτ as shown in Figure 3 and used to output data for the distance Lt to the target Xt. Figures 9 to 13 and Figures 20 to 25 described later schematically show the response output Os, the response number Nr as a count value, and the output integrated value ΣOs using rectangular blocks corresponding to the end timing of each repeated sampling period τs.

[0038] The control device 1 shown in Figures 1, 3, 7, and 8 is connected to the optical sensor 10 via at least one of the following: a LAN (Local Area Network), a wire harness, and an internal bus. The control device 1 is comprised of at least one dedicated computer. The dedicated computer comprising the control device 1 may be a sensor ECU (Electronic Control Unit) specifically designed to control the optical sensor 10, and in this case, the sensor ECU may be housed within the housing 11. The dedicated computer comprising the control device 1 may also be a driving control ECU that controls the operation of the vehicle 5.

[0039] The dedicated computer constituting the control device 1 has at least one memory 1a and one processor 1b, as shown in Figure 1. Memory 1a is at least one type of non-transitory tangible storage medium, such as semiconductor memory, magnetic media, and optical media, which non-temporarily stores programs and data that can be read by the computer. Processor 1b includes at least one type as a core, such as a CPU (Central Processing Unit), GPU (Graphics Processing Unit), RISC (Reduced Instruction Set Computer)-CPU, DFP (Data Flow Processor), and GSP (Graph Streaming Processor).

[0040] The processor 1b executes multiple instructions contained in the control program stored in memory 1a. This allows the control device 1 to construct multiple functional blocks for controlling the optical sensor 10. In this way, the control device 1 constructs multiple functional blocks by having the processor 1b execute multiple instructions from the control program stored in memory 1a for controlling the optical sensor 10. The multiple functional blocks constructed by the control device 1 include the irradiation control block 100 and the output control block 110, as shown in Figure 3.

[0041] Through the combined action of these blocks 100 and 110, the control method by which the control device 1 controls the optical sensor 10 is executed according to the control flow shown in Figure 14. This control flow is repeatedly executed for each detection frame Fτ while the vehicle 5 is starting up. In the control flow, each "S" represents multiple steps executed by multiple instructions included in the control program.

[0042] In control flow S10, the irradiation control block 100 resets the execution count Nd of the detection period τ in the current detection frame Fτ to 0. In control flow S20, the irradiation control block 100 sets the value of the execution count Nd of the detection period τ to the current value, which is incremented by 1.

[0043] In step S30 of the control flow, the irradiation control block 100 controls the irradiation timing of the pulsed irradiation light from the light emitter 22 to a timing where the execution count Nd corresponds to the detection period τ of the current value (see Figures 3, 9-12). Specifically, in step S30, the irradiation control block 100 controls the irradiation light as follows: a single type of reference light Lb whose irradiation timing is matched to the start timing T of the detection period τ, as shown in Figure 9, and multiple types of delayed light Ld whose irradiation timing is delayed by a delay period τd from the said timing T, as shown in Figures 10-12.

[0044] In S30, the irradiation control block 100 assumes that the delay period τd is less than the sampling period τs according to the following equation 1. In equation 1, K is set to a multiplier value of the distance resolution that is increased by this embodiment compared to the normal distance resolution corresponding to the sampling period τs. Therefore, the multiplier value K in this embodiment is matched to the number of decompositions of the decomposition period τp obtained by decomposing the sampling period τs, as shown in Figures 15 to 18 described later. At the same time, the multiplier value K in this embodiment is matched to the total number of types of irradiation light, which is the sum of the number of types of reference light Lb and the number of types of delay light Ld.

number

[0045] In S30, the irradiation control block 100 controls the delay control time t(k) from the start timing T of the detection period τ to the irradiation timing of each irradiation light, as shown in Figures 9 to 12, according to the following equation 2 using the delay period τd in equation 1. In equation 2, k is set to an integer from 0 to K-1 as an alphabetical index for classifying the type of irradiation light. Here, k=0 as exemplified in Figure 9, where K=4, represents the reference light Lb, whose irradiation timing matches the start timing T of the detection period τ, due to the delay control time t(k)=0 according to equation 2.

[0046] On the other hand, k=1 to K-1() in equation 2 represent multiple types of delayed light Ld, each with a different delay control time t(k) at which the irradiation timing is delayed from the start timing T of the detection period τ. In particular, k=1, as exemplified in Figure 10 for the case of K=4, represents the first delayed light Ld1, which is controlled by equation 2 to a delay control time t(k) = τd, among the multiple types of delayed light Ld. Similarly, k=2, as exemplified separately in Figure 11 for the case of K=4, represents the second delayed light Ld2, which is controlled by equation 2 to a delay control time t(k) = 2·τd, among the multiple types of delayed light Ld. Furthermore, k=3, as exemplified yet again in Figure 12 for the case of K=4, represents the third delayed light Ld3, which is controlled by equation 2 to a delay control time t(k) = 3·τd, among the multiple types of delayed light Ld.

number

[0047] In S30, the irradiation control block 100 controls the delay control time t(k) for all types of delayed light Ld1, Ld2, and Ld3 corresponding to k=1 to K-1 to be less than the dead time ω of the SPAD pixel 46 according to the following equation 3. In this case, if the maximum delay control time t(K-1) at k=K-1 satisfies equation 3, then the other delay control times t(k) will also necessarily satisfy equation 3.

number

[0048] In S30, the irradiation control block 100 controls the number of individual irradiations Ni for each type of irradiation light corresponding to k=0 to K-1, according to the following number 4, as shown in Figures 9 to 12 (three times each in the examples in Figures 9 to 12). At this time, the reference light Lb, the first delay light Ld1, the second delay light Ld2, and the third delay light Ld3 are controlled to be irradiated in this order for each individual irradiation number Ni. However, the order in which each type of irradiation light is irradiated may be changed, as long as each type of irradiation light is irradiated for each individual irradiation number Ni during the detection frame Fτ.

number

[0049] In S30, the irradiation control block 100 controls the rotation angle of the scanning mirror 32 to an angle θ that matches the detection period τ for the current execution count Nd (see Figure 3). At this time, it can be assumed that the rotation angle of the scanning mirror 32 is substantially the same for each detection period τ, for example, every 2000 ns, within the current detection frame Fτ. Therefore, it can also be said that in S30, the rotation angle of the scanning mirror 32 is controlled to match the angle of the current detection frame Fτ.

[0050] As shown in Figure 14, in the control flow S40, the output control block 110 controls the light reception period τr at each SPAD pixel 46 in the detection period τ where the execution count Nd is the current value, in accordance with the start timing T of the period τ when the irradiation of the irradiation light is started by the irradiation control block 100 (see Figures 3, 9-12). At this time, the light reception period τr is set to a common length of time that is substantially independent of the execution count Nd, starting from the control signal that triggers the irradiation control by S30. As a result, in S40 as shown in Figures 9-13, the histogram Ho of the output integrated value ΣOs, obtained by integrating the response output Os for each SPAD pixel 46 over the entire detection period τ up to the execution count Nd of the current value, is stored in the histogram memory 49 for each SPAD pixel 46.

[0051] In this S40, the number of individual integrations Na, which are the number of times the response output Os is integrated for each type of irradiation light, out of the total number of integrations Ns of the response output Os integrated in the current detection frame Fτ, coincides with the number of individual irradiations Ni, as shown in Figures 9-12 and Equation 4 above, resulting in a common number of times for each. Furthermore, in S40, it can be said that the histogram Ho is stored in the histogram memory 49 as the time distribution of the output integrated value ΣOs obtained by integrating the number of responses Nr of the SPAD pixels 46 for each type of irradiation light.

[0052] As shown in Figure 14, in control flow S50, the output control block 110 determines whether the number of executions Nd of the detection period τ with the light reception period τ controlled has reached the total number of cumulative executions Ns of the response output Os. If the result is negative (see Figures 9-11, 13), the control flow returns to S20. On the other hand, if the result is positive (see Figure 12), the control flow proceeds to S60.

[0053] In step S60 of the control flow, the output control block 110 obtains a histogram Ho of the output integrated value ΣOs spanning the entire detection period τ for the total number of integrations Ns from the histogram memory 49 for each SPAD pixel 46 (see Figures 3, 12 and Figures 21-25 described later). Then, in step S60, the output control block 110 outputs the detection result of the distance Lt to the target Xt based on the histogram Ho of the output integrated value ΣOs for each SPAD pixel 46 (see Figure 3).

[0054] Specifically, the output control block 110 in S60 assumes a decomposition period τp obtained by decomposing the sampling period τs, which is repeated within the detection period τ, into delay periods τd, as shown in Figures 15-18. In this case, for example, if a sampling period τs of 1 ns is assumed to be decomposed into delay periods τd of 0.25 ns, the number of decompositions in the decomposition period τp within the same period τs becomes equal to the expected magnification value K of the distance resolution (4 in Figures 15-18, corresponding to these example times).

[0055] Under these assumptions, as shown in Figure 15, the response start timing Tb of the SPAD pixel 46 to the reference light Lb occurs in the sampling period τs shown in Figure 15, and the resolution period τp (i.e., τpb described later) that includes this timing Tb depends on the distance Lt to the target Xt. At the same time, as shown in Figures 16-18, the resolution period τp that includes the response start timing Td of the SPAD pixel 46 to each delayed light Ld1, Ld2, Ld3 is shifted by a delay period τd from the resolution period τp that includes the response start timing Tb of the SPAD pixel 46 to the reference light Lb.

[0056] Therefore, whether each resolution period τp containing the response start timing Td for each delayed light Ld1, Ld2, and Ld3 falls within the same sampling period τs as the resolution period τp containing the response start timing Tb for the reference light Lb depends on the distance Lt to the target Xt. That is, the sampling period τs at which the response start timing Td for each delayed light Ld1, Ld2, and Ld3 occurs will have a time relationship with the sampling period τs at which the response start timing Tb of the SPAD pixel 46 for the reference light Lb occurs, which will be either the same period or a later period, depending on the distance Lt.

[0057] As shown in Figure 15, the time difference from the initial timing Ts of the sampling period τs at which the response start timing Tb of the SPAD pixel 46 with respect to the reference light Lb occurs, to that timing Tb, is defined as the response timing difference ΔT. At the same time, the elapsed time from the initial timing Ts to the start timing of each resolution period τp in the sampling period τs at which the response start timing Tb occurs is defined as the resolution shift time δ(κ) according to the following equation 5, using the delay period τd of equation 1, which is the length of those resolution periods τp. In equation 5, κ is set to an integer from 0 to K-1 as the Greek letter index that identifies the resolution period τp in which the response start timing Tb is contained. Figure 15 shows representative examples of the resolution shift time δ(κ) up to the resolution period τp (more specifically τpb described later) in which the response start timing Tb is contained, and the resolution shift time δ(κ+1) up to the next resolution period τp.

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[0058] Under these definitions, in the sampling period τs at which the response start timing Tb of the reference light Lb occurs, the resolution period τp that satisfies the following equation 6 in relation to the resolution shift times δ(κ) and δ(κ+1) of the reference light Lb, where the response timing difference ΔT of the reference light Lb occurs, represents the specific resolution period τpb that includes that timing Tb. As a result, as shown in Figures 15-19, the response start timing Td for each delayed light Ld1, Ld2, and Ld3 can be said to occur in the same period τs or a later period τs as the response start timing Tb, depending on the response timing difference ΔT that determines the resolution shift time δ(κ) of the specific resolution period τpb. Note that Figures 15-18 illustrate the case where κ=2 in equation 6 in Figure 19.

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[0059] This temporal relationship of the sampling period τs is established when, for each resolution period τp whose length coincides with the delay period τd, the delay control time t(k) of each delay light Ld1, Ld2, Ld3, whose length corresponds to the period τd, satisfies the above equation 3. In other words, if the delay control time t(k) of at least one of the delay lights Ld1, Ld2, Ld3 is greater than or equal to the dead time ω, then, as shown in Figure 20, a multimodal pattern appears in the temporal distribution of the integrated output value ΣOs in the histogram Ho, and the above temporal relationship of the sampling period τs fails to hold.

[0060] From the above findings, in the histogram Ho spanning the entire detection period τ over the total number of integration counts Ns, the time distribution of the integrated output value ΣOs will fluctuate as shown in Figure 21, according to the response timing difference ΔT that determines the resolution shift time δ(κ) of a specific resolution period τpb. Therefore, the output control block 110 in S60 identifies a specific resolution period τpb from the time distribution of the integrated output value ΣOs represented by the histogram Ho.

[0061] In detail, the identification in S60 is based on the value of interest ΣOsp, which is the output integrated value ΣOs at the previous period τsp (the previous sampling period τs) relative to the saturation period τss (the sampling period τs) at which the output integrated value ΣOs first reached the saturation value ΣOss for each detection frame Fτ, as shown in Figures 22-25. Here, the saturation value ΣOss is set to the upper limit of the response according to the following number 7, where Ne (see Figures 7 and 8) is the number of pairs of elements 460 and 461 in each SPAD pixel 46.

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[0062] In S60, the output control block 110 outputs the distance Lt to the target Xt as a detection result corresponding to a specific resolution period τpb. At this time, the output control block 110 detects a distance Lt that correlates with the distance measurement time ε from the reference timing T0 (see Figure 5), which is defined at the start timing T of the detection period τ controlled for the first time in each detection frame Fτ, to the specific resolution period τpb shown in Figures 26-29.

[0063] Here, the distance measurement time ε is expressed by equation 8, which is the number of preceding periods Np (see Figure 12), where Np is the number of preceding sampling periods τs that precede the initial timing Ts of the sampling period τs to which the specific resolution period τpb belongs, after the reference timing T0 in the current detection frame Fτ. In particular, in the example shown in Figures 22 and 26, where the value of interest ΣOsp satisfies the following equation 9 when K=4, the resolution period τp at κ=0 is identified as the specific resolution period τpb belonging to the saturation period τss, and the distance Lt is detected according to the following equation 10. In equation 10, C is the speed of light.

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[0064] On the other hand, in the example shown in Figures 23 and 27 where the value of interest ΣOsp satisfies equation 11 when K=4, the decomposition period τp with κ=1 is identified as a specific decomposition period τpb belonging to the previous period τsp, and the distance Lt is detected according to equation 10. In another example shown in Figures 24 and 28 where the value of interest ΣOsp satisfies equation 11 when K=4, the decomposition period τp with κ=2 is identified as a specific decomposition period τpb belonging to the previous period τsp, and the distance Lt is detected according to equation 10. In the example shown in Figures 25 and 29 where the value of interest ΣOsp satisfies equation 11 when K=4, the decomposition period τp with κ=3 is identified as a specific decomposition period τpb belonging to the previous period τsp, and the distance Lt is detected according to equation 10.

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[0065] In S60, the output control block 110 stores the distance Lt detected according to the specific decomposition period τpb in at least one of the memory 1a in the control device 1 and the storage medium 5a (see Figure 1) in the vehicle 5 by outputting its data. The output control block 110 in S60 may also transmit the distance Lt detected according to the specific decomposition period τpb to the outside of the vehicle 5 via the communication unit 5b (see Figure 1) in the vehicle 5 by outputting its data.

[0066] (Effects and Benefits) The effects and advantages of this embodiment, as described above, will be explained below.

[0067] In this embodiment, the illumination light is controlled for each detection frame Fτ, in which the response output Os of the SPAD pixel 46 is repeatedly sampled with a sampling period τs, and the response output Os is integrated over multiple detection periods τ to obtain the time distribution (specifically, histogram Ho) of the integrated output value ΣOs. At this time, a reference light Lb whose illumination timing is aligned with the start timing T of the detection period τ, and multiple types of delayed lights Ld (specifically Ld1, Ld2, Ld3) whose illumination timing is delayed by a delay period τd less than the sampling period τs from the start timing T are controlled as the illumination light. Therefore, for the reference light Lb and each delayed light Ld, the integrated output value ΣOs at the SPAD pixel 46 is obtained for each detection frame Fτ.

[0068] According to this embodiment, among the resolution periods τp obtained by decomposing the sampling period τs into delay periods τd, the resolution period τp that includes the response start timing Tb of the SPAD pixel 46 to the reference light Lb depends on the distance Lt to the target Xt. At the same time, the resolution period τp that includes the response start timing Td of the SPAD pixel 46 to each delay light Ld will be shifted by a delay period τd from the resolution period τp that includes the response start timing Tb of the SPAD pixel 46 to the reference light Lb. As a result, whether each resolution period τp that includes the response start timing Tb for each delay light Ld falls within the same sampling period τs as the resolution period τp that includes the response start timing Tb for the reference light Lb depends on the distance Lt to the target Xt, which can cause fluctuations in the time distribution of the output integrated value ΣOs.

[0069] Therefore, in this embodiment, for each detection frame Fτ, a distance Lt corresponding to a specific resolution period τpb identified from the time distribution of the integrated output value ΣOs is output as data, which includes the response start timing Tb to the reference light Lb as the resolution period τp. This allows for increasing the distance resolution in relation to a resolution period τp that is less than the sampling period τs. Moreover, since the above-described one-step sampling process is repeated for each detection frame Fτ to output the distance Lt as data, the frame rate can also be increased. Thus, by achieving both high distance resolution and a high frame rate, high distance detection accuracy can be realized.

[0070] In this embodiment, for each detection frame Fτ, data is output for a distance Lt corresponding to a specific resolution period τpb, which is determined based on the output integrated value ΣOs at the previous sampling period τs (specifically τsp), with respect to the sampling period τs (specifically τss) at which the output integrated value ΣOs reaches the saturation value ΣOss. This allows for the accurate determination of a specific resolution period τpb, including the response start timing Tb with respect to the reference light Lb, from the output integrated value ΣOs at the previous sampling period τs, which fluctuates within a range below the saturation value ΣOss depending on the distance Lt to the target Xt. Therefore, it is possible to improve not only the distance resolution but also its resolution accuracy, contributing to the realization of high distance detection accuracy.

[0071] In this embodiment, for each detection frame Fτ, data is output showing the distance Lt correlated with the distance measurement time ε, from the start timing T (specifically T0) of the initial detection period τ to a specific resolution period τpb. This allows for the accurate determination of the distance measurement time ε, which depends on the distance Lt to the target Xt, from the start of detection to the response start timing Tb for the reference light Lb, within a resolution period τp that is less than the sampling period τs. Therefore, it is possible to improve reliability in distance resolution accuracy and, consequently, distance detection accuracy.

[0072] In this embodiment, for each detection frame Fτ, the delay control time t(k) from the start timing T of the detection period τ to the irradiation of each delay light Ld is set to less than the dead time ω of the SPAD pixel 46. This prevents the situation in which it becomes difficult to accurately identify a specific resolution period τpb due to the appearance of multimodality in the time distribution of the output integrated value ΣOs. Therefore, it is possible to improve not only the distance resolution but also its resolution accuracy, contributing to the realization of high distance detection accuracy.

[0073] In this embodiment, for each detection frame Fτ, a distance Lt corresponding to a specific resolution period τpb is output as data and stored in at least one of memory 1a and storage medium 5a. This makes it possible to read the distance Lt data with improved accuracy from the storage location and use it, for example, for the automatic driving of vehicle 5.

[0074] In this embodiment, for each detection frame Fτ, the specific resolution period τpb is determined from the time distribution of the integrated output value ΣOs, where the number of individual integration counts Na of the response output Os for each of the reference light Lb and each delay light Ld is set to a common multiple number of times. This prevents the situation in which fluctuation errors in the integrated output value ΣOs caused by disturbances affect the determination of the specific resolution period τpb. Therefore, it is possible to improve not only the distance resolution but also its resolution accuracy, contributing to the realization of high distance detection accuracy. At the same time, it is possible to avoid a situation in which the processing load for determining the specific resolution period τpb increases due to the complexity of the fluctuation pattern given to the time distribution of the integrated output value ΣOs caused by the difference in the number of individual integration counts Na between types of irradiated light. Therefore, it is possible to shorten the processing time until data output and increase the frame rate.

[0075] In this embodiment, for each detection frame Fτ, the number of responses Nr of the SPAD pixels 46 is integrated as the response output Os for the reference light Lb and each delayed light Ld. According to this, whether each resolution period τp including the response start timing Tb for each delayed light Ld falls within the same sampling period τs as the resolution period τp including the response start timing Tb for the reference light Lb can cause a time-axis variation in the number of responses Nr of the SPAD pixels 46. Therefore, according to this embodiment, it is possible to achieve distance Lt data output with increased resolution according to a specific resolution period τpb identified from the time distribution of the integrated output value ΣOs obtained by integrating the number of responses Nr of the SPAD pixels 46. Thus, it becomes possible to achieve high distance detection accuracy.

[0076] (Other embodiments) Although one embodiment has been described above, this disclosure is not to be construed as being limited to the embodiment described herein, and can be applied to various embodiments without departing from the gist of this disclosure.

[0077] In the modified example, the dedicated computer constituting the control device 1 may have at least one of the digital circuit and analog circuit as a processor. Here, the digital circuit is at least one of the following, for example, ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), SOC (System on a Chip), PGA (Programmable Gate Array), and CPLD (Complex Programmable Logic Device). Furthermore, such a digital circuit may have a memory that stores a program.

[0078] In this modified example, the individual cumulative counts Na (i.e., individual irradiation counts Ni) may differ between at least two types of irradiation light. In this modified example, for example, when the total cumulative count Ns is not divisible by the magnification value of the distance resolution (i.e., the number of resolutions in the resolution period τp and the total number of types of irradiation light) K, it is preferable to set the difference between counts Na (i.e., the difference between counts Ni) to be minimized.

[0079] In modified versions, various scanning methods may be employed for the scanning unit 31, such as a mechanical oscillation type limited to the horizontal direction as in the above-described embodiment, a mechanical oscillation type limited to the vertical direction, or a mechanical oscillation type in both the horizontal and vertical directions. In modified versions, a solid-state unit such as a MEMS (Micro Electro Mechanical Systems) may be used instead of units 21 and 31, provided that the irradiation of the illumination light can be controlled by the control device 1.

[0080] In the modified examples, the vehicle 5 to which the control device 1, optical detection system 2, control method, and control program are applied may be, for example, an autonomous robot capable of transporting cargo or collecting information by autonomous driving or remote driving. In addition to the embodiments described so far, the above embodiments and modified examples may be implemented in the form of a semiconductor device (e.g., a semiconductor chip) as a control device configured to be mounted on the vehicle 5 and having at least one memory 1a and one processor 1b.

[0081] (Additional note) This specification discloses several technical concepts and several combinations thereof, as listed below.

[0082] (Technical thought 1) A control device for controlling an optical sensor (10) which has a processor (1b) and detects the distance (Lt) to the target by receiving reflected light from a target (Xt) to an irradiated light emitted by light emission using SPAD pixels (46), The aforementioned processor, For each detection frame (Fτ) in which the response output (Os) of the SPAD pixel is repeatedly sampled at a sampling period (τs), and the response output is integrated over multiple detection periods (τ) to obtain the time distribution (Ho) of the integrated output value (ΣOs), the irradiation light is controlled to include a reference light (Lb) whose irradiation timing is aligned with the start timing (T) of the detection period, and multiple types of delayed light (Ld) whose irradiation timing is delayed by a delay period (τd) less than the sampling period from the start timing. A control device configured to output data for each detection frame, wherein for each detection frame, the distance corresponds to a specific decomposition period (τpb) identified from the time distribution of the output integrated value, which is a decomposition period (τp) obtained by decomposing the sampling period into each delay period, and which includes the response start timing (Tb) of the SPAD pixel to the reference light.

[0083] (Technical thought 2) Outputting the aforementioned distance as data means The control device according to technical concept 1, which includes outputting data for each detection frame, the distance corresponding to the specific decomposition period, which is determined based on the output integrated value in the previous sampling period, for the sampling period in which the output integrated value reached a saturation value (ΣOss).

[0084] (Technical Thought 3) Outputting the aforementioned distance as data means The control device according to technical concept 2, which includes outputting data of the distance correlated with the distance measurement time (ε) for each detection frame, from the start timing of the initial detection cycle to the specific resolution period.

[0085] (Technical Thought 4) Controlling the aforementioned irradiated light means A control device according to any one of the technical ideas 1 to 3, which includes controlling the delay control time from the start timing of the detection cycle to the irradiation timing of each of the irradiation lights for each detection frame to be less than the dead time (ω) of the SPAD pixel.

[0086] (Technical Thought 5) Outputting the aforementioned distance as data means A control device according to any one of the technical ideas 1 to 4, which includes storing the distance corresponding to the specified decomposition period in a storage medium (1a, 5a) by data output.

[0087] (Technical Thought 6) Outputting the aforementioned distance as data means A control device according to any one of technical ideas 1 to 5, which includes outputting the distance as data according to a specific resolution period identified from the time distribution of the output integrated values, where the number of times the response output is integrated for each of the reference light and each of the delay light is a common number for each detection frame.

[0088] (Technical Thought 7) Outputting the aforementioned distance as data means A control device according to any one of technical ideas 1 to 6, which includes outputting the distance as data according to a specific resolution period identified from the time distribution of the integrated output values ​​obtained by integrating the number of responses (Nr) of the SPAD pixels as the response output for each of the reference light and each of the delayed light for each detection frame.

[0089] (Technical Thought 8) An optical sensor (10) detects the distance (Lt) to the target by receiving the reflected light from the target (Xt) in response to the illumination light emitted by the light emission using SPAD pixels (46), An optical detection system comprising a control device (1) described in any one of the technical concepts 1 to 7.

[0090] Furthermore, the technical ideas 1 to 7 described above may be implemented in the form of methods and programs. [Explanation of symbols]

[0091] 1: Control device, 1a: Memory, 5a: Storage medium, 1b: Processor, 10: Optical sensor, 46: SPAD pixel, Fτ: Detection frame, Ho: Time distribution, Lb: Reference light, Ld: Delay light, Nr: Number of responses, Os: Response output, T: Start timing, Tb: Response start timing, Xt: Target, ΣOs: Output integrated value, ΣOss: Saturation value, ε: Distance measurement time, τ: Detection period, τd: Delay period, τp: Resolution period, τpb: Specific resolution period, τs: Sampling period, ω: Dead time

Claims

1. A control device for controlling an optical sensor (10) which has a processor (1b) and detects the distance (Lt) to the target by receiving reflected light from a target (Xt) to an illumination light emitted by light emission using SPAD pixels (46), The aforementioned processor, For each detection frame (Fτ) in which the response output (Os) of the SPAD pixel is repeatedly sampled at a sampling period (τs) and the response output is integrated over multiple detection periods (τ) to obtain the time distribution (Ho) of the integrated output value (ΣOs), the irradiation light is controlled to include a reference light (Lb) whose irradiation timing is aligned with the start timing (T) of the detection period, and multiple types of delayed light (Ld) whose irradiation timing is delayed by a delay period (τd) less than the sampling period from the start timing. A control device configured to output data for each detection frame, wherein for each detection frame, the distance corresponds to a specific decomposition period (τpb) identified from the time distribution of the output integrated value, which is a decomposition period (τp) obtained by decomposing the sampling period into each delay period, and which includes the response start timing (Tb) of the SPAD pixel to the reference light.

2. Outputting the aforementioned distance as data means The control device according to claim 1, further comprising outputting data for each detection frame, the distance corresponding to the specific decomposition period, which is determined based on the output integrated value in the previous sampling period, with respect to the sampling period in which the output integrated value reached a saturation value (ΣOss).

3. Outputting the aforementioned distance as data means The control device according to claim 2, which includes outputting data of the distance correlated with the distance measurement time (ε) for each detection frame, from the start timing of the initial detection cycle to the specific decomposition period.

4. Controlling the aforementioned irradiated light means The control device according to any one of claims 1 to 3, comprising controlling the delay control time from the start timing of the detection cycle to the irradiation timing of each of the irradiation lights for each detection frame to be less than the dead time (ω) of the SPAD pixel.

5. Outputting the aforementioned distance as data means The control device according to any one of claims 1 to 3, further comprising storing the distance corresponding to the specified decomposition period in a storage medium (1a, 5a) by data output.

6. Outputting the aforementioned distance as data means The control device according to any one of claims 1 to 3, further comprising outputting the distance as data according to the specific decomposition period determined from the time distribution of the output integrated values, wherein for each detection frame, the number of times the response output is integrated for each of the reference light and each of the delay light is set to a common number of times.

7. Outputting the aforementioned distance as data means The control device according to any one of claims 1 to 3, further comprising outputting the distance as data according to the specific resolution period identified from the time distribution of the integrated output values, obtained by integrating the number of responses (Nr) of the SPAD pixels as the response output for each of the reference light and each of the delayed light for each detection frame.

8. An optical sensor (10) detects the distance (Lt) to the target by receiving reflected light from the target (Xt) in response to the illumination light emitted by the emission of light using a SPAD pixel (46), An optical detection system comprising a control device (1) according to any one of claims 1 to 3.

9. A control method executed by a processor (1b) to control an optical sensor (10) that detects the distance (Lt) to a target (Xt) by receiving reflected light from a target (Xt) to an illumination light emitted by light emission using a SPAD pixel (46), wherein For each detection frame (Fτ) in which the response output (Os) of the SPAD pixel is repeatedly sampled at a sampling period (τs) and the response output is integrated over multiple detection periods (τ) to obtain the time distribution (Ho) of the integrated output value (ΣOs), the irradiation light is controlled to include a reference light (Lb) whose irradiation timing is aligned with the start timing (T) of the detection period, and multiple types of delayed light (Ld) whose irradiation timing is delayed by a delay period (τd) less than the sampling period from the start timing. A control method comprising outputting data for each detection frame, wherein the distance corresponds to a specific decomposition period (τpb) identified from the time distribution of the output integrated value, which is a decomposition period (τp) obtained by decomposing the sampling period into each delay period, and which includes the response start timing (Tb) of the SPAD pixel to the reference light.

10. A control program including instructions executed by a processor (1b) to control an optical sensor (10) which is stored in a storage medium (1a) and detects the distance (Lt) to the target by receiving reflected light from a target (Xt) to an illumination light emitted by emission using SPAD pixels (46), wherein The aforementioned instruction is, For each detection frame (Fτ) in which the response output (Os) of the SPAD pixel is repeatedly sampled at a sampling period (τs) and the response output is integrated over multiple detection periods (τ) to obtain the time distribution (Ho) of the integrated output value (ΣOs), the irradiation light is controlled to include a reference light (Lb) whose irradiation timing is aligned with the start timing (T) of the detection period, and multiple types of delayed light (Ld) whose irradiation timing is delayed by a delay period (τd) less than the sampling period from the start timing. A control program that, for each detection frame, outputs data of the distance corresponding to a specific decomposition period (τpb) identified from the time distribution of the output integrated value, which is a decomposition period (τp) obtained by decomposing the sampling period into each of the delay periods, and which includes the response start timing (Tb) of the SPAD pixel to the reference light.

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