Distance measuring device and distance measuring method

Abstract

A distance measuring device according to one embodiment of the present disclosure comprises: a light emitting unit that switches and emits first light and second light that is weaker than the first light; and a light receiving unit that has a first light receiving region including a plurality of pixels that respectively detect reflected light of the first light, and a second light receiving region that is different from the first light receiving region and includes a plurality of pixels that respectively detect reflected light of the second light.

Description

Distance measuring device and distance measuring method

[0001] The present disclosure relates to a distance measuring device and a distance measuring method.

[0002] In recent years, distance measuring devices that measure distances using the ToF (Time-of-Flight) method have been attracting attention. Examples of distance measuring devices include ToF sensors that measure the distance to an object using multiple light-receiving elements arranged on a plane (see, for example, Patent Document 1). The ToF sensor measures, for example, the time of flight from when a light source emits light until the light reflected by the object is incident on the light-receiving elements multiple times as a physical quantity, and calculates the distance to the object based on a histogram of the physical quantity generated from the measurement results.

[0003] Japanese Patent Application Laid-Open No. 2023-37966

[0004] However, if the reflectivity of an object is high, that is, if the object is highly reflective, the reflected light from the object may cause flare (light leakage). It is usually difficult to distinguish whether the reflected light is actually reflected from the object or is flare, and the ToF sensor may mistakenly recognize an object as being present in a position where no object actually exists, resulting in reduced ranging accuracy. For example, when strong reflected light returns from a highly reflective object, multiple reflections occur at the light receiving element and optical system, and the reflected light leaks into light receiving elements in positions where no object actually exists.

[0005] Therefore, the present disclosure provides a distance measuring device and a distance measuring method that can suppress a decrease in distance measurement accuracy.

[0006] A distance measuring device according to one embodiment of the present disclosure includes an emitter that switches between emitting a first light and a second light that is weaker than the first light, a first light receiving region that includes a plurality of pixels that each detect reflected light of the first light, and a light receiving region that is different from the first light receiving region and includes a plurality of pixels that each detect reflected light of the second light.

[0007] A distance measurement method according to one embodiment of the present disclosure includes an emitting unit emitting a first light, a receiving unit receiving reflected light of the first light in a first light receiving area, the emitting unit emitting a second light weaker than the first light, and the light receiving unit receiving reflected light of the second light in a second light receiving area different from the first light receiving area.

[0008] FIG. 1 is a diagram illustrating an example configuration of a ToF sensor according to an embodiment of the present disclosure. FIG. 2 is a diagram illustrating an optical system of a ToF sensor according to an embodiment of the present disclosure. FIG. 3 is a diagram illustrating an example configuration of a light receiving unit according to an embodiment of the present disclosure. FIG. 4 is a diagram illustrating an example configuration of a light source and a SPAD array used according to an embodiment of the present disclosure. FIG. 5 is a circuit diagram illustrating an example configuration of a SPAD pixel according to an embodiment of the present disclosure. FIG. 6 is a diagram illustrating an example configuration of a SPAD adder according to an embodiment of the present disclosure. FIG. 7 is a diagram illustrating an example processing of flare removal according to an embodiment of the present disclosure. FIG. 8 is a diagram illustrating an example ranging for each divided region according to an embodiment of the present disclosure. FIG. 9 is a flowchart illustrating the flow of an example processing of ranging according to an embodiment of the present disclosure. FIG. 10 is a diagram illustrating flare removal when switching between strong light emission and weak light emission line by line according to an embodiment of the present disclosure. FIG. 11 is a diagram illustrating flare removal when switching between strong light emission and weak light emission frame by frame according to an embodiment of the present disclosure. FIG. 12 is a diagram illustrating a first example configuration of a laser unit according to an embodiment of the present disclosure. FIG. 13 is a diagram illustrating a second example configuration of a laser unit according to an embodiment of the present disclosure. FIG. 14 is a diagram illustrating a third example configuration of a laser unit according to an embodiment of the present disclosure. FIG. 15 is a diagram illustrating an example advantage of separating light receiving regions according to an embodiment of the present disclosure. FIG. 16 is a block diagram illustrating an example of a schematic configuration of a vehicle control system. FIG. 17 is an explanatory diagram illustrating an example of installation positions of an outside vehicle information detection unit and an imaging unit.

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The embodiments include examples and modified examples. Note that the devices, methods, systems, etc. according to the present disclosure are not limited to the embodiments of the present disclosure. Furthermore, in the following embodiments, essentially identical components are designated by the same reference numerals, and redundant explanations will be omitted.

[0010] The present disclosure will be described in the following order: 1. Embodiments 1-1. Configuration example of ToF sensor 1-2. Configuration example of optical system 1-3. Configuration example of light receiving unit 1-4. Configuration example of light source and SPAD array used 1-5. Configuration example of SPAD pixel 1-6. Configuration example of SPAD adder 1-7. Processing example of flare removal 1-8. Example of distance measurement for each divided area 1-9. Processing example of distance measurement 1-10. Configuration example of laser unit 1-11. Example of advantage of separating light receiving areas 1-12. Actions and effects 2. Other embodiments 3. Application examples 4. Supplementary notes

[0011] <1. Embodiment> <1-1. Configuration Example of ToF Sensor> An example configuration of a ToF sensor 1 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing an example configuration of a ToF sensor 1 according to this embodiment. The ToF sensor 1 is an example of a distance measuring device.

[0012] As shown in FIG. 1 , the ToF sensor 1 includes a control unit 11 , a light emitting unit 13 , a light receiving unit 14 , a calculation unit 15 , and an external I / F (interface) 19 .

[0013] The control unit 11 controls each unit of the ToF sensor 1. The control unit 11 is configured by an information processing device such as a CPU (Central Processing Unit), for example.

[0014] The external I / F 19 is, for example, a communication adapter for establishing communication with an external host 80 via a communication network. The communication network may be, for example, a wireless local area network (LAN) or a wired LAN, or may be a communication network conforming to any standard such as a controller area network (CAN), a local interconnect network (LIN), or FlexRay (registered trademark).

[0015] Here, for example, when the ToF sensor 1 is mounted on a moving body such as an automobile, the host 80 may be an ECU (Electronic Control Unit) mounted on the moving body.Also, when the ToF sensor 1 is mounted on an autonomous moving body such as a domestic pet robot, a robot vacuum cleaner, an unmanned aerial vehicle, or a follow-up transport robot, the host 80 may be a control device that controls the autonomous moving body.

[0016] The light-emitting unit 13 includes, for example, one or more semiconductor laser diodes as a light source, and emits pulsed laser light L1 having a predetermined duration at a predetermined cycle (also referred to as a light-emitting cycle). The light-emitting unit 13 emits laser light L1 having a duration of 1 ns (nanosecond) at a cycle of, for example, 1 MHz (megahertz). For example, if an object (measurement target) 90 is present within the distance measurement range, the laser light L1 emitted from the light-emitting unit 13 is reflected by the object 90 and enters the light-receiving unit 14 as reflected light L2.

[0017] The light receiving unit 14 includes, for example, a plurality of SPAD (Single Photon Avalanche Diode) pixels arranged in a two-dimensional lattice pattern, and outputs information (e.g., equivalent to the number of detection signals described below) regarding the number of SPAD pixels that detect incident photons (hereinafter referred to as the detection number) after light emission by the light emitting unit 13. For example, the light receiving unit 14 detects incident photons at a predetermined sampling period for each light emission by the light emitting unit 13, and outputs the detection number.

[0018] The calculation unit 15 tally up the detection counts output from the light receiving unit 14 for each of multiple SPAD pixels (e.g., corresponding to one or more macro pixels described below), and based on the pixel values ​​obtained by this tallying up, creates a histogram with the horizontal axis representing flight time and the vertical axis representing cumulative pixel values.

[0019] For example, the calculation unit 15 calculates pixel values ​​by tallying the number of detections at a predetermined sampling frequency for one light emission from the light-emitting unit 13, and repeats this process for multiple light emissions from the light-emitting unit 13. Then, the calculation unit 15 creates a histogram in which the horizontal axis (histogram bins) represents the sampling period corresponding to the time of flight, and the vertical axis represents the cumulative pixel value obtained by accumulating the pixel values ​​calculated at each sampling period.

[0020] The calculation unit 15 also performs a predetermined filtering process on the created histogram, and then identifies the time-of-flight at which the cumulative pixel value peaks from the filtered histogram. The calculation unit 15 then calculates the distance L from the ToF sensor 1 or a device equipped with the ToF sensor 1 to an object 90 present within the ranging range based on the identified time-of-flight. Information about the distance L calculated by the calculation unit 15 may be output to the host 80 or the like via the external I / F 19, for example.

[0021] <1-2. Configuration Example of Optical System> An example of the configuration of the optical system of the ToF sensor 1 according to this embodiment will be described with reference to Fig. 2. Fig. 2 is a diagram for explaining the optical system of the ToF sensor 1 according to this embodiment. Fig. 2 illustrates a so-called scanning type optical system that scans the angle of view of the light receiving unit 14 in the horizontal direction.

[0022] 2, the ToF sensor 1 includes, as an optical system, a light source 131, a collimator lens 132, a mirror 133, a scanner 135, a light-receiving lens 146, and a SPAD array 141. The light source 131, the collimator lens 132, the mirror 133, and the scanner 135 are included in, for example, the light-emitting unit 13 in FIG. 1. The scanner 135, the mirror 133, the light-receiving lens 146, and the SPAD array 141 are included in, for example, the light-receiving unit 14 in FIG. 1.

[0023] In the configuration shown in FIG. 2 , laser light L1 emitted from light source 131 is converted by collimator lens 132 into rectangular parallel light whose cross-sectional intensity spectrum is elongated in the vertical direction, and then enters mirror 133. Mirror 133 reflects a portion of the incident laser light L1. The laser light L1 reflected by mirror 133 enters scanner 135. Scanner 135 is vibrated in the horizontal direction around a predetermined rotation axis as the vibration center by, for example, a drive unit 134 operating under control of control unit 11. This causes horizontal scanning of laser light L1 such that the angle of view SR of laser light L1 reflected by scanner 135 reciprocates horizontally across a distance measurement range AR. Note that a MEMS (Micro Electro Mechanical System), a micromotor, or the like can be used as drive unit 134.

[0024] The laser light L1 reflected by the scanner 135 is reflected by an object 90 present within the distance measurement range AR and enters the scanner 135 as reflected light L2. A portion of the reflected light L2 that enters the scanner 135 passes above or below the mirror 133 and enters the light-receiving lens 146, which then forms an image on a specific used SPAD array 142 in the SPAD array 141. The used SPAD array 142 is, for example, a region that is used in the SPAD array 141, and may be the entire SPAD array 141 or a portion of the SPAD array 141.

[0025] 2 illustrates a scanning optical system that horizontally scans the angle of view of the light receiving unit 14, but the present invention is not limited to this. For example, the ToF sensor 1 may be a so-called flash-type ToF sensor in which the angle of view of the light receiving unit 14 is fixed.

[0026] <1-3. Configuration Example of Light Receiving Unit> A configuration example of the light receiving unit 14 according to this embodiment will be described with reference to Fig. 3. Fig. 3 is a diagram showing a configuration example of the light receiving unit 14 according to this embodiment.

[0027] As shown in FIG. 3, the light receiving unit 14 includes a SPAD array 141 , a timing control circuit 143 , a drive circuit 144 , and an output circuit 145 .

[0028] The SPAD array 141 includes a plurality of SPAD pixels 20 arranged in a two-dimensional lattice pattern. Pixel drive lines LD (vertical in the drawing) are connected to the plurality of SPAD pixels 20 for each column, and output signal lines LS (horizontal in the drawing) are connected to the plurality of SPAD pixels 20 for each row. One end of the pixel drive line LD is connected to an output terminal of the drive circuit 144 corresponding to each column, and one end of the output signal line LS is connected to an input terminal of the output circuit 145 corresponding to each row.

[0029] In this embodiment, the reflected light L2 is detected using all or a part of the SPAD array 141. The area used in the SPAD array 141 (the used SPAD array 142) may be a rectangle that is long in the vertical direction, the same as the image of the reflected light L2 that is formed on the SPAD array 141 when the entire laser light L1 is reflected as the reflected light L2. However, the area is not limited to this, and may be variously modified, such as being larger or smaller than the image of the reflected light L2 that is formed on the SPAD array 141.

[0030] The drive circuit 144 includes a shift register, an address decoder, etc., and drives each SPAD pixel 20 of the SPAD array 141, for example, all pixels at the same time or column by column. Therefore, the drive circuit 144 includes at least a circuit that applies a quench voltage V_QCH (described later) to each SPAD pixel 20 in a selected column in the SPAD array 141, and a circuit that applies a selection control voltage V_SEL (described later) to each SPAD pixel 20 in the selected column. The drive circuit 144 applies the selection control voltage V_SEL to the pixel drive line LD corresponding to the column to be read out, thereby selecting, column by column, the SPAD pixels 20 to be used for detecting incident photons.

[0031] A signal (referred to as a detection signal) V_OUT output from each SPAD pixel 20 in a column selected and scanned by the drive circuit 144 is input to the output circuit 145 through each output signal line LS. The output circuit 145 outputs the detection signal V_OUT input from each SPAD pixel 20 to a SPAD adder unit 40 provided for each macro pixel 30, which will be described later.

[0032] The timing control circuit 143 includes a timing generator that generates various timing signals, and controls the drive circuit 144 and the output circuit 145 based on the various timing signals generated by the timing generator.

[0033] <1-4. Configuration Examples of Light Source and Used SPAD Array> A configuration example of the light source 131 and used SPAD array 142 according to this embodiment will be described with reference to Fig. 4. Fig. 4 is a diagram showing a configuration example of the light source 131 and used SPAD array 142 according to this embodiment.

[0034] As shown in Fig. 4, the light source 131 is, for example, a laser array having a plurality of laser units 13a to 13h. The laser units 13a to 13h are arranged in a one-dimensional array along the vertical direction. In the example of Fig. 4, the light source 131 has eight laser units 13a to 13h, but the number is not limited thereto.

[0035] The used SPAD array 142 has, for example, a configuration in which a plurality of macro pixels 30 are arranged in a two-dimensional lattice. Each macro pixel 30 is composed of, for example, a predetermined number of SPAD pixels 20 arranged in the row direction and / or column direction. In other words, each SPAD pixel 20 is grouped into a predetermined number of macro pixels 30.

[0036] The used SPAD array 142 is also divided into multiple regions (hereinafter referred to as SPAD regions) in the vertical direction, for example. In the example of FIG. 4, the used SPAD array 142 is divided into eight SPAD regions 14a to 14h, each of which receives the laser light L1 (actually, the reflected light L2). Each of the SPAD regions 14a to 14h is composed of a total of 48 (=8×6) macro pixels 30, arranged, for example, eight in the horizontal direction (corresponding to the row direction) and six in the vertical direction (corresponding to the column direction). The topmost SPAD region 14a corresponds to, for example, the topmost 1 / 8 region of the field of view SR of the used SPAD array 142, and receives the laser light L1 emitted by the laser unit 13a. Similarly, the SPAD region 14b below it corresponds to, for example, the second-highest 1 / 8 region of the field of view SR, and receives the laser light L1 emitted by the laser unit 13b. Similarly, each of the SPAD regions 14c to 14h corresponds to 1 / 8 of the area in the angle of view SR, and receives the laser light L1 emitted by the corresponding laser unit 13c to 13h.

[0037] Here, the number of each of the SPAD regions 14a to 14h is set to match the number of each of the laser units 13c to 13h, but this is not limited to this. Also, although the size of each of the SPAD regions 14a to 14h is the same, this is not limited to this. For example, if any of the SPAD regions 14a to 14h is composed of eight macro pixels 30 arranged in the horizontal direction, the size of each of the SPAD regions 14a to 14h does not have to be the same.

[0038] The SPAD array 142 includes a first light-receiving region R1 and a second light-receiving region R2. Each of the first light-receiving region R1 and the second light-receiving region R2 includes a plurality of macropixels 30 arranged in the vertical direction. In the example of FIG. 4 , each of the first light-receiving region R1 and the second light-receiving region R2 includes 42 macropixels 30 arranged in a single vertical column. The first light-receiving region R1 and the second light-receiving region R2 are separated horizontally by a predetermined distance equivalent to two 30 macropixels.

[0039] The first light-receiving region R1 includes a plurality of macro pixels 30 that each detect the reflected light L2 of strong light emission (first light). The second light-receiving region R2 includes a plurality of macro pixels 30 that each detect the reflected light L2 of weak light emission (second light). Light generated by weak light emission is weaker than light generated by strong light emission. In addition, in the used SPAD array 142, only the first light-receiving region R1 is used for the reflected light L2 of strong light emission, and only the second light-receiving region R2 is used for the reflected light L2 of weak light emission. Light intensity is expressed, for example, by luminous intensity (cd), luminous flux (lm), illuminance (lx), or a combination thereof.

[0040] Each of the first light receiving region R1 and the second light receiving region R2 includes a plurality of macro pixels 30 arranged in a single vertical row, but is not limited to this. For example, each of the first light receiving region R1 and the second light receiving region R2 may include a plurality of macro pixels 30 arranged in multiple vertical rows (e.g., two or three rows).

[0041] Furthermore, the first light receiving region R1 and the second light receiving region R2 are separated by a predetermined distance of two 30 macropixels in the horizontal direction, but this is not limiting. For example, the first light receiving region R1 and the second light receiving region R2 may be separated by one or three or more 30 macropixels in the horizontal direction, or may be adjacent to each other without being separated.

[0042] 1-5. Configuration Example of SPAD Pixel A configuration example of the SPAD pixel 20 according to this embodiment will be described with reference to Fig. 5. Fig. 5 is a circuit diagram showing a configuration example of the SPAD pixel 20 according to this embodiment.

[0043] 5, the SPAD pixel 20 includes a photodiode 21 as a light receiving element and a readout circuit 22 that detects that a photon has been incident on the photodiode 21. When a photon is incident on the photodiode 21 while a reverse bias voltage V_SPAD equal to or greater than the breakdown voltage is applied between the anode and cathode of the photodiode 21, the photodiode 21 generates an avalanche current.

[0044] The readout circuit 22 includes a quench resistor 23, a digital converter 25, an inverter 26, a buffer 27, and a selection transistor 24. The quench resistor 23 is configured, for example, by an N-type MOSFET (Metal Oxide Semiconductor Field Effect Transistor), i.e., an NMOS transistor. The drain of this NMOS transistor is connected to the anode of the photodiode 21, and the source is grounded via the selection transistor 24. A quench voltage V_QCH, which is preset to cause the NMOS transistor to function as a quench resistor, is applied to the gate of the NMOS transistor that configures the quench resistor 23 from the drive circuit 144 via the pixel drive line LD.

[0045] In this embodiment, the photodiode 21 is a SPAD. A SPAD is an avalanche photodiode that operates in Geiger mode when a reverse bias voltage equal to or greater than the breakdown voltage is applied between its anode and cathode, and is capable of detecting the incidence of a single photon.

[0046] The digital converter 25 includes a resistor 251 and an NMOS transistor 252. The drain of the NMOS transistor 252 is connected to the power supply voltage VDD via the resistor 251, and the source of the NMOS transistor 252 is grounded. The voltage at the connection point N1 between the anode of the photodiode 21 and the quench resistor 23 is applied to the gate of the NMOS transistor 252.

[0047] The inverter 26 includes a P-type MOSFET, i.e., a PMOS transistor 261, and an NMOS transistor 262. The drain of the PMOS transistor 261 is connected to the power supply voltage VDD, and the source is connected to the drain of the NMOS transistor 262. The drain of the NMOS transistor 262 is connected to the source of the PMOS transistor 261, and the source is grounded. The voltage of the connection point N2 between the resistor 251 and the drain of the NMOS transistor 252 is applied to the gates of the PMOS transistor 261 and NMOS transistor 262, respectively. The output of the inverter 26 is input to the buffer 27.

[0048] The buffer 27 is a circuit for impedance conversion, and when the output signal from the inverter 26 is input, the buffer 27 converts the impedance of the input output signal and outputs the result as a detection signal V_OUT.

[0049] The selection transistor 24 is, for example, an NMOS transistor, and its drain is connected to the source of the NMOS transistor that constitutes the quench resistor 23, and its source is grounded. The selection transistor 24 is connected to the drive circuit 144, and when a selection control voltage V_SEL from the drive circuit 144 is applied to the gate of the selection transistor 24 via the pixel drive line LD, the selection transistor 24 changes from an OFF state to an ON state.

[0050] 5 operates, for example, as follows. First, while the selection control voltage V_SEL is applied from the drive circuit 144 to the selection transistor 24 and the selection transistor 24 is in the on state, a reverse bias voltage V_SPAD equal to or greater than the breakdown voltage is applied to the photodiode 21. This allows the photodiode 21 to operate (for example, perform detection).

[0051] On the other hand, when the selection control voltage V_SEL is not applied from the drive circuit 144 to the selection transistor 24 and the selection transistor 24 is in the off state, the reverse bias voltage V_SPAD is not applied to the photodiode 21, and therefore the operation of the photodiode 21 is prohibited.

[0052] When a photon is incident on the photodiode 21 while the selection transistor 24 is in the ON state, an avalanche current is generated in the photodiode 21. This causes the avalanche current to flow through the quench resistor 23, increasing the voltage at the connection point N1. When the voltage at the connection point N1 becomes higher than the ON voltage of the NMOS transistor 252, the NMOS transistor 252 turns ON, and the voltage at the connection point N2 changes from the power supply voltage VDD to 0 V. When the voltage at the connection point N2 changes from the power supply voltage VDD to 0 V, the PMOS transistor 261 changes from the OFF state to the ON state, and the NMOS transistor 262 changes from the ON state to the OFF state, causing the voltage at the connection point N3 to change from 0 V to the power supply voltage VDD. As a result, a high-level detection signal V_OUT is output from the buffer 27.

[0053] Thereafter, as the voltage at the connection point N1 continues to rise, the voltage applied between the anode and cathode of the photodiode 21 becomes smaller than the breakdown voltage, thereby stopping the avalanche current and decreasing the voltage at the connection point N1. When the voltage at the connection point N1 becomes lower than the on-voltage of the NMOS transistor 252, the NMOS transistor 252 turns off, and the output of the detection signal V_OUT from the buffer 27 stops (low level).

[0054] In this way, the readout circuit 22 outputs a high-level detection signal V_OUT during the period from the timing when a photon is incident on the photodiode 21, generating an avalanche current and thereby turning on the NMOS transistor 252, to the timing when the avalanche current stops and the NMOS transistor 252 turns off. The output detection signal V_OUT is input to the SPAD adder 40 for each macro pixel 30 via the output circuit 145. Therefore, each SPAD adder 40 receives a detection signal V_OUT corresponding to the number of SPAD pixels 20 (detection number) at which incident photons have been detected among the multiple SPAD pixels 20 constituting one macro pixel 30.

[0055] <1-6. Configuration Example of SPAD Adder> An example of the configuration of the SPAD adder 40 according to this embodiment will be described with reference to Fig. 6. Fig. 6 is a diagram showing an example of the configuration of the SPAD adder 40 according to this embodiment. Note that the SPAD adder 40 may be configured to be included in the light receiving unit 14 or may be configured to be included in the calculation unit 15.

[0056] As shown in FIG. 6, the SPAD adder 40 includes, for example, a pulse shaping unit 41 and a light reception number counting unit 42.

[0057] The pulse shaping unit 41 shapes the pulse waveform of the detection signal V_OUT input from the SPAD array 141 via the output circuit 145 into a pulse waveform with a time width according to the operation clock of the SPAD adding unit 40 .

[0058] The light reception counting unit 42 counts the detection signal V_OUT input from the corresponding macro pixel 30 for each sampling period, thereby counting the number of SPAD pixels 20 (detection number) at which incident photons are detected for each sampling period, and outputs this count value as the pixel value of the macro pixel 30.

[0059] (Sampling Period) The sampling period is a period for measuring the time (time of flight) from when the light-emitting unit 13 emits the laser light L1 until the light-receiving unit 14 detects the incidence of a photon. This sampling period is set to be shorter than the light-emitting period of the light-emitting unit 13. For example, by shortening the sampling period, it becomes possible to calculate the time of flight of a photon emitted from the light-emitting unit 13 and reflected by the object 90 with higher time resolution. This means that by increasing the sampling frequency, it becomes possible to calculate the distance L to the object 90 with higher ranging resolution.

[0060] For example, if the flight time from when the light emitting unit 13 emits the laser light L1, when this laser light L1 is reflected by the object 90, until this reflected light L2 is incident on the light receiving unit 14 is t, then since the speed of light C is constant (C≈300,000,000 m (meters) / s (seconds)), the distance L to the object 90 can be calculated by the following formula (1): L=C×t / 2 (1)

[0061] Therefore, if the sampling frequency is 1 GHz, the sampling period is 1 ns (nanosecond). In this case, one sampling period corresponds to 15 cm (centimeter). This indicates that the distance measurement resolution when the sampling frequency is 1 GHz is 15 cm. Furthermore, if the sampling frequency is doubled to 2 GHz, the sampling period becomes 0.5 ns (nanosecond), and one sampling period corresponds to 7.5 cm (centimeter). This indicates that doubling the sampling frequency can reduce the distance measurement resolution by half. In this way, by increasing the sampling frequency and shortening the sampling period, it is possible to calculate the distance L to the object 90 with greater accuracy.

[0062] <1-7. Example of Flare Removal Processing> An example of flare removal processing according to this embodiment will be described with reference to Fig. 7. Fig. 7 is a diagram for explaining an example of flare removal processing according to this embodiment.

[0063] As shown in FIG. 7 , with strong light emission, light spreads over a wide area in the ON region (reading region) of the strong light emission ranging image G1, and in the strong light emission ranging image G1, for example, the entire ON region becomes the detection region F1 where light is detected. On the other hand, when the light emission intensity of the light-emitting unit 13 is weakened compared to the strong light emission, the spread of light becomes smaller. Therefore, in the weak light emission ranging image G2, only a portion of the ON region becomes the detection region F2 where light is detected. This detection region F2 is narrower than the detection region F1. By utilizing such differences in light emission intensity (for example, the difference in size between the detection regions F1 and F2 depending on the light emission intensity), it is possible to determine and remove flare.

[0064] The ON region is a region in which the SPAD pixel 20 (e.g., the photodiode 21) is operable (a region in which the aforementioned selection transistor 24 is in an ON state), that is, a read region in which a signal can be read from the SPAD pixel 20. This ON region is set by a control signal from the control unit 11. That is, the control unit 11 sets an ON region in the used SPAD array 142. For example, the control unit 11 sequentially sets each of the SPAD regions 14a to 14h of the used SPAD array 142 as an ON region. More specifically, within each of the SPAD regions 14a to 14h, only the first light-receiving region R1 or the second light-receiving region R2 is set as an ON region depending on the intensity of light emission.

[0065] Furthermore, the detection area F1 in the strong light-emitting ranging image G1 and the detection area F2 in the weak light-emitting ranging image G2 are areas in which reflected light L2 (including flare) from the object 90 is detected. Each of the detection areas F1 and F2 includes an object detection area corresponding to the object 90 and a flare detection area surrounding the object detection area. Typically, the flare detection area (strong flare) in the strong light-emitting detection area F1 is wider than the flare detection area (weak flare) in the weak light-emitting detection area F2. Flare often occurs, for example, when the reflectivity of the object 90 is high, that is, when the object 90 is a highly reflective object.

[0066] The light-emitting unit 13 switches the intensity of light emitted by the light source 131, and the calculation unit 15 performs flare determination and flare removal based on each of the distance measurement images G1 and G2 according to the intensity of light emission. For example, the calculation unit 15 determines whether the detection area F1 in the distance measurement image G1 with strong light emission and the detection area F2 in the distance measurement image G2 with weak light emission are the same in size, and if the sizes are different, detects the occurrence of flare in the distance measurement image G1 with strong light emission (flare determination). The calculation unit 15 performs flare removal if it detects the occurrence of flare, and does not perform flare removal if it does not detect the occurrence of flare.

[0067] Next, when the calculation unit 15 detects the occurrence of flare in the strong-light ranging image G1, it removes the flare from the strong-light ranging image G1 by removing the area corresponding to the detection area F2 in the weak-light ranging image G2 from the detection area F1 in the strong-light ranging image G1, leaving only the area corresponding to the detection area F2 in the weak-light ranging image G2, thereby generating a ranging image G3 (flare removal). This makes it possible to achieve high-precision ranging by removing the flare. The calculation unit 15 can identify various areas, for example, based on the position information (e.g., coordinate information) of each macro pixel 30.

[0068] In the detection area F1 of the strong light-emitting ranging image G1, the area other than the area corresponding to the detection area F2 of the weak light-emitting ranging image G2 is a flare detection area due to strong light emission. Also, in the detection area F1 of the strong light-emitting ranging image G1, the area corresponding to the detection area F2 of the weak light-emitting ranging image G2 certainly includes an object detection area. Note that, in order to maintain or improve the detection distance, it is desirable to use the strong light-emitting ranging image G1, i.e., the detection result (detection signal) of the detection area F1.

[0069] The calculation unit 15 that executes such flare determination and flare removal processing functions as a processing unit. Furthermore, the strong light emission ranging image G1 functions as a first ranging image, and the weak light emission ranging image G2 functions as a second ranging image. The detection area F1 functions as a first detection area, and the detection area F2 functions as a second detection area.

[0070] In addition, in detecting the occurrence of flare as described above, in addition to determining whether the sizes of the detection area F1 of the strong illumination ranging image G1 and the detection area F2 of the weak illumination ranging image G2 are the same, it is also possible to determine, for example, whether the size difference between each of the detection areas F1 and F2 is greater than or equal to a predetermined value (a predetermined threshold value for flare detection), and detect the occurrence of flare in the strong illumination ranging image G1 if the size difference is greater than or equal to the predetermined value.

[0071] <1-8. Example of distance measurement for each divided region> An example of distance measurement for each divided region according to this embodiment will be described with reference to Fig. 8. Fig. 8 is a diagram for explaining an example of distance measurement for each divided region according to this embodiment.

[0072] As shown in FIG. 8, for example, the light source 131 of the light-emitting unit 13 is composed of eight laser units 13a to 13h, and the SPAD array 142 used by the light-receiving unit 14 is divided into eight SPAD areas 14a to 14h (see FIG. 4). Each of the SPAD areas 14a to 14h functions as a divided area. The control unit 11 controls the distance measurement to be repeated for each divided area. As a result, flare occurs for each divided area.

[0073] Here, if the light source 131 is made to emit weak light, the returning light, i.e., the signal strength, will be weak, and it may become impossible to detect the object 90, which originally has low reflectivity. It is difficult to distinguish whether the reason for the lack of returning light due to this weak light emission is that the flare has disappeared, or that the actual object 90 can no longer be detected.

[0074] Therefore, as a countermeasure for the above, it is effective to divide the light-emitting region and the light-receiving region so that the range in which flare occurs during strong light emission is narrowed to within the divided regions. In this way, when light does not return due to weak light emission, the range in which it is impossible to determine whether the cause is the disappearance of flare or non-detection of object 90 can be narrowed to the divided regions.

[0075] 1-9. Example of distance measurement processing> An example of distance measurement processing according to this embodiment will be described with reference to Fig. 9. Fig. 9 is a flowchart showing the flow of an example of distance measurement processing according to this embodiment.

[0076] As shown in FIG. 9 , the light emitter 13 emits laser light L1 while switching between strong and weak illumination (step S11). The light receiver 14 receives reflected light L2 from the laser light L1 reflected by the object 90 (step S12). The processor 15 then generates a histogram of cumulative pixel values ​​for strong illumination (strong illumination histogram) based on the strong illumination ranging image G1 generated by the detection signal output from the light receiver 14. Similarly, the processor 15 generates a histogram of cumulative pixel values ​​for weak illumination (weak illumination histogram) based on the weak illumination ranging image G2 generated by the detection signal output from the light receiver 14 (step S13). The processor 15 compares the strong illumination histogram and the weak illumination histogram and removes flare from the strong illumination histogram (strong illumination ranging image G1) (step S14). The processor 15 then calculates the distance L to the object 90 based on the strong illumination histogram from which flare has been removed (step S15). The calculation unit 15 outputs the calculated distance L to the host 80 (step S16), and ends the process.

[0077] (Switching Between Strong and Weak Light Emission for Each Line) Fig. 10 is a diagram for explaining flare removal when switching between strong and weak light emission for each line according to this embodiment. The lines are image lines.

[0078] As shown in Fig. 10 (1), the light-emitting unit 13 switches between strong and weak light emission for each line (odd and even lines). The light-receiving unit 14 switches between the first light-receiving region R1 and the second light-receiving region R2 for each line depending on whether the light emission is strong or weak. That is, the control unit 11 alternately switches the first light-receiving region R1 and the second light-receiving region R2 to the ON region for each line depending on whether the light emission is strong or weak. This changes the readout line.

[0079] In step (2), the calculation unit 15 acquires and compares a ranging image G1 with strong illumination (normal ranging) and a ranging image G2 with weak illumination (for flare determination). The flare in the ranging image G1 with strong illumination is stronger than the flare in the ranging image G2 with weak illumination, and the detection area F1 in the ranging image G1 with strong illumination is wider than the detection area F2 in the ranging image G2 with weak illumination. Note that because strong illumination and weak illumination occur repeatedly on each line, the detection areas F1 and F2 appear striped in both the ranging image G1 with strong illumination and the ranging image G2 with weak illumination.

[0080] In (3), the calculation unit 15 removes flare from the strong light ranging image G1 by deleting the detection area F1 of the strong light ranging image G1, leaving only the area corresponding to the detection area F2 of the weak light ranging image G2, and thereby generates a ranging image G3.

[0081] In this way, by performing distance measurement processing for each line, high-precision distance measurement can be achieved by removing flare, while high-speed distance measurement is also possible.

[0082] In the above-described example of line-by-line processing, the first light-receiving region R1 and the second light-receiving region R2 are alternately set as ON regions depending on the intensity of light emission, but in reality, each of the SPAD regions 14a to 14h is also sequentially selected as ON regions. Therefore, in each of the SPAD regions 14a to 14h selected as ON regions, only the first light-receiving region R1 or the second light-receiving region R2 is set as ON regions depending on the intensity of light emission.

[0083] Here, the light emission period (length of time during which light is emitted) for each line is the light irradiation time (light emission time) for the object 90, and may be set within a range of 10 to 100 μs, for example. The light emission period for each line functions as an image line period. The light emission periods for strong light emission and weak light emission may be the same or different. In other words, the period from the timing of switching from weak light emission to strong light emission to the timing of switching from strong light emission to weak light emission may be the same or different from the period from the timing of switching from strong light emission to weak light emission to the timing of switching from weak light emission to strong light emission. Note that, because strong light emission contributes to the detection of distant objects 90, the detection distance can be improved by making the light emission period for strong light emission longer than the light emission period for weak light emission.

[0084] Furthermore, although strong light emission and weak light emission are executed alternately, it is desirable that the light emission periods of the strong light emission and weak light emission do not overlap in time, for example, to facilitate processing and improve distance measurement accuracy, etc. Similarly, it is desirable that the first reading period in which the first light-receiving region R1 is the ON region and the second reading period in which the second light-receiving region R2 is the ON region do not overlap in time, for example, to facilitate processing and improve distance measurement accuracy, etc.

[0085] 10, the strong light-emitting ranging image G1 is generated from detection information for each line (e.g., odd-numbered lines). At this time, to supplement the missing detection information, detection information for each line (e.g., even-numbered lines) of the weak light-emitting ranging image G2 may be used. For example, the calculation unit 15 may superimpose the weak light-emitting ranging image G2 on the strong light-emitting ranging image G1 from which flare has been removed.

[0086] (Switching Between Strong and Weak Light Emission for Each Frame) Fig. 11 is a diagram for explaining flare removal when switching between strong and weak light emission for each frame according to this embodiment. The frames are image frames.

[0087] As shown in Figure 11, in (1), the light-emitting unit 13 switches between strong and weak light emission for each frame (odd and even frames). The light-receiving unit 14 switches between the first light-receiving region R1 and the second light-receiving region R2 for each frame depending on whether the light emission is strong or weak. That is, the control unit 11 alternately switches the first light-receiving region R1 and the second light-receiving region R2 to the ON region for each frame depending on whether the light emission is strong or weak. This changes the readout frame.

[0088] In step (2), the calculation unit 15 acquires and compares a strong light (normal distance measurement) distance measurement image G1 and a weak light (for flare determination) distance measurement image G2. The flare in the strong light measurement image G1 is stronger than the flare in the weak light measurement image G2, and the detection area F1 in the strong light measurement image G1 is wider than the detection area F2 in the weak light measurement image G2.

[0089] In (3), the calculation unit 15 removes flare from the strong light ranging image G1 by deleting the detection area F1 of the strong light ranging image G1, leaving only the area corresponding to the detection area F2 of the weak light ranging image G2, and thereby generates a ranging image G3.

[0090] In this way, by performing distance measurement processing for each frame, high-precision distance measurement is achieved by removing flare, and further, since the strong light-emitting distance measurement image G1 contains sufficient detection information, even higher-precision distance measurement is possible.

[0091] In the above-described frame-by-frame processing example, the first light-receiving region R1 and the second light-receiving region R2 are alternately set as ON regions depending on the intensity of light emission, but in reality, as in the above-described line-by-line processing example, each of the SPAD regions 14a to 14h is also sequentially selected as ON regions. Therefore, in each of the SPAD regions 14a to 14h selected as ON regions, only the first light-receiving region R1 or the second light-receiving region R2 is set as ON regions depending on the intensity of light emission.

[0092] Here, the frame period for each frame may be the same for strong light emission and weak light emission, or may be different. Because strong light emission contributes to the detection of distant objects 90, the detection distance can be improved by making the frame period for strong light emission longer than the frame period for weak light emission.

[0093] As in the above-described example of line-by-line processing, strong light emission and weak light emission are alternately performed, but it is desirable that the light emission periods of strong light emission and weak light emission do not overlap in time, for example, to facilitate processing and improve distance measurement accuracy, etc. Similarly, it is desirable that the first reading period in which the first light-receiving region R1 is the ON region and the second reading period in which the second light-receiving region R2 is the ON region do not overlap in time, for example, to facilitate processing and improve distance measurement accuracy, etc.

[0094] <1-10. Configuration example of laser unit> Configuration examples of each of the laser units 13a to 13h according to this embodiment will be described with reference to Fig. 12 to Fig. 14. Since each of the laser units 13a to 13h has the same structure, the laser unit 13a will be described as a representative. Each of Fig. 12 to Fig. 14 is a diagram showing a configuration example of the laser unit 13a according to this embodiment.

[0095] (Different Light Sources) As shown in FIG. 12 , the laser unit 13a includes multiple laser diodes 13a1 and 13a2 and a light-emitting substrate 13a3. The laser unit 13a functions as a light source. The laser diode 13a1 is a strong light source (first light source) that emits laser light L1a. The laser diode 13a2 is a weak light source (second light source) that emits laser light L1b. The laser diodes 13a1 and 13a2 are two types of light sources with different light emission intensities (light emission powers), i.e., two types of light sources with different original light emission capabilities. The light emission intensity of the laser diode 13a2 is weaker than that of the laser diode 13a1. The light emission intensities of the laser diodes 13a1 and 13a2 differ from each other by, for example, about 100 times. The light-emitting substrate 13a3 is a substrate that supports the laser diodes 13a1 and 13a2.

[0096] (Changing Applied Voltage or Charging Time) As shown in FIG. 13 , the laser unit 13 a includes a plurality of laser diodes 13 a 1 and 13 a 2 and a light-emitting substrate 13 a 3 , similar to FIG. 12 . This laser unit 13 a functions as a light source. As in FIG. 12 , the laser diode 13 a 1 is a light source for strong light emission, and the laser diode 13 a 2 is a light source for weak light emission. The applied voltage or the charging time for the capacitors of the laser diodes 13 a 1 and 13 a 2 are different. For example, the amount of light emitted by the laser diode 13 a 2, i.e., the light emission intensity, may be reduced by applying a voltage smaller than that applied to the laser diode 13 a 2 than that applied to the laser diode 13 a 1 or by shortening the charging time for the laser diode 13 a 2 than that for the laser diode 13 a 1.

[0097] (Neutral Density Filter) As shown in FIG. 14 , the laser unit 13a includes multiple laser diodes 13a1 and 13a2, a light-emitting substrate 13a3, and a neutral density filter 13a4. The laser unit 13a functions as a light source. The neutral density filter 13a4 functions as a neutral density filter. As in FIG. 12 , the laser diode 13a1 is a light source for strong light emission, and the laser diode 13a2 is a light source for weak light emission. The neutral density filter 13a4 is provided above the laser diode 13a2, i.e., on the optical path of the laser light L1b emitted from the laser diode 13a2. The neutral density filter 13a4 attenuates the laser light L1b emitted from the laser diode 13a2. In this way, by providing the neutral density filter 13a4 on the optical path of the laser diode 13a2, the amount of light emitted by the laser diode 13a2, i.e., the light intensity, may be reduced.

[0098] <1-11. Example of Advantages of Separating Light Receiving Regions> Example of advantages of separating light receiving regions according to this embodiment (example of advantages of the first light receiving region R1 and the second light receiving region R2) will be described with reference to Fig. 15. Fig. 15 is a diagram for explaining example advantages of separating light receiving regions according to this embodiment.

[0099] 15, in (1), there is one set of the light emitting substrate 13a3 and the collimator lens 132. Because the first light receiving region R1 for strong light emission and the second light receiving region R2 for weak light emission are different, only one set of the light emitting substrate 13a3 and the collimator lens 132 is required.

[0100] In (2), there are two sets of light-emitting substrate 13a3 and collimator lens 132. Each light beam emitted from a different position through one collimator lens 132 is emitted with a tilted optical axis and is focused at a different position on the light-receiving side. For this reason, if it is desired to receive light at the same position without dividing the light-receiving region as described above, it is necessary to prepare two sets of light-emitting substrate 13a3 and collimator lens 132 so that the optical axis is not tilted. Therefore, in order to simplify the configuration, it is effective to prepare a first light-receiving region R1 for strong light emission and a second light-receiving region R2 for weak light emission, as described above.

[0101] In (3), although it is possible to switch between strong and weak light emission using the same laser diode 13a1, it may be difficult to achieve a 100-fold difference in light emission intensity with a single laser diode 13a1. For this reason, as described above, it is effective to provide a first light-receiving region R1 for strong light emission and a second light-receiving region R2 for weak light emission. By installing laser diodes 13a1 and 13a2 with different light emission intensities, it is easy to achieve different light emission intensities.

[0102] <1-12. Actions and Effects> As described above, according to the embodiment, the distance measuring device (e.g., ToF sensor 1) includes: a light-emitting unit 13 that selectively emits a first light (e.g., laser light L1a) and a second light (e.g., laser light L1b) that is weaker than the first light; a first light-receiving region R1 that includes a plurality of pixels (e.g., SPAD pixels 20 or macro pixels 30) that detect reflected light L2 of the first light; and a light-receiving unit 14 that includes a second light-receiving region R2 that is different from the first light-receiving region R1 and includes a plurality of pixels (e.g., SPAD pixels 20 or macro pixels 30) that detect reflected light L2 of the second light (see FIGS. 1 to 4 ). This makes it possible to obtain a distance measurement image G1 based on the first light and a distance measurement image G2 based on the second light that is weaker than the first light, and to eliminate flare from the distance measurement image G1 by comparing the distance measurement image G1 and the distance measurement image G2. This makes it possible to suppress a decrease in distance measurement accuracy.

[0103] Alternatively, the light-receiving unit 14 may have different emission timings for the first light and the second light, with the first light-receiving region R1 set as a reading region for reading signals from each of the plurality of pixels in accordance with the emission timing of the first light, and the second light-receiving region R2 set as a reading region in accordance with the emission timing of the second light (see FIGS. 10 and 11 ). This makes it possible to reliably obtain a ranging image G1 based on the first light and a ranging image G2 based on the second light, which is weaker than the first light, thereby reliably preventing a decrease in ranging accuracy.

[0104] Furthermore, the first reading period in which the first light-receiving region R1 is used as the reading region and the second reading period in which the second light-receiving region R2 is used as the reading region do not have to overlap in time (see FIGS. 10 and 11 ). This makes it possible to reliably obtain a ranging image G1 based on the first light and a ranging image G2 based on the second light that is weaker than the first light, thereby reliably preventing a decrease in ranging accuracy.

[0105] Furthermore, the first reading period in which the first light receiving region R1 is the reading region and the second reading period in which the second light receiving region R2 is the reading region may be the same (see FIGS. 10 and 11). This can simplify the processing.

[0106] Furthermore, the light emission periods of the first light and the second light may be the same (see FIGS. 10 and 11), which can simplify processing.

[0107] Furthermore, the emission period of the first light may be longer than the emission period of the second light (see FIG. 10 ). Since the strong light contributes to the detection of a distant object 90, the detection distance can be improved by making the emission period of the strong light longer than the emission period of the weak light.

[0108] Furthermore, the first light receiving region R1 and the second light receiving region R2 may have the same size (see FIG. 4), which can simplify processing.

[0109] Furthermore, the first light receiving region R1 and the second light receiving region R2 may have the same shape (see FIG. 4), which can simplify processing.

[0110] The first light receiving region R1 and the second light receiving region R2 may be separated by a predetermined distance (see FIG. 4 ). This makes it possible to reliably obtain a distance measurement image G1 based on the first light and a distance measurement image G2 based on the second light that is weaker than the first light, thereby reliably preventing a decrease in distance measurement accuracy.

[0111] Furthermore, the light emitting unit 13 may switch between the first light and the second light for each image line (see FIG. 10), thereby realizing faster processing.

[0112] Furthermore, the image line period of the first light may be longer than the image line period of the second light (see FIG. 10 ). This allows the strong light emission to contribute to the detection of a distant object 90, and so by making the image line period of the strong light emission longer than the image line period of the weak light emission, the detection distance can be improved.

[0113] Furthermore, the light-emitting unit 13 may switch between the first light and the second light for each image frame (see FIG. 11 ), which can improve the angular resolution compared to when the first light and the second light are switched for each image line.

[0114] Furthermore, the frame period of the first light may be longer than the frame period of the second light (see FIG. 11 ). This allows the strong light emission to contribute to the detection of a distant object 90, and so by making the frame period of the strong light emission longer than the frame period of the weak light emission, the detection distance can be improved.

[0115] The distance measuring device may further include a processing unit (e.g., calculation unit 15) that compares a first distance measuring image (e.g., distance measuring image G1) obtained from the reflected light L2 of the first light with a second distance measuring image (e.g., distance measuring image G2) obtained from the reflected light L2 of the second light, and detects the occurrence of flare in the first distance measuring image or removes flare from the first distance measuring image (see FIGS. 7 and 9 to 11). This makes it possible to reliably remove flare from the first distance measuring image, thereby reliably preventing a decrease in distance measurement accuracy.

[0116] The processing unit may also compare the sizes of the first detection area in the first ranging image and the second detection area in the second ranging image to detect the occurrence of flare in the first ranging image, and remove the flare from the first ranging image only when the occurrence of flare in the first ranging image is detected (see FIG. 7 ). This makes it possible to avoid performing the flare removal process when no flare has occurred in the first ranging image, thereby achieving faster processing.

[0117] Alternatively, the processing unit may remove flare from the first ranging image by leaving only a region of the first detection region (e.g., detection region F1) in the first ranging image that corresponds to the second detection region (e.g., detection region F2) in the second ranging image (see FIGS. 7 and 9 to 11). This makes it possible to reliably remove flare from the first ranging image, thereby reliably suppressing a decrease in ranging accuracy.

[0118] Furthermore, the light-emitting unit 13 may have a light source unit (e.g., a laser unit 13a) that switches between emitting the first light and the second light, and the light source unit may have a first light source (e.g., a laser diode 13a1) that emits the first light and a second light source (e.g., a laser diode 13a2) that emits the second light (see FIGS. 12 and 13 ). This makes it possible to switch between irradiating the object 90 with the first light and the second light that is weaker than the first light, thereby making it possible to reliably obtain a ranging image G1 based on the first light and a ranging image G2 based on the second light.

[0119] The emission intensity of the second light source may be weaker than the emission intensity of the first light source, which makes it easy to generate second light that is weaker than the first light (see FIG. 12).

[0120] The light source unit may further include a light-reducing unit (e.g., a light-reducing filter 13a4) that is provided on the optical path of the second light emitted from the second light source and that attenuates the second light (see FIG. 14 ). This makes it possible to easily generate second light that is weaker than the first light.

[0121] Furthermore, the light-emitting unit 13 may have a plurality of light source units, and each of the first light-receiving region R1 and the second light-receiving region R2 may be divided into a plurality of regions (e.g., a plurality of SPAD regions 14a-14h) according to the number of light source units (see FIGS. 4 and 8). This makes it possible to narrow the range in which flare occurs during strong light emission to within the divided regions. For example, when light does not return due to weak light emission, the range in which it is impossible to determine whether the cause is the disappearance of flare or non-detection of the object 90 can be narrowed to the divided regions.

[0122] 2. Other Embodiments The configurations and processes according to the above-described embodiments (including examples and modified examples) may be implemented in various different forms other than the above-described embodiments. For example, the configurations and processes are not limited to the above-described examples and may be implemented in various forms. Furthermore, for example, the configurations, processing procedures, specific names, or information including various data and parameters shown in the above documents and drawings may be changed arbitrarily unless otherwise specified.

[0123] Furthermore, the components and processes according to the above-described embodiments (including examples and modifications) do not necessarily have to be physically configured as shown in the drawings. In other words, the specific forms of distribution and integration of the components and processes are not limited to those shown in the drawings, and all or part of them may be functionally or physically distributed or integrated in any unit depending on various loads, usage conditions, etc.

[0124] Furthermore, the configurations and processes of the above-described embodiments (including examples and modified examples) may be combined as appropriate. For example, at least a part of an embodiment may be combined as appropriate with at least a part of another embodiment. Furthermore, the effects of the embodiments are merely examples and are not intended to be limiting, and other effects may also be obtained.

[0125] 3. Application Examples The technology according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of moving body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, a robot, construction machinery, or agricultural machinery (tractor). Furthermore, for example, the technology according to the present disclosure may be realized as a device mounted on an endoscopic surgery system, a microsurgery system, or the like.

[0126] 16 is a block diagram showing a schematic configuration example of a vehicle control system 7000, which is an example of a mobile object control system to which the technology according to the present disclosure can be applied. The vehicle control system 7000 includes a plurality of electronic control units connected via a communication network 7010. In the example shown in FIG. 16, the vehicle control system 7000 includes a drive system control unit 7100, a body system control unit 7200, a battery control unit 7300, an outside-vehicle information detection unit 7400, an inside-vehicle information detection unit 7500, and an integrated control unit 7600. The communication network 7010 connecting these multiple control units may be an in-vehicle communication network conforming to any standard, such as a Controller Area Network (CAN), a Local Interconnect Network (LIN), a Local Area Network (LAN), or FlexRay (registered trademark).

[0127] Each control unit includes a microcomputer that performs arithmetic processing according to various programs, a memory unit that stores the programs executed by the microcomputer or parameters used in various calculations, and a drive circuit that drives various controlled devices. Each control unit includes a network I / F for communicating with other control units via a communication network 7010, and a communication I / F for communicating with devices or sensors inside and outside the vehicle via wired or wireless communication. Figure 16 illustrates the functional configuration of the integrated control unit 7600, including a microcomputer 7610, a general-purpose communication I / F 7620, a dedicated communication I / F 7630, a positioning unit 7640, a beacon receiving unit 7650, an in-vehicle device I / F 7660, an audio / video output unit 7670, an in-vehicle network I / F 7680, and a memory unit 7690. The other control units also include a microcomputer, a communication I / F, a memory unit, and the like.

[0128] The drivetrain control unit 7100 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 7100 functions as a control device for a drive force generating device for generating drive force for the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating braking force for the vehicle. The drivetrain control unit 7100 may also function as a control device for an ABS (Antilock Brake System) or an ESC (Electronic Stability Control), etc.

[0129] A vehicle state detection unit 7110 is connected to the drivetrain control unit 7100. The vehicle state detection unit 7110 includes at least one of a gyro sensor that detects the angular velocity of the axial rotational motion of the vehicle body, an acceleration sensor that detects the acceleration of the vehicle, or a sensor that detects the amount of operation of the accelerator pedal, the amount of operation of the brake pedal, the steering angle of the steering wheel, the engine rotation speed, the rotation speed of the wheels, etc. The drivetrain control unit 7100 performs arithmetic processing using signals input from the vehicle state detection unit 7110, and controls the internal combustion engine, the drive motor, the electric power steering device, the brake device, etc.

[0130] The body system control unit 7200 controls the operation of various devices equipped in the vehicle body according to various programs. For example, the body system control unit 7200 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches can be input to the body system control unit 7200. The body system control unit 7200 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0131] The battery control unit 7300 controls the secondary battery 7310, which is the power supply source for the drive motor, in accordance with various programs. For example, information such as battery temperature, battery output voltage, or remaining battery capacity is input to the battery control unit 7300 from a battery device equipped with the secondary battery 7310. The battery control unit 7300 performs arithmetic processing using these signals, and controls the temperature regulation of the secondary battery 7310 or a cooling device or the like equipped in the battery device.

[0132] The outside vehicle information detection unit 7400 detects information outside the vehicle equipped with the vehicle control system 7000. For example, at least one of an imaging unit 7410 and an outside vehicle information detection unit 7420 is connected to the outside vehicle information detection unit 7400. The imaging unit 7410 includes at least one of a time-of-flight (ToF) camera, a stereo camera, a monocular camera, an infrared camera, and other cameras. The outside vehicle information detection unit 7420 includes at least one of an environmental sensor for detecting the current weather or climate, or a surrounding information detection sensor for detecting other vehicles, obstacles, pedestrians, etc. around the vehicle equipped with the vehicle control system 7000.

[0133] The environmental sensor may be, for example, at least one of a raindrop sensor that detects rain, a fog sensor that detects fog, a sunshine sensor that detects the degree of sunshine, and a snow sensor that detects snowfall. The surrounding information detection sensor may be at least one of an ultrasonic sensor, a radar device, and a LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) device. The imaging unit 7410 and the outside vehicle information detection unit 7420 may each be provided as an independent sensor or device, or may be provided as a device in which multiple sensors or devices are integrated.

[0134] 17 shows an example of the installation positions of the imaging unit 7410 and the vehicle exterior information detection unit 7420. The imaging units 7910, 7912, 7914, 7916, and 7918 are provided, for example, at least one of the front nose, side mirrors, rear bumper, back door, and upper part of the windshield inside the vehicle cabin of the vehicle 7900. The imaging unit 7910 provided on the front nose and the imaging unit 7918 provided on the upper part of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 7900. The imaging units 7912 and 7914 provided on the side mirrors mainly acquire images of the sides of the vehicle 7900. The imaging unit 7916 provided on the rear bumper or back door mainly acquires images of the rear of the vehicle 7900. The imaging unit 7918 provided on the upper part of the windshield inside the vehicle cabin is mainly used to detect leading vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0135] 17 shows an example of the imaging ranges of the imaging units 7910, 7912, 7914, and 7916. Imaging range a indicates the imaging range of the imaging unit 7910 provided on the front nose, imaging ranges b and c indicate the imaging ranges of the imaging units 7912 and 7914 provided on the side mirrors, respectively, and imaging range d indicates the imaging range of the imaging unit 7916 provided on the rear bumper or back door. For example, by overlaying the image data captured by the imaging units 7910, 7912, 7914, and 7916, a bird's-eye view image of the vehicle 7900 viewed from above can be obtained.

[0136] The outside vehicle information detection units 7920, 7922, 7924, 7926, 7928, and 7930 provided on the front, rear, sides, corners, and above the windshield inside the vehicle cabin of the vehicle 7900 may be, for example, ultrasonic sensors or radar devices. The outside vehicle information detection units 7920, 7926, and 7930 provided on the front nose, rear bumper, back door, and above the windshield inside the vehicle cabin of the vehicle 7900 may be, for example, LIDAR devices. These outside vehicle information detection units 7920 to 7930 are mainly used to detect preceding vehicles, pedestrians, obstacles, etc.

[0137] Returning to FIG. 16 , the explanation will be continued. The outside-vehicle information detection unit 7400 causes the imaging unit 7410 to capture an image outside the vehicle and receives the captured image data. The outside-vehicle information detection unit 7400 also receives detection information from the connected outside-vehicle information detection unit 7420. If the outside-vehicle information detection unit 7420 is an ultrasonic sensor, a radar device, or a LIDAR device, the outside-vehicle information detection unit 7400 emits ultrasonic waves or electromagnetic waves and receives information on the received reflected waves. Based on the received information, the outside-vehicle information detection unit 7400 may perform object detection processing or distance detection processing for people, vehicles, obstacles, signs, text on the road, etc. Based on the received information, the outside-vehicle information detection unit 7400 may also perform environmental recognition processing for recognizing rainfall, fog, road conditions, etc. Based on the received information, the outside-vehicle information detection unit 7400 may also calculate the distance to an object outside the vehicle.

[0138] The outside vehicle information detection unit 7400 may also perform image recognition processing or distance detection processing to recognize people, vehicles, obstacles, signs, or characters on the road surface based on the received image data. The outside vehicle information detection unit 7400 may perform processing such as distortion correction or alignment on the received image data, and may also generate an overhead image or a panoramic image by combining image data captured by different image capturing units 7410. The outside vehicle information detection unit 7400 may also perform viewpoint conversion processing using image data captured by different image capturing units 7410.

[0139] The interior information detection unit 7500 detects information inside the vehicle. A driver state detection unit 7510 that detects the driver's state is connected to the interior information detection unit 7500, for example. The driver state detection unit 7510 may include a camera that captures an image of the driver, a biosensor that detects the driver's biometric information, or a microphone that collects sound from within the vehicle cabin. The biosensor is provided, for example, on the seat or steering wheel, and detects the biometric information of a passenger sitting in the seat or the driver gripping the steering wheel. The interior information detection unit 7500 may calculate the driver's level of fatigue or concentration based on the detection information input from the driver state detection unit 7510, or may determine whether the driver is dozing off. The interior information detection unit 7500 may perform processing such as noise canceling on the collected audio signal.

[0140] The integrated control unit 7600 controls the overall operation of the vehicle control system 7000 according to various programs. An input unit 7800 is connected to the integrated control unit 7600. The input unit 7800 may be implemented by a device that can be operated by a passenger, such as a touch panel, a button, a microphone, a switch, or a lever. Data obtained by voice recognition of a voice input through a microphone may be input to the integrated control unit 7600. The input unit 7800 may be, for example, a remote control device using infrared or other radio waves, or an externally connected device such as a mobile phone or a personal digital assistant (PDA) that can operate the vehicle control system 7000. The input unit 7800 may be, for example, a camera, in which case the passenger can input information using gestures. Alternatively, data obtained by detecting the movement of a wearable device worn by the passenger may be input. Furthermore, the input unit 7800 may include, for example, an input control circuit that generates an input signal based on information input by the passenger using the input unit 7800 and outputs the input signal to the integrated control unit 7600. Passengers and the like operate this input unit 7800 to input various data to the vehicle control system 7000 and to instruct processing operations.

[0141] The storage unit 7690 may include a ROM (Read Only Memory) that stores various programs executed by the microcomputer, and a RAM (Random Access Memory) that stores various parameters, calculation results, sensor values, etc. The storage unit 7690 may also be realized by a magnetic storage device such as an HDD (Hard Disc Drive), a semiconductor storage device, an optical storage device, a magneto-optical storage device, or the like.

[0142] The general-purpose communication I / F 7620 is a general-purpose communication I / F that mediates communication with various devices present in the external environment 7750. The general-purpose communication I / F 7620 may implement a cellular communication protocol such as GSM (Global System of Mobile communications), WiMAX (registered trademark), LTE (Long Term Evolution), or LTE-Advanced (LTE-A), or other wireless communication protocols such as a wireless LAN (also referred to as Wi-Fi (registered trademark)) or Bluetooth (registered trademark). The general-purpose communication I / F 7620 may connect to a device (e.g., an application server or a control server) present on an external network (e.g., the Internet, a cloud network, or an operator-specific network) via, for example, a base station or an access point. In addition, the general-purpose communication I / F 7620 may connect to a terminal located near the vehicle (e.g., a terminal of a driver, pedestrian, or store, or an MTC (Machine Type Communication) terminal) using, for example, P2P (Peer To Peer) technology.

[0143] The dedicated communication I / F 7630 is a communication I / F that supports a communication protocol designed for use in vehicles. The dedicated communication I / F 7630 may implement a standard protocol such as WAVE (Wireless Access in Vehicle Environment), which is a combination of a lower layer IEEE 802.11p and an upper layer IEEE 1609, DSRC (Dedicated Short Range Communications), or a cellular communication protocol. The dedicated communication I / F 7630 typically performs V2X communication, which is a concept including one or more of vehicle-to-vehicle communication, vehicle-to-infrastructure communication, vehicle-to-home communication, and vehicle-to-pedestrian communication.

[0144] The positioning unit 7640 performs positioning by receiving, for example, GNSS signals from GNSS (Global Navigation Satellite System) satellites (for example, GPS signals from GPS (Global Positioning System) satellites), and generates position information including the latitude, longitude, and altitude of the vehicle. Note that the positioning unit 7640 may identify the current position by exchanging signals with a wireless access point, or may obtain position information from a terminal such as a mobile phone, PHS, or smartphone that has a positioning function.

[0145] The beacon receiving unit 7650 receives, for example, radio waves or electromagnetic waves transmitted from radio stations or the like installed on the road, and acquires information such as the current location, congestion, road closures, required travel time, etc. The function of the beacon receiving unit 7650 may be included in the dedicated communication I / F 7630 described above.

[0146] The in-vehicle device I / F 7660 is a communication interface that mediates connections between the microcomputer 7610 and various in-vehicle devices 7760 present in the vehicle. The in-vehicle device I / F 7660 may establish wireless connections using wireless communication protocols such as wireless LAN, Bluetooth (registered trademark), NFC (Near Field Communication), or WUSB (Wireless USB). Furthermore, the in-vehicle device I / F 7660 may establish a wired connection such as USB (Universal Serial Bus), HDMI (High-Definition Multimedia Interface), or MHL (Mobile High-Definition Link) via a connection terminal (and a cable, if necessary) not shown. The in-vehicle device 7760 may include, for example, at least one of a mobile device or a wearable device owned by a passenger, or an information device carried into or attached to the vehicle. The in-vehicle device 7760 may also include a navigation device that searches for a route to an arbitrary destination. The in-vehicle device I / F 7660 exchanges control signals or data signals with these in-vehicle devices 7760.

[0147] The in-vehicle network I / F 7680 is an interface that mediates communication between the microcomputer 7610 and the communication network 7010. The in-vehicle network I / F 7680 transmits and receives signals in accordance with a predetermined protocol supported by the communication network 7010.

[0148] The microcomputer 7610 of the integrated control unit 7600 controls the vehicle control system 7000 in accordance with various programs based on information acquired via at least one of the general-purpose communication I / F 7620, the dedicated communication I / F 7630, the positioning unit 7640, the beacon receiving unit 7650, the in-vehicle device I / F 7660, and the in-vehicle network I / F 7680. For example, the microcomputer 7610 may calculate control target values ​​for the driving force generating device, the steering mechanism, or the braking device based on the acquired information inside and outside the vehicle, and output control commands to the drivetrain control unit 7100. For example, the microcomputer 7610 may perform cooperative control aimed at realizing functions of an Advanced Driver Assistance System (ADAS), including vehicle collision avoidance or impact mitigation, following driving based on the following distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane departure warning, etc. In addition, the microcomputer 7610 may perform cooperative control for the purpose of autonomous driving, in which the vehicle travels autonomously without relying on driver operation, by controlling a driving force generating device, a steering mechanism, a braking device, etc. based on information acquired about the vehicle's surroundings.

[0149] The microcomputer 7610 may generate three-dimensional distance information between the vehicle and objects such as surrounding structures and people, and create local map information including information about the vicinity of the vehicle's current location, based on information acquired via at least one of the general-purpose communication I / F 7620, the dedicated communication I / F 7630, the positioning unit 7640, the beacon receiving unit 7650, the in-vehicle device I / F 7660, and the in-vehicle network I / F 7680. Furthermore, the microcomputer 7610 may predict dangers, such as a vehicle collision, the approach of a pedestrian, or entry into a closed road, based on the acquired information, and generate a warning signal. The warning signal may be, for example, a signal for generating a warning sound or turning on a warning lamp.

[0150] The audio / image output unit 7670 transmits at least one audio and / or image output signal to an output device capable of visually or audibly notifying the vehicle occupants or the outside of the vehicle. In the example of FIG. 16 , an audio speaker 7710, a display unit 7720, and an instrument panel 7730 are illustrated as examples of the output devices. The display unit 7720 may include, for example, at least one of an on-board display and a head-up display. The display unit 7720 may have an AR (Augmented Reality) display function. The output device may also be other devices, such as headphones, a wearable device such as an eyeglass-type display worn by the occupant, a projector, or a lamp. When the output device is a display device, the display device visually displays results obtained by various processes performed by the microcomputer 7610 or information received from other control units in various formats, such as text, images, tables, and graphs. When the output device is an audio output device, the audio output device converts audio signals, such as reproduced audio data or acoustic data, into analog signals and audibly outputs the analog signals.

[0151] In the example shown in FIG. 16 , at least two control units connected via the communication network 7010 may be integrated into a single control unit. Alternatively, each control unit may be composed of multiple control units. Furthermore, the vehicle control system 7000 may include another control unit not shown. In the above description, some or all of the functions performed by one of the control units may be assigned to another control unit. In other words, as long as information is transmitted and received via the communication network 7010, predetermined arithmetic processing may be performed by one of the control units. Similarly, a sensor or device connected to one of the control units may be connected to another control unit, and multiple control units may transmit and receive detection information to and from each other via the communication network 7010.

[0152] A computer program for realizing each function of the ToF sensor 1 according to this embodiment described with reference to FIG. 1 can be implemented in any control unit or the like. A computer-readable recording medium storing such a computer program can also be provided. Examples of the recording medium include a magnetic disk, an optical disk, a magneto-optical disk, and a flash memory. The computer program may also be distributed, for example, via a network without using a recording medium.

[0153] In the vehicle control system 7000 described above, the ToF sensor 1 according to this embodiment described using Fig. 1 can be applied to the integrated control unit 7600 of the application example shown in Fig. 16. For example, the control unit 11, the calculation unit 15, and the external I / F 19 of the ToF sensor 1 correspond to the microcomputer 7610, the storage unit 7690, and the in-vehicle network I / F 7680 of the integrated control unit 7600. However, without being limited thereto, the vehicle control system 7000 may correspond to the host 80 in Fig. 1.

[0154] Furthermore, at least some of the components of the ToF sensor 1 according to the present embodiment described with reference to Fig. 1 may be implemented in a module (for example, an integrated circuit module configured on a single die) for the integrated control unit 7600 shown in Fig. 16. Alternatively, the ToF sensor 1 according to the present embodiment described with reference to Fig. 1 may be implemented by a plurality of control units of the vehicle control system 7000 shown in Fig. 16.

[0155] <4. Supplementary Notes> The present technology may also be configured as follows. (1) A distance measuring device comprising: a light emitting unit that switchably emits a first light and a second light that is weaker than the first light; and a light receiving unit having a first light receiving region including a plurality of pixels that detect reflected light of the first light, and a second light receiving region that is different from the first light receiving region and includes a plurality of pixels that detect reflected light of the second light. (2) The distance measuring device described in (1), in which the emission timings of the first light and the second light are different, and the light receiving unit uses the first light receiving region as a reading region that reads signals from each of the plurality of pixels in accordance with the emission timing of the first light, and uses the second light receiving region as the reading region in accordance with the emission timing of the second light. (3) The distance measuring device described in (2), in which a first reading period in which the first light receiving region is the reading region and a second reading period in which the second light receiving region is the reading region do not overlap in time. (4) The distance measuring device according to (2) or (3), wherein a first reading period in which the first light receiving area is the reading area and a second reading period in which the second light receiving area is the reading area are the same. (5) The distance measuring device according to any one of (1) to (4), wherein the emission periods of the first light and the second light are the same. (6) The distance measuring device according to any one of (1) to (4), wherein the emission period of the first light is longer than the emission period of the second light. (7) The distance measuring device according to any one of (1) to (6), wherein the first light receiving area and the second light receiving area have the same size. (8) The distance measuring device according to any one of (1) to (7), wherein the first light receiving area and the second light receiving area have the same shape. (9) The distance measuring device according to any one of (1) to (8), wherein the first light receiving area and the second light receiving area are separated by a predetermined distance. (10) The distance measuring device according to any one of (1) to (9), wherein the light emitting unit switches between the first light and the second light for each image line.(11) The ranging device according to (10), wherein an image line period of the first light is longer than an image line period of the second light. (12) The ranging device according to any one of (1) to (9), wherein the light emitting unit switches between the first light and the second light for each image frame. (13) The ranging device according to (12), wherein a frame period of the first light is longer than a frame period of the second light. (14) The ranging device according to any one of (1) to (13), further comprising a processing unit that compares a first ranging image obtained from the reflected light of the first light with a second ranging image obtained from the reflected light of the second light, and detects the occurrence of flare in the first ranging image or removes flare from the first ranging image. (15) The ranging device according to (14), wherein the processing unit compares the sizes of a first detection area in the first ranging image and a second detection area in the second ranging image to detect the occurrence of flare in the first ranging image, and removes the flare from the first ranging image when the occurrence of flare in the first ranging image is detected. (16) The ranging device according to (14) or (15), wherein the processing unit leaves only a region of the first detection area in the first ranging image that corresponds to the second detection area in the second ranging image, and removes the flare from the first ranging image. (17) The ranging device according to any one of (1) to (16), wherein the light emitting unit has a light source unit that switchably emits the first light and the second light, and the light source unit has: a first light source that emits the first light; and a second light source that emits the second light. (18) The distance measuring device according to (17), wherein the emission intensity of the second light source is weaker than the emission intensity of the first light source. (19) The distance measuring device according to (17), wherein the light source unit further includes an attenuation unit provided on an optical path of the second light emitted from the second light source and attenuating the second light. (20) The distance measuring device according to any one of (17) to (19), wherein the light emitting unit includes a plurality of the light source units, and wherein each of the first light receiving region and the second light receiving region is divided into a plurality of regions according to the number of the light source units.(21) A distance measuring method including: a light emitting unit emitting a first light; a light receiving unit receiving reflected light of the first light in a first light receiving area; the light emitting unit emitting a second light weaker than the first light; and the light receiving unit receiving reflected light of the second light in a second light receiving area different from the first light receiving area. (22) An electronic device including the distance measuring device according to any one of (1) to (20). (23) A moving object including the distance measuring device according to any one of (1) to (20). (24) A distance measuring method using the distance measuring device according to any one of (1) to (20).

[0156] 1 ToF sensor 11 Control unit 13 Light emitting unit 13a Laser unit 13a1 Laser diode 13a2 Laser diode 13a3 Light emitting substrate 13a4 Neutral density filter 13b Laser unit 13c Laser unit 13d Laser unit 13e Laser unit 13f Laser unit 13g Laser unit 13h Laser unit 14 Light receiving unit 14a SPAD area 14b SPAD area 14c SPAD area 14d SPAD area 14e SPAD area 14f SPAD area 14g SPAD area 14h SPAD area 15 Arithmetic unit 19 External I / F (interface) 20 SPAD pixel 21 Photodiode 22 Readout circuit 23 Quench resistor 24 Select transistor 25 Digital converter 26 Inverter 27 Buffer 30 Macro pixel 40 SPAD adder 41 Pulse shaping unit 42 Light-receiving number counter 80 Host 90 Object 131 Light source 132 Collimator lens 133 Mirror 134 Driver 135 Scanner 141 SPAD array 142 SPAD array used 143 Timing control circuit 144 Driver circuit 145 Output circuit 146 Light-receiving lens 251 Resistor 252 NMOS transistor 261 PMOS transistor 262 NMOS transistor F1 Detection area F2 Detection area G1 Range-finding image G2 Range-finding image G3 Range-finding image L Distance L1 Laser light L1a Laser light L1b Laser light L2 Reflected light N1 Connection point N2 Connection point N3 Connection point R1 First light-receiving area R2 Second light receiving region

Claims

1. A distance measuring device comprising: a light emitting unit that selectively emits a first light and a second light that is weaker than the first light; a light receiving unit that has a first light receiving area including a plurality of pixels that detect reflected light of the first light, and a second light receiving area that is different from the first light receiving area and includes a plurality of pixels that detect reflected light of the second light.

2. The distance measuring device of claim 1, wherein the emission timings of the first light and the second light are different, and the light receiving unit uses the first light receiving area as a reading area for reading signals from each of the plurality of pixels in accordance with the emission timing of the first light, and uses the second light receiving area as the reading area in accordance with the emission timing of the second light.

3. The distance measuring device according to claim 2, wherein a first reading period in which the first light receiving region is the reading region and a second reading period in which the second light receiving region is the reading region do not overlap in time.

4. The distance measuring device according to claim 2, wherein a first reading period in which the first light receiving region is the reading region and a second reading period in which the second light receiving region is the reading region are the same.

5. The distance measuring device according to claim 1, wherein the light emission periods of the first light and the second light are the same.

6. The distance measuring device according to claim 1, wherein the emission period of the first light is longer than the emission period of the second light.

7. The distance measuring device according to claim 1, wherein the first light receiving area and the second light receiving area are the same size.

8. The distance measuring device according to claim 1, wherein the first light receiving area and the second light receiving area have the same shape.

9. The distance measuring device according to claim 1, wherein the first light receiving area and the second light receiving area are separated by a predetermined distance.

10. The distance measuring device according to claim 1, wherein the light emitting unit switches between the first light and the second light for each image line.

11. The distance measuring device according to claim 10, wherein the image line period of the first light is longer than the image line period of the second light.

12. The distance measuring device according to claim 1, wherein the light emitting unit switches between the first light and the second light for each image frame.

13. The distance measuring device according to claim 12, wherein the frame period of the first light is longer than the frame period of the second light.

14. The distance measuring device according to claim 1, further comprising a processing unit that compares a first distance measuring image obtained from the reflected light of the first light with a second distance measuring image obtained from the reflected light of the second light, and detects the occurrence of flare in the first distance measuring image or removes flare from the first distance measuring image.

15. The distance measuring device of claim 14, wherein the processing unit compares the sizes of a first detection area in the first distance measuring image and a second detection area in the second distance measuring image, detects the occurrence of flare in the first distance measuring image, and, if the occurrence of flare in the first distance measuring image is detected, removes the flare from the first distance measuring image.

16. The distance measuring device according to claim 14, wherein the processing unit removes the flare from the first distance measuring image, leaving only a region of the first detection region of the first distance measuring image that corresponds to the second detection region of the second distance measuring image.

17. A distance measuring device as described in claim 1, wherein the light emitting unit has a light source unit that switches between emitting the first light and the second light, and the light source unit has: a first light source that emits the first light; and a second light source that emits the second light.

18. The distance measuring device according to claim 17, wherein the emission intensity of the second light source is weaker than the emission intensity of the first light source.

19. The distance measuring device according to claim 17, wherein the light source section further comprises an attenuation section provided on the optical path of the second light emitted from the second light source and attenuating the second light.

20. A distance measurement method comprising: an emitting unit emitting a first light; a light receiving unit receiving reflected light of the first light in a first light receiving area; the emitting unit emitting a second light weaker than the first light; and the light receiving unit receiving reflected light of the second light in a second light receiving area different from the first light receiving area.

Images