Control device, optical sensor, control method, and control program

Abstract

A processor of this control device executes: acquiring, in each detection cycle (Cd) and in association with respective detection pixels, light reception intensity with respect to the detection distance; counting, a first extraction number (N1) of, among detection pixels that have detected a fail echo in which a light reception intensity is equal to or more than a fail threshold with respect to a detection distance within a fail range closer to an appropriate range, detection pixels that have not detected an appropriate echo having a detection distance within the appropriate range in the same detection cycle as that of the fail echo; counting a second extraction number (N2) of, among detection pixels that have not detected a fail echo, detection pixels that have detected an appropriate echo in the same detection cycle as that of the fail echo; generating detection data (Dd) that provides notification of a shielded state in response to the first extraction number (N1) that has increased to equal or greater than a first determination threshold (Nt1); and generating detection data (Dd) that provides notification of a tainted state in response to the second extraction number (N2) that has increased to equal or greater than a second determination threshold (Nt2).

Description

Control device, optical sensor, control method, and control program CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2024-12278 filed in Japan on January 30, 2024, and the contents of the original application are incorporated by reference in their entirety.

[0002] The present disclosure relates to techniques for controlling optical sensors.

[0003] The optical sensor disclosed in Patent Document 1 is controlled to receive a reflected echo from a target in response to a light beam projected into the outside world and output detection data. As one type of such control technology, Patent Document 1 proposes determining whether an obstacle is blocking the window of the optical sensor and reducing the effect of the obstacle.

[0004] Special Publication No. 2023-538023

[0005] However, in the technology disclosed in Patent Document 1, if the window that provides the detection surface of the optical sensor becomes dirty, the results of the frequency analysis will appear similar to the case of obstruction by an obstacle. Therefore, even if the window is dirty, it will not be distinguished from the case of obstruction and will be confused, which raises the concern of false detection.

[0006] An object of the present disclosure is to provide a control device that suppresses false detection in an optical sensor. Another object of the present disclosure is to provide a control method that suppresses false detection in an optical sensor. Yet another object of the present disclosure is to provide a control program that suppresses false detection in an optical sensor. Yet another object of the present disclosure is to provide an optical sensor equipped with a control device that suppresses false detection.

[0007] The technical means of the present disclosure for solving the problems will be described below.

[0008] A first aspect of the present disclosure is a control device having a processor for controlling an optical sensor that receives a reflected echo from a target in response to a projected beam of light projected to the outside world in each detection cycle and outputs detection data, wherein the processor: acquires, for each detection cycle, the received intensity of the reflected echo by the optical sensor in association with the detection distance to the target according to the timing of receiving the reflected echo by the optical sensor, for each detection pixel of the detection data; counts a first extraction number of detection pixels that have detected a fail echo as a reflected echo whose received intensity is equal to or greater than a fail threshold for a detection distance within a fail range that is closer than the appropriate range, but that have not detected a proper echo as a reflected echo whose detection distance is within the appropriate range in the same detection cycle as the fail echo; counts a second extraction number of detection pixels that have detected a proper echo in the same detection cycle as the fail echo, among the detection pixels that have detected a fail echo; and generates detection data that notifies of a blocked state in which the detection surface of the optical sensor is blocked in response to the first extraction number increasing to or greater than a first determination threshold. In response to the second extraction number increasing to or exceeding the second determination threshold, generating detection data that notifies that the detection surface is in a dirty state.

[0009] A second aspect of the present disclosure is a control method executed by a processor to control an optical sensor that receives a reflected echo from a target in response to a projected beam of light projected to the outside world in each detection cycle and outputs detection data, the method comprising: acquiring, for each detection cycle, the intensity of the reflected echo from the optical sensor associated with the detection distance to the target according to the timing of receiving the reflected echo from the optical sensor, for each detection pixel of the detection data; counting a first extraction number of detection pixels that have detected a fail echo as a reflected echo whose received intensity is equal to or greater than a fail threshold for a detection distance within a fail range that is closer than the appropriate range, but that have not detected a proper echo as a reflected echo whose detection distance is within the appropriate range, in the same detection cycle as the fail echo; counting a second extraction number of detection pixels that have detected a proper echo in the same detection cycle as the fail echo, among the detection pixels that have detected a fail echo; and generating detection data that notifies of a blocked state in which the detection surface of the optical sensor is blocked, in response to the first extraction number increasing to or greater than a first determination threshold. and generating detection data informing that the detection surface is in a dirty state in response to the second extraction number increasing to or exceeding the second determination threshold.

[0010] A third aspect of the present disclosure is a control program stored in a storage medium for controlling an optical sensor that receives a reflected echo from a target in response to a projected beam of light projected to the outside world in each detection cycle and outputs detection data, and including instructions to cause a processor to execute the program, the control program comprising: acquiring, for each detection cycle, the received intensity of the reflected echo by the optical sensor in association with the detection distance to the target according to the timing of receiving the reflected echo by the optical sensor for each detection pixel of the detection data; counting a first extraction number of detection pixels that have detected a fail echo as a reflected echo whose received intensity is equal to or greater than a fail threshold for a detection distance within a fail range that is closer than the appropriate range, but that have not detected a proper echo as a reflected echo whose detection distance is within the appropriate range in the same detection cycle as the fail echo; counting a second extraction number of detection pixels that have detected a proper echo in the same detection cycle as the fail echo, among the detection pixels that have detected a fail echo; generating detection data that notifies of a blocked state in which the detection surface of the optical sensor is blocked in response to the first extraction number increasing to or greater than a first determination threshold; and generating detection data informing that the detection surface is in a dirty state in response to the second extraction number increasing to or exceeding the second determination threshold.

[0011] In this way, in the first to third aspects, the received light intensity of the reflected echo by the optical sensor is associated with the detection distance to the target according to the timing of receiving the reflected echo by the optical sensor, and is acquired for each detection pixel of the detection data in each detection cycle. Therefore, according to the first to third aspects, attention is paid to the detection pixel that detected the fail echo, whose received light intensity is associated with a fail threshold or more for a detection distance that is within the fail range closer than the appropriate range.

[0012] Specifically, among the detection pixels that detected a fail echo in the first to third modes, a first extraction number is counted for detection pixels that did not detect a valid echo within the valid range in the same detection cycle as the fail echo. This allows a blocked state, in which the detection surface of the optical sensor is blocked, to be notified based on the count value of the first extraction number that has increased to or above the first determination threshold, so that the blocked state can be accurately identified by generating and outputting detection data in response to this increase.

[0013] Furthermore, among the detection pixels that detected a failing echo in the first to third modes, the second extraction number of detection pixels that detected a proper echo whose detection distance was within the proper range in the same detection cycle as the failing echo is also counted. This allows the contamination state of the detection surface of the optical sensor to be accurately reported based on the count value of the second extraction number that has increased to within the second judgment range, and the contamination state can be accurately identified by generating and outputting detection data in response to this increase.

[0014] As described above, the first to third aspects can distinguish between the blocked state and the dirty state, and can suppress erroneous detections caused by confusing the two.

[0015] A fourth aspect of the present disclosure is an optical sensor that receives a reflected echo from a target in response to a projected beam projected into the outside world in each detection cycle and outputs detection data, and is configured to include the control device of the first aspect and is equipped with a control unit that generates detection data, a light projecting unit that projects the projected beam in accordance with control by the control unit, and a light receiving unit that receives the reflected echo in accordance with control by the control unit.

[0016] The optical sensor of the fourth aspect can achieve the same effects based on the same principle as the control device of the first aspect.

[0017] FIG. 1 is a cross-sectional view showing the overall configuration of an optical sensor according to a first embodiment. FIG. 2 is a block diagram showing the functional configuration of an optical sensor according to the first embodiment. FIG. 3 is a schematic diagram showing a light projecting light source unit according to the first embodiment. FIG. 4 is a schematic diagram showing a light receiving and detecting unit according to the first embodiment. FIG. 5 is a schematic diagram for explaining detection data according to the first embodiment. FIG. 6 is a flowchart showing a control flow according to the first embodiment. FIG. 7 is a graph showing a control flow according to the first embodiment. FIG. 8 is a characteristic table showing a control flow according to the first embodiment. FIG. 9 is a graph showing a control flow according to the first embodiment. FIG. 10 is a characteristic table showing a control flow according to the first embodiment. FIG. 11 is a characteristic table showing a control flow according to the first embodiment. FIG. 12 is a schematic diagram for explaining a shielded state according to the first embodiment. FIG. 13 is a schematic diagram for explaining a dirty state according to the first embodiment. FIG. 14 is a flowchart showing a control flow according to a second embodiment. FIG. 15 is a schematic diagram for explaining detection data according to the second embodiment. FIG. 16 is a schematic diagram for explaining the relationship between detection data and a detection field of view according to the second embodiment.

[0018] Hereinafter, multiple embodiments of the present disclosure will be described with reference to the drawings. Note that corresponding components in each embodiment are designated by the same reference numerals, and redundant description may be omitted. Furthermore, when only a portion of the configuration is described in each embodiment, the configuration of another previously described embodiment may be applied to the remaining portions of the configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of multiple embodiments may be partially combined together even if not explicitly stated, provided that there is no particular problem with the combination.

[0019] As shown in FIG. 1 , an optical sensor 10 according to a first embodiment of the present disclosure is a LiDAR (Light Detection and Ranging / Laser Imaging Detection and Ranging) sensor that can be mounted on a mobile object 1 and optically detects the external environment of the mobile object 1. The mobile object 1 to which the optical sensor 10 is applied is, for example, an automobile capable of at least one of manual driving, automatic driving, and remote driving. In the following description, unless otherwise specified, the directions indicated as front, rear, up, down, left, and right are defined with respect to the mobile object 1 on a horizontal plane. In the following description, the horizontal direction and the vertical direction refer to the directions parallel to and perpendicular to the horizontal plane, respectively, of the mobile object 1 on the horizontal plane. However, in FIG. 1 , the left side of the dashed-dotted line along the vertical direction (the side of a cover panel 12 described below) actually illustrates a cross section perpendicular to the right side of the dashed-dotted line (the side of components 21 and 41 described below).

[0020] The optical sensor 10 is disposed in at least one location on the mobile body 1, such as the front, left and right side portions, rear portion, or upper roof. As shown in Figures 1 and 2, the optical sensor 10 projects a projected beam Bp toward a detection area Ad in the outside world that corresponds to the location of the optical sensor 10 on the mobile body 1 and a detection field of view Vd (see Figures 13 and 14 described below). The optical sensor 10 detects, as a reflected echo Er, a beam that is returned when the projected beam Bp is reflected by a target Ot in the detection area Ad in the outside world. The projected beam Bp that becomes the reflected echo Er is selected to be light in the near-infrared range that is difficult for humans to see.

[0021] The optical sensor 10 detects a target Ot present in a detection area Ad in the outside world by receiving a reflected echo Er reflected from the projected light beam Bp. Here, the detection of the target Ot involves sensing multiple types of information, including at least distance and intensity, such as the distance from the optical sensor 10 to the target Ot, the intensity of the reflected echo Er reflected from the target Ot, and the direction in which the target Ot exists.

[0022] The target Ot that is a typical detection target in the optical sensor 10 applied to the moving body 1 may be at least one of moving objects such as a pedestrian, a cyclist, a non-human animal, another vehicle, etc. The target Ot that is a typical detection target in the optical sensor 10 applied to the moving body 1 may be at least one of stationary objects such as a guardrail, a road sign, a roadside structure, and an object that has fallen on the road.

[0023] As shown in FIG. 1 , the optical sensor 10 includes a housing 11, a light-projecting unit 21, a scanning unit 31, a light-receiving unit 41, and a control unit 51. The light-shielding housing 11 is formed into a box shape using, for example, metal or resin. The housing 11 houses the light-projecting unit 21, the scanning unit 31, and the light-receiving unit 41 inside. An opening penetrating the housing 11 from the inside to the outside is closed by a cover panel 12. The light-transmitting cover panel 12 is formed using, for example, resin or glass, and separates the inside from the outside of the housing 11. As a result, the outer surface of the cover panel 12 forms a detection surface 12a of the optical sensor 10 that is exposed to the outside world.

[0024] As shown in FIGS. 1 and 2 , the light projecting unit 21 includes a light projecting light source unit 22 and a light projecting lens unit 26. As shown in FIG. 3 , the light projecting light source unit 22 is constructed by mounting a plurality of light source elements 24 in an array on a substrate. The light source elements 24 are laser diodes arranged in a single row (as shown in the example of FIG. 3 ) or in multiple rows (not shown) along the vertical direction. In response to a control signal from the control unit 51, the light source elements 24 generate pulsed laser light that becomes a portion of the projected beam Bp. The light source elements 24 may be edge-emitter lasers or vertical cavity surface-emitting lasers (VCSELs).

[0025] The light projecting light source unit 22 has a light source window 25 formed on one side of the substrate, the light source window 25 being defined as a quasi-rectangular outline with its long sides extending vertically and its short sides extending horizontally. The light source window 25 is configured as a collection of laser oscillation apertures in each light source element 24. The laser light projected from the laser oscillation aperture of each light source element 24 is projected from the light source window 25 as a projecting beam Bp that is simulated to be a line beam extending vertically at least in the external detection area Ad.

[0026] As shown in FIG. 1 , the light-projecting lens unit 26 is constructed in a structure in which at least one light-projecting lens 27 is held in a lens barrel 28. The light-transmitting light-projecting lens 27 is formed mainly from a base material such as resin or glass and has a lens shape corresponding to the optical function to be exerted. The light-projecting lens 27 exerts at least one optical function, such as focusing, collimating, and shaping, on the light-projecting beam Bp from the light-projecting light source unit 22. The light-projecting lens 27 is positioned within a light-blocking lens barrel 28 made of, for example, metal or resin. The light-projecting lens unit 26 configured in this manner is aligned with the light-projecting light source unit 22 to form a light-projecting optical axis that guides the light-projecting beam Bp toward the scanning unit 31.

[0027] 1 and 2, the scanning unit 31 has a scanning mirror 32 and a scanning motor 35. The scanning mirror 32 is constructed in the shape of a plate with a reflective film deposited on a reflective surface 33, which is one side of 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 oscillates within a driving range that is limited by a mechanical or electrical stopper.

[0028] The scanning motor 35 is, for example, a voice coil motor, a brushed DC motor, or a stepping motor. The output shaft of the scanning motor 35 is coupled directly to the scanning mirror 32 or indirectly via a drive mechanism such as a reducer. The scanning motor 35 is held by the housing 11 so as to be able to rotate the scanning mirror 32 together with its output shaft. The scanning motor 35 rotates (i.e., oscillates) the scanning mirror 32 within a limited driving range in accordance with a control signal from the control unit 51.

[0029] The scanning mirror 32 reflects the projected beam Bp incident from the light projecting unit 21 by the reflecting surface 33 and projects it onto the detection area Ad through the cover panel 12, thereby scanning the area Ad in accordance with the rotation angle of the scanning motor 35. At this time, scanning of the detection area Ad by the projected beam Bp is substantially limited to scanning in the horizontal direction in this embodiment, in accordance with the rotational drive of the scanning mirror 32.

[0030] The scanning mirror 32 reflects the reflected echo Er, which is incident from the target Ot in the detection area Ad through the cover panel 12, toward the light receiving unit 41 by the reflecting surface 33 in accordance with the rotation angle of the scanning motor 35. At this time, the speeds of the projected beam Bp and the reflected echo Er are sufficiently greater than the rotational speed of the scanning mirror 32. As a result, the reflected echo Er is reflected by the scanning mirror 32, whose rotation angle with respect to the projected beam Bp can be assumed to be substantially the same, and is guided toward the light receiving unit 41 in the opposite direction to the projected beam Bp.

[0031] The light receiving section 41 includes a light receiving lens unit 42 and a light receiving and detecting unit 45. As shown in FIG. 1 , the light receiving lens unit 42 is constructed such that at least one light receiving lens 43 is held by a lens barrel 44. The light transmitting light receiving lens 43 is formed primarily from a base material such as resin or glass into a lens shape corresponding to the optical function to be exerted. The light receiving lens 43 exerts an optical function to form an image of the reflected echo Er from the scanning mirror 32 on the light receiving and detecting unit 45. The light receiving lens 43 is positioned within the light blocking lens barrel 44, which is formed from, for example, metal or resin. By aligning the light receiving lens unit 42 configured in this manner with the light receiving and detecting unit 45, the light receiving optical axis that guides the reflected echo Er from the scanning section 31 toward the unit 45 is shifted vertically from the light projecting optical axis of the light projecting lens unit 26.

[0032] As shown in FIG. 4 , the light receiving / detecting unit 45 is constructed by mounting a plurality of light receiving pixels 46 in an array on a substrate. The light receiving pixels 46 are arranged at least vertically. The light receiving / detecting unit 45 has a light receiving surface 450 formed on one side of the substrate, the light receiving surface 450 having a rectangular outline with its long sides extending vertically and its short sides extending horizontally. The light receiving surface 450 is configured as a collection of the incident surfaces of the light receiving pixels 46. Each light receiving pixel 46 is composed of a plurality of light receiving elements 460, such as single photon avalanche diodes. Each light receiving pixel 46 receives a reflected echo Er incident on the light receiving surface 450 from the light receiving lens unit 42, as shown in FIG. 1 .

[0033] 1 and 2, the light receiving and detecting unit 45 is provided with an output circuit 47. The output circuit 47 performs sampling processing for each scanning line in accordance with the rotation angle of the scanning mirror 32, which is synchronized with the timing of projection of the light projecting beam Bp from the light projecting light source unit 22, for each detection cycle Cd (see FIG. 5 described later) in accordance with a control signal from the control unit 51. At this time, the output circuit 47 generates a detection signal by combining response outputs from the light receiving elements 460 of each light receiving pixel 46 for each detection cycle Cd. The detection signals generated in this manner are output from the output circuit 47 to the control unit 51 for each scanning line.

[0034] The control unit 51 is configured as a control device including at least one dedicated computer mounted on a circuit board. The dedicated computer constituting the control device as the control unit 51 may be a sensor ECU (Electronic Control Unit) specialized for controlling the optical sensor 10, in which case the sensor ECU is housed in the housing unit 11 (example of FIG. 1). The dedicated computer constituting the control device as the control unit 51 may be a driving control ECU specialized for controlling the driving of the mobile object 1, in which case the driving control ECU is located outside the housing unit 11 in the mobile object 1 (not shown).

[0035] 1, the dedicated computer constituting the control device as the control unit 51 has at least one memory 51a and one processor 51b. The memory 51a is at least one type of non-transitory tangible storage medium, such as a semiconductor memory, a magnetic medium, or an optical medium, that non-temporarily stores computer-readable programs and data. The processor 51b includes at least one type of core, such as a central processing unit (CPU), a graphics processing unit (GPU), a reduced instruction set computer (RISC)-CPU, a data flow processor (DFP), or a graph streaming processor (GSP).

[0036] The control unit 51 configured as above is connected to the light projecting light source unit 22, the scanning motor 35, and the light receiving and detecting unit 45. The control unit 51 controls the light projecting light source unit 22 to generate the light projecting beam Bp for each detection cycle Cd. At the same time, the control unit 51 controls the scanning motor 35 to control, for each detection cycle Cd, the scanning and reflection by the scanning mirror 32 synchronized with the light projecting timing by the light projecting light source unit 22. Furthermore, the control unit 51 processes, for each detection cycle Cd, the detection signal output from the output circuit 47 of the light receiving and detecting unit 45, which is controlled in accordance with the light projecting by the light projecting light source unit 22 and the scanning and reflection by the scanning mirror 32. As a result, the control unit 51 can generate and output the detection data Dd shown in FIG. 5 so as to represent, for each detection cycle Cd, the detection distance L to the target Ot in the detection area Ad and the received light intensity I of the reflected echo Er from the target Ot (both L and I are shown in FIGS. 7 to 12, which will be described later). In this case, in the detection data Dd, even if the detection distance L and the light intensity I are detected by the same physical light-receiving pixel 46, as shown in Figure 5, they are reflected as data values ​​associated with different detection pixels 46a between different scanning lines α within the detection cycle Cd.

[0037] To specifically realize such control, the processor 51b executes a plurality of instructions included in a control program stored in the memory 51a, causing the control unit 51 to construct a plurality of functional blocks for controlling the optical sensor 10. The functional blocks thus constructed by the control unit 51 include a detection block 100, a counting block 110, and a data generation block 120, as shown in FIG.

[0038] The control method in which the control unit 51 controls the optical sensor 10 through cooperation of these blocks 100, 110, and 120 is executed according to the control flow shown in Fig. 6. This control flow is repeatedly executed for each detection cycle Cd during the startup of the mobile object 1. Note that each "S" in the control flow represents a plurality of steps executed by a plurality of commands included in the control program.

[0039] In S100, the detection block 100 acquires detection signals for each scanning line α in the current detection cycle Cd from the output circuit 47. Subsequently, in S110, the detection block 100 generates light reception data Dr (see FIG. 5) for all detection pixels 46a in the light-receiving detection unit 45 based on the detection signals for each scanning line α acquired in the current detection cycle Cd. Specifically, in S110, the detection distance L to the target Ot is acquired based on the elapsed time from the time when the light projecting light source unit 22 projects the light beam Bp to the time when the light receiving detection unit 45 receives the light at the peak of the reflected echo Er. The acquired detection distance L is associated with each detection pixel 46a in accordance with the detection data Dd as a data value of the light reception data Dr used to generate detection data Dd, which will be described later. Furthermore, the light reception intensity I at the peak of the reflected echo Er by the light-receiving detection unit 45 is also acquired and associated with each detection pixel 46a as a data value of the light reception data Dr. At this time, the light receiving intensity I of the reflected echo Er may be corrected, for example, by subtracting the intensity of background light estimated according to the light receiving intensity I associated with the detection pixel 46 a where the peak of the reflected echo Er is not detected. As a result, in the light receiving data Dr, the detection distance L and the light receiving intensity I are also associated with each other.

[0040] In the next step S120, the count block 110 extracts, from the light reception data Dr generated for the current detection cycle Cd, fail candidate pixels 45f among all the detection pixels 46a that satisfy the main fail condition Fm. In this case, the main fail condition Fm is satisfied when the detection distance L at the detection pixel 46a is within a fail range ΔLf that is closer than the appropriate range ΔLa, and the received light intensity I at the detection pixel 46a is equal to or greater than the fail threshold Itf, as shown in FIGS. 7 to 12 . In other words, a fail candidate pixel 45f refers to a detection pixel 46a that has detected at least one fail echo Erf as a reflected echo Er associated with a received light intensity I equal to or greater than the fail threshold Itf and a detection distance L within the fail range ΔLf that is closer than the appropriate range ΔLa.

[0041] Therefore, the fail range ΔLf is preferably set to a range of detection distance L that is less than or equal to a threshold distance corresponding to, for example, the distance from the detection surface 12a to the light-receiving surface 450, but is equal to or greater than 0. At the same time, the appropriate range ΔLa is preferably set to a range of detection distance L that is greater than or equal to the threshold distance, which is outside the fail range ΔLf. Furthermore, the fail threshold Itf is preferably set to, for example, a lower limit value of the received light intensity I predicted from experiments or simulations when an obstruction or stain is detected on the detection surface 12a. Note that the indexes (INDEX) of the reflected echo Er in Figures 8 and 10 to 12 are also included in the light-receiving data Dr as integer values ​​in ascending order corresponding to the order of the light-receiving timing of the reflected echo Er, but the integer values ​​may also correspond to, for example, an ascending or descending order of the received light intensity I.

[0042] 6, in the next step S130, the count block 110 extracts first and second fail pixels 45f1, 45f2 for which the first and second sub-fail conditions Fs1, Fs2, respectively, are satisfied from among the fail candidate pixels 45f extracted for the current detection cycle Cd. The first sub-fail condition Fs1 is satisfied when, as shown in FIGS. 7 and 8, a proper echo Era (see FIG. 9, described later) defined as a reflected echo Er whose detection distance L is within a proper range ΔLa that is farther away than the fail range ΔLf, is not detected in the current detection cycle Cd. That is, the first fail pixel 45f1 refers to a fail candidate pixel 45f for which a proper echo Era representing a detection distance L within the proper range ΔLa was not detected in the same detection cycle Cd as the fail echo Erf.

[0043] In S130, a noise range is defined as a range of received light intensity I lower than the fail threshold Itf to eliminate noise echoes caused by, for example, natural light. Here, the noise range may be set to a range of received light intensity I equal to or less than a threshold intensity corresponding to, for example, the intensity of ambient light. Therefore, as shown in Figures 7 and 8, after a single fail echo Erf is detected at a received light intensity I equal to or greater than the fail threshold Itf outside the noise range, a fail candidate pixel 45f in which a proper echo Era outside the noise range has not been detected is extracted as a first fail pixel 45f1. In other words, the extracted first fail pixel 45f1 is a fail candidate pixel 45f in which the reflected echo Er received in the current detection cycle Cd is limited to a single fail echo Erf.

[0044] 9 to 12, the second sub-failure condition Fs2 in S130 is met when a proper echo Era within the proper range ΔLa, in which the detection distance L is farther than the fail range ΔLf, is detected in the current detection cycle Cd. That is, the second fail pixel 45f2 refers to a fail candidate pixel 45f in which at least one proper echo Era representing a detection distance L within the proper range ΔLa is detected in the same detection cycle Cd as the fail echo Erf.

[0045] 9 to 12, in S130, a fail candidate pixel 45f that detects at least one fail echo Erf at a received light intensity I equal to or greater than the fail threshold Itf outside the same noise range as described above and then detects at least one proper echo Era outside the noise range is extracted as the second fail pixel 45f2. That is, the extracted second fail pixel 45f2 is a fail candidate pixel 45f in which, for the multiple reflected echoes Er received in the current detection cycle Cd, the light-receiving timing of the proper echo Era appears later than the light-receiving timing of the fail echo Erf.

[0046] As shown in FIG. 6 , in the next step S140, the count block 110 counts a first extraction number N1, which is defined as the number of first fail pixels 45f1 extracted in the current detection cycle Cd. Thus, in the current detection cycle Cd, the first extraction number N1 is counted in response to the received reflected echo Er being limited to the fail echo Erf. At the same time, in step S140, the count block 110 also counts a second extraction number N2, which is defined as the number of second fail pixels 45f2 extracted in the current detection cycle Cd. Thus, in the current detection cycle Cd, the second extraction number N2 is counted in response to the light reception timing of the proper echo Era appearing later than the light reception timing of the fail echo Erf.

[0047] In the next step S150, the data generation block 120 determines whether the counted first extraction number N1 is equal to or greater than a first determination threshold Nt1. The first determination threshold Nt1 may be set to correspond to, for example, the minimum value of the first extraction number N1 at which the required accuracy of the detection distance L is no longer satisfied due to the expansion of the blocked portion on the detection surface 12a of the optical sensor 10.

[0048] If a positive determination is made in S150, the control flow proceeds to S160. That is, S160 is executed in response to the first sampling number N1 increasing to or exceeding the first determination threshold Nt1. In S160, the data generation block 120 generates detection data Dd, which includes diagnostic information and is output to the mobile object 1 on which the optical sensor 10 is mounted, indicating an obstructed state (cross-hatched area in FIG. 13 ) in which the detection surface 12a of the optical sensor 10 is obstructed by an obstructing object such as a sheet, paper, or bag. The detection data Dd may be generated to include the light reception data Dr that failed the current detection cycle Cd due to the obstructed state. During startup of the mobile object 1, when the current execution of the control flow in the current detection cycle Cd ends upon completion of execution of S160, the next execution of the control flow in the next detection cycle Cd begins.

[0049] The output of the detection data Dd by S160 may be performed for each positive determination in S150. The output of the detection data Dd by S160 may be performed when the positive determination in S150 is repeated in multiple consecutive executions of the control flow, causing the first extraction number N1 to increase to or exceed the first determination threshold Nt1 for a predetermined first increase-side threshold time or longer. Note that the latter may be substantially equivalent to the output of the detection data Dd when the number of consecutive positive determinations in S150 is equal to or exceeds the first increase-side threshold number corresponding to the first increase-side threshold time.

[0050] If a negative determination is made in S150, the control flow proceeds to S170. However, the transition from S150 to S170 may be performed not only when a negative determination is made in S150, but also when the first sampling number N1 decreases to less than a first hysteresis value that is smaller than the first determination threshold Nt1. The transition from S150 to S170 may also be performed when a negative determination is made in S150 repeatedly during multiple consecutive executions of the control flow, thereby causing the first sampling number N1 to decrease below the first determination threshold Nt1 for a first decrease-side threshold time or longer. Note that the latter case may be substantially equivalent to the transition to S170 being performed when the number of consecutive negative determinations made in S150 is equal to or greater than the first decrease-side threshold number corresponding to the first decrease-side threshold time.

[0051] In S170, the data generation block 120 determines whether the counted second extraction number N2 is equal to or greater than a second determination threshold Nt2. The second determination threshold Nt2 may be set to correspond to, for example, the minimum value of the second extraction number N2 at which the required accuracy of the detection distance L is no longer met due to the expansion of the dirty portion on the detection surface 12a of the optical sensor 10. Here, the second determination threshold Nt2 and the above-mentioned first determination threshold Nt1 may be a common value that is independent of the corresponding state, or may be different values ​​that differ depending on the corresponding state.

[0052] If a positive determination is made in S170, the control flow proceeds to S180. That is, S180 is executed in response to the second sampling number N2 increasing to or exceeding the second determination threshold Nt2. In S180, the data generation block 120 generates detection data Dd, which includes diagnostic information and is output to the mobile object 1, indicating a soiled state of the detection surface 12a of the optical sensor 10, such as soiled with water, dust, or sludge (as shown in FIG. 14, indicated by dotted hatching). The detection data Dd may be generated to include the light reception data Dr that failed the current detection cycle Cd due to the soiled state. During startup of the mobile object 1, when the current execution of the control flow in the current detection cycle Cd ends upon completion of execution of S180, the next execution of the control flow in the next detection cycle Cd begins.

[0053] The output of the detection data Dd in S180 may be performed for each positive determination in S170. The output of the detection data Dd in S180 may also be performed when the positive determination in S170 is repeated multiple times during consecutive execution of the control flow, causing the second extraction number N2 to increase to or exceed the second determination threshold Nt2 for a predetermined second increase-side threshold time or longer. Note that the latter may be substantially equivalent to outputting the detection data Dd when the number of consecutive positive determinations in S170 is equal to or exceeds the second increase-side threshold number corresponding to the second increase-side threshold time.

[0054] If a negative determination is made in S170, the control flow proceeds to S190. That is, S190 is executed in response to both the first sampling number N1 being less than the first determination threshold Nt1 and the second sampling number N2 being less than the second determination threshold Nt2. However, the transition from S170 to S190 may be executed not only when a negative determination is made in S170, but also when the second sampling number N2 has decreased to less than a second hysteresis value that is smaller than the second determination threshold Nt2. The transition from S170 to S190 may also be executed when a negative determination is made in S170 multiple times in succession, thereby causing the second sampling number N2 to decrease below the second determination threshold Nt2 for a second decrease-side time or longer. Note that the latter case may be substantially equivalent to the transition to S190 being executed when the number of consecutive negative determinations made in S170 is equal to or greater than the second decrease-side threshold number corresponding to the second decrease-side threshold time.

[0055] Therefore, in S190, the data generation block 120 generates detection data Dd to be output to the mobile object 1 in a normal state where neither the blocked state nor the dirty state is determined, so as to include normal light reception data Dr in the current detection cycle Cd. At this time, the detection data Dd may be generated to include diagnostic information that notifies of such a normal state. Note that while the mobile object 1 is running, when the current execution of the control flow in the current detection cycle Cd ends in response to the completion of execution of S190, the next execution of the control flow in the next detection cycle Cd will be started.

[0056] (Operations and Effects) Operations and effects of the first embodiment described above will be described below.

[0057] In the first embodiment, the received light intensity I of the reflected echo Er by the optical sensor 10 is associated with each detection pixel 46a in the detection data Dd and acquired for each detection cycle Cd, with respect to the detection distance L to the target Ot corresponding to the timing of receiving the reflected echo Er by the optical sensor 10. Therefore, according to the first embodiment, attention is paid to the detection pixel 46a that has detected the fail echo Erf, whose received light intensity I is associated with the fail threshold value Itf or more and is associated with the detection distance L within the fail range ΔLf that is closer than the appropriate range ΔLa.

[0058] Specifically, in the first embodiment, among the detection pixels 46a that detected the fail echo Erf, the first extraction number N1 of the detection pixels 46a that did not detect the proper echo Era in the same detection cycle Cd as the fail echo Erf and whose detection distance L is within the proper range ΔLa is counted. This allows a blocked state in which the detection surface 12a of the optical sensor 10 is blocked to be notified based on the count value of the first extraction number N1 that has increased to or exceeds the first determination threshold Nt1, and therefore the blocked state can be accurately identified by generating and outputting detection data Dd in response to this increase.

[0059] Furthermore, among the detection pixels 46a that detected the fail echo Erf in the first embodiment, the second extraction number N2 of the detection pixels 46a that detected the proper echo Era whose detection distance L was within the proper range ΔLa in the same detection cycle Cd as the fail echo Erf is also counted. This allows the contamination state of the detection surface 12a of the optical sensor 10 to be accurately reported based on the count value of the second extraction number N2 that has increased to or exceeds the second determination threshold Nt2, and the contamination state can be accurately identified by generating and outputting detection data Dd in response to this increase.

[0060] As described above, the first embodiment can distinguish between the blocked state and the dirty state, and can suppress erroneous detection due to confusion between the two.

[0061] The first extraction number N1 according to the first embodiment is counted in response to the reflected echo Er received in the detection cycle Cd being limited to the fail echo Erf, thereby enabling accurate determination of the occlusion state of the detection surface 12a. Meanwhile, the second extraction number N2 according to the first embodiment is counted in response to the proper echo Era appearing later than the fail echo Erf, thereby enabling accurate determination of the contamination state of the detection surface 12a. These features make it possible to increase the reliability of the effect of suppressing erroneous detection due to confusion between the occlusion state and the contamination state.

[0062] According to the first embodiment, when the first extraction number N1 continues to increase to or exceed the first determination threshold Nt1 for a first threshold time or longer, detection data Dd reporting an obstructed state of the detection surface 12a may be output. Also, according to the first embodiment, when the second extraction number N2 continues to increase to or exceed the second determination threshold Nt2 for a second threshold time or longer, detection data Dd reporting an unclean state of the detection surface 12a may be output. In these cases, it is possible to suppress erroneous detections caused by an accidental increase in the extraction number N1 or N2 to or exceed the corresponding determination threshold Nt1 or Nt2.

[0063] Second Embodiment The second embodiment is a modification of the first embodiment.

[0064] 15, in the control flow of the second embodiment, the control subroutines S140, S150, S160, S170, S180, and S190 are executed repeatedly in order for each of a plurality of pixel areas 46b by executing the control subroutines S2100 and S2110 sandwiched between them. Here, each pixel area 46b is defined to include a set number of detection pixels 46a, as shown by the dot hatching of different coarseness in FIG. 16, and corresponds to each of the division sections Vdb obtained by dividing the entire detection field Vd defined by all the scanning lines α as shown in FIG.

[0065] Therefore, in S2100, the count block 110 increments an index k (k = an integer from 1 to K) for identifying the pixel area 46b for which each control subroutine is executed from an initial value of 0 immediately after transition from S130 at the start of each control subroutine. Meanwhile, in each control subroutine, which transitions from S160, S180, or S190, in S2110, the count block 110 determines whether the index k of the pixel area 46b has reached K, the total number of pixel areas 46b. If the determination in S2110 is negative, the process returns to S2100 to start the next control subroutine, whereas if the determination in S2110 is positive, the current execution of the control flow ends.

[0066] In the second embodiment, in S140 of each control subroutine, the extraction numbers N1 and N2 are counted for each pixel area 46b. Then, in S150 of each control subroutine, it is determined whether the first extraction number N1 for the corresponding pixel area 46b is equal to or greater than a first determination threshold Nt1, which is set smaller than that in the first embodiment. As a result, in S160 of a control subroutine for which a positive determination is made in S150, detection data Dd indicating an obstructed state for the pixel area 46b corresponding to that control subroutine is generated and output in the same manner as in the first embodiment. However, the detection data Dd may be finally output to the moving object 1 after the detection data Dd for the pixel area 46b with index k=K is generated.

[0067] On the other hand, in the second embodiment, in S170 of a control subroutine in which a negative determination is made in S150, it is determined whether the second extraction number N2 for the pixel area 46b corresponding to that control subroutine is equal to or greater than a second determination threshold Nt2 that is set smaller than that in the first embodiment. As a result, in S180 of a control subroutine in which a positive determination is made in S170, detection data Dd indicating the soiled state for the pixel area 46b corresponding to that control subroutine is generated and output in the same manner as in the first embodiment. However, the detection data Dd may be finally output to the mobile object 1 after the detection data Dd for the pixel area 46b with index k=K is generated.

[0068] In the second embodiment, in S190 of a control subroutine in which a negative determination is made in S170, detection data Dd including normal light reception data Dr for the pixel area 46b corresponding to that control subroutine is generated and output in the same manner as in the first embodiment. However, the detection data Dd may be finally output to the moving object 1 after the detection data Dd for the pixel area 46b with index k=K is generated.

[0069] According to the second embodiment, the first extraction number N1 is counted for each pixel area 46b defined by including a set number of detection pixels 46a, so that the occlusion state of the detection surface 12a can be determined for each division section Vdb corresponding to each pixel area 46b in the detection field of view Vd. Meanwhile, the second extraction number N2 according to the first embodiment is counted for each pixel area 46b defined by including a set number of detection pixels 46a, so that the contamination state of the detection surface 12a can be determined for each division section Vdb corresponding to each pixel area 46b in the detection field of view Vd. These features enable precise suppression of false detections caused by confusion between the occlusion state and the contamination state of the detection surface 12a, even for a detection field of view Vd that covers a relatively wide detection surface 12a, by dividing the detection field of view Vd into the division sections Vdb.

[0070] (Other Embodiments) Although multiple embodiments have been described above, the present disclosure should not be construed as being limited to those embodiments, and can be applied to various embodiments and combinations within the scope that does not deviate from the gist of the present disclosure.

[0071] In a modified example, the dedicated computer constituting the control device as the control unit 51 may have at least one of a digital circuit and an analog circuit as a processor. Here, the digital circuit is at least one of an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a system on a chip (SOC), a programmable gate array (PGA), and a complex programmable logic device (CPLD). Such a digital circuit may also have a memory that stores a program.

[0072] In a modified example, the mobile body 1 to which the control device that executes the above-described control method and control program as the control unit 51 and the optical sensor 10 that includes the same are applied may be, for example, an autonomous robot that is capable of transporting luggage or collecting information by autonomous or remote driving. In a modified example, the control device that executes the above-described control method and control program as the control unit 51 and the optical sensor 10 that includes the same may be applied to infrastructure equipment other than the mobile body 1, for example, a smart pole.

[0073] In S130 of the modified example, the number of fail echoes Erf when the first sub-fail condition Fs1 is satisfied may be counted as the first extraction number N1. In S130 of the modified example, the number of fail echoes Erf when the second sub-fail condition Fs2 is satisfied may be counted as the second extraction number N2. In addition to the forms described so far, the above-mentioned embodiments and modified examples may be implemented in the form of a semiconductor device (e.g., a semiconductor chip) as the control device serving as the control unit 51.

[0074] (Additional Remarks) This specification discloses the following technical ideas and their combinations. Note that the reference symbols in parentheses in this Additional Remarks section indicate the correspondence with the specific means described in the above detailed embodiments, and do not limit the technical scope of the present disclosure.

[0075] (Technical Idea 1) A control device having a processor (51b) for controlling an optical sensor (10) that receives a reflected echo (Er) from a target (Ot) in response to a projected beam (Bp) projected to the outside for each detection cycle (Cd) and outputs detection data (Dd), wherein the processor: acquires, for each detection cycle, a light intensity (I) of the reflected echo by the optical sensor associated with a detection distance (L) to the target according to a timing of receiving the reflected echo by the optical sensor for each detection pixel (46a) of the detection data; and counts a first extraction number (N1) of detection pixels that have detected a fail echo (Erf) as the reflected echo, the received light intensity being equal to or greater than a fail threshold (Itf) for the detection distance within a fail range (ΔLf) closer than an appropriate range (ΔLa), and that have not detected a proper echo (Era) as the reflected echo within the appropriate range in the same detection cycle as the fail echo; The control device is configured to execute the following operations: counting a second extraction number (N2) of the detection pixels that detected the proper echo in the same detection cycle as the failed echo, among the detection pixels that detected the failed echo; generating the detection data notifying a blocked state in which the detection surface (12a) of the optical sensor is blocked, in response to the first extraction number increasing to or above a first determination threshold (Nt1); and generating the detection data notifying a dirty state in which the detection surface is dirty, in response to the second extraction number increasing to or above a second determination threshold (Nt2).

[0076] (Technical Idea 2) The control device according to Technical Idea 1, wherein counting the first extraction number includes counting the first extraction number in response to the reflected echoes received in the detection cycle being limited to the fail echoes.

[0077] (Technical Idea 3) The control device according to Technical Idea 1 or 2, wherein counting the second extraction number includes counting the second extraction number in response to the light receiving timing of the proper echo appearing later than the light receiving timing of the fail echo in the detection cycle.

[0078] (Technical Idea 4) The control device according to any one of Technical Ideas 1 to 3, wherein counting the first extracted number includes counting the first extracted number for each pixel area (46b) defined to include a set number of the detection pixels.

[0079] (Technical Idea 5) The control device according to any one of Technical Ideas 1 to 4, wherein counting the second extracted number includes counting the second extracted number for each pixel area (46b) defined to include a set number of the detection pixels.

[0080] (Technical Idea 6) The control device according to any one of Technical Ideas 1 to 5, wherein generating the detection data that notifies the blocked state includes outputting the detection data that notifies the blocked state when the first extraction number continues to increase to or exceed the first determination threshold for a first threshold time or longer.

[0081] (Technical Idea 7) A control device described in any one of Technical Ideas 1 to 6, wherein generating the detection data that notifies the contamination state includes outputting the detection data that notifies the contamination state when the increase in the second extraction number to above the second judgment threshold continues for a second threshold time or more.

[0082] (Technical Idea 8) An optical sensor that receives a reflected echo (Er) from a target (Ot) in response to a projected beam (Bp) projected to the outside world for each detection cycle (Cd) and outputs detection data (Dd), the optical sensor including the control device described in any one of Technical Ideas 1 to 7, and comprising: a control unit (51) that generates the detection data; a light projecting unit (21) that projects the projected beam in accordance with the control of the control unit; and a light receiving unit (41) that receives the reflected echo in accordance with the control of the control unit.

[0083] The above-mentioned technical concepts 1 to 7 may be understood as the respective technical concepts of the method and the program.

Claims

1. A control device having a processor (51b) for controlling an optical sensor (10) that receives a reflected echo (Er) from a target (Ot) in response to a projected beam (Bp) projected to the outside world for each detection cycle (Cd) and outputs detection data (Dd), wherein the processor: acquires, for each detection cycle, the received light intensity (I) of the reflected echo by the optical sensor in association with the detection distance (L) to the target according to the timing of receiving the reflected echo by the optical sensor for each detection pixel (46a) of the detection data; and counts a first extraction number (N1) of detection pixels that have detected a fail echo (Erf) as the reflected echo, the received light intensity of which is equal to or greater than a fail threshold (Itf) and is associated with the detection distance within a fail range (ΔLf) closer than an appropriate range (ΔLa), and that have not detected a proper echo (Era) as the reflected echo within the appropriate range in the same detection cycle as the fail echo; The control device is configured to execute the following operations: counting a second extraction number (N2) of the detection pixels that detected the proper echo in the same detection cycle as the failed echo, among the detection pixels that detected the failed echo; generating the detection data notifying a blocked state in which the detection surface (12a) of the optical sensor is blocked, in response to the first extraction number increasing to or above a first determination threshold (Nt1); and generating the detection data notifying a dirty state in which the detection surface is dirty, in response to the second extraction number increasing to or above a second determination threshold (Nt2).

2. The control device according to claim 1, wherein counting the first number of samples includes counting the first number of samples in response to the reflected echoes received in the detection cycle being limited to the fail echoes.

3. The control device according to claim 1, wherein counting the second number of samples includes counting the second number of samples in response to the light reception timing of the correct echo occurring later than the light reception timing of the fail echo in the detection cycle.

4. The control device according to claim 1, wherein counting the first extracted number includes counting the first extracted number for each pixel area (46b) defined to include a set number of the detection pixels.

5. The control device according to claim 1, wherein counting the second extracted number includes counting the second extracted number for each pixel area (46b) defined to include a set number of the detection pixels.

6. The control device according to claim 1, wherein generating the detection data that notifies the obscured state includes outputting the detection data that notifies the obscured state when the first extracted number continues to increase to or exceed the first determination threshold for a first threshold time or longer.

7. The control device described in claim 1, wherein generating the detection data that notifies the contamination state includes outputting the detection data that notifies the contamination state when the increase in the second extraction number above the second judgment threshold continues for a second threshold time or more.

8. An optical sensor that receives a reflected echo (Er) from a target (Ot) in response to a projected beam (Bp) projected into the outside world for each detection cycle (Cd) and outputs detection data (Dd), the optical sensor including a control device according to any one of claims 1 to 7, and comprising: a control unit (51) that generates the detection data; a light projecting unit (21) that projects the projected beam in accordance with the control of the control unit; and a light receiving unit (41) that receives the reflected echo in accordance with the control of the control unit.

9. A control method executed by a processor (51b) for controlling an optical sensor (10) that receives a reflected echo (Er) from a target (Ot) in response to a projected beam (Bp) projected to the outside world for each detection cycle (Cd) and outputs detection data (Dd), comprising: acquiring, for each detection cycle, the intensity (I) of the reflected echo received by the optical sensor for each detection pixel (46a) of the detection data in association with the detection distance (L) to the target according to the timing of receiving the reflected echo by the optical sensor; and counting a first extraction number (N1) of detection pixels that have detected a fail echo (Erf) as the reflected echo, the received intensity of which is equal to or greater than a fail threshold (Itf) and is associated with the detection distance within a fail range (ΔLf) closer than an appropriate range (ΔLa), and that have not detected a proper echo (Era) as the reflected echo within the appropriate range in the same detection cycle as the fail echo; A control method including: counting a second extraction number (N2) of the detection pixels that detected the proper echo in the same detection cycle as the failed echo, among the detection pixels that detected the failed echo; generating the detection data notifying a blocked state in which the detection surface (12a) of the optical sensor is blocked, in response to the first extraction number increasing to or above a first determination threshold (Nt1); and generating the detection data notifying a dirty state in which the detection surface is dirty, in response to the second extraction number increasing to or above a second determination threshold (Nt2).

10. A control program stored in a storage medium (51a) for controlling an optical sensor (10) that receives a reflected echo (Er) from a target (Ot) in response to a projected beam (Bp) projected to the outside world for each detection cycle (Cd) and outputs detection data (Dd), the control program including instructions for causing a processor (51b) to execute the control program, the control program comprising: acquiring, for each detection cycle, the intensity (I) of the reflected echo received by the optical sensor in association with each detection pixel (46a) of the detection data for the detection distance (L) to the target according to the timing of receiving the reflected echo by the optical sensor; a control program including instructions for executing the following: counting a first extraction number (N1) of detection pixels that have detected a fail echo (Erf) as the reflected echo, in which the received light intensity equal to or greater than a fail threshold (Itf) is associated with the detection distance within a fail range (ΔLf) that is closer than the appropriate range (ΔLa), and in which a proper echo (Era) as the reflected echo, whose detection distance is within the appropriate range, has not been detected in the same detection cycle as the fail echo; counting a second extraction number (N2) of detection pixels that have detected the fail echo and have detected the proper echo in the same detection cycle as the fail echo; generating the detection data that notifies a blocked state in which the detection surface (12a) of the optical sensor is blocked, in response to the first extraction number increasing to or greater than a first determination threshold (Nt1); and generating the detection data that notifies a dirty state in which the detection surface is dirty, in response to the second extraction number increasing to or greater than a second determination threshold (Nt2).