Distancing system

Abstract

This reduces the error in the measured distance compared to using the received light results without correction. [Solution] The processor drives the light-emitting unit to have a first lighting state in which one light-emitting section that irradiates light toward one area in each of the multiple arranged light sources is lit, and a second lighting state in which multiple light-emitting sections, including one light-emitting section, are lit simultaneously in at least some of the light sources. The processor acquires a partially illuminated image, which is the result of light reception by the light-receiving unit in the first lighting state, and a full-surface illuminated image, which is the result of light reception by the light-receiving unit in the second lighting state (S201, S202), and performs processing to correct the distance to one area measured based on the first light reception result using the acquired partially illuminated image and full-surface illuminated image (S205).

Description

Technical Field

[0001] The present invention relates to a distance measurement system.

Background Art

[0002] For example, Patent Document 1 discloses a measuring device including a light emitting unit including a first light emitting section that emits light toward a first region and a second light emitting section that emits light toward a second region different from the first region. The measuring device further includes a light receiving unit including a first light receiving section that receives light reflected in the first region and a second light receiving section that receives light reflected in the second region. The measuring device further includes an acquisition unit that acquires information regarding the second region from a result of light received by the second light receiving section after light emitted from the first light emitting section is reflected in the second region.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, there is a light emitting device in which a plurality of light sources each having a plurality of light emitting sections are arranged. Consider a case where one light emitting section that irradiates light toward one region is turned on in each of the plurality of light sources. When driving the light emitting sections of the plurality of light sources to be turned on only once with respect to one region, it is assumed that the influence of the deviation of the light emitting sections with respect to one region becomes large due to the accuracy when assembling the plurality of light sources. Therefore, when measuring the distance based on the result of receiving the reflected light reflected in one region, there is a risk that the distance error will become large if the result of the reception is used without correction. An object of the present invention is to reduce the error in the measured distance as compared with the case where the result of the reception is used without correction. [Means for solving the problem]

[0005] The invention described in claim 1 is a distance measuring system comprising: a light-emitting unit having a plurality of light sources, each having a plurality of individually emitting light-emitting compartments; a light-receiving unit that receives reflected light from the light-emitting unit; and a processor, wherein the processor drives the light-emitting unit to have a first lighting state in which one light-emitting compartment that irradiates light toward one area in each of the plurality of arranged light sources is lit, and a second lighting state in which a plurality of light-emitting compartments, including the said one light-emitting compartment, are lit simultaneously in at least some of the light sources; a first light-receiving result which is the result of light reception by the light-receiving unit in the first lighting state and a second light-receiving result which is the result of light reception by the light-receiving unit in the second lighting state, and a process to correct the distance to the one area measured based on the first light-receiving result using the acquired first and second light-receiving results. The invention described in claim 2 is a distance measuring system according to claim 1, characterized in that it performs a process to correct the distance to the one region measured based on the first light reception result by the difference between the first light reception result and the second light reception result. The invention described in claim 3 is a distance measuring system according to claim 1, characterized in that the processor switches between all of the plurality of light sources and at least some of the light sources that are set to the first illuminated state and the second illuminated state. The invention described in claim 4 is a distance measuring system according to claim 3, characterized in that the number of light sources in the first lighting state is the same as the number of at least some of the light sources in the second lighting state. The invention described in claim 5 is a distance measuring system according to claim 1, characterized in that the processor performs the correction process when the first light reception result satisfies predetermined conditions. The invention described in claim 6 is a distance measuring system according to claim 5, characterized in that the predetermined condition is that the difference between the center and the edge when the first light receiving result is divided into the center and the edge is greater than a threshold. The invention described in claim 7 is a distance measuring system according to claim 2, characterized in that, if the difference exceeds a predetermined value, the processor performs a process to reduce the influence of indirect light on the first light reception result before correcting the distance to the one region. [Effects of the Invention]

[0006] According to the invention of claim 1, it becomes possible to reduce the error in the measured distance compared to when the light reception result is used without correction. According to the invention of claim 2, it becomes possible to reduce the error in the measured distance compared to the case where the light reception result is used without correction. According to the invention of claim 3, the processor can respond according to the situation, compared to a configuration in which the light source in the first illuminated state and at least some of the light sources that are set to the second illuminated state are either all of the multiple light sources or some of the multiple light sources. According to the invention of claim 4, it becomes possible to enhance the effect of correction compared to a configuration in which the number of light sources in the first lighting state and the number of at least some of the light sources in the second lighting state are the same. According to the invention of claim 5, the processor can reduce the processing burden compared to a system that does not have a configuration to perform correction processing when the first light reception result satisfies predetermined conditions. According to the invention of claim 6, the predetermined condition is that the difference between the center and the edge when the first light reception result is divided into the center and the edge is greater than a threshold value. Compared to a configuration that does not have this condition, it is possible to reduce the processing burden. According to the invention of claim 7, the processor can further reduce the error in the measured distance compared to a configuration in which, when the difference exceeds a predetermined value, processing is performed to reduce the effect of indirect light on the first light-receiving result before correcting the distance for one region. [Brief explanation of the drawing]

[0007] [Figure 1] This block diagram shows an example of a schematic configuration of a distance measuring device to which this embodiment is applied. [Figure 2] This diagram illustrates the relationship between the light-emitting surface of the light-emitting unit according to this embodiment and the irradiation surface that is illuminated by the light emitted from the light-emitting unit. [Figure 3] This figure shows an example of a light-emitting unit according to this embodiment. [Figure 4] This diagram illustrates the relationship between the light-receiving surface and the illumination surface of the light-receiving unit according to this embodiment. [Figure 5] This diagram illustrates an example of the irradiation sequence for the irradiation sections of the irradiation surface. [Figure 6] This figure illustrates the distance image in this embodiment, where (a) shows the positional relationship between the distance measuring device and the object, (b) shows an example of a distance image created by the control unit, and (c) shows the state of the illuminated surface. [Figure 7] This is a perspective view showing a schematic configuration example of a distance measuring device to which this embodiment is applied. [Figure 8] This diagram illustrates a first configuration of the light-emitting and light-receiving sections. (a) shows a state in which each of the multiple light sources is lit, and (b) shows the light intensity distribution of the light-receiving section of the light-receiving section in the case of (a). [Figure 9] This figure illustrates a second configuration of the light-emitting and light-receiving sections. (a) shows a state in which multiple light-emitting sections of each of the multiple light sources are lit, and (b) shows the light intensity distribution of the light-receiving sections of the light-receiving section in the case of (a). [Figure 10] This flowchart shows an example of control associated with the illumination of a light source. [Figure 11] This flowchart illustrates an example of control when performing corrections. [Figure 12] This flowchart illustrates an example of a process for generating and saving correction parameters. [Figure 13] This graph illustrates the process of calculating a distance image from a segmented irradiation image. (a) shows the case using the acquired segmented irradiation image, and (b) shows the case using the corrected segmented irradiation image. [Figure 14]This is a flowchart for explaining an example of a process including a process for suppressing the influence of indirect light. [Figure 15] This is a diagram for explaining the lighting states of a modified example of a plurality of light sources. In (a) of this figure, a state where a single light-emitting section is lit is shown, and in (b), a state where a plurality of light-emitting sections are lit is shown. [Figure 16] This is a diagram for explaining the lighting states of another modified example of a plurality of light sources. In (a), a state where a single light-emitting section is lit is shown, and in (b), a state where a plurality of light-emitting sections are lit is shown.

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the technical scope of the present invention is not limited to the scope described as embodiments below. It is clear from the description of the claims that combinations of a plurality of embodiments and those obtained by making various changes or improvements to these embodiments are also included in the technical scope of the present invention.

[0009] [[ID=I9]] <Distance measurement device 1> (Overall configuration) FIG. 1 is a block diagram showing an example of the schematic configuration of a distance measurement device 1 to which this embodiment is applied. The distance measurement device 1 measures the distance to an object based on the time from the timing when light is emitted from the light-emitting unit 4 to the timing when the light reflected by the object is received by the light-receiving unit 5. That is, the distance measurement device 1 is a device that performs distance measurement based on the ToF method. The ToF method includes an indirect ToF (iToF: indirect ToF) method for measuring time from the difference between the phase of the emitted light and the phase of the received light, and a direct ToF (dToF: direct ToF) method for directly measuring the time from the emission to the reception of light. In this embodiment, the distance measurement device 1 will be described as performing distance measurement based on the indirect ToF method. The distance measurement device 1 is an example of a distance measurement system.

[0010] As shown in FIG. 1, the distance measurement device 1 includes an optical device 3 and a control unit 8. The optical device 3 comprises a light-emitting unit 4 that emits light toward a predetermined irradiation range, a light-receiving unit 5 that receives light emitted from the light-emitting unit 4 and reflected by objects present in the irradiation range, a light-emitting drive unit 6 that drives the light-emitting unit 4, and a light-receiving drive unit 7 that drives the light-receiving unit 5. The configuration of the light-emitting unit 4 and the light-receiving unit 5 of the optical device 3 will be described in detail later. The configuration of the light-emitting device 2 is shown by a dashed line.

[0011] The control unit 8 controls the operation of the light-emitting unit 4 and the light-receiving unit 5 of the optical device 3. Furthermore, the control unit 8 acquires the light reception result from the light receiving unit 5 and measures the distance from the distance measuring device 1 to the object using the Time of Flight (ToF) method based on this light reception result.

[0012] The light-receiving unit 5 detects infrared radiation emitted from objects within the irradiation area (irradiation surface 60 in Figure 2, described later). The control unit 8 generates an infrared image from the detection results. The control unit 8 continuously or intermittently at predetermined time intervals detects infrared radiation in the irradiation area and generates an infrared image. The control unit 8 analyzes the acquired infrared images to understand the status of the object within the irradiation range. The control unit 8 determines whether the object is a moving object or a stationary object within the irradiation range. The control unit 8 also determines which irradiation section 61 (see Figure 2, described later) the object is located in within the irradiation range. Furthermore, if the object is a moving object, the control unit 8 determines the direction of movement of the object within the irradiation range and the relative amount of movement of the object within the irradiation range.

[0013] (Light-emitting part 4) Figure 2 illustrates the relationship between the light-emitting surface 40 of the light-emitting unit 4 according to this embodiment and the illumination surface 60 that is irradiated by the light emitted from the light-emitting unit 4. In Figure 2, the left direction of the paper is the +x direction, the top direction of the paper is the +y direction, and the back direction of the paper is the +z direction, with the opposite directions being -x, -y, and -z. In Figure 2, the light-emitting surface 40 and the illumination surface 60 are shown offset in the vertical direction (±y direction) of the paper, but in reality, the light-emitting surface 40 and the illumination surface 60 are arranged to face each other. In Figure 2, the light-emitting surface 40 of the light-emitting unit 4 is located in the front direction (-z direction) of the paper, and the illumination surface 60 is located in the back direction (+z direction) of the paper. In other words, Figure 2 shows the light-emitting unit 4 emitting light onto the illumination surface 60, viewed from the side opposite to the side from which the light-emitting unit 4 emits light. The light-emitting unit 4 is composed of, for example, one or more light-emitting chips.

[0014] The light-emitting unit 4 comprises a light-emitting surface 40 on which multiple vertical cavity surface-emitting lasers (VCSELs, indicated by reference numeral 43 in Figure 3, which will be described later) are arranged. The light-emitting unit 4 emits light toward the irradiation surface 60 through the emission of light from the VCSELs 43. In Figure 2, the VCSELs 43 are not shown. Furthermore, as will be described later, the light-emitting unit 4 may also be configured to have multiple light-emitting surfaces 40.

[0015] The light-emitting surface 40 is divided into multiple light-emitting compartments 41, each containing at least one VCSEL 43. Here, as an example, the light-emitting surface 40 is divided into a total of 12 light-emitting compartments 41, four in the x direction and three in the y direction. As shown in the figure, when it is necessary to distinguish between each light-emitting compartment 41, they are distinguished as light-emitting compartments A1 to A12, starting from the upper left side (the +x and +y ends) in Figure 2. In this specification, "~" indicates multiple components, each distinguished by a number, and means that it includes those listed before and after "~" as well as those numbered in between. For example, light-emitting sections A1 to A12 include 12 light-emitting sections 41, numbered from light-emitting section A1 to light-emitting section A12.

[0016] Each light-emitting section 41 is independently driven by the light-emitting drive unit 6 (see Figure 1) to perform light emission operations. In addition, each light-emitting section 41 emits light when power is supplied to the VCSEL 43 contained in the light-emitting section 41 by the light-emitting drive unit 6. In this embodiment, the power supplied to the VCSEL 43 contained in each light-emitting section 41, and the VCSEL 43 emit light due to the supplied power. The amount of light emitted from each light-emitting section 41 can be adjusted according to environmental factors such as the brightness of the illumination area and operations by the user of the distance measuring device 1. In this embodiment, driving the light-emitting section 41 refers to power being supplied to the VCSEL 43 contained in the light-emitting section 41 so that it emits light, and the light-emitting operation refers to the VCSEL 43 contained in the light-emitting section 41 emitting light for a predetermined period of time. Furthermore, "independently driven" means that each light-emitting section 41 is driven and illuminated individually. The light-emitting drive unit 6 drives each light-emitting section 41 in accordance with the control signal from the control unit 8 (see Figure 1). Therefore, each light-emitting section 41 does not necessarily illuminate all at the same time; for example, in the example in Figure 2, light-emitting section A1 may be emitting light, but light-emitting section A12 may not be emitting light.

[0017] The illumination surface 60 is the surface to which light from the light-emitting unit 4 is irradiated, at a certain distance in the direction (+z direction) from the center 40C of the light-emitting surface 40, and perpendicular to the direction in which light is emitted. In the example shown in Figure 2, the light-emitting unit 4 emits light in the +z direction, so the illumination surface 60 extends in the x and y directions at a certain distance in the +z direction. Here, the central axis Ax (dotted line) passing through the center 60C of the illumination surface 60 and the center 40C of the light-emitting surface 40 is perpendicular to the light-emitting surface 40 and the illumination surface 60. In this embodiment, the illumination surface 60 is rectangular in shape, corresponding to the rectangular shape of the light-emitting surface 40.

[0018] As shown in the figure, the irradiation surface 60 is divided into multiple irradiation sections 61, corresponding to the light-emitting sections 41 on the light-emitting surface 40. In the example in Figure 2, it is divided into 12 irradiation sections 61, with 4 in the x direction and 3 in the y direction. If it is necessary to distinguish between each irradiation section 61, they will be labeled as Irradiation Sections B1 to B12, starting from the upper left side (the +x and +y ends) in Figure 2. In some cases, an illumination area Bi assigned the same number i as an illumination area Bi is referred to as a "corresponding illumination area." For example, illumination area A1 is the illumination area corresponding to illumination area B1. Conversely, an illumination area Bi assigned the same number i as an illumination area Ai is also referred to as a "corresponding illumination area."

[0019] Irradiation sections B1 to B12 are arranged symmetrically with respect to the xy-plane with respect to emission sections A1 to A12. For example, in Figure 2, just as emission sections A1, A2, A3, and A4 are arranged in this order in the -x direction, irradiation sections B1, B2, B3, and B4 are arranged in this order in the -x direction. Each light-emitting section 41 emits light toward its corresponding illumination section 61. Each illumination section 61 is then illuminated by the light emitted from its corresponding light-emitting section 41. Here, "light-emitting section 41 emitting light toward its corresponding illumination section 61" means that the optical axis of the light emitted from each light-emitting section 41 is directed toward its corresponding illumination section 61. It is not limited to all of the light emitted from a light-emitting section 41 illuminating its corresponding illumination section 61. In other words, some of the light emitted from a certain light-emitting section 41 may illuminate an illumination section 61 different from its corresponding illumination section 61, or outside the range of the illumination surface 60.

[0020] Figure 3 shows an example of the light-emitting unit 4 according to this embodiment. Unlike Figure 2, Figure 3 shows the light-emitting unit 4 as viewed from the side that emits light. Therefore, in Figure 3, the right direction on the paper is the +x direction, the top direction on the paper is the +y direction, and the front direction on the paper is the +z direction. As shown in Figure 3, the light-emitting unit 4 has a substrate 42 and a light-emitting surface 40 on which a plurality of VCSELs 43 are arranged. More specifically, the substrate 42 and the light-emitting surface 40 are arranged on top of each other in the direction of light emission (+z direction, the front direction of the paper). Note that the substrate 42 may have wiring for power supply and electrical signal exchange, as well as electronic components related to the operation of the light-emitting unit 4, but these are omitted from the description.

[0021] As described above, the light-emitting unit 4 has 12 light-emitting sections 41 (light-emitting sections A1 to A12) on the light-emitting surface 40, each of which has a VCSEL 43 arranged on it. As shown in Figure 3, all light-emitting sections A1 to A12 have the same area. In addition, each of the light-emitting sections A1 to A12 has the same number of VCSELs 43 (7 in this example) arranged in it. Furthermore, the area of ​​each light-emitting section 41 and the number of VCSELs 43 to be placed are not limited, and some or all of the light-emitting sections 41 may have different areas, and different numbers of VCSELs 43 may be placed in each section.

[0022] The light emitted from each light-emitting section 41 of the light-emitting unit 4 is spread by an irradiation lens section (not shown) into a plane perpendicular to the emission direction (the axial direction of the central axis Ax) and irradiated onto the irradiation surface 60. The irradiation lens section may use optical components such as a diffuser plate provided in the optical path of the light to diffuse the light by scattering, a diffractive optical element (DOE) that changes the angle of incident light before emission, and / or a lens.

[0023] (Light receiving part 5) Figure 4 is a diagram illustrating the relationship between the light-receiving surface 50 of the light-receiving unit 5 according to this embodiment and the illumination surface 60 described above. In Figure 4, as in Figure 2, the left direction of the paper is the +x direction, the top direction of the paper is the +y direction, and the back direction of the paper is the z direction, with the opposite directions being the -x, -y, and -z directions, respectively. Note that in Figure 4, the light-receiving surface 50 and the illumination surface 60 are shown offset in the vertical direction (±y direction) of the paper, but in reality, the light-receiving surface 50 and the illumination surface 60 are arranged to face each other. In Figure 4, the light-receiving unit 5 (light-receiving surface 50) is located in the front direction (-z direction) of the paper, and the illumination surface 60 is located in the back direction (+z direction) of the paper. In other words, Figure 4 shows the light-receiving unit 5, which receives light reflected from the illumination surface 60, as viewed from the side opposite to the side from which the light-receiving unit 5 receives light.

[0024] The light-receiving unit 5 extends in the x and y directions and has a light-receiving surface 50 on which multiple light-receiving elements (not shown) are arranged. The light-receiving unit 5 receives light that is emitted from the light-emitting unit 4 and reflected by an object on the illumination surface 60, using each of the light-receiving elements. The central axis Bx (dotted line) passing through the center 60C of the illumination surface 60 and the center 50C of the light-receiving surface 50 is perpendicular to the illumination surface 60 and the light-receiving surface 50. In this embodiment, the light-receiving surface 50 is rectangular in shape, similar to the light-emitting surface 40 (see Figure 2) and the illumination surface 60.

[0025] The light-receiving surface 50 is divided into multiple light-receiving sections 51, corresponding to the light-emitting section 41 (see Figure 2) of the light-emitting surface 40 (see Figure 2) and the irradiation section 61 of the irradiation surface 60. In the example in Figure 4, it is divided into 12 light-receiving sections 51, with 4 in the x direction and 3 in the y direction. If it is necessary to distinguish between each light-receiving section 51, they are distinguished as light-receiving sections C1 to C12, starting from the upper left side (the +x and +y ends) in Figure 4. In some cases, a light-receiving area Ci assigned the same number i as a light-emitting area Ai or a light-illuminating area Bi is referred to as a "corresponding light-receiving area." For example, light-receiving area C1 is a light-receiving area corresponding to light-emitting area A1 or light-illuminating area B1. Conversely, a light-emitting area Ai assigned the same number as a light-receiving area Ci is referred to as a "corresponding light-emitting area," and a light-receiving area Bi assigned the same number as a light-receiving area Ci is referred to as a "corresponding light-illuminating area."

[0026] The light-receiving sections C1 to C12 are arranged symmetrically with respect to the xy-plane with respect to the illumination sections B1 to B12. For example, in Figure 4, the light-receiving sections C1, C2, C3, C4 are arranged in the same order in the -x direction as the illumination sections B1, B2, B3, B4 are arranged in the same order in the -x direction. Each light-receiving section 51 receives light emitted from the light-emitting section 4 and reflected by an object located in the corresponding irradiation section 61.

[0027] Each light-receiving section 51 has multiple light-receiving elements arranged in a regular pattern. Each light-receiving element receives light emitted from the light-emitting section 4 and reflected by an object on the illumination surface 60, and can output an electrical signal according to the received light. Examples of light-receiving elements include photodiodes and phototransistors.

[0028] Each light-receiving section 51 is independently driven by the light-receiving drive unit 7 (see Figure 1) to perform light-receiving operations. Here, driving a light-receiving section 51 means bringing the light-receiving section 51 into a state where it can accumulate charge in response to light reception by the light-receiving element, and light-receiving operation means that the light-receiving element of the light-receiving section 51 accumulates charge in response to light reception. Furthermore, "independently driven" means driving each light-receiving section 51 individually to bring it into a state where it can accumulate charge in response to light reception. The light-receiving drive unit 7 drives each light-receiving section 51 in response to a control signal from the control unit 8 (see Figure 1). Furthermore, the light receiving unit 5 outputs an electrical signal to the control unit 8 corresponding to the charge accumulated in the light receiving section 51, that is, the result of light reception in the light receiving section 51, in accordance with the readout operation of the control unit 8 (details will be described later).

[0029] Figure 5 illustrates an example of the irradiation sequence for the irradiation sections 61 of the irradiation surface 60. In one example of the sequence shown in Figure 5, irradiation of the irradiation section 61 is performed sequentially in the direction of arrow 64. That is, when the irradiation section 61 is divided into upper, middle, and lower sections, the irradiation is performed in the order of upper section B1-B4, middle section B5-B8, and lower section B9-B12. In the upper section, the order is B1-B4. In the middle section, the direction is the opposite of the upper section, and the order is B8-B5. In the lower section, the direction is the same as the upper section, and the order is B9-B12.

[0030] The emission of light from the light-emitting section 41 of the light-emitting unit 4 is driven in the order of arrows 44 so that the irradiation of the irradiation section 61 is in the order of arrows 64. In addition, the reception of light from the light-receiving section 51 of the light-receiving unit 5 in response to the reflected light from the irradiation section 61 is driven in the order of arrows 54, which correspond to arrows 64.

[0031] (Control Unit 8) Returning to Figure 1, the control unit 8 is composed of a CPU (Central Processing Unit) 81, a ROM (Read Only Memory) 82, and a RAM (Random Access Memory) 83. CPU81 is an example of a processor that loads various programs stored in ROM82, etc., into RAM83 and executes them to realize the functions described later. RAM83 is memory used as working memory for CPU81, etc. ROM82 is memory that stores various programs, etc., that are executed by CPU81.

[0032] Here, the program executed by the CPU 81 may be provided stored on a computer-readable recording medium such as a magnetic recording medium (magnetic tape, magnetic disk, etc.), an optical recording medium (optical disk, etc.), a magneto-optical recording medium, or semiconductor memory. Alternatively, the program executed by the CPU 81 may be provided using communication means such as the Internet.

[0033] In this embodiment, each process is executed on any computer. Furthermore, any computer may execute these processes using a processor as hardware, a program as software, or a combination thereof. In that case, the processor is configured to work in cooperation with the program to execute the various processes in this embodiment, and can function as a unit or means in this embodiment. Also, the execution order of the processes by the processor is not limited to the order described and may be changed as appropriate. Any computer may be a general-purpose computer, a computer designed for a specific purpose, a workstation, or any other system capable of executing each process.

[0034] A processor may consist of one or more hardware components, and the type of hardware is not limited. For example, a processor may consist of a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a programmable logic device such as an FPGA (Field Programmable Gate Array), a dedicated circuit for executing a specific process such as an ASIC (Application Specific Integrated Circuit), a GPU (Graphic Processing Unit), or an NPU (Neural Processing Unit). Furthermore, the type of hardware may be a combination of different types of hardware. When multiple hardware components are configured to execute one or more processes of a processor, these components may reside in physically separate devices or in the same device. Also, in any embodiment, the order of each process performed by the processor is not limited to the order described above and may be changed as appropriate. Hardware is composed of electrical circuits (circuitry) that combine circuit elements such as semiconductor elements.

[0035] Furthermore, the program may be firmware or software such as microcode. Alternatively, the program may be, for example, a set of program modules, each function of which may be implemented by a processor configured to perform its respective function. The program may be program code or multiple code segments stored on one or more non-temporary computer-readable media (e.g., storage media or other storage). The program may be divided and stored on multiple non-temporary computer-readable media located on physically separate devices. Program code or code segments may represent any combination of procedures, functions, subprograms, routines, subroutines, modules, software packages, classes, or instructions, data structures, or program statements. Program code or code segments may be connected to other code segments or hardware circuits by sending and receiving information, data, arguments, parameters, or memory contents.

[0036] The control unit 8 controls the light emission operation of the light emission unit 4 through the light emission drive unit 6, and controls the light receiving operation of the light receiving unit 5 through the light receiving drive unit 7. Furthermore, the control unit 8 performs a readout operation on the light receiving unit 5 through the light receiving drive unit 7. Here, "readout operation" means that the control unit 8 controls the light receiving unit 5 through the light receiving drive unit 7 and outputs an electrical signal corresponding to the result of light reception by the light receiving element in the light receiving section 51, and acquires the result of light reception for each light receiving section 51. In this embodiment, the control unit 8 can perform a readout operation independently for each light receiving section 51. For example, if one light receiving section Ci and another light receiving section Cj are performing a light reception operation and accumulating charge, the control unit 8 can perform a readout operation on both light receiving section Ci and light receiving section Cj, or it can perform a readout operation on only light receiving section Ci.

[0037] The control unit 8 measures the distance of each irradiation area 61 based on the light reception results in each light receiving area 51. The control unit 8 then summarizes the distance measurement results in each irradiation area 61 and creates a distance image representing the distance between the distance measuring device 1 and the object. More specifically, the control unit 8 applies predetermined calculation processing to the four electrical signals obtained from the light receiving unit 5 as the result of four light receptions in each light receiving area 51. This calculates (measures) the distance between the distance measuring device 1 and the object in each irradiation area 61 of the irradiation surface 60 and creates a distance image.

[0038] <Distance image 100> Figure 6 illustrates the distance image 100 in this embodiment, where (a) shows the positional relationship between the distance measuring device 1 and the objects S1 and S2, (b) shows the appearance of the illumination surface 60, and (c) shows an example of the distance image 100 created by the control unit 8. The distance image 100 shown in Figure 6(c) was created as a result of measuring the distance for all illuminated sections 61 on the illuminated surface 60. In the example in Figure 6, the objects S1 and S2 (sometimes referred to simply as object S) were stationary and did not change their position relative to the distance measuring device 1, at least from the start to the completion of the distance measurement necessary for creating the distance image 100.

[0039] As shown in Figure 6(c), the distance image 100 has multiple image sections 101 corresponding to the light-emitting section 41 of the light-emitting surface 40, the illumination section 61 of the illumination surface 60, and the light-receiving section 51 of the light-receiving surface 50 (see Figures 2 and 4). In the example in Figure 6(c), the distance image 100 has 12 image sections 101, four arranged horizontally in the figure corresponding to the ±x directions of the illumination surface 60 and the light-receiving surface 50, and three arranged vertically in the figure corresponding to the ±y directions. If it is necessary to distinguish between each image section 101, they are distinguished as image sections D1 to D12 in order from the upper left in Figure 6(c).

[0040] In the distance image 100, the image section Di is an image obtained based on light emitted from the light-emitting section Ai of the light-emitting surface 40, reflected by the object at the illumination section Bi of the illumination surface 60, and received at the light-receiving section Ci of the light-receiving surface 50. Note that an image section Di assigned the same number i to the light-emitting section Ai, illumination section Bi, and light-receiving section Ci may be referred to as the "corresponding image section." Conversely, an image section Di assigned the same number i to the light-emitting section Ai may be referred to as the "corresponding light-emitting section." Furthermore, an illumination section Bi assigned the same number i to the image section Di may be referred to as the "corresponding illumination section," and a light-receiving section Ci assigned the same number to the image section Di may be referred to as the "corresponding light-receiving section."

[0041] Each image section 101 of the distance image 100 has multiple pixels (not shown) associated with multiple light-receiving elements in the corresponding light-receiving section 51. In the distance image 100, the pixel value of each pixel in the image section 101 corresponds to the distance from the distance measuring device 1 to the object, calculated from the electrical signals from each light-receiving element in the light-receiving section 51.

[0042] In the example shown in Figure 6(a), objects S1 and S2 are located at a certain distance from the distance measuring device 1. As shown in Figure 6(b), in this example, object S1 is located in the area spanning irradiation sections B1, B5, and B9 of the irradiation surface 60, and object S2 is located in the area spanning irradiation sections B2 and B6. Furthermore, the distance from the distance measuring device 1 to object S1 (for example, about 1 m) is smaller than the distance from the distance measuring device 1 to object S2 (for example, about 3 m).

[0043] As shown in Figure 6(c), the depth image 100 depicts an image S1' representing object S1 and an image S2' representing object S2 (sometimes referred to simply as image S') using pixels contained in each image section 101. More specifically, image S1' is depicted across image sections D1, D5, and D9 of the depth image 100, corresponding to illumination sections B1, B5, and B9, and image S2' is depicted across image sections D2 and D6 of the depth image 100, corresponding to illumination sections B2 and B6. In this example, information relating to the distance from the distance measuring device 1 to object S1 and the distance from the distance measuring device 1 to object S2 can be obtained from the pixel values ​​of the pixels that make up images S1' and S2' in the distance image 100 (represented by shading in Figure 6(c)).

[0044] Furthermore, since the distance image 100 includes distance information between each point on the surface of the object S and the distance measuring device 1, it can also be considered to include information about the three-dimensional shape of the object S. Therefore, the distance measuring device 1 to which this embodiment is applied can also be used for three-dimensional measurement.

[0045] <Example of a schematic configuration of distance measuring device 1> Figure 7 is a perspective view showing a schematic configuration example of the distance measuring device 1 to which this embodiment is applied. The distance measuring device 1 illustrated in Figure 7 comprises at least a housing 1a and a printed circuit board 1b housed within the housing 1a. Note that in Figure 7, some parts of the housing 1a are omitted from the illustration.

[0046] The printed circuit board 1b is equipped with the aforementioned light-emitting unit 4 and light-receiving unit 5, which constitute the optical device 3. The printed circuit board 1b is also equipped with the CPU 81, ROM 82, and RAM 83 (see Figure 1), which constitute the control unit 8.

[0047] To further explain, in the configuration example shown in Figure 7, the light-emitting unit 4 comprises four light sources 410, 420, 430, and 440. Each of the light sources 410 to 440 has a light-emitting surface 40 (see, for example, Figure 3) which is divided into a plurality of light-emitting sections 41. The light sources 410 to 440 are arranged around the light-receiving unit 5. Note that while Figure 7 shows an example with four light sources 410-440, it is also possible to have a number other than four, such as two, three, or five light sources.

[0048] Here, if the light-emitting unit 4 is equipped with multiple light sources 410 to 440, consider the case where, for example, the light from each of the multiple light sources 410 to 440's light-emitting section A1 is irradiated onto, for example, irradiation section B1 of the irradiation sections B1 to B12 (see, for example, Figure 2) of the irradiation surface 60. When irradiating with the light from the light-emitting section A1 of multiple light sources 410 to 440, the irradiation section B1 (see, for example, Figure 2) can be irradiated with a higher energy density compared to irradiating with the light from the light-emitting section A1 of just one light source, for example, light source 410. Also, when irradiating the irradiation section B1 with the light from each of the multiple light sources 410 to 440's light-emitting section A1, the exposure time of the light-receiving element (not shown) in the light-receiving section C1 (see, Figure 4) of the light-receiving unit 5 is shortened, and the acquisition of the global component, which is background light, can be suppressed. As a result, outdoor long-distance distance measurement becomes possible.

[0049] However, due to variations during assembly, it is difficult to match the illumination area of ​​the illumination surface 60 by multiple light sources 410-440 with the light-receiving area of ​​the light-receiving section 51 corresponding to the illumination section 61. As a result, a misalignment with the illumination section 61 may occur, potentially leading to a large distance measurement error. Therefore, in this embodiment, a configuration is adopted to suppress distance measurement errors even when a shift occurs in the illumination area 61 due to the light-emitting areas 41 of the multiple light sources 410 to 440. This will be explained below.

[0050] A configuration for suppressing distance measurement errors will be described below. The first and second embodiments of the light-emitting unit 4 and the light-receiving unit 5 will be described below. The total light sources of the light-emitting unit 4 in the distance measuring device 1 are multiple light sources 410 to 440. In the first and second embodiments, the lighting state is when four light sources 410 to 440 are lit simultaneously. Note that the lighting state is when at least two or more are lit simultaneously. Therefore, if the total number of light sources in the light-emitting unit 4 is three or more, there may be light sources that are not lit.

[0051] <First aspect of the light-emitting unit 4 and light-receiving unit 5> Figure 8 illustrates a first configuration of the light-emitting unit 4 and the light-receiving unit 5. Figure (a) shows the state in which each of the multiple light sources 410 to 440 has a single light-emitting section A1 lit, and Figure (b) shows the light intensity distribution of the light-receiving section of the light-receiving unit 5 in the case of (a). The lighting state of the light-emitting unit 4 shown in Figure 8(a) is a state in which each of the light-emitting sections A1 of the multiple light sources 410 to 440 is lit. That is, all four light sources 410 to 440 are lit (all four lights are lit). Also, only one light-emitting section A1 is lit, and the other light-emitting sections A2 to A12 are not lit.

[0052] The light from light sources 410-440 is received by the light-receiving section C1 of the light-receiving unit 5, as shown in Figure 8(b). This light reception is segmented reception performed on the light-receiving unit 5 for each light-receiving section. However, due to variations during assembly as described above, the light from light sources 410 to 440 (see, for example, Figure 8) is received with a shift relative to the light receiving section C1 of the light receiving unit 5. The light from light source 410 is in the region 411 shown by the dashed line, the light from light source 420 is in the region 421 shown by the dashed line, the light from light source 430 is in the region 431 shown by the dashed line, and the light from light source 440 is in the region 441 shown by the solid line. This type of irradiation is sometimes called fractionated irradiation.

[0053] Figure 9 illustrates a second configuration of the light-emitting unit 4 and the light-receiving unit 5. Figure (a) shows the state in which multiple light-emitting sections A1 to A12 of each of the multiple light sources 410 to 440 are lit, and (b) shows the light intensity distribution of the light-receiving section of the light-receiving unit 5 in the case of (a). The illumination state of the light-emitting section 4 shown in Figure 9(a) is when all of the multiple light sources 410 to 440 are lit (4 lights lit). In addition, the light-emitting sections A1 to A12 are illuminated by the light sources 410 to 440.

[0054] In the example shown in Figure 9(b), the light from light source 410 is in region 412 indicated by the dashed line, the light from light source 420 is in region 422 indicated by the dashed line, the light from light source 430 is in region 432 indicated by the dashed line, and the light from light source 440 is in region 442 indicated by the solid line.

[0055] Note that Figures 8(b) and 9(b) show the light-receiving section C1, etc., but they can also be seen as the illumination section B1 (see Figure 4), etc. That is, in the case shown in Figure 8(a), partial illumination of light-emitting sections A1 to A12 is performed, resulting in segmented illumination on the illumination surface 60 (see Figure 2). In the case shown in Figure 9(a), all of the light-emitting sections A1 to A12 are illuminated, resulting in full-surface illumination on the illumination surface 60 (see Figure 2). Images acquired by full-surface illumination are sometimes called full-surface illuminated images.

[0056] In this case, illumination area B1 is an example of a single region, and light emission area A1 is an example of a single light emission area. Light emission areas A1 to A12 are examples of multiple light emission areas. Light sources 410 to 440 are examples of multiple light sources, and are examples of at least some of the light sources. The illumination of light sources 410-440 shown in Figure 8(a) is an example of the first illumination state, and the illumination of light sources 410-440 shown in Figure 9(a) is an example of the second illumination state.

[0057] Here, it is possible to switch between the first configuration of the light-emitting unit 4 shown in Figure 8(a) and the second configuration of the light-emitting unit 4 shown in Figure 9(a). Note that in the first and second embodiments shown in Figures 8(a) and 9(a), four light sources 410-440 are illuminated. That is, the number of light sources illuminated in the first embodiment is the same as the number of light sources illuminated in the second embodiment, but it is also possible that the numbers are different. In other words, it is possible that two or three of the four light sources 410-440 are illuminated in the first embodiment. It is also possible that only one of the multiple light sources 410-440 is illuminated in the second embodiment (see Figure 15(b) described later).

[0058] <Control Example> Figure 10 is a flowchart showing an example of control associated with the illumination of light sources 410-440. This control example is performed by the control unit 8 (see Figure 1). In the control example shown in Figure 10, the light-emitting sections A1 to A12 of the light sources 410 to 440 are turned on (see Figure 9(a)) (step 101). The corresponding light-receiving sections C1 to C12 (see Figure 9(b)) are also activated (step 102). This generates an infrared image 100 (see Figure 6(c)), which is a full-surface illumination image, from the acquired light-receiving amount (step 103). The light-emitting sections A1 to A12 are turned on simultaneously, and the light-receiving sections C1 to C12 are activated simultaneously. The infrared image 100 acquired in this case can be called a "flash image".

[0059] After setting the variable n to 1 (step 104), the light-emitting section An of the light sources 410-440 is turned on (step 105). In this case, the light-emitting section A1 of the light sources 410-440 is turned on (see Figure 8(a)). The corresponding light-receiving section C1 (see Figure 8(b)) is also activated (step 106). This generates an infrared image 100 (see Figure 6(c)) of the light-emitting section A1 when it is turned on from the acquired amount of light received (step 107).

[0060] Then, 1 is added to the variable n (step 108), and it is determined whether the variable n exceeds 12 (step 109). If the variable n does not exceed 12 (No in step 109), the process returns to step 105. For example, if the variable n is 2, the light-emitting section A2 of the light sources 410-440 is turned on (see, for example, Figure 8(a)). Subsequently, the light-emitting sections An of the light sources 410-440 are turned on until the variable n is between 3 and 12, and the corresponding light-receiving section Cn is activated accordingly.

[0061] In this way, by sequentially illuminating the light-emitting sections A1 to A12 of the light sources 410 to 440 and operating the corresponding light-receiving sections C1 to C12, an infrared image 100 is acquired for each section. The infrared images 100 acquired sequentially are sometimes called "segmented illumination images." Such segmented illumination images can be called "scanned images."

[0062] If the variable n is greater than 12 (Yes in step 109), the process is terminated after calculating a distance image from the acquired light amount (step 110). This calculation involves adding a full-area illumination image to the segmented illumination image. This makes it possible to reduce the error in the measured distance. The segmented illumination image is an example of the first light reception result, and the full-surface illumination image is an example of the second light reception result.

[0063] In the control example shown in Figure 10, when each of the multiple light sources 410-440 is driven to the first lighting state once, it is driven to the second lighting state only once. That is, it is driven to the second lighting state once for every 12 times it is driven to the first lighting state. This reduces the number of times the second lighting state is driven, thereby reducing the control burden. Of course, control examples that alternate between the first and second lighting states are also conceivable, as is a control example that performs the first lighting state multiple times followed by the second lighting state once. Furthermore, the order in which the first and second lighting states are performed does not matter.

[0064] Next, we will explain the case where correction is performed in the calculation in step 110. This example of processing is implemented by the CPU 81. Figure 11 is a flowchart illustrating an example of control when performing correction. The control example in Figure 11 is an example of a process for correcting the distance to a single region.

[0065] In the processing example shown in Figure 11, a full-surface irradiation image is acquired (step 201), and then 12 segmented irradiation images are acquired (step 202). These 12 segmented irradiation images are then combined (step 203). This results in a single combined image. Then, the charge amount of the composite image is subtracted from the charge amount of the full-surface illuminated image to generate a difference image (step 204).

[0066] The gain of the composite image is corrected by multiplying the charge of the composite image by the charge of the difference image (step 205). This multiplication can involve using the charge of the difference image directly, or by multiplying it by a coefficient. This suppresses the distance measurement error. Correction data can be acquired at predetermined timings during setup or distance measurement, and until then, the pre-update data can be used as the correction value.

[0067] Next, we will explain a more detailed example of the processing example shown in Figure 11. The values ​​used for the gain correction described above will be referred to as "correction parameters" below. Figure 12 is a flowchart illustrating an example of the process for generating and saving correction parameters. In the specific example shown in Figure 12, after acquiring a full-surface illumination image (step 301), a bandpass filter is applied to remove noise components (step 302). The full-surface illumination image is the infrared image 100 (see Figure 6(c)), which visualizes the accumulated charge.

[0068] Then, the difference between the full-area illumination image and the segmented illumination image is extracted for each time gate of the multi-tap image sensor (step 303). More specifically, for example, if there are six taps (energy storage elements), the level is adjusted for each of the six time gate signals and the difference is extracted. This difference is due to the uneven illumination caused by the difference between FOV (Field of View) and FOI (Field of Illumination) during the 12 segmented illuminations, and the difference in charge amount due to the difference in sensor gain. Note that there is no difference between FOV and FOI in the full-area illumination image.

[0069] The taps referred to here are each formed from different semiconductor elements. If there is variation in the six time gate characteristics, adjustment is required for each time gate. Therefore, correction is performed for each time gate.

[0070] To explain further, the acquired image is, for example, 480 x 720 pixel data. The frame rate can be selected within a range of up to 30 fps (frames per second). When reflected light is received, an electric charge is accumulated in each pixel. If the resolution of the accumulated charge in one pixel is 12 bits, it can represent 4096 gradations. Each of the six time gates has a set order in which it opens, based on time intervals.

[0071] For each tap as described above, data on the charge amount for each pixel is obtained. The data structure consists of 6 taps as one set.

[0072] Returning to Figure 12, we continue the explanation. For every six time gates (6 taps), the difference described above is normalized (step 304). The normalized value is then saved as a correction parameter (step 305). The saved correction parameter can be used in subsequent distance measurements.

[0073] Figure 13 is a graph illustrating the calculation of a distance image from a segmented irradiation image. (a) shows the case using the acquired segmented irradiation image, and (b) shows the case using the corrected segmented irradiation image. Figures 13(a) and (b) show the average values ​​over several frames, with the vertical axis representing distance (m) and the horizontal axis representing position in X-pixels. As an example, we show the case where the distance was measured to an object located 6m away. In Figures 13(a) and (b), the 6m position is shown by a dashed line. Figures 13(a) and (b) show the split-relief irradiation images before and after correction, respectively.

[0074] According to the uncorrected segmented irradiation image shown in Figure 13(a), the distance to the target object varies from 5.85 to 5.95 m. On the other hand, according to the corrected segmented illumination image shown in Figure 13(b), the distance to the object approaches the dashed line of 6m. This is because the slope and height of the measured distance values ​​were corrected by the correction.

[0075] Next, we will explain the case where a portion of the light emitted from the light-emitting unit 4 (see, for example, Figure 5) towards the object is reflected by, for example, a highly reflective material (not shown). When the emitted light is reflected by a highly reflective material, it is conceivable that in addition to the reflected light from the object, indirect light from the highly reflective material may enter the light-receiving unit 5 (see, for example, Figure 5). Such indirect light is unintended optical noise and affects the distance measurement value. Therefore, in this embodiment, the following processing is performed to suppress the effect of indirect light on the distance measurement value.

[0076] Figure 14 is a flowchart illustrating an example of processing that includes a process to suppress the effects of indirect light. This example of processing is performed by the control unit 8 (see Figure 1). In the processing example shown in Figure 14, the light-emitting unit 4 (see, for example, Figure 5) irradiates the object with light, and it is determined whether there is indirect light in the irradiated image (step 401). This determination is made by calculating the difference between the amount of light received in the full-surface irradiated image and the amount of light received in the segmented irradiated images, and checking whether this difference is greater than a predetermined threshold.

[0077] More specifically, consider the case where the light-emitting unit 4 (see, for example, Figure 5) illuminates the entire surface, and the light-receiving unit 5 (see, for example, the same figure) receives indirect light. When the light-receiving unit 5 receives indirect light, the amount of light received by the light-receiving unit 5 increases by the amount of indirect light compared to the case where the light-receiving unit 5 does not receive indirect light. Therefore, if the difference between the amount of light received in the fully illuminated image and the amount of light received in the segmented illuminated images is greater than a predetermined threshold, it is determined that there is indirect light in the illuminated image (Yes in step 401). If this difference is not greater than a predetermined threshold, it is determined that there is no indirect light in the illuminated image (No in step 401).

[0078] The amount of light received in the segmented irradiation images referred to here may be the sum of the light received in each of the 12 segmented irradiation images, or it may be the light received in the composite image (see step 203 in Figure 11) obtained by combining the segmented irradiation images as described above. Furthermore, the number of segments may be less than 12, in addition to the case of 12 as described above (see Figure 5), by emitting light in multiple light-emitting sections simultaneously.

[0079] If it is determined that indirect light is present (Yes in step 401), indirect light processing is performed (step 402), the system enters a measurement-ready state (step 403), and waits until instructed to measure the distance. As a result, the amount of light emitted from the corresponding light-emitting section is reduced during the next irradiation. If it is determined that there is no indirect light (No in step 401), proceed to step 404, which will be described below. Alternatively, if it is determined that there is no indirect light, proceed to step 403 and wait until an instruction to measure distance is given.

[0080] The indirect light processing described here identifies the light-receiving area containing indirect light among the light-receiving areas C1 to C12 (see Figure 4), and reduces the irradiation amount of the light-emitting area corresponding to the identified light-receiving area. Specifically, the CPU 81 (see Figure 1) stores information identifying the corresponding light-emitting area and information identifying the reduced irradiation amount for the identified light-emitting area in the RAM 83 (see the same figure).

[0081] In Figure 14, steps 401 to 403 are preprocessing steps performed before the correction processing of the segmented irradiation images. To further explain, it is also possible to omit steps 401-403 and skip the preprocessing. In such cases, the process will proceed from step 404, which will be described later.

[0082] When a distance measurement instruction is received, the segmented illumination image correction process is performed as shown in steps 404 to 406 described later. In response to the distance measurement instruction, the drive control of the light-emitting unit 4 and the light-receiving unit 5 (see Figure 5) is performed. This acquires the segmented illumination image described above (see, for example, step 202 in Figure 11). Then, it is determined whether correction is necessary for the fractionated irradiation image (step 404). This determination is made based on whether the fractionated irradiation image meets predetermined conditions.

[0083] The predetermined conditions referred to here include, for example, when the region of the acquired segmented illumination image is divided into the center and the edge, the difference between the amount of light received in the center and the amount of light received in the edge is greater than a threshold. If the difference is greater than the threshold, it is determined that correction is necessary (Yes in step 404), and if the difference is less than or equal to the threshold, it is determined that correction is not necessary (No in step 404). The term "center" here refers to the region that does not include the edges of the four sides of the segmented image, while the term "edge" here refers to the region of the edges of the four sides of the segmented image. It is conceivable that the boundary between the central region and the edge region be defined uniformly.

[0084] Furthermore, the predetermined conditions referred to here include, for example, whether, when the region of the acquired segmented illumination image is divided into the center and the edge, the average amount of light received in the center and / or the average amount of light received at the edge is greater than a threshold.

[0085] If it is determined in step 404 that correction is necessary (Yes in step 404), correction data is generated by performing the processes shown in steps 301 to 304 above (see Figure 12) (step 405). The generated correction data is saved as the correction parameters as described above (see step 305 in Figure 12). After saving the correction data, the device enters a measurement-ready state (step 406) and waits until instructed to perform the next distance measurement.

[0086] <Regarding variations in the lighting state of light sources 410-440> Next, we will describe variations in the lighting state of light sources 410 to 440. Figure 15 illustrates the lighting state of one modified example of multiple light sources 410-440. Figure (a) shows the state in which a single light-emitting section A1 is lit, and (b) shows the state in which multiple light-emitting sections A1-A12 are lit. The lighting state shown in Figure 15(a) is a state in which each light-emitting section A1 of light sources 410 to 440 is lit. That is, all four light sources 410 to 440 are lit (all four lights are lit). Also, only one light-emitting section A1 is lit, and the other light-emitting sections A2 to A12 are not lit. In this respect, one modification is the same as the case in Figure 8(a) described above.

[0087] The lighting state shown in Figure 15(b) is when light source 440 is lit among the light sources 410 to 440. That is, one of the four light sources 410 to 440, light source 440, is lit, and the other light sources 410 to 430 are not lit (one light lit). Also, the light-emitting sections A1 to A12 are lit by light source 440. In this respect, one modification differs from the case in Figure 9(a) described above, where all four lights are lit.

[0088] In the light-emitting unit 4, the light source 440 enters the illuminated state shown in Figures 15(a) and (b). Furthermore, the light sources 410-430 enter the illuminated state shown in Figure 15(a) but do not enter the illuminated state shown in Figure 15(b). In one modified example, the illumination state is driven by the light-emitting drive unit 6 (see Figure 1).

[0089] Figure 16 illustrates the lighting states of other variations of the multiple light sources 410-440. Figure (a) shows the state in which a single light-emitting section A1 is lit, and (b) shows the state in which multiple light-emitting sections A1, A2, A5, and A6 are lit. The lighting state shown in Figure 16(a) is a state in which each light-emitting section A1 of light sources 410 to 440 is lit. That is, all four light sources 410 to 440 are lit (all four lights lit). Also, only one light-emitting section A1 is lit, and the other light-emitting sections A2 to A12 are not lit. In this respect, other modifications are the same as the case in Figure 8(a) described above.

[0090] The lighting state shown in Figure 16(b) is when light source 440 is lit among the light sources 410 to 440. That is, one of the four light sources 410 to 440, light source 440, is lit, and the other light sources 410 to 430 are not lit (one light lit). Furthermore, the light sources 440 illuminate light sources A1, A2, A5, and A6 of the light-emitting sections A1 to A12, while the other light-emitting sections A3 to A4 and A7 to A12 are not lit. In this respect, the other modifications differ from the case in Figure 9(a) described above, where all four lights are lit.

[0091] Figure 16 illustrates the case where a single light-emitting section A1 is lit, but the case where a single other light-emitting section is lit will be explained below. For example, when a single light-emitting section A2 is illuminated, multiple light-emitting sections A1-A3 and A5-A7, including section A2, will also illuminate. In this way, multiple light-emitting sections can be considered as sections located around a single light-emitting section.

[0092] The lighting state shown in Figure 16(b) represents a state in which only light source 440 is lit and a portion of light-emitting sections A1 to A12 is lit, but is not limited to this. For example, it is also conceivable that light sources 410 to 440 are lit and a portion of light-emitting sections A1 to A12 is lit.

[0093] (Distance measurement device 1) In Figure 1, the distance measuring device 1, shown by a solid line, comprises a light-emitting unit 4 having multiple light sources 410 to 440, each having multiple individually emitting light-emitting sections A1 to A12; a light-receiving unit 5 that receives reflected light from the light-emitting unit 4; and a CPU 81. The CPU 81 has a first lighting state in which one light-emitting section A1 that irradiates light toward a single region B1 in each of the multiple arranged light sources 410 to 440 is lit, and a second state in which one light-emitting section A1 in at least some of the light sources 410 to 440 is lit. This is an example of a distance measuring system 1 that drives the light-emitting unit 4 to have a second lighting state in which multiple light-emitting sections A2 to A12 including the first lighting state are lit simultaneously, acquires a first light-receiving result which is the result of light-receiving by the light-receiving unit 5 in the first lighting state and a second light-receiving result which is the result of light-receiving by the light-receiving unit 5 in the second lighting state, and performs a process to correct the distance to a region B1 measured based on the first light-receiving result using the acquired first and second light-receiving results. This invention can also be applied to programs and program products.

[0094] <Note> (((1))) A light-emitting section comprising multiple light sources, each having multiple individually emitting light-emitting sections, A light receiving unit that receives reflected light from the light-emitting unit, Processor and Equipped with, The aforementioned processor, The light-emitting unit is driven to have a first lighting state in which one light-emitting section that irradiates light toward a certain area in each of the multiple arranged light sources is lit, and a second lighting state in which multiple light-emitting sections, including the said one light-emitting section, are lit simultaneously in at least some of the light sources. The system obtains a first light reception result, which is the result of light reception by the light receiving unit in the first lighting state, and a second light reception result, which is the result of light reception by the light receiving unit in the second lighting state. The acquired first light reception result and the second light reception result are used to perform a process to correct the distance to the one region measured based on the first light reception result. Distancing system. (((2))) The difference between the first light reception result and the second light reception result is used to perform a correction process on the distance to the first region measured based on the first light reception result. The distance measuring system according to (((1))), characterized in that (((3))) The aforementioned processor, Switching between the light source in the first illuminated state and at least some of the light sources to be in the second illuminated state, where all of the plurality of light sources are present and where some of the plurality of light sources are present. A distance measuring system according to (((1))) or (((2))), characterized in that (((4))) The number of light sources in the first lighting state and the number of at least some of the light sources in the second lighting state are the same. The distance measuring system according to (((3))), characterized in that (((5))) The aforementioned processor, The correction process is performed when the first light reception result satisfies predetermined conditions. A distance measuring system according to any one of (((1))) to (((4))) characterized by the above. (((6))) The predetermined condition is that when the first light reception result is divided into the center and the edge, the difference between the center and the edge is greater than a threshold. The distance measuring system according to (((5))), characterized in that (((7))) The aforementioned processor, If the difference exceeds a predetermined value, before correcting the distance to the first region, a process is performed to reduce the influence of indirect light on the first light reception result. The distance measuring system according to (((2))), characterized in that

[0095] According to the invention of (((1))), it is possible to reduce the error in the measured distance compared to when the result of light reception is used without correction. According to the invention of (((2))), it is possible to reduce the error in the measured distance compared to when the light reception result is used without correction. According to the invention of (((3))), the processor can respond according to the situation, compared to a configuration in which the light source in the first lit state and at least some of the light sources that bring the light source to the second lit state are either all of the multiple light sources or some of the multiple light sources. According to the invention of (((4))), it becomes possible to enhance the effect of correction compared to a configuration in which the number of light sources in the first lighting state and the number of at least some of the light sources in the second lighting state are the same. According to the invention of (((5))), the processor can reduce the processing burden compared to a system that does not have a configuration that performs correction processing when the first light reception result satisfies predetermined conditions. According to the invention of (((6))), the predetermined condition is that the difference between the center and the edge when the first light reception result is divided into the center and the edge is greater than the threshold. This configuration makes it possible to reduce the processing burden compared to a configuration that does not have this condition. According to the invention of (((7))), the processor can further reduce the error in the measured distance compared to a configuration in which the processor does not have a process to reduce the effect of indirect light on the first light-receiving result before correcting the distance for one region when the difference exceeds a predetermined value. [Explanation of Symbols]

[0096] 1... Distance measuring device, 4... Light-emitting unit, 5... Light-receiving unit, 6... Light-emitting drive unit, 7... Light-receiving drive unit, 8... Control unit, 41, A1~A12... Light-emitting section, 51, C1~C12... Light-receiving section, 61, B1~B12... Irradiation section, 81... CPU, 410, 420, 430, 440... Light source

Claims

1. A light-emitting unit comprising multiple light sources, each having multiple individually emitting light-emitting sections, A light receiving unit that receives reflected light from the light-emitting unit, Processor and Equipped with, The aforementioned processor, The light-emitting unit is driven to have a first lighting state in which one light-emitting section that irradiates light toward one area in each of the multiple arranged light sources is lit, and a second lighting state in which multiple light-emitting sections, including the said one light-emitting section, are lit simultaneously in at least some of the light sources. The first light reception result, which is the result of light reception by the light receiving unit in the first lighting state, and the second light reception result, which is the result of light reception by the light receiving unit in the second lighting state, are obtained. The acquired first light reception result and the second light reception result are used to perform a process to correct the distance to the one region measured based on the first light reception result. Distancing system.

2. The difference between the first light reception result and the second light reception result is used to perform a correction process on the distance to the first region measured based on the first light reception result. The distance measuring system according to claim 1.

3. The aforementioned processor, Switching between the light source in the first illuminated state and at least some of the light sources that are brought to the second illuminated state, between all of the plurality of light sources and some of the plurality of light sources. The distance measuring system according to claim 1.

4. The number of light sources in the first lighting state and the number of at least some of the light sources in the second lighting state are the same. The distance measuring system according to claim 3.

5. The aforementioned processor, The correction process is performed when the first light reception result satisfies predetermined conditions. The distance measuring system according to claim 1.

6. The predetermined condition is that when the first light reception result is divided into the center and the edge, the difference between the center and the edge is greater than a threshold. The distance measuring system according to claim 5.

7. The aforementioned processor, If the difference exceeds a predetermined value, before correcting the distance to the first region, the first light reception result is subjected to a process to reduce the influence of indirect light. The distance measuring system according to feature 2.

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