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

Abstract

The processor of the control device is configured to execute the following processing: for each detection frame of a time distribution of an output integrated value by integrating response outputs (Os) across a detection period in which sampling processing is repeatedly performed on the response outputs (Os) of (SPAD) pixels at a sampling period (tau s) for a plurality of times; a control unit that controls, as irradiation light, reference light in which the irradiation timing is aligned with the start timing of the detection period, and a plurality of types of delayed light in which the irradiation timing is delayed from the start timing by a delay period (tau d) shorter than the sampling period (tau s) each time; and outputting a distance corresponding to the specific decomposition period ([tau] pb) for each detection frame, the specific decomposition period (taupb) is a decomposition period which is determined from the time distribution of the output integrated value as a decomposition period including the response start timing (Tb) of the (SPAD) pixel to the reference light among decomposition periods (taup) obtained by decomposing the sampling period (taus) for each delay period.

Description

[0001] Cross-reference to Related Applications

[0002] This application is based on Japanese Patent Application No. 2022-186709 filed on November 22, 2022, and the entire contents of the base application are incorporated herein by reference in their entirety. Technical Field

[0003] The present disclosure relates to a technique for controlling an optical sensor. Background Art

[0004] In recent years, an optical sensor that detects the distance to a target by receiving reflected light, which is the reflected light of irradiated light irradiated by light emission, with a single photon avalanche diode (SPAD: Single Photon Avalanche Diode) pixel has attracted attention. In the disclosed technique of Patent Document 1 that controls such an optical sensor, a histogram is generated by repeatedly sampling and accumulating the outputs of SPAD pixels that respond in one detection frame to detect the distance. At this time, the disclosed technique of Patent Document 1 changes the time resolution by adjusting the sampling frequency. Therefore, the disclosed technique of Patent Document 1 re-samples the range determined by sampling at a low time resolution at a high time resolution, and thus detects the distance based on the histogram of the latter sampling.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2021-001763 Summary of the Invention

[0008] However, in the disclosed technique of Patent Document 1, even if it is possible to ensure the distance resolution based on the high-side time resolution, since sampling in two stages is repeated in the detection frame, the frame rate is limited, and thus there is a limit to the final distance detection accuracy.

[0009] An object of the present disclosure is to provide a control device that improves the distance detection accuracy of an optical sensor. Another object of the present disclosure is to provide an optical detection system that improves the distance detection accuracy of an optical sensor. Another object of the present disclosure is to provide a control method that improves the distance detection accuracy of an optical sensor. Another object of the present disclosure is to provide a control program that improves the distance detection accuracy of an optical sensor.

[0010] Hereinafter, the technical solutions of the present disclosure for solving the problems will be described.

[0011] A first aspect of the present disclosure is a control device that has a processor and controls an optical sensor. The optical sensor detects the distance to a target by receiving reflected light that is reflected from the target after irradiating light emitted through SPAD pixels, and in the control device,

[0012] the processor performs the following processes:

[0013] For each detection frame of the time distribution of the output cumulative value obtained by accumulating the response output of the SPAD pixels over a detection period that repeatedly samples the response output of the SPAD pixels at a sampling period over multiple times, control is performed such that reference light with an irradiation timing aligned with the start timing of the detection period and multiple categories of delayed light obtained by delaying the irradiation timing from the start timing by a delay period shorter than the sampling period each time are used as the irradiation light; and

[0014] For each detection frame, data is output for a distance corresponding to a specific decomposition period. The specific decomposition period is a decomposition period obtained by decomposing the sampling period according to each delay period and including the response start timing of the SPAD pixels to the reference light, and is determined based on the time distribution of the output cumulative value.

[0015] A second aspect of the present disclosure is configured to include:

[0016] an optical sensor that detects the distance to a target by receiving reflected light that is reflected from the target after irradiating light emitted through SPAD pixels; and

[0017] the control device of the first aspect.

[0018] A third aspect of the present disclosure is a control method, which is a control method executed by a processor to control an optical sensor. The optical sensor detects the distance to a target by receiving reflected light that is reflected from the target after irradiating light emitted through SPAD pixels, and the control method includes:

[0019] For each detection frame of the time distribution of the output cumulative value obtained by accumulating the response output of the SPAD pixels over a detection period that repeatedly samples the response output of the SPAD pixels at a sampling period over multiple times, control is performed such that reference light with an irradiation timing aligned with the start timing of the detection period and multiple categories of delayed light obtained by delaying the irradiation timing from the start timing by a delay period shorter than the sampling period each time are used as the irradiation light; and

[0020] For each detection frame, data is output for a distance corresponding to a specific decomposition period. The specific decomposition period is a decomposition period obtained by decomposing the sampling period according to each delay period and including the response start timing of the SPAD pixels to the reference light, and is determined based on the time distribution of the output cumulative value.

[0021] A fourth aspect of the present disclosure is a control program stored in a storage medium, including commands executed by a processor to control an optical sensor. The optical sensor receives reflected light reflected by a target after irradiating light emitted through SPAD pixels and detects the distance to the target. In the control program,

[0022] the commands include:

[0023] For each detection frame of the time distribution of the output cumulative value obtained by accumulating the response output of the SPAD pixels according to a detection period in which sampling processing is repeatedly performed on the response output of the SPAD pixels at a sampling period multiple times, control the irradiation light by using a reference light with the irradiation timing aligned with the start timing of the detection period and multiple types of delayed lights obtained by delaying the irradiation timing from the start timing by a delay period shorter than the sampling period each time; and

[0024] For each detection frame, output the distance corresponding to a specific decomposition period, where the specific decomposition period is a decomposition period obtained by decomposing the sampling period according to each delay period and including the start timing of the response of the SPAD pixels to the reference light, and is determined according to the time distribution of the output cumulative value.

[0025] In these first to fourth aspects, for each detection frame of the time distribution of the output cumulative value obtained by accumulating the response output of the SPAD pixels according to a detection period in which sampling processing is repeatedly performed on the response output of the SPAD pixels at a sampling period multiple times, control the irradiation light. At this time, the reference light with the irradiation timing aligned with the start timing of the detection period and multiple types of delayed lights obtained by delaying the irradiation timing from the start timing by a delay period shorter than the sampling period each time are controlled as the irradiation light. Therefore, for the reference light and each delayed light, the output cumulative value in the SPAD pixels is obtained for each detection frame.

[0026] According to such first to fourth aspects, the decomposition period including the start timing of the response of the SPAD pixels to the reference light among the decomposition periods obtained by decomposing the sampling period according to each delay period depends on the distance to the target. And the decomposition periods including the start timing of the response of the SPAD pixels to each delayed light are each offset by a delay period from the decomposition period including the start timing of the response of the SPAD pixels to the reference light. Thus, whether each decomposition period including the start timing of the response to each delayed light is within the same sampling period as the decomposition period including the start timing of the response to the reference light depends on the distance to the target, and thus it is possible to impart variations to the time distribution of the output cumulative value.

[0027] Therefore, according to the first to fourth methods of outputting data on the distance corresponding to a specific decomposition period determined from the time distribution of the output cumulative value during the decomposition period including the start timing of the response to the reference light for each detection frame, the distance resolution can be improved corresponding to a decomposition period shorter than the sampling period. Moreover, for each detection frame, the sampling process of the above-described one stage is repeated to output data on the distance, so that the frame rate can also be improved. As a result, high distance resolution and high frame rate can be achieved simultaneously, and thus high distance detection accuracy can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a block diagram showing the overall configuration of an optical detection system according to an embodiment.

[0029] Figure 2 is a schematic diagram showing the physical configuration of an optical sensor according to an embodiment.

[0030] Figure 3 is a block diagram showing the functional configuration of an optical detection system according to an embodiment.

[0031] Figure 4 is a schematic diagram showing a light projector according to an embodiment.

[0032] Figure 5 is a diagram for explaining a detection frame according to an embodiment.

[0033] Figure 6 is a schematic diagram showing a light receiver according to an embodiment.

[0034] Figure 7 is a block diagram showing a configuration example of a SPAD pixel according to an embodiment.

[0035] Figure 8 is a block diagram showing another configuration example of a SPAD pixel according to an embodiment.

[0036] Figure 9 is a diagram for explaining a control flow according to an embodiment.

[0037] Figure 10 is a diagram for explaining a control flow according to an embodiment.

[0038] Figure 11 is a diagram for explaining a control flow according to an embodiment.

[0039] Figure 12 is a diagram for explaining a control flow according to an embodiment.

[0040] Figure 13 is a diagram for explaining a control flow according to an embodiment.

[0041] Figure 14 It is a flowchart showing the control flow of an embodiment.

[0042] Figure 15 It is a diagram for explaining the control flow of an embodiment.

[0043] Figure 16 It is a diagram for explaining the control flow of an embodiment.

[0044] Figure 17 It is a diagram for explaining the control flow of an embodiment.

[0045] Figure 18 It is a diagram for explaining the control flow of an embodiment.

[0046] Figure 19 It is a diagram for explaining the control flow of an embodiment.

[0047] Figure 20 It is a diagram for explaining the control flow of an embodiment.

[0048] Figure 21 It is a diagram for explaining the control flow of an embodiment.

[0049] Figure 22 It is a diagram for explaining the control flow of an embodiment.

[0050] Figure 23 It is a diagram for explaining the control flow of an embodiment.

[0051] Figure 24 It is a diagram for explaining the control flow of an embodiment.

[0052] Figure 25 It is a diagram for explaining the control flow of an embodiment.

[0053] Figure 26 It is a diagram for explaining the control flow of an embodiment.

[0054] Figure 27 It is a diagram for explaining the control flow of an embodiment.

[0055] Figure 28 It is a diagram for explaining the control flow of an embodiment.

[0056] Figure 29 It is a diagram for explaining the control flow of an embodiment. Specific Embodiments

[0057] Such as Figure 1As shown, one embodiment of the present disclosure relates to an optical detection system 2 including an optical sensor 10 and a control device 1. The optical detection system 2 is mounted on a vehicle 5 which is a moving body. The vehicle 5 is a moving body such as an automobile that can travel on a driving road in a state where an occupant is on board.

[0058] The vehicle 5 can stably or temporarily travel automatically in an autonomous driving control mode. Here, the autonomous driving control mode can also be achieved by autonomous driving control in which the system performs all driving tasks during operation such as conditional driving automation, highly automated driving, or fully automated driving. The autonomous driving control mode can also be achieved in highly automated driving assistance control in which an occupant performs part or all of the driving tasks such as driving assistance or partial driving automation. The autonomous driving control mode can also be achieved by any one, combination, or switching of these autonomous driving control and highly automated driving assistance control.

[0059] In addition, in the following description, unless otherwise restricted, the front, rear, upper, lower, left, and right directions are defined based on the vehicle 5 on the horizontal plane. In addition, the horizontal direction represents a direction parallel to the horizontal plane that is the direction reference of the vehicle 5. And the vertical direction represents the vertical direction that is the up and down direction with respect to the horizontal plane that is the direction reference of the vehicle 5.

[0060] The optical sensor 10 is a so-called light detection and ranging / laser imaging detection and ranging (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 the automatic control driving mode. The optical sensor 10 is disposed, for example, at at least one part of the vehicle 5 such as the front part, the left and right side parts, the rear part, and the upper roof.

[0061] As Figure 2 , Figure 3 shown, the optical sensor 10 irradiates light to a detection area DA in a range corresponding to the disposed part and the viewing angle in the external space of the vehicle 5. The optical sensor 10 receives the reflected light that is incident after the irradiated light is reflected from the detection area DA. Based on the reception of the reflected light, the optical sensor 10 detects the target Xt that has reflected light in the detection area DA. Here, the detection in this embodiment means sensing the distance Lt from the optical sensor 10 to the target Xt as schematically shown in Figure 3 .

[0062] In the optical sensor 10 applied to the vehicle 5, the target object Xt that is a representative detection target may be, for example, at least one of moving objects such as pedestrians, cyclists, animals other than humans, and other vehicles. In the optical sensor 10 applied to the vehicle 5, the target object Xt that is a representative detection target may be, for example, at least one of stationary objects such as guardrails, road signs, structures beside the road, and fallen objects on the road.

[0063] As Figure 2 shown, the optical sensor 10 includes a housing 11, an irradiation unit 21, a scanning unit 31, and a light receiving unit 41. The housing 11 is formed in a box shape and has light-shielding properties. The housing 11 houses the irradiation unit 21, the scanning unit 31, and the light receiving unit 41 inside. The housing 11 has a light-transmissive cover plate 12. In addition, in Figure 2 , a cross-section perpendicular to the right side portion (unit 21, 41 side) compared to the single-dot chain line is shown for the left side portion (cover plate 12 side) compared to the single-dot chain line.

[0064] As Figure 2 , Figure 3 shown, the irradiation unit 21 includes a light projector 22 and an irradiation optical system 26. As Figure 4 shown, the light projector 22 includes a plurality of laser diodes 24 arranged along the vertical direction. Each laser diode 24 may be an edge-emitting laser or a vertical cavity surface emitting laser (VCSEL: Vertical Cavity Surface Emitting Laser). Each laser diode 24 emits light in the near-infrared region that is difficult for humans to visually recognize in the external space including the detection area DA of the vehicle 5. Each time the laser diode 24 emits light, it is executed as pulsed light following the control signal from the control device 1 when the detection frame Fτ shown in Figure 5 is repeated a set number of times (specifically, the total cumulative number Ns described later) in the detection period τ.

[0065] As Figure 4 shown, the light projector 22 is formed with a light projection window 25 on one side of the substrate, which is defined analogously with a rectangular contour having a long side along the vertical direction. The light projection window 25 is constructed as an aggregate of projection openings of each laser diode 24. The light emitted from the projection openings of each laser diode 24 is projected from the light projection window 25 as a long strip-shaped linear irradiation light in the detection area DA. The irradiation light may also include non-light-emitting portions corresponding to the arrangement intervals of the laser diodes 24 in the vertical direction. In this case, the non-light-emitting portions can be macroscopically eliminated by diffraction to form linear irradiation light in the vertical direction.

[0066] As Figure 2As shown, the illumination optical system 26 guides the illumination light emitted from the light projector 22 toward the scanning mirror 32 of the scanning unit 31. In order to perform at least one optical function such as condensing, collimating, and shaping, the illumination optical system 26 includes one or more optical lenses.

[0067] As Figure 2 , Figure 3 shown, the scanning unit 31 includes a scanning mirror 32 and a scanning motor 35. The scanning mirror 32 is formed as a plate on which a reflective film is vapor-deposited on a reflective surface 33 on one side as a base material. The scanning mirror 32 is supported by the housing 11 so as to be rotatable about a rotation center line along the vertical direction. The scanning mirror 32 performs a swinging motion within a limited driving range by means of a mechanical or electrical stopper. The scanning motor 35 rotationally drives (i.e., swings) the scanning mirror 32 within a limited driving range. At this time, the rotation angle of the scanning mirror 32 changes sequentially according to the control signal from the control device 1 for each detection frame Fτ (refer to Figure 5 ).

[0068] The scanning mirror 32 reflects the illumination light incident from the illumination optical system 26 of the illumination unit 21 by the reflective surface 33 and irradiates the detection area DA through the cover plate 12, thereby scanning the area DA according to the rotation angle of the scanning motor 35. Here, in the present embodiment, the mechanical scanning of the illumination light on the detection area DA is substantially limited to the horizontal direction.

[0069] The scanning mirror 32 reflects the reflected light incident from the detection area DA through the cover plate 12 according to the rotation angle of the scanning motor 35 toward the light receiving unit 41 side by the reflective surface 33. Here, the speeds of the illumination light and the reflected light are sufficiently high relative to the rotational movement speed of the scanning mirror 32. Thus, the reflected light of the illumination light is further reflected toward the light receiving unit 41 side in a manner opposite to the illumination light in the scanning mirror 32 at substantially the same rotation angle as the illumination light.

[0070] 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 offset from the illumination optical system 26 in the vertical direction. 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 includes one or more optical lenses in order to image the reflected light on the light receiver 45.

[0071] The light receiver 45 generates an output corresponding to the distance Lt to the target Xt by receiving the reflected light from the detection area DA imaged by the light receiving optical system 42. For this purpose, the light receiver 45 is as Figure 6As shown, a light-receiving surface 47 with a rectangular contour whose long side is along the vertical direction is formed on one side of the substrate. The reflected light from the target Xt with respect to the irradiated light enters the light-receiving surface 47 as a linearly extended light beam through the light-receiving optical system 42. The light-receiving surface 47 is configured as an aggregate of incident surfaces where the reflected light enters a plurality of SPAD pixels 46. Each SPAD pixel 46 is arranged along at least the vertical direction among the vertical direction and the horizontal direction.

[0072] As Figure 7 , Figure 8 shown, each SPAD pixel 46 is constituted by including at least one set of SPAD elements 460 and an 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 Figure 5 shown, the switching element 462 controls the light-receiving period τr during which the SPAD pixel 46 corresponding to the reflected light responds in the detection period τ repeated for each detection frame Fτ according to the control signal from the control device 1. Therefore, during the light-receiving period τr, an SPAD voltage Vs that varies with respect to the bias voltage Vb is output from the SPAD pixel 46 that has responded due to light reception. Figures 9 - 12

[0073] As Figure 7 , Figure 8 shown, in the SPAD circuit 461, an inverter 463 is connected to the midpoint between the SPAD element 460 and the switching element 462. The inverter 463 outputs a pulse signal during a dead time ω from when the SPAD voltage Vs of the SPAD pixel 46 that has responded as Figures 9 - 12 shown crosses the threshold Vth until it crosses the threshold Vth again and recovers. At this time, the pulse signal that is quantized in the amplitude direction and output from the inverter 463 becomes the response output Os of the SPAD pixel 46. Thus, the response start timing (Tb, Td shown later as Figures 15 - 18 shown) at which the response output Os of the SPAD pixel 46 starts is defined as the timing at which the SPAD voltage Vs crosses the threshold Vth toward the inversion side.

[0074] As Figure 7 , Figure 8 shown, in the SPAD circuit 461, a sampling circuit 464 is connected to the output side of the inverter 463. The sampling circuit 464 further performs a sampling process on the response output Os as Figures 9 - 12 shown in each detection period τ repeated for each detection frame Fτ. Through such repeated sampling processes, the response output Os of the SPAD pixel 46 is converted into a digital signal value that is discretized in the time direction.

[0075] Here, as Figure 7As shown, in the light receiver 45 where each SPAD pixel 46 is composed of a group of SPAD elements 460 and an SPAD circuit 461, the digital signal value from the sampling circuit 464 is provided to the subsequent stage as the response output Os of the SPAD pixel 46 as it is. Additionally, especially for simplicity of explanation, in Figures 9 - 12 and the following Figure 13 、 Figures 20 - 25 the number of groups of the elements 460 and 461 that make up each SPAD pixel 46 is representatively shown as Figure 7 a single group as shown.

[0076] On the other hand, as Figure 8 shown, in the light receiver 45 where each SPAD pixel 46 is composed of multiple groups of SPAD elements 460 and an SPAD circuit 461, the digital signal values from the sampling circuits 464 of each SPAD pixel 46 are further added by separate adders 48 corresponding to the number of multiple groups for these respective SPAD pixels 46. Here, Figure 8 multiple cells of a single SPAD pixel 46 schematically show multiple groups of elements 460 and 461 ( Figure 8 an example of 16 groups in Figure 8 ). In the light receiver 45 configured with multiple groups as shown in this way, the added value of the adder 48 is provided to the subsequent stage as the response output Os of the SPAD pixel 46.

[0077] As Figure 3 、 Figure 7 、 Figure 8 shown, in the light receiver 45, a histogram memory 49 is provided separately for each SPAD pixel 46. The histogram memory 49 counts the response output Os, that is, the digital signal value or its added value, of the corresponding SPAD pixel 46 every time the sampling period τs (the period between the dotted lines in Figures 9 - 13 ) repeats in each detection period τ of each detection frame Fτ as Figures 9 - 12 . The counted value means, from the perspective of the entire light receiver 45, the number of SPAD pixels 46 that respond within one sampling period τs, that is, the response number Nr.

[0078] For each SPAD pixel 46, the histogram memory 49 obtains and stores the total cumulative number Ns of multiple quantities across the detection period τ, that is, the output cumulative value ΣOs obtained by accumulating the counted values of the response output Os (refer to Figure 5 、 Figure 12 ). At this time, in the histogram memory 49, as Figures 9 - 13As shown, the start timing Ts are time-aligned with each other between the respective detection periods τ of the layer stacking to accumulate the count values of the response output Os, and the time distribution of the obtained output accumulation value ΣOs is stored as a histogram Ho.

[0079] In this way, the histogram Ho of the output accumulation value ΣOs stored in the histogram memory 49 of each SPAD pixel 46 is read out by the control device 1 for each detection frame Fτ as Figure 3 such, and is used for data output of the distance Lt to the target Xt. In addition, Figures 9 - 13 and as described later Figures 20 - 25 a rectangular block corresponding to the end timing of each repeated sampling period τs is shown schematically showing the response output Os, the response number Nr as a count value, and the output accumulation value ΣOs.

[0080] Figure 1 , Figure 3 , Figure 7 , Figure 8 As shown, the control device 1 is connected to the optical sensor 10 via at least one of, for example, a LAN (Local Area Network), a wiring harness, and an internal bus. The control device 1 is constituted by including at least one dedicated computer. The dedicated computer constituting the control device 1 may be a sensor ECU (Electronic Control Unit) dedicated to controlling the optical sensor 10, and in this case, the sensor ECU may also be housed in the housing 11. The dedicated computer constituting the control device 1 may also be a driving control ECU for controlling the driving of the vehicle 5.

[0081] As Figure 1 shown, the dedicated computer constituting the control device 1 has at least one memory 1a and a processor 1b each. The memory 1a is at least one non-temporary tangible storage medium such as a semiconductor memory, a magnetic medium, and an optical medium that non-temporarily stores programs and data that can be read by a computer (non-transitory tangiblestorage medium). The processor 1b includes at least one of, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a RISC (Reduced Instruction Set Computer)-CPU, a DFP (Data Flow Processor), and a GSP (Graph Streaming Processor) as a core.

[0082] The processor 1b executes a plurality of commands included in the control program stored in the memory 1a. Thus, the control device 1 constructs a plurality of functional blocks for controlling the optical sensor 10. In this way, in the control device 1, the control program stored in the memory 1a to control the optical sensor 10 causes the processor 1b to execute a plurality of commands, thereby constructing a plurality of functional blocks. As Figure 3 shown, the plurality of functional blocks constructed by the control device 1 include an irradiation control block 100 and an output control block 110.

[0083] Through the cooperation of these blocks 100 and 110, the control method of the control device 1 for controlling the optical sensor 10 is executed according to the Figure 14 shown control flow. This control flow is repeatedly executed for each detection frame Fτ during the start of the vehicle 5. In addition, each "S" in the control flow respectively means a plurality of steps executed by a plurality of commands included in the control program.

[0084] In S10 of the control flow, the irradiation control block 100 resets the execution count Nd of the detection period τ in the current detection frame Fτ to a value of 0. In S20 of the control flow, the irradiation control block 100 sets the value of the execution count Nd of the detection period τ to the current value increased by 1.

[0085] In S30 of the control flow, the irradiation control block 100 controls the irradiation timing of the pulsed irradiation light emitted from the light projector 22 to the timing corresponding to the execution count Nd and the current detection period τ (refer to Figure 3 , Figures 9 - 12 ). Specifically, in S30, the irradiation control block 100 controls, as the irradiation light, a single type of reference light Lb that makes the irradiation timing coincide with the start timing T of the detection period τ as shown in Figure 9 , and a plurality of types of delayed lights Ld that make the irradiation timing delayed by the delay period τd from this timing T as shown in Figures 10 - 12 .

[0086] 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. K in Equation 1 is set to a magnification value of the distance resolution improved by this embodiment with respect to the normal distance resolution corresponding to the sampling period τs. Therefore, the magnification value K of this embodiment coincides with the decomposition number of the decomposition period τp obtained by decomposing the sampling period τs as shown in Figures 15 - 18 described later. And the total number of types of irradiation light, which is the sum of the number of types of the reference light Lb and the number of types of the delayed lights Ld, coincides with the magnification value K of this embodiment.

[0087] [Equation 1]

[0088] τd = τs / K

[0089] The irradiation control block 100 in S30 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 according to the next number 2 using the delay period τd of the number 1, as Figures 9 - 12 shown. The k in the number 2 is set as an integer from 0 to K - 1 as an index of the letter classifying the category of the irradiation light. Here, in the case of K = 4, Figure 9 the exemplified k = 0 indicates the reference light Lb whose irradiation timing coincides with the start timing T of the detection period τ since it follows the delay control time t(k) = 0 of the number 2.

[0090] On the other hand, k = 1 to K - 1 in the number 2 respectively indicate a plurality of categories of delay lights Ld with different delay control times t(k) in which the irradiation timing is delayed from the start timing T of the detection period τ. In particular, in the case of K = 4, Figure 10 the exemplified k = 1 indicates the first delay light Ld1 among the plurality of categories of delay lights Ld that is controlled to have the delay control time t(k) = τd by the number 2. In addition, in the case of K = 4, Figure 11 the additionally exemplified k = 2 in indicates the second delay light Ld2 among the plurality of categories of delay lights Ld that is controlled to have the delay control time t(k) = 2·τd by the number 2. And, in the case of K = 4, Figure 12 the further additionally exemplified k = 3 in indicates the third delay light Ld3 among the plurality of categories of delay lights Ld that is controlled to have the delay control time t(k) = 3·τd by the number 2.

[0091] [Number 2]

[0092] t(k) = k·τd = k·τs / K

[0093] For any category of delay lights Ld1, Ld2, Ld3 corresponding to k = 1 to K - 1, the irradiation control block 100 in S30 controls the delay control time t(k) to be less than the dead time ω of the SPAD pixel 46 according to the following number 3. At this time, if the maximum delay control time t(K - 1) in k = K - 1 satisfies the number 3, then the other delay control times t(k) also necessarily satisfy the number 3.

[0094] [Number 3]

[0095] t(k) < ω

[0096] The irradiation control block 100 in S30 controls the individual irradiation times Ni of each category of irradiation light corresponding to k = 0 to K - 1 to follow the common multiple times ( Figures 9 - 12 as shown respectively according to the following number 4. Figures 9 - 12For example, each is performed three times). At this time, the reference light Lb, the first delayed light Ld1, the second delayed light Ld2, and the third delayed light Ld3 are controlled to be irradiated in the order of the individual irradiation times Ni in turn. However, the order of irradiating the irradiation lights of each category can be changed as long as the irradiation lights of each category are irradiated the individual irradiation times Ni in the detection frame Fτ.

[0097] [Number 4]

[0098] Ni = Ns / K = Na

[0099] In the irradiation control block 100 in S30, the rotation angle of the scanning mirror 32 is controlled to an angle θ where the execution number Nd is consistent with the detection period τ of the current value (refer to Figure 3 ). At this time, in each detection period τ such as every 2000 ns in the current detection frame Fτ, it can be assumed that the rotation angle of the scanning mirror 32 is substantially the same angle. Therefore, S30 can also be said to be the rotation angle of the scanning mirror 32 is controlled to an angle consistent with the current detection frame Fτ.

[0100] As Figure 14 shown, in S40 of the control flow, the output control block 110 controls the light reception period τr in each SPAD pixel 46 in the detection period τ where the execution number Nd is the current value to be aligned with the start timing T of the period τ when the irradiation of the irradiation light starts by the irradiation control block 100 (refer to Figure 3 , Figures 9 - 12 ). At this time, the light reception period τr is set to a time of the same length that is substantially independent of the execution number Nd with the control signal that is the trigger for the irradiation control in S30 as the starting point. Thus, as Figures 9 - 13 shown, in S40, the histogram Ho of the output cumulative value ΣOs obtained by accumulating the response outputs Os of each SPAD pixel 46 for all detection periods τ up to the execution number Nd of the current value is stored in the histogram memories 49 of these respective SPAD pixels 46.

[0101] In such S40, among the total cumulative number Ns of the response outputs Os accumulated in the current detection frame Fτ, the individual cumulative number Na of the response outputs Os accumulated according to each category of the irradiation light is consistent with the individual irradiation time Ni as Figures 9 - 12 and the aforementioned Number 4 show, and thus becomes the same multiple times. 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 cumulative value ΣOs obtained by accumulating the response numbers Nr of the SPAD pixels 46 for each category of the irradiation light.

[0102] As Figure 14As shown, in S50 of the control flow, the output control block 110 determines whether the execution count Nd of the detection period τ that controls the light reception period τr has reached the total cumulative count Ns of the response output Os. As a result, in the case of a negative determination (refer to Figures 9 - 11 , Figure 13 ), the control flow returns to S20. On the other hand, in the case of an affirmative determination (refer to Figure 12 ), the control flow moves to S60.

[0103] In S60 of the control flow, the output control block 110 obtains, for each SPAD pixel 46, the histogram Ho of the output cumulative value ΣOs of the entire detection period τ across the total cumulative count Ns from the histogram memory 49 (refer to Figure 3 , Figure 12 and Figures 21 - 25 described later). Therefore, in S60, the output control block 110 performs data output of the detection result of the distance Lt to the target Xt based on the histogram Ho of the output cumulative value ΣOs of each SPAD pixel 46 (refer to Figure 3 ).

[0104] Specifically, the output control block 110 in S60 assumes that the sampling period τs repeated within the detection period τ is decomposed into the decomposition period τp after being decomposed into each delay period τd as Figures 15 - 18 shown. At this time, for example, a 1 ns sampling period τs is decomposed by a 0.25 ns delay period τd, so that the number of decompositions of the decomposition period τp within the same period τs is equal to the magnification value K of the expected distance resolution (in Figures 15 - 18 it is 4 corresponding to these exemplified times).

[0105] Under such an assumption, as Figure 15 shown, in the sampling period τs generated at the response start timing Tb of the SPAD pixel 46 to the reference light Lb, the decomposition period τp (i.e., τpb described later) including this timing Tb depends on the distance Lt to the target Xt. And, as Figure 15 shown, the decomposition period τp including the response start timing Td of the SPAD pixel 46 to each delayed light Ld1, Ld2, Ld3 is offset by the delay period τd from the decomposition period τp including the response start timing Tb of the SPAD pixel 46 to the reference light Lb. Figures 16 - 18

[0106] ​Therefore, whether each decomposition period τp including the response start timing Td of each of the delayed lights Ld1, Ld2, Ld3 is within the same sampling period τs as the decomposition period τp including the response start timing Tb of the reference light Lb depends on the distance Lt to the target Xt. That is, the sampling period τs for generating the response start timing Td of each of the delayed lights Ld1, Ld2, Ld3 and the sampling period τs for generating the response start timing Tb of the SPAD pixel 46 with respect to the reference light Lb become the same period and a certain time relationship corresponding to the distance Lt in a subsequent period.

[0107] Therefore, as Figure 15 shown, the time difference from the start timing Ts of the sampling period τs for generating the response start timing Tb of the SPAD pixel 46 with respect to the reference light Lb to this timing Tb is defined as the response timing difference ΔT. And, the elapsed time from the cut-off start timing Ts to the start timing of each decomposition period τp in the sampling period τs for generating the response start timing Tb is defined as the decomposition deviation time δ(κ) of the length of the delay period τd of the number 1 using these decomposition periods τp, which follows the following number 5. In number 5, κ is set as an integer from 0 to K - 1 as an index of the Greek letter identifying the decomposition period τp including the response start timing Tb. Figure 15 Typically, the decomposition deviation time δ(κ) until the decomposition period τp (specifically τpb described later) including the response start timing Tb and the decomposition deviation time δ(κ + 1) until the next decomposition period τp are shown.

[0108] [Equation 5]

[0109] δ(κ) = κ·τd

[0110] Under these definitions, in the sampling period τs for generating the response start timing Tb of the reference light Lb, the response timing difference ΔT of the reference light Lb satisfies the following number 6 in the relationship with the decomposition deviation times δ(κ) and δ(κ + 1). The decomposition period τp represents a specific decomposition period τpb including this timing Tb. As a result, it can be said that Figures 15 - 19 as such, the response start timings Td of each of the delayed lights Ld1, Ld2, Ld3 are generated in the same period τs or a subsequent period τs as the response start timing Tb according to the response timing difference ΔT that determines the decomposition deviation time δ(κ) of the specific decomposition period τpb. Additionally, Figures 15 - 18 an example of Figure 19 the case where κ = 2 in number 6 is illustrated.

[0111] [Equation 6]

[0112] δ(κ) ≤ ΔT < δ(κ + 1)

[0113] The time relationship of such a sampling period τs is established by the delay control time t(k) of each of the delayed lights Ld1, Ld2, and Ld3 having a length corresponding to the period τd for each decomposition period τp whose length is consistent with the delay period τd satisfying the aforementioned equation (3). In other words, when the delay control time t(k) of at least one of the delayed lights Ld1, Ld2, and Ld3 is equal to or greater than the dead time ω, as Figure 20 shown, multimodality appears in the time distribution of the output cumulative value ΣOs in the histogram Ho, and thus the time relationship of the aforementioned sampling period τs does not hold.

[0114] Based on the above understanding, in the histogram Ho of the entire detection period τ spanning the total cumulative number Ns, according to the response time difference ΔT that determines the relationship of the decomposition deviation time δ(κ) of the specific decomposition period τpb, the time distribution of the output cumulative value ΣOs changes as Figure 21 shown. Therefore, the output control block 110 in S60 determines the specific decomposition period τpb based on the time distribution of the output cumulative value ΣOs represented by the histogram Ho.

[0115] Specifically, the determination in S60 is made based on, as Figures 22 - 25 shown, the sampling period τs at which the output cumulative value ΣOs first reaches the saturation value ΣOss in each detection frame Fτ, that is, the saturation period τss, with respect to the value of interest ΣOsp of the output cumulative value ΣOs in the previous sampling period τs, that is, the previous period τsp. Here, the number of groups of the elements 460 and 461 in each SPAD pixel 46 is set to Ne (refer to Figure 7 , Figure 8 ), and the saturation value ΣOss is set to the response upper limit value that follows the following equation (7).

[0116] [Equation 7]

[0117] ∑Oss = Ne·Ns

[0118] The output control block 110 in S60 outputs the distance Lt to the target Xt as a detection result corresponding to such a specific decomposition period τpb. At this time, the output control block 110 detects the distance Lt related to the ranging time ε from the reference timing T0 (refer to Figure 5 ) defined as the start timing of the first controlled detection period τ in each detection frame Fτ to Figures 26 - 29 the specific decomposition period τpb shown.

[0119] Here, the ranging time ε is obtained by using the number of preceding periods Np (refer to Figure 12) The number 8 indicates that the number of leading cycles Np is the number of all sampling periods τs that precede the start timing Ts of the sampling period τs to which the specific decomposition period τpb belongs after the reference timing T0 in the current detection frame Fτ. Therefore, especially in the case of K = 4, when the attention value ΣOsp satisfies the following number 9 Figure 22 、 Figure 26 In the illustration of, the decomposition period τp with κ = 0 is determined as the specific decomposition period τpb belonging to the saturation period τss, and thus the distance Lt is detected according to the following number 10. C in number 10 is the speed of light.

[0120] [Number 8]

[0121] ε = Np·τs + δ(κ)

[0122] [Number 9]

[0123] ∑Osp = 0

[0124] [Number 10]

[0125] Lt = C·ε = C·{Np·τs + δ(κ)} / 2

[0126] On the other hand, in the case of K = 4, when the attention value ΣOsp satisfies the following number 11 Figure 23 、 Figure 27 In the illustration of, the decomposition period τp with κ = 1 is determined as the specific decomposition period τpb belonging to the previous period τsp, and thus the distance Lt is detected according to the aforementioned number 10. In the case of K = 4, when the attention value ΣOsp satisfies number 11 Figure 24 、 Figure 28 In another illustration of, the decomposition period τp with κ = 2 is determined as the specific decomposition period τpb belonging to the previous period τsp, and thus the distance Lt is detected according to number 10. In the case of K = 4, when the attention value ΣOsp satisfies number 11 Figure 25 、 Figure 29 In the illustration of, the decomposition period τp with κ = 3 is determined as the specific decomposition period τpb belonging to the previous period τsp, and thus the distance Lt is detected according to number 10.

[0127] [Number 11]

[0128] Na·Ne·{K - (+1)} < ∑Osp ≤ Na·Ne·(K - κ)

[0129] The output control block 110 in S60 stores the distance Lt detected according to the specific decomposition period τpb in the memory 1a in the control device 1 and the storage medium 5a in the vehicle 5 through its data output (refer to Figure 1) to at least one of them. The output control block 110 in S60 can also output the distance Lt detected according to the specific decomposition period τpb through its data output, and send it out of the vehicle 5 via the communication unit 5b in the vehicle 5 (refer to Figure 1 ) to the outside of the vehicle 5.

[0130] (Function and effect)

[0131] The function and effect of the above-described embodiment will be described below.

[0132] In this embodiment, the irradiation light is controlled according to each detection frame Fτ. The detection frame Fτ spans a detection period τ in which the response output Os of the SPAD pixel 46 is repeatedly sampled at a sampling period τs multiple times, and the time distribution (specifically, the histogram Ho) of the output cumulative value ΣOs obtained by accumulating the response output Os is obtained. At this time, the reference light Lb with the irradiation timing aligned with the start timing T of the detection period τ and the plurality of types of delayed lights Ld (specifically, Ld1, Ld2, Ld3) obtained by delaying the irradiation timing from the start timing T by a delay period τd shorter than the sampling period τs each time are controlled as the irradiation light. Therefore, for the reference light Lb and each delayed light Ld, the output cumulative value ΣOs in the SPAD pixel 46 is obtained according to each detection frame Fτ.

[0133] According to such an embodiment of the present invention, in the decomposition period τp obtained by decomposing the sampling period τs according to each delay period τd, the decomposition period τp including the response start timing Tb of the SPAD pixel 46 to the reference light Lb depends on the distance Lt to the target Xt. And the decomposition period τp including the response start timing Td of the SPAD pixel 46 to each delayed light Ld is offset from the decomposition period τp including the response start timing Tb of the SPAD pixel 46 to the reference light Lb by the delay period τd respectively. Thus, whether each decomposition period τp including the response start timing Tb to each delayed light Ld is within the same sampling period τs as the decomposition period τp including the response start timing Tb to the reference light Lb depends on the distance Lt to the target Xt, so that a variation can be given to the time distribution of the output cumulative value ΣOs.

[0134] Therefore, in this embodiment where, according to each detection frame Fτ, as the decomposition period τp including the response start timing Tb to the reference light Lb, the distance Lt corresponding to the specific decomposition period τpb determined according to the time distribution of the output cumulative value ΣOs is output as data, the distance resolution can be improved corresponding to the decomposition period τp shorter than the sampling period τs. Moreover, according to each detection frame Fτ, the above-described one-stage sampling process is repeated to output the distance Lt as data, so the frame rate can also be improved. Thereby, high distance resolution and high frame rate can be balanced, and thus high distance detection accuracy can be achieved.

[0135] In each detection frame Fτ of the present embodiment, for the sampling period τs (specifically τss) in which the output cumulative value ΣOs has reached the saturation value ΣOss, the data outputs the distance Lt corresponding to the specific decomposition period τpb determined based on the output cumulative value ΣOs in the previous sampling period τs (specifically τsp). Thus, based on the output cumulative value ΣOs in the previous sampling period τs that varies within a range less than the saturation value ΣOss depending on the distance Lt to the target Xt, the specific decomposition period τpb including the response start timing Tb of the reference light Lb can be accurately determined. Therefore, not only can the distance resolution be improved, but also its decomposition accuracy can be improved, contributing to achieving high distance detection accuracy.

[0136] In each detection frame Fτ of the present embodiment, the data outputs the distance Lt related to the ranging time ε from the start timing T (specifically T0) of the initial detection period τ to the specific decomposition period τpb. Thus, as the time depending on the distance Lt to the target Xt, the ranging time ε from the start of detection to the response start timing Tb of the reference light Lb can be accurately determined within the decomposition period τp less than the sampling period τs. Therefore, the reliability of the high distance decomposition accuracy can be improved, and further the distance detection accuracy can be improved.

[0137] In each detection frame Fτ of the present embodiment, the delay control time t(k) from the start timing T of the detection period τ to the irradiation of each delayed light Ld is set to be shorter than the dead time ω of the SPAD pixel 46. Thus, the situation where it is difficult to accurately determine the specific decomposition period τpb due to the appearance of multimodality in the time distribution of the output cumulative value ΣOs can be suppressed. Therefore, not only can the distance resolution be improved, but also its decomposition accuracy can be improved, contributing to achieving high distance detection accuracy.

[0138] In each detection frame Fτ of the present embodiment, the distance Lt corresponding to the specific decomposition period τpb is stored in at least one of the memory 1a and the storage medium 5a through data output. Thus, the data of the distance Lt with improved accuracy can be read out from the storage destination, for example, for use in the autonomous driving of the vehicle 5, etc.

[0139] In each detection frame Fτ of the present embodiment, based on the time distribution of the output cumulative value ΣOs obtained by repeatedly setting the individual cumulative counts Na of the response outputs Os for the reference light Lb and each of the delayed lights Ld to be the same, a specific decomposition period τpb is determined. Thereby, it is possible to suppress the case where the variation error of the output cumulative value ΣOs caused by interference affects the determination of the specific decomposition period τpb. Therefore, not only can the range resolution be improved, but also its decomposition accuracy can be improved, contributing to the achievement of high range detection accuracy. Also, it is possible to avoid the case where the processing load increases in the determination of the specific decomposition period τpb due to the complication of the variation pattern in the time distribution of the output cumulative value ΣOs caused by the difference in the individual cumulative counts Na between different types of irradiation light. Therefore, the processing time until data output can be shortened, and the frame rate can be increased.

[0140] It can also be said that in each detection frame Fτ of the present embodiment, as the response output Os for the reference light Lb and each of the delayed lights Ld, the response count Nr of the SPAD pixel 46 is accumulated. Thus, whether each decomposition period τp including the response start timing Tb of each delayed light Ld is within the same sampling period τs as the decomposition period τp including the response start timing Tb of the reference light Lb will cause a variation in the time axis of the response count Nr of the SPAD pixel 46. Therefore, according to the present embodiment, based on the specific decomposition period τpb determined from the time distribution of the output cumulative value ΣOs obtained by accumulating the response count Nr of the SPAD pixel 46, it is possible to output data of the range Lt with improved resolution. Therefore, high range detection accuracy can be achieved.

[0141] (Other Embodiments)

[0142] Although one embodiment has been described above, the present disclosure is not to be construed as being limited to the embodiments described in this specification, and can be applied to various embodiments without departing from the gist of the present disclosure.

[0143] In a modification, the dedicated computer constituting the control device 1 may further include at least one of a digital circuit and an analog circuit as a processor. Here, the digital circuit is, for example, at least one of an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), a SOC (System on a Chip), a PGA (Programmable Gate Array), and a CPLD (Complex Programmable Logic Device). In addition, such a digital circuit may further include a memory storing a program.

[0144] In a modified example, the individual cumulative number of times Na (i.e., the individual irradiation number of times Ni) can also be different between at least two types of irradiation light. In this modified example, for example, when the total cumulative number of times Ns cannot be divided evenly by the magnification value of the distance resolution (i.e., the number of divisions of the decomposition period τp and the total number of types of irradiation light) K, etc., it can be set such that the difference between the numbers of times Na (i.e., the difference between the numbers of times Ni) becomes the minimum.

[0145] In a modified example, in addition to the mechanically oscillating type restricted in the horizontal direction as in the foregoing embodiment, various scanning methods such as a mechanically oscillating type restricted in the vertical direction or a mechanically oscillating type in both the horizontal and vertical directions can also be adopted in the scanning unit 31. In a modified example, as long as the irradiation of the irradiation light can be controlled by the control device 1, a solid-state type unit such as MEMS (Micro Electro Mechanical Systems) etc. can also be adopted in place of the units 21 and 31.

[0146] In a modified example, the vehicle 5 to which the control device 1, the optical detection system 2, the control method, and the control program are applied can, for example, also be an autonomous driving robot capable of performing cargo handling or information collection etc. by autonomous driving or remote driving. In addition to the description methods so far, the foregoing embodiment and modified example can also be implemented in the form of a semiconductor device (such as a semiconductor chip etc.) as a control device configured to be mountable on the vehicle 5 and each having at least one memory 1a and a processor 1b.

[0147] (Postscript)

[0148] Multiple technical ideas listed below and their multiple combinations are disclosed in this specification.

[0149] (Technical idea 1)

[0150] A control device having a processor (1b) and controlling an optical sensor (10), the optical sensor (10) detecting the distance (Lt) of a target (Xt) by receiving reflected light of irradiation light irradiated by light emission and reflected by the target through SPAD pixels (46), in the control device,

[0151] The processor performs the following processing:

[0152] For each detection frame (Fτ) of the time distribution (Ho) of the output cumulative value (ΣOs) obtained by accumulating the response output (Os) of the SPAD pixel repeatedly according to a detection period (τ) that samples the response output across multiple times at a sampling period (τs), control the reference light (Lb) with the irradiation timing aligned with the start timing (T) of the detection period and multiple categories of delayed light (Ld) obtained by delaying the irradiation timing from the start timing by a delay period (τd) shorter than the sampling period each time as the irradiation light; and

[0153] For each of the detection frames, output data of the distance corresponding to a specific decomposition period (τpb), where the specific decomposition period (τpb) is a decomposition period (τp) obtained by decomposing the sampling period according to each of the delay periods and includes the start timing (Tb) of the response of the SPAD pixel to the reference light, and is determined based on the time distribution of the output cumulative value.

[0154] (Technical idea 2)

[0155] The control device according to Technical idea 1, wherein the process of outputting data of the distance includes: for each of the detection frames, for the sampling period in which the output cumulative value reaches the saturation value (ΣOss), output data of the distance corresponding to the specific decomposition period determined based on the output cumulative value in the previous sampling period.

[0156] (Technical idea 3)

[0157] The control device according to Technical idea 1, wherein the process of outputting data of the distance includes: for each of the detection frames, output data of the distance related to the ranging time (ε) from the start timing of the first detection period to the specific decomposition period.

[0158] (Technical idea 4)

[0159] The control device according to any one of Technical ideas 1 to 3, wherein the process of controlling the irradiation light includes: for each of the detection frames, control the delay control time from the start timing of the detection period to the irradiation timing of each of the irradiation lights to be shorter than the dead time (ω) of the SPAD pixel.

[0160] (Technical idea 5)

[0161] The control device according to any one of Technical ideas 1 to 4, wherein the process of outputting data of the distance includes: storing the distance corresponding to the specific decomposition period in a storage medium (1a, 5a) by data output

[0162] (Technical idea 6)

[0163] The control device according to any one of Technical ideas 1 to 5, wherein the process of data-outputting the distance includes: for each of the detection frames, determining the specific decomposition period according to the time distribution of the output cumulative values obtained by making the cumulative number of times of the response outputs to the reference light and each of the delayed lights the same multiple times, and data-outputting the distance according to the specific decomposition period.

[0164] (Technical idea 7)

[0165] The control device according to any one of Technical ideas 1 to 6, wherein the process of data-outputting the distance includes: for each of the detection frames, determining the specific decomposition period according to the time distribution of the output cumulative values obtained by cumulatively adding the number of responses (Nr) of the SPAD pixels as the response outputs to the reference light and each of the delayed lights, and data-outputting the distance according to the specific decomposition period.

[0166] (Technical idea 8)

[0167] An optical detection system, comprising:

[0168] An optical sensor (10) that detects the distance (Lt) to the target (Xt) by receiving the reflected light of the irradiated light irradiated by light emission and reflected by the target (Xt) through the SPAD pixels (46); and

[0169] The control device (1) according to any one of Technical ideas 1 to 7.

[0170] In addition, in the foregoing, Technical ideas 1 to 7 can also be implemented by means of methods and programs.

Claims

1. A control device having a processor (1b) controls an optical sensor (10). The optical sensor (10) receives reflected light reflected by a target (Xt) from irradiated light irradiated by light emission through SPAD pixels (46) to detect the distance (Lt) to the target. The control device is characterized in that the processor performs the following processes: For each detection frame (Fτ) of a time distribution (Ho) of an output cumulative value (ΣOs) obtained by accumulating the response output (Os) of the SPAD pixels repeatedly at a detection period (τ) that spans multiple times and samples the response output at a sampling period (τs), control is performed such that reference light (Lb) with an irradiation timing aligned with the start timing (T) of the detection period and multiple categories of delayed light (Ld) with irradiation timings each delayed by a delay period (τd) shorter than the sampling period from the start timing are used as the irradiated light; and For each of the detection frames, data is output of the distance corresponding to a specific decomposition period (τpb). The specific decomposition period (τpb) is a decomposition period that is determined based on the time distribution of the output cumulative value among decomposition periods (τp) obtained by decomposing the sampling period according to each of the delay periods and that includes the response start timing (Tb) of the SPAD pixels to the reference light.

2. The control device according to claim 1, characterized in that Processing for data-outputting the distance includes: for each of the detection frames, for the sampling period in which the output cumulative value has reached the saturation value (ΣOss), data-outputting the distance corresponding to a specific decomposition period determined based on the output cumulative value in the previous sampling period.

3. The control device according to claim 2, characterized in that Processing for data-outputting the distance includes: for each of the detection frames, data-outputting the distance related to the ranging time (ε) from the start timing of the initial detection period to the specific decomposition period.

4. The control device according to any one of claims 1 to 3, characterized in that Processing for controlling the irradiation light includes: for each of the detection frames, controlling the delay control time from the start timing of the detection period to the irradiation timing of each of the irradiation lights to be shorter than the dead time (ω) of the SPAD pixel.

5. The control device according to any one of claims 1 to 3, characterized in that Processing for data-outputting the distance includes: storing, by data-outputting, the distance corresponding to the specific decomposition period in a storage medium (1a, 5a).

6. The control device according to any one of claims 1 to 3, characterized in that Processing for data-outputting the distance includes: for each of the detection frames, determining the specific decomposition period based on the time distribution of the output cumulative value obtained by making the cumulative number of times of the response output for each of the reference light and the respective delay lights the same for multiple times, and data-outputting the distance according to the specific decomposition period.

7. The control device according to any one of claims 1 to 3, characterized in that Processing for data-outputting the distance includes: for each of the detection frames, determining the specific decomposition period based on the time distribution of the output cumulative value obtained by cumulatively counting the number of responses (Nr) of the SPAD pixel as the response output for each of the reference light and the respective delay lights, and data-outputting the distance according to the specific decomposition period.

8. An optical detection system, characterized in that Comprising: An optical sensor (10) that detects the distance (Lt) to a target (Xt) by receiving, through an SPAD pixel (46), reflected light obtained by reflecting irradiation light emitted by a light source; And The control device (1) according to any one of claims 1 to 3.

9. A control method is a control method executed by a processor (1b) to control an optical sensor (10). The optical sensor (10) receives reflected light reflected by a target (Xt) from irradiated light irradiated by light emission through SPAD pixels (46) to detect the distance (Lt) of the target. The control method is characterized by including: For each detection frame (Fτ) of a time distribution (Ho) of an output cumulative value (ΣOs) obtained by repeatedly sampling and processing a response output (Os) of the SPAD pixel at a sampling period (τs) over multiple times in a detection period (τ), controlling the reference light (Lb) with its irradiation timing aligned with the start timing (T) of the detection period and multiple types of delay lights (Ld) each having an irradiation timing delayed from the start timing by a delay period (τd) shorter than the sampling period as the irradiation light; And For each of the detection frames, data-outputting the distance corresponding to a specific decomposition period (τpb), where the specific decomposition period (τpb) is a decomposition period among the decomposition periods (τp) obtained by decomposing the sampling period according to the respective delay periods and including the response start timing (Tb) of the SPAD pixel to the reference light, and is determined based on the time distribution of the output cumulative value.

10. A control program is stored in a storage medium (1a) and includes commands executed by a processor (1b) to control an optical sensor (10). The optical sensor (10) receives reflected light reflected by a target (Xt) from irradiated light irradiated by light emission through SPAD pixels (46) to detect the distance (Lt) of the target. The control program is characterized in that the commands include: For each detection frame (Fτ) of the time distribution (Ho) of the output integration value (ΣOs) obtained by integrating the response output (Os) of the SPAD pixel repeatedly according to the detection period (τ) that spans multiple times and samples the response output at the sampling period (τs), control the reference light (Lb) with the irradiation timing aligned with the start timing (T) of the detection period and the multiple types of delayed light (Ld) obtained by delaying the irradiation timing from the start timing by a delay period (τd) shorter than the sampling period each time as the irradiation light; And For each of the detection frames, output the distance corresponding to a specific decomposition period (τpb), where the specific decomposition period (τpb) is a decomposition period in the decomposition periods (τp) obtained by decomposing the sampling period according to each of the delay periods and includes the start timing (Tb) of the response of the SPAD pixel to the reference light, and is determined according to the time distribution of the output integration value.

Images