WO2021161858A1 - Rangefinder and rangefinding method - Google Patents

Abstract

A rangefinder (1) of the present invention is provided with a light-emitting unit (13), a light-receiving unit (14), and a control unit (11). The light-emitting unit (13) emits light (L1) that scans a specific rangefinding area. The light-receiving unit (14) has multiple light-receiving elements (20) which are two-dimensionally arranged and receive reflected light (L2) resulting from the light emitted from light-emitting unit (13) having been reflected. The control unit (11) controls rangefinding by reading the detection signals from, among multiple light-receiving elements, the light-receiving elements that are at positions corresponding to the scanning position of the light-emitting unit (13).

Description

Distance measuring device and distance measuring method

This disclosure relates to a distance measuring device and a distance measuring method.

Conventionally, there is a distance measuring device such as LiDAR (Light Detection and Ringing) that measures the distance to an object that is a reflector by emitting laser light to the outside and receiving the reflected light. This type of ranging device is composed of a light emitting unit that emits a plurality of laser beams and one light receiving element that receives the laser beams (see, for example, Patent Document 1).

Special Table 2019-507340 Gazette

However, in the prior art, there is room for improvement in that the light from the light emitting portion is efficiently received by the light receiving portion.

Therefore, in the present disclosure, a distance measuring device and a distance measuring method capable of efficiently receiving light are proposed.

In order to solve the above problems, the ranging device of one form according to the present disclosure includes a light emitting unit, a light receiving unit, and a control unit. The light emitting unit emits light that scans a predetermined ranging range. In the light receiving unit, a plurality of light receiving elements that receive the reflected light reflected by the light emitting unit are arranged two-dimensionally. The control unit controls to read a detection signal from the light receiving element at a position corresponding to the scanning position of the light emitting unit among the plurality of light receiving elements and measure the distance.

It is a block diagram which shows the schematic configuration example of the ToF sensor as a distance measuring device which concerns on this embodiment. It is a figure for demonstrating the optical system of the ToF sensor which concerns on this embodiment. It is a block diagram which shows the schematic structure example of the light receiving part which concerns on this embodiment. It is a schematic diagram which shows the schematic structure example of the SPAD array which concerns on this embodiment. It is a circuit diagram which shows the schematic structure example of the SPAD pixel which concerns on this embodiment. It is a block diagram which shows the more detailed composition example of the SPAD addition part which concerns on this embodiment. It is a figure which shows the scanning timing of each of a light emitting part and a light receiving part. It is a figure which shows the scanning timing of each of the light emitting part and the light receiving part which concerns on a modification. It is a figure which shows the scanning timing of each of the light emitting part and the light receiving part which concerns on a modification. It is a figure which shows the scanning timing of each of the light emitting part and the light receiving part which concerns on a modification. It is a figure which shows the scanning timing of each of the light emitting part and the light receiving part which concerns on a modification. It is a figure explaining the abnormality detection method of a light emitting part. It is a figure explaining the abnormality detection method of a light emitting part. It is a figure which shows the discrimination process of reflected light and disturbance light. It is a figure which shows the discrimination process of reflected light and disturbance light. It is a figure which shows the scanning direction of the light emitting part which concerns on a modification. It is a figure which shows the scanning direction of the light receiving part which concerns on the modification. It is a flowchart which shows the processing procedure of the whole processing which ToF sensor executes. It is a flowchart which shows the processing procedure of the abnormality detection processing executed by the ToF sensor. It is a flowchart which shows the processing procedure of the detection process executed by a ToF sensor. It is a block diagram which shows the schematic structure example of the vehicle control system which is an example of the mobile body control system to which the technique which concerns on this disclosure can be applied. It is a figure which shows the example of the installation position of the image pickup unit and the vehicle exterior information detection unit.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In each of the following embodiments, the same parts are designated by the same reference numerals, so that duplicate description will be omitted.

Further, in the present specification and drawings, a plurality of components having substantially the same functional configuration may be distinguished by adding different numbers after the same reference numerals. However, if it is not necessary to distinguish each of the plurality of components having substantially the same functional configuration, only the same reference numerals are given.

The explanations will be given in the following order.
1. 1. Embodiment 1.1 Distance measuring device (ToF sensor)
1.2 Optical system 1.3 Light receiving part 1.4 SPAD array 1.5 SPAD pixel 1.6 Schematic operation example of SPAD pixel 1.7 SPAD adding part 1.8 Sampling cycle 1.9 Scanning of light emitting part and light receiving part Timing 1.10 Abnormality detection of light emitting part 1.11 Discrimination between reflected light and ambient light 2. Application example 3. summary

1. 1. Embodiment First, the embodiment will be described in detail with reference to the drawings below.

1.1 Distance measuring device (ToF sensor)
FIG. 1 is a block diagram showing a schematic configuration example of a ToF sensor as a distance measuring device according to the present embodiment. 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 interface (I / F) 19.

The control unit 11 is composed of, for example, an information processing device such as a CPU (Central Processing Unit), and controls each unit of the ToF sensor 1. Twice

The external I / F19 is, for example, a communication network compliant with any standard such as wireless LAN (Local Area Network), wired LAN, CAN (Controller Area Network), LIN (Local Interconnect Network), FlexRay (registered trademark), etc. It may be a communication adapter for establishing communication with an external host 80 via. Twice

Here, the host 80 may be, for example, an ECU (Engine Control Unit) mounted on the automobile or the like when the ToF sensor 1 is mounted on the automobile or the like. When the ToF sensor 1 is mounted on an autonomous mobile robot such as a domestic pet robot or an autonomous mobile body such as a robot vacuum cleaner, an unmanned aerial vehicle, or a follow-up transport robot, the host 80 controls the autonomous mobile body. It may be a control device or the like. Twice

The light emitting unit 13 includes, for example, one or a plurality of semiconductor laser diodes as a light source, and emits pulsed laser light L1 having a predetermined time width at a predetermined period (also referred to as a light emitting cycle). Further, the light emitting unit 13 emits the laser beam L1 having a time width of 1 ns (nanosecond) in a period of, for example, 1 MHz (megahertz). For example, when an object 90 exists within the ranging range, the laser beam L1 emitted from the light emitting unit 13 is reflected by the object 90 and is incident on the light receiving unit 14 as reflected light L2. Twice

The details of the light receiving unit 14 will be described later, but for example, the number of SPAD pixels that include a plurality of SPAD pixels arranged in a two-dimensional grid and detect the incident of photons after the light emitting unit 13 emits light (hereinafter, the number of detections). Information about (for example, corresponding to the number of detection signals described later) is output. For example, the light receiving unit 14 detects the incident of photons at a predetermined sampling cycle for one light emission of the light emitting unit 13 and outputs the detected number. Twice

The calculation unit 15 aggregates the number of detections output from the light receiving unit 14 for each of a plurality of SPAD pixels (for example, corresponding to one or a plurality of macro pixels described later), and based on the pixel value obtained by the aggregation, the calculation unit 15 is used. Create a histogram with the horizontal axis as the flight time and the vertical axis as the cumulative pixel value. For example, the calculation unit 15 repeatedly executes the calculation of the pixel value by totaling the number of detections at a predetermined sampling frequency for one light emission of the light emitting unit 13 for a plurality of light emissiones of the light emitting unit 13. As a result, a histogram is created in which the horizontal axis (histogram bin) is the sampling cycle corresponding to the flight time, and the vertical axis is the cumulative pixel value obtained by accumulating the pixel values obtained in each sampling cycle.

Further, the calculation unit 15 applies a predetermined filter process to the created histogram, and then specifies the flight time when the cumulative pixel value peaks from the filtered histogram. Then, the calculation unit 15 calculates the distance from the ToF sensor 1 or the device on which the ToF sensor 1 is mounted to the object 90 existing in the distance measuring range based on the specified flight time. The distance information calculated by the calculation unit 15 may be output to the host 80 or the like via the external I / F 19, for example.

1.2 Optical system FIG. 2 is a diagram for explaining an optical system of the ToF sensor according to the present embodiment. Note that FIG. 2 illustrates a so-called scan-type optical system that scans the angle of view of the light receiving unit 14 in the horizontal direction, but the present invention is not limited to this, and for example, the angle of view of the light receiving unit 14 is fixed, so-called. It is also possible to use a flash type ToF sensor.

As shown in FIG. 2, the ToF sensor 1 includes a light source 131, a collimator lens 132, a half mirror 133, a galvano mirror 135, a light receiving lens 146, and a SPAD array 141 as an optical system. The light source 131, the collimator lens 132, the half mirror 133, and the galvano mirror 135 are included in the light emitting unit 13 in FIG. 1, for example. Further, the light receiving lens 146 and the SPAD array 141 are included in the light receiving unit 14 in FIG. 1, for example.

In the configuration shown in FIG. 2, the laser beam L1 emitted from the light source 131 is converted into rectangular parallel light whose cross-sectional intensity spectrum is long in the vertical direction by the collimator lens 132, and then incident on the half mirror 133. The half mirror 133 reflects a part of the incident laser beam L1. The laser beam L1 reflected by the half mirror 133 is incident on the galvano mirror 135. The galvanometer mirror 135 vibrates in the horizontal direction with a predetermined rotation axis as the vibration center by, for example, a drive unit 134 that operates based on control from the control unit 11. As a result, the laser beam L1 is horizontally scanned so that the angle of view SR of the laser beam L1 reflected by the galvano mirror 135 reciprocates in the ranging range AR in the horizontal direction. A MEMS (Micro Electro Mechanical System), a micro motor, or the like can be used for the drive unit 134.

The laser beam L1 reflected by the galvano mirror 135 is reflected by the object 90 existing in the ranging range AR, and is incident on the galvano mirror 135 as reflected light L2. A part of the reflected light L2 incident on the galvano mirror 135 passes through the half mirror 133 and is incident on the light receiving lens 146, whereby the image is formed on the specific SPAD array 142 in the SPAD array 141. The SPAD array 142 may be the whole or a part of the SPAD array 141.

1.3 Light-receiving part FIG. 3 is a block diagram showing a schematic configuration example of the light-receiving part according to the present embodiment. 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.

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

In this embodiment, the reflected light L2 is detected by using all or a part of the SPAD array 141. The region used in the SPAD array 141 (SPAD array 142) is a rectangular shape long in the vertical direction, which is the same as the image of the reflected light L2 imaged on the SPAD array 141 when the entire laser light L1 is reflected as the reflected light L2. It may be there. However, the present invention is not limited to this, and various modifications may be made, such as a region larger or smaller than the image of the reflected light L2 imaged on the SPAD array 141.

The drive circuit 144 includes a shift register, an address decoder, and the like, and drives each SPAD pixel 20 of the SPAD array 141 at the same time for all pixels, in a column unit, or the like. Therefore, the drive circuit 144 applies at least a circuit that applies a quench voltage V_QCH described later to each SPAD pixel 20 in the selection row in the SPAD array 141, and a selection control voltage V_SEL described later to each SPAD pixel 20 in the selection row. Includes a circuit to apply. Then, the drive circuit 144 selects the SPAD pixel 20 used for detecting the incident of photons in column units by applying the selection control voltage V_SEL to the pixel drive line LD corresponding to the row to be read.

The signal (referred to as a detection signal) V_OUT output from each SPAD pixel 20 in the row selected and scanned by the drive circuit 144 is input to the output circuit 145 through each of the output signal lines LS. The output circuit 145 outputs the detection signal V_OUT input from each SPAD pixel 20 to the SPAD addition unit 40 provided for each macro pixel described later.

The timing control circuit 143 includes a timing generator and the like that generate 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.

1.4 SPAD Array FIG. 4 is a schematic diagram showing a schematic configuration example of the SPAD array according to the present embodiment. As shown in FIG. 4, the SPAD array 142 includes, for example, a configuration in which a plurality of SPAD pixels 20 are arranged in a two-dimensional grid pattern. The plurality of SPAD pixels 20 are grouped into a plurality of macro pixels 30 composed of a predetermined number of SPAD pixels 20 arranged in the row and / or column direction. The shape of the region connecting the outer edges of the SPAD pixels 20 located on the outermost periphery of each macro pixel 30 has a predetermined shape (for example, a rectangle).

The SPAD array 142 is composed of, for example, a plurality of macro pixels 30 arranged in the vertical direction (corresponding to the column direction). In the present embodiment, the SPAD array 142 is divided into, for example, a plurality of regions (hereinafter, referred to as SPAD regions) in the vertical direction. In the example shown in FIG. 4, the SPAD array 142 is divided into four SPAD regions 142-1 to 142-4. The lowest SPAD region 142-1 corresponds to, for example, the lowest 1/4 region in the angle of view SR of the SPAD array 142, and the SPAD region 142-2 above it corresponds to, for example, the lower in the angle of view SR. The SPAD region 142-3 above it corresponds to the second 1/4 region from the bottom, for example, the third 1/4 region from the bottom in the angle of view SR, and the highest SPAD region 142-4 For example, it corresponds to the highest 1/4 area in the angle of view SR.

1.5 SPAD Pixel FIG. 5 is a circuit diagram showing a schematic configuration example of the SPAD pixel according to the present embodiment. As shown in FIG. 5, the SPAD pixel 20 includes a photodiode 21 as a light receiving element and a readout circuit 22 for detecting that a photon is incident on the photodiode 21. The photodiode 21 generates an avalanche current when photons are incident in a state where a reverse bias voltage V_SPAD equal to or higher than the breakdown voltage (breakdown voltage) is applied between the anode and the cathode.

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 composed of, for example, an N-type MOSFET (Metal Oxide Semiconductor Field Effect Transistor, hereinafter referred to as an NMOS transistor), its drain is connected to the anode of the photodiode 21, and its source is via the selection transistor 24. It is grounded. Further, a preset quench voltage V_QCH for allowing the NMOS transistor to act as a quench resistor is applied to the gate of the NMOS transistor constituting the quench resistor 23 from the drive circuit 144 via the pixel drive line LD. ..

In this embodiment, the photodiode 21 is SPAD. The SPAD is an avalanche photodiode that operates in Geiger mode when a reverse bias voltage equal to or higher than the breakdown voltage (breakdown voltage) is applied between its anode and cathode, and can detect the incident of one photon.

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 its source is grounded. Further, 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.

The inverter 26 includes a P-type MOSFET (hereinafter referred to as a MPa transistor) 261 and an NMOS transistor 262. The drain of the NMOS transistor 261 is connected to the power supply voltage VDD, and the source of the epitaxial transistor 261 is connected to the drain of the NMOS transistor 262. The drain of the NMOS transistor 262 is connected to the source of the NMOS transistor 261, and the source is grounded. A voltage at the connection point N2 between the resistor 251 and the drain of the NMOS transistor 252 is applied to the gate of the MOSFET transistor 261 and the gate of the NMOS transistor 262, respectively. The output of the inverter 26 is input to the buffer 27.

The buffer 27 is a circuit for impedance conversion, and when an output signal is input from the inverter 26, the input output signal is impedance-converted and output as a detection signal V_OUT.

The selection transistor 24 is, for example, an NMOS transistor, and its drain is connected to the source of the NMOS transistor constituting the quench resistor 23, and the source is grounded. The selection transistor 24 is connected to the drive circuit 144, and when the 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. ..

1.6 Schematic operation example of the SPAD pixel The readout circuit 22 illustrated in FIG. 5 operates as follows, for example. That is, first, during the period in which the selective control voltage V_SEL is applied from the drive circuit 144 to the selective transistor 24 and the selective transistor 24 is in the ON state, the photodiode 21 has a reverse bias voltage V_SPAD equal to or higher than the breakdown voltage (breakdown voltage). Is applied. As a result, the operation of the photodiode 21 is permitted.

On the other hand, since the selective control voltage V_SEL is not applied to the selection transistor 24 from the drive circuit 144 and the reverse bias voltage V_SPAD is not applied to the photodiode 21 while the selection transistor 24 is in the off state, the photodiode 21 Operation is prohibited.

If photons are incident on the photodiode 21 while the selection transistor 24 is on, an avalanche current is generated in the photodiode 21. As a result, an avalanche current flows through the quench resistor 23, and the voltage at the connection point N1 rises. When the voltage at the connection point N1 becomes higher than the on voltage of the NMOS transistor 252, the NMOS transistor 252 is turned on and the voltage at the connection point N2 changes from the power supply voltage VDD to 0V. Then, when the voltage at the connection point N2 changes from the power supply voltage VDD to 0V, the NMOS transistor 261 changes from the off state to the on state, the NMOS transistor 262 changes from the on state to the off state, and the voltage at the connection point N3 changes to 0V. Changes from to the power supply voltage VDD. As a result, the high level detection signal V_OUT is output from the buffer 27.

After that, when the voltage at the connection point N1 continues to rise, the voltage applied between the anode and the cathode of the photodiode 21 becomes smaller than the breakdown voltage, whereby the avalanche current stops and the connection point N1 The voltage drops. Then, when the voltage at the connection point N1 becomes lower than the on voltage of the NMOS transistor 452, the NMOS transistor 452 is turned off and the output of the detection signal V_OUT from the buffer 27 is stopped (low level).

In this way, in the readout circuit 22, the avalanche current is generated when the photon is incident on the photodiode 21, and the avalanche current is stopped and the NMOS transistor 452 is turned off from the timing when the NMOS transistor 452 is turned on. A high-level detection signal V_OUT is output until the timing becomes. The output detection signal V_OUT is input to the SPAD addition unit 40 for each macro pixel 30 via the output circuit 145. Therefore, the detection signal V_OUT of the number (detection number) of the SPAD pixels 20 in which the incident of photons is detected among the plurality of SPAD pixels 20 constituting one macro pixel 30 is input to each SPAD addition unit 40. ..

1.7 SPAD addition unit FIG. 6 is a block diagram showing a more detailed configuration example of the SPAD addition unit according to the present embodiment. The SPAD addition unit 40 may have a configuration included in the light receiving unit 14 or a configuration included in the calculation unit 15.

As shown in FIG. 6, the SPAD addition unit 40 includes, for example, a pulse shaping unit 41 and a light receiving number counting unit 42.

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 having a time width corresponding to the operating clock of the SPAD adding unit 40.

The light receiving number counting unit 42 counts the detection signal V_OUT input from the corresponding macro pixel 30 for each sampling cycle, thereby counting the number (detection number) of the SPAD pixels 20 in which the incident of photons is detected for each sampling cycle. It counts and outputs this count value as a pixel value of the macro pixel 30.

1.8 Sampling cycle Here, the sampling cycle is a cycle for measuring the time (flight time) from the emission of the laser beam L1 by the light emitting unit 13 to the detection of the incident of photons by the light receiving unit 14. A period shorter than the light emission cycle of the light emitting unit 13 is set in this sampling cycle. For example, by shortening the sampling period, it is possible to calculate the flight time of the 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 is possible to calculate the distance to the object 90 with a higher ranging resolution.

For example, assuming that the flight time until the light emitting unit 13 emits the laser light L1, the laser light L1 is reflected by the object 90, and the reflected light L2 is incident on the light receiving unit 14, the speed of light C is constant ( Since C≈300,000,000 m (meters) / s (seconds), the distance L to the object 90 can be calculated by the following equation (1).
L = C × t / 2 (1)

Therefore, if the sampling frequency is 1 GHz, the sampling period is 1 ns (nanoseconds). In that case, one sampling period corresponds to 15 cm (centimeter). This indicates that the ranging resolution is 15 cm when the sampling frequency is 1 GHz. Further, when the sampling frequency is doubled to 2 GHz, the sampling period is 0.5 ns (nanoseconds), so one sampling period corresponds to 7.5 cm (centimeters). This indicates that the ranging resolution can be halved when the sampling frequency is doubled. By increasing the sampling frequency and shortening the sampling period in this way, it is possible to calculate the distance to the object 90 more accurately.

1.9 Scanning timing of the light emitting unit and the light receiving unit Here, the scanning timings of the light emitting unit 13 and the light receiving unit 14 will be described with reference to FIG. 7. FIG. 7 is a diagram showing scanning timings of the light emitting unit 13 and the light receiving unit 14, respectively. Note that FIG. 7 shows an example in which the ranging range AR (see FIG. 2) is scanned three times.

The control unit 11 controls to read a detection signal from the light receiving element at a position corresponding to the scanning position of the light emitting unit 13 among the plurality of light receiving elements and measure the distance. Specifically, the control unit 11 reads out the detection signal of the SPAD pixel 20 included in the SPAD array 142 according to the scanning position of the light emitting unit 13 in the SPAD array 141.

More specifically, as shown in FIG. 7, at time t1, the control unit 11 starts scanning the laser beam L1 by the light emitting unit 13, and corresponds to the scanning position of the light emitting unit 13 in the SPAD array 141. Read the SPAD array 142 at the desired position. For example, when the light emitting unit 13 scans the ranging range AR from the left end to the right end, the position to be read out at time t1 is the first SPAD array 142 on the left end of the SPAD array 141. That is, the control unit 11 aligns the scanning start position (angle) of the light emitting unit 13 with the scanning start position (angle) of the light receiving unit 14.

Then, as shown in FIG. 7, the scanning of the light of the light emitting unit 13 is linear, while the scanning of the reading of the light receiving unit 14 is stepwise. That is, the control unit 11 gradually changes the scanning position of the light emitting unit 13 and changes the scanning position (reading position) of the light receiving unit 14 in predetermined angle units. Then, in the example shown in FIG. 7, the control unit 11 reads out the first SPAD array 142 from the time t1 to the time t2.

Then, at time t2, the control unit 11 reads out the SPAD array 142 at the position corresponding to the scanning position of the light emitting unit 13, that is, the second SPAD array 142 located to the right of the leftmost SPAD array 142. After that, similarly, the control unit 11 reads out the SPAD array 142 on the right side at each timing of time t3, time t4, time t5, and time t6, and reads out the rightmost SPAD array 142 at time t6. ..

In this way, the control unit 11 reads out the SPAD array 142 at a position corresponding to the scanning position of the light emitting unit 13 among the light receiving units 14 in which the SPAD pixels 20 are arranged two-dimensionally, so that the light of the light emitting unit 13 is emitted. Can be efficiently received (read) by the light receiving unit 14.

Although FIG. 7 shows a case where the light emitting unit 13 is scanned linearly, for example, as shown in FIG. 8, the light emitting unit 13 may scan the light in a stepped manner. FIG. 8 is a diagram showing scanning timings of the light emitting unit 13 and the light receiving unit 14 according to the modified example.

As shown in FIG. 8, the control unit 11 steps the scanning of light by the light emitting unit 13. That is, the control unit 11 changes the scanning positions of the light emitting unit 13 and the light receiving unit 14 for each predetermined angle. Specifically, as shown in FIG. 8, the control unit 11 emits light in a state where the scanning position of the light emitting unit 13 is fixed at a predetermined angle during the period from time t1 to time t2.

Further, the control unit 11 reads out the SPAD array 142 at a position corresponding to the scanning position of the light emitting unit 13 from time t1 to time t2.

Then, at time t2, the control unit 11 changes the scanning position of the light emitting unit 13 to the next predetermined angle, and reads out the next (next to the right) SPAD array 142 in the light receiving unit 14.

That is, the control unit 11 makes the scanning position of the light emitting unit 13 step-like according to the scanning of the light receiving unit 14. As a result, the angle of view difference between the light emitting unit 13 and the light receiving unit 14 is eliminated, so that the light of the light emitting unit 13 can be efficiently received by the light receiving unit 14.

Further, the control unit 11 is not limited to the case where the light emitting unit 13 is scanned in a stepped manner, and for example, as shown in FIG. 9, the scanning position of the light receiving unit 14 may be shifted from the scanning position of the light emitting unit 13. .. FIG. 9 is a diagram showing scanning timings of the light emitting unit 13 and the light receiving unit 14 according to the modified example.

As shown in FIG. 9, the control unit 11 reads out the SPAD array 142 at a position deviated by a predetermined deviation angle α with respect to the angle of the light emitting unit 13 that scans linearly. That is, the control unit 11 makes the scanning start position of the light emitting unit 13 different from the scanning start position of the light receiving unit 14 by a deviation angle α. Specifically, as shown in FIG. 9, the control unit 11 starts scanning the light emitting unit 13 from the angle A1 at time t1.

On the other hand, the control unit 11 reads out the SPAD array 142 at the position corresponding to the angle B1 at the time t1. The angle B1 is smaller than the angle A1 by a deviation angle α. More specifically, the deviation angle α is an angle interval of the light receiving unit 14, that is, an angle corresponding to approximately half of the amount of change from the angle B1 to the angle B2.

Then, at the time t2 when the scanning position of the light emitting unit 13 reaches the angle A2, the control unit 11 changes the scanning position of the light receiving unit 14 from the angle B1 to the angle B2 and scans. That is, the control unit 11 changes the scanning position of the light receiving unit 14 by a predetermined angle.

As a result, between the time t1 and the time t2, the deviation between the scanning position of the light emitting unit 13 and the scanning position of the light receiving unit 14 is within the deviation angle α at the maximum, so that the decrease in the light receiving efficiency by the light receiving unit 14 can be suppressed. Can be done.

The scanning timings of the light emitting unit 13 and the light receiving unit 14 shown in FIGS. 7 to 9 are based on the premise that the scanning positions of the light emitting unit 13 and the light receiving unit 14 are substantially parallel, but the scanning positions of the light emitting unit 13 and the light receiving unit 14 are substantially parallel. If they are not parallel, it is necessary to change the scanning timing. This point will be described with reference to FIGS. 10A and 10B.

10A and 10B are diagrams showing scanning timings of the light emitting unit 13 and the light receiving unit 14 according to the modified example. FIG. 10A shows an example in which the scanning position of the laser beam L1 (reflected light L2) of the light emitting unit 13 is not substantially parallel to the scanning position ( SPAD arrays 142a, 142b) of the light receiving unit 14.

Even if either the SPAD array 142a or the SPAD array 142b is read out with respect to the scanning position of the laser beam L1 shown in FIG. 10A, it cannot be said that the light receiving efficiency is high.

Therefore, the control unit 11 divides the SPAD array 142a and the SPAD array 142b into a plurality of regions and reads them out in units of the divided regions. FIG. 10A shows an example in which each of the SPAD arrays 142a and 142b is divided into four SPAD regions 142a-1 to 142a-4 and 142b-1 to 142b-4 (see FIG. 4), but the number of divisions is large. It may be 3 or less or 5 or more.

In FIG. 10A, the two lower SPAD regions 142a-1 to 142a-2 and 142b-1 to 142b-2 are referred to as the first regions 142a-10 and 142b-10, respectively, and the upper two SPAD regions are referred to. 142a-3 to 142a-4 and 142b-3 to 142b-4 are referred to as second regions 142a-20 and 142b-20, respectively.

The control unit 11 shifts the scanning timing between the first region 142a-10, 142b-10 and the second region 142a-20, 142b-20. Specifically, the control unit 11 scans the first region 142a-10 of the SPAD array 142a and the second region 142b-20 of the SPAD array 142b at the same scanning timing.

In other words, the control unit 11 makes the scanning timings different between the first region 142a-10 and the second region 142a-20 in the SPAD array 142a. For example, the control unit 11 may, with respect to the second region 142a-20 of the SPAD array 142a, at the scanning timing before the scanning timing of the first region 142a-10 of the SPAD array 142a and the second region 142b-20 of the SPAD array 142b. Scan.

Further, regarding the first region 142b-10 of the SPAD array 142b, the control unit 11 sets the scanning timing after the scanning timing of the first region 142a-10 of the SPAD array 142a and the second region 142b-20 of the SPAD array 142b. Scan.

More specifically, it will be described with reference to FIG. 10B. FIG. 10B shows the scanning timings of the first region 142-10 and the second region 142-20 in one SPAD array 142.

As shown in FIG. 10B, the control unit 11 starts scanning the laser beam L1 by the light emitting unit 13 at time t1 and scans the first region 142-10 in the SPAD array 142.

Then, the control unit 11 scans the second region 142-20 in the SPAD array 142 at time t2. The time t2 is substantially intermediate between the time t1 and the time t3. Then, at time t3, the control unit 11 moves the scanning position of the first region 142-10 in the SPAD array 142 to the right.

As a result, even when the scanning position of the light L1 of the light emitting unit 13 is not substantially parallel to the SPAD array 142, it is possible to suppress a decrease in the light receiving efficiency of the light receiving unit 14.

1.10 Abnormality detection of the light emitting unit Next, a method of detecting an abnormality of the light emitting unit 13 will be described with reference to FIGS. 11 and 12. 11 and 12 are views for explaining the abnormality detection method of the light emitting unit 13. For example, if scanning is stopped due to a failure of the drive unit 134 of the light emitting unit 13 or the galvano mirror 135, light is emitted only to a specific position in the ranging range AR. In this case, distance measurement cannot be performed, and the laser beam may not meet the class 1 safety standard.

Regarding this point, in the past, an abnormality in the light emitting part was detected by branching the optical path of the light emitting part and incident a part of the light into a dedicated photodetector or the like to monitor whether the light was correctly projected.

However, with the conventional technology, it is difficult to deal with various failure factors of the light emitting part, and since it is necessary to add special parts, there are problems that the cost of the device is increased and the efficiency is decreased.

Therefore, the control unit 11 detects an abnormality such that the scanning of the light emitting unit 13 is stopped. Specifically, the control unit 11 detects an abnormality in the light emitting unit 13 when the cumulative pixel value based on the detection signals for each predetermined number of SPAD pixels 20 output from the light receiving unit 14 is equal to or greater than a predetermined threshold value.

11 and 12 show a histogram generated by the above-mentioned calculation unit 15. Specifically, FIGS. 11 and 12 show a linearized gram of a histogram in which the vertical axis is the cumulative pixel value and the horizontal axis is the time (flight time).

Note that FIG. 11 is a graph when the light emitting unit 13 is normal, and FIG. 12 is a graph when the pulse width of the light emitting unit 13 is widened. As shown in FIG. 11, when the light emitting unit 13 is normal, the peak P1 corresponding to the object 90 (see FIG. 1) which is a reflector appears. The peak P1 has a peak width close to the pulse width of the laser beam L1. However, as shown in FIG. 12, when an abnormality occurs in the light emitting unit 13, the pulse width of the laser beam L1 becomes wider, and the peak width W of the peak P2 inevitably becomes wider.

Focusing on this point, the control unit 11 detects an abnormality in the light emitting unit 13 when the peak width W of the detected peak P2 is equal to or greater than a predetermined threshold value. As a result, the abnormality of the light emitting unit 13 can be detected with high accuracy.

The threshold value of the peak width W is set according to the pulse width of the laser beam L1. That is, when the light emitting unit 13 is normal, the peak width of the peak P1 which is the reflected light L2 and the pulse width of the laser light L1 are substantially the same, so that the peak width W of the peak P2 is the pulse width of the laser light L1. If it is wider than a predetermined value, it is determined that the light emitting unit 13 is abnormal.

Further, since the control unit 11 detects the abnormality of the light emitting unit 13 from the detection signal of the light receiving unit 14 for performing distance measurement, a dedicated photodetector for detecting the laser beam is not required as in the conventional case. Therefore, according to the control unit 11 according to the embodiment, it is possible to detect the abnormality of the light emitting unit 13 with high accuracy at low cost.

The position of the peak width W (cumulative pixel value) may be any position, but for example, abnormality detection is performed by the peak width W of the cumulative pixel value in the threshold value TH (FIG. 13) for peak detection described later. You may go. Alternatively, the abnormality may be detected by the peak width W at the middle (half value) between the peak value and the threshold value TH.

Further, as a method of detecting an abnormality in which scanning of the light emitting unit 13 is stopped, the control unit 11 receives light for each row or column of the light receiving unit 14 in which the light receiving elements (SPAD pixels 20) are arranged two-dimensionally. There is a detection method based on the amount of light received by the element.

Specifically, the control unit 11 has a light receiving light amount (cumulative pixel value) of a specific row or column light receiving element among the light receiving elements arranged two-dimensionally in the row and column directions, which is equal to or higher than a predetermined threshold value. In this case, an abnormality in which scanning of the light emitting unit 13 is stopped is detected. When the scanning direction of the light emitting unit 13 is the horizontal direction (FIG. 2), the control unit 11 detects an abnormality based on the amount of light received by the light receiving element for each row, and the scanning direction of the light emitting unit 13 is vertical. In the case of the direction (FIG. 15), the abnormality is detected based on the amount of light received by the light receiving element for each row. As a result, it is possible to detect an abnormality in which scanning of the light emitting unit 13 is stopped with high accuracy.

1.11 Discrimination between reflected light and ambient light Next, the process of discriminating between the reflected light L2 and the ambient light will be described with reference to FIGS. 13 and 14. 13 and 14 are diagrams showing a process of discriminating between the reflected light L2 and the ambient light. Disturbed light referred to here is light caused by the surrounding environment such as sunlight. When such ambient light is relatively strong, in the above-mentioned histogram, the reflected light L2 may be buried due to the disturbance light, and the distance may not be measured correctly. In particular, when the distance to the object 90 is long and the reflected light L2 with a sufficient amount of light cannot be obtained, accurate distance measurement cannot be performed if the ambient light is strong.

Therefore, the control unit 11 discriminates between the peak corresponding to the reflected light L2 and the peak corresponding to the ambient light based on the histogram generated by the calculation unit 15. Specifically, the control unit 11 detects a peak whose calculated value and peak width satisfy a predetermined condition from a plurality of peaks included in the histogram.

Specifically, as shown in FIG. 13, the control unit 11 first extracts a peak whose cumulative pixel value is equal to or higher than a predetermined threshold value TH from a plurality of peaks included in the histogram. Then, the control unit 11 detects the extracted peak whose peak width is equal to or greater than a predetermined threshold value as the reflected light L2.

For example, the control unit 11 performs detection processing using the peak width Wth of the cumulative pixel value at the threshold value TH. Alternatively, the control unit 11 may perform the detection process using the peak width Wh in the middle (half value) between the peak value and the threshold value TH. Alternatively, the detection process may be performed using both the peak width Wth and the peak width Wh.

In other words, the control unit 11 detects a peak whose cumulative pixel value is less than a predetermined threshold value TH and a peak whose peak widths Wth and Wh are less than a predetermined threshold value as ambient light. In this way, the control unit 11 can discriminate between the reflected light L2 and the disturbance light by using the cumulative pixel value and the peak width of the histogram. That is, the control unit 11 according to the embodiment can discriminate between the ambient light and the reflected light L2 even in an environment where the ambient light is strong, so that the distance can be measured with high accuracy.

Note that the control unit 11 may further extract peaks satisfying a predetermined condition when there are a predetermined number or more of peaks whose cumulative pixel value is equal to or higher than a predetermined threshold value TH. For example, the control unit 11 may extract a predetermined number of peaks in the order of shorter time (closer distance) from the peaks whose cumulative pixel value is equal to or higher than the predetermined threshold value TH. As a result, for example, when applied to an emergency brake of a vehicle, an object 90 having a short distance can be detected at an early stage.

Further, the control unit 11 may extract a predetermined number of peaks in descending order of the cumulative pixel value from the peaks whose cumulative pixel value is equal to or higher than the predetermined threshold value TH. As a result, a peak with high reliability as the reflected light L2 can be extracted, so that the object 90 can be detected (distance measurement) with higher accuracy.

Note that the control unit 11 may discriminate between the reflected light L2 and the ambient light based on the shape of the laser light L1 reflected inside the ToF sensor 1, for example. This point will be described with reference to FIG.

As shown in FIG. 14, the control unit 11 first extracts the peak P1 detected at a short distance of less than a predetermined time as the laser beam L1 due to internal reflection. For example, it may be determined whether or not the peak P1 is the laser beam L1 due to internal reflection based on the peak shape at the time of internal reflection of the laser beam L1 obtained in advance by an experiment or the like.

Then, the control unit 11 detects the peak P2 having a peak shape similar to that of the peak P1 which is the internal reflection of the laser beam L1 as the reflected light L2. Specifically, the control unit 11 detects peaks P2 having similar feature amounts with respect to the peak shape of peak P1. The feature amount is, for example, information about a cumulative pixel value and a peak width which are peak values. For example, the control unit 11 may image the histogram and search for the peak P2 by pattern matching.

In this way, by using the peak shape of the internal reflection peak P1, the reflected light L2 can be detected with high accuracy.

Although the case where the angle of view of the light emitting unit 13 is scanned in the horizontal direction is shown as an example in the above description, the angle of view of the light emitting unit 13 may be scanned in the vertical direction. This point will be described with reference to FIGS. 15 and 16.

FIG. 15 is a diagram showing the scanning direction of the light emitting unit 13 according to the modified example. FIG. 16 is a diagram showing the scanning direction of the light receiving unit 14 according to the modified example.

As shown in FIG. 15, the laser beam L1 emitted from the galvano mirror 135 of the light emitting unit 13 is rectangular parallel light having a long cross-sectional intensity spectrum in the horizontal direction. Then, the galvano mirror 135 vibrates in the vertical direction with a predetermined rotation axis as the vibration center by, for example, a drive unit 134 (see FIG. 2) that operates based on the control from the control unit 11. As a result, the laser beam L1 is vertically scanned so that the angle of view SR of the laser beam L1 reflected by the galvano mirror 135 reciprocates in the ranging range AR in the vertical direction.

The laser beam L1 reflected by the galvano mirror 135 is reflected by the object 90 existing in the ranging range AR, and is incident on the galvano mirror 135 as reflected light L2. The reflected light L2 incident on the galvano mirror 135 is incident on the light receiving unit 14.

Then, as shown in FIG. 16, the light receiving unit 14 reads out the SPAD array 142 in the row corresponding to the scanning position of the light emitting unit 13 among the light receiving elements (SPAD array 141) arranged in two dimensions. As shown in FIG. 16, the region shape of the SPAD array 142 to be read out has a rectangular shape that is long in the horizontal direction, because the laser beam L1 has a rectangular shape that is long in the horizontal direction. Is. Therefore, the SPAD regions 142-1 to 142-4 in which the SPAD array 142 is divided are divided in the horizontal direction and have a rectangular shape that is long in the horizontal direction.

Next, the processing procedure of the processing executed by the ToF sensor 1 will be described with reference to FIGS. 17 to 19. FIG. 17 is a flowchart showing a processing procedure of the entire processing executed by the ToF sensor 1.

As shown in FIG. 17, the light emitting unit 13 emits laser light L1 by emitting light (step S101).

Subsequently, the light receiving unit 14 receives the reflected light L2 reflected by the object 90 by the laser light L1 (step S102).

Subsequently, the calculation unit 15 generates a histogram of the cumulative pixel value based on the detection signal output from the light receiving unit 14 (step S103).

Subsequently, the control unit 11 calculates the distance to the object 90 based on the generated histogram (step S104).

Subsequently, the control unit 11 outputs the calculated distance to the host 80 (step S105), and ends the process.

FIG. 18 is a flowchart showing a processing procedure of the abnormality detection process executed by the ToF sensor 1.

As shown in FIG. 18, the control unit 11 determines whether or not there is a peak whose cumulative pixel value is equal to or greater than a predetermined threshold value among the plurality of peaks included in the histogram (step S201), and the cumulative pixel value is determined. When there is no peak equal to or greater than a predetermined threshold value (step S201: No), the process ends.

When the cumulative pixel value has a peak of a predetermined threshold value or more (step S201: Yes), the control unit 11 determines whether or not there is a peak having a peak width W of the predetermined threshold value or more among the peaks. (Step S202).

When the peak width W has a peak equal to or larger than a predetermined threshold value (step S202: Yes), the control unit 11 detects that the light emitting unit 13 is abnormal (step S203), and ends the process.

On the other hand, the control unit 11 detects that the light emitting unit 13 is normal (step S204) when there is no peak whose peak width W is equal to or greater than a predetermined threshold value (step S202: No).

Subsequently, the control unit 11 detects the reflected light L2 from the peaks whose cumulative pixel value is equal to or higher than a predetermined threshold value (step S205), and ends the process.

FIG. 19 is a flowchart showing a processing procedure of the detection process executed by the ToF sensor 1.

As shown in FIG. 19, the control unit 11 determines whether or not there is a peak whose cumulative pixel value is equal to or greater than a predetermined threshold value (step S301), and when there is no peak whose cumulative pixel value is equal to or greater than a predetermined threshold value. (Step S301: No), the process ends.

When the cumulative pixel value has peaks equal to or greater than a predetermined threshold value (step S301: Yes), the control unit 11 extracts a predetermined number of peaks in a predetermined order (step S302). For example, the control unit 11 extracts a predetermined number of peaks in descending order of cumulative pixel value or in ascending order of time.

Subsequently, the control unit 11 determines whether or not the peaks are valid in a predetermined order (step S303). Whether or not it is effective is, for example, whether or not the shape of the peak and the time of the peak satisfy a predetermined condition.

When the peak is valid (step S303: Yes), the control unit 11 determines whether or not the peak widths Wth and Wh of the peak are equal to or greater than a predetermined threshold value (step S304). The control unit 11 determines whether or not there is a remaining peak when the peak is invalid (step S303: No) or when the peak widths Wth and Wh are less than a predetermined threshold value (step S304: No). Is determined (step S305). That is, among the peaks extracted in step S302, it is determined whether or not there is a peak for which the determination processing of steps S303 to S304 has not been performed.

The control unit 11 returns to step S303 when there is a remaining peak (step S305: Yes), and ends the process when there is no remaining peak (step S305: No).

On the other hand, in step S304, when the peak widths Wth and Wh are equal to or greater than a predetermined threshold value (step S304: Yes), the control unit 11 detects such a peak as reflected light L2 (step S306) and ends the process.

2. Application Examples The technology according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure includes any type of movement such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility, airplanes, drones, ships, robots, construction machines, agricultural machines (tractors), and the like. It may be realized as a device mounted on the body.

FIG. 20 is a block diagram showing a schematic configuration example of a vehicle control system 7000, which is an example of a mobile control system to which the technique according to the present disclosure can be applied. The vehicle control system 7000 includes a plurality of electronic control units connected via the communication network 7010. In the example shown in FIG. 20, the vehicle control system 7000 includes a drive system control unit 7100, a body system control unit 7200, a battery control unit 7300, an external information detection unit 7400, an in-vehicle information detection unit 7500, and an integrated control unit 7600. .. The communication network 7010 connecting these plurality of control units conforms to any standard such as CAN (Controller Area Network), LIN (Local Interconnect Network), LAN (Local Area Network) or FlexRay (registered trademark). It may be an in-vehicle communication network.

Each control unit includes a microcomputer that performs arithmetic processing according to various programs, a storage unit that stores a program executed by the microcomputer or parameters used for various arithmetics, and a drive circuit that drives various control target devices. To be equipped. Each control unit is provided with a network I / F for communicating with other control units via the communication network 7010, and is connected to devices or sensors inside or outside the vehicle by wired communication or wireless communication. A communication I / F for performing communication is provided. In FIG. 20, as the functional configuration of the integrated control unit 7600, the microcomputer 7610, general-purpose communication I / F 7620, dedicated communication I / F 7630, positioning unit 7640, beacon receiving unit 7650, in-vehicle device I / F 7660, audio image output unit 7670, The vehicle-mounted network I / F 7680 and the storage unit 7690 are shown. Other control units also include a microcomputer, a communication I / F, a storage unit, and the like.

The drive system control unit 7100 controls the operation of the device related to the drive system of the vehicle according to various programs. For example, the drive system control unit 7100 provides a driving force generator for generating the driving force of the vehicle such as an internal combustion engine or a driving motor, a driving force transmission mechanism for transmitting the driving force to the wheels, and a steering angle of the vehicle. It functions as a control device such as a steering mechanism for adjusting and a braking device for generating braking force of the vehicle. The drive system control unit 7100 may have a function as a control device such as ABS (Antilock Brake System) or ESC (Electronic Stability Control).

The vehicle condition detection unit 7110 is connected to the drive system control unit 7100. The vehicle state detection unit 7110 may include, for example, a gyro sensor that detects the angular velocity of the axial rotation motion of the vehicle body, an acceleration sensor that detects the acceleration of the vehicle, an accelerator pedal operation amount, a brake pedal operation amount, or steering wheel steering. Includes at least one of the sensors for detecting angular velocity, engine speed, wheel speed, and the like. The drive system control unit 7100 performs arithmetic processing using a signal input from the vehicle state detection unit 7110 to control an internal combustion engine, a drive motor, an electric power steering device, a braking device, and the like.

The body system control unit 7200 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 7200 functions as a keyless entry system, a smart key system, a power window device, or a control device for various lamps such as head lamps, back lamps, brake lamps, blinkers or fog lamps. In this case, the body system control unit 7200 may be input with radio waves transmitted from a portable device that substitutes for the key or signals of various switches. The body system control unit 7200 receives inputs of these radio waves or signals and controls a vehicle door lock device, a power window device, a lamp, and the like.

The battery control unit 7300 controls the secondary battery 7310, which is the power supply source of the drive motor, according to various programs. For example, information such as the battery temperature, the battery output voltage, or the remaining capacity of the battery is input to the battery control unit 7300 from the battery device including the secondary battery 7310. The battery control unit 7300 performs arithmetic processing using these signals, and controls the temperature control of the secondary battery 7310 or the cooling device provided in the battery device.

The vehicle outside information detection unit 7400 detects information outside the vehicle equipped with the vehicle control system 7000. For example, at least one of the image pickup unit 7410 and the vehicle exterior information detection unit 7420 is connected to the vehicle exterior information detection unit 7400. The imaging unit 7410 includes at least one of a ToF (Time Of Flight) camera, a stereo camera, a monocular camera, an infrared camera, and other cameras. The vehicle exterior information detection unit 7420 is used to detect, for example, the current weather or an environmental sensor for detecting the weather, or other vehicles, obstacles, pedestrians, etc. around the vehicle equipped with the vehicle control system 7000. At least one of the ambient information detection sensors is included.

The environmental sensor may be, for example, at least one of a raindrop sensor that detects rainy weather, a fog sensor that detects fog, a sunshine sensor that detects the degree of sunshine, and a snow sensor that detects snowfall. The ambient 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 image pickup unit 7410 and the vehicle exterior information detection unit 7420 may be provided as independent sensors or devices, or may be provided as a device in which a plurality of sensors or devices are integrated.

Here, FIG. 21 is a diagram showing an example of installation positions of the image pickup unit 7410 and the vehicle exterior information detection unit 7420. The imaging units 7910, 7912, 7914, 7916, 7918 are provided, for example, at at least one of the front nose, side mirrors, rear bumpers, back door, and upper part of the windshield of the vehicle interior of the vehicle 7900. The image pickup unit 7910 provided on the front nose and the image pickup section 7918 provided on the upper part of the windshield in the vehicle interior mainly acquire an image in front of the vehicle 7900. The imaging units 7912 and 7914 provided in the side mirrors mainly acquire images of the side of the vehicle 7900. The image pickup unit 7916 provided on the rear bumper or the back door mainly acquires an image of the rear of the vehicle 7900. The imaging unit 7918 provided on the upper part of the windshield in the vehicle interior is mainly used for detecting a preceding vehicle, a pedestrian, an obstacle, a traffic light, a traffic sign, a lane, or the like.

Note that FIG. 21 shows an example of the shooting range of each of the imaging units 7910, 7912, 7914, 7916. The imaging range a indicates the imaging range of the imaging unit 7910 provided on the front nose, the imaging ranges b and c indicate the imaging ranges of the imaging units 7912 and 7914 provided on the side mirrors, respectively, and the imaging range d indicates the imaging range d. The imaging range of the imaging unit 7916 provided on the rear bumper or the back door is shown. For example, by superimposing the image data captured by the imaging units 7910, 7912, 7914, 7916, a bird's-eye view image of the vehicle 7900 as viewed from above can be obtained.

The vehicle exterior information detection units 7920, 7922, 7924, 7926, 7928, 7930 provided on the front, rear, side, corners of the vehicle 7900 and the upper part of the windshield in the vehicle interior may be, for example, an ultrasonic sensor or a radar device. The vehicle exterior information detection units 7920, 7926, 7930 provided on the front nose, rear bumper, back door, and upper part of the windshield in the vehicle interior of the vehicle 7900 may be, for example, a lidar device. These out-of-vehicle information detection units 7920 to 7930 are mainly used for detecting a preceding vehicle, a pedestrian, an obstacle, or the like.

Return to Fig. 20 and continue the explanation. The vehicle outside information detection unit 7400 causes the image pickup unit 7410 to capture an image of the outside of the vehicle and receives the captured image data. Further, the vehicle exterior information detection unit 7400 receives detection information from the connected vehicle exterior information detection unit 7420. When the vehicle exterior information detection unit 7420 is an ultrasonic sensor, a radar device, or a lidar device, the vehicle exterior information detection unit 7400 transmits ultrasonic waves, electromagnetic waves, or the like, and receives received reflected wave information. The vehicle exterior information detection unit 7400 may perform object detection processing or distance detection processing such as a person, a vehicle, an obstacle, a sign, or a character on a road surface based on the received information. The vehicle exterior information detection unit 7400 may perform an environment recognition process for recognizing rainfall, fog, road surface conditions, etc., based on the received information. The vehicle outside information detection unit 7400 may calculate the distance to an object outside the vehicle based on the received information.

Further, the vehicle exterior information detection unit 7400 may perform image recognition processing or distance detection processing for recognizing a person, a vehicle, an obstacle, a sign, a character on the road surface, or the like based on the received image data. The vehicle exterior information detection unit 7400 performs processing such as distortion correction or alignment on the received image data, and synthesizes the image data captured by different imaging units 7410 to generate a bird's-eye view image or a panoramic image. May be good. The vehicle exterior information detection unit 7400 may perform the viewpoint conversion process using the image data captured by different imaging units 7410.

The in-vehicle information detection unit 7500 detects the in-vehicle information. For example, a driver state detection unit 7510 that detects the driver's state is connected to the in-vehicle information detection unit 7500. The driver state detection unit 7510 may include a camera that captures the driver, a biosensor that detects the driver's biological information, a microphone that collects sound in the vehicle interior, and the like. The biosensor is provided on, for example, the seat surface or the steering wheel, and detects the biometric information of the passenger sitting on the seat or the driver holding the steering wheel. The in-vehicle information detection unit 7500 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 7510, and may determine whether the driver is dozing or not. You may. The in-vehicle information detection unit 7500 may perform processing such as noise canceling processing on the collected audio signal.

The integrated control unit 7600 controls the overall operation in 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 is realized by a device such as a touch panel, a button, a microphone, a switch or a lever, which can be input-operated by a passenger. Data obtained by recognizing the voice input by the microphone may be input to the integrated control unit 7600. The input unit 7800 may be, for example, a remote control device using infrared rays or other radio waves, or an externally connected device such as a mobile phone or a PDA (Personal Digital Assistant) that supports the operation of the vehicle control system 7000. You may. The input unit 7800 may be, for example, a camera, in which case the passenger can input information by gesture. Alternatively, data obtained by detecting the movement of the wearable device worn by the passenger may be input. Further, the input unit 7800 may include, for example, an input control circuit that generates an input signal based on the information input by the passenger or the like using the input unit 7800 and outputs the input signal to the integrated control unit 7600. By operating the input unit 7800, the passenger or the like inputs various data to the vehicle control system 7000 and instructs the processing operation.

The storage unit 7690 may include a ROM (Read Only Memory) for storing various programs executed by the microcomputer, and a RAM (Random Access Memory) for storing various parameters, calculation results, sensor values, and the like. Further, the storage unit 7690 may be realized by a magnetic storage device such as an HDD (Hard Disc Drive), a semiconductor storage device, an optical storage device, an optical magnetic storage device, or the like.

The general-purpose communication I / F 7620 is a general-purpose communication I / F that mediates communication with various devices existing in the external environment 7750. General-purpose communication I / F7620 is a cellular communication protocol such as GSM (registered trademark) (Global System of Mobile communications), WiMAX (registered trademark), LTE (registered trademark) (Long Term Evolution) or LTE-A (LTE-Advanced). , Or other wireless communication protocols such as wireless LAN (also referred to as Wi-Fi®), Bluetooth® may be implemented. The general-purpose communication I / F 7620 connects to a device (for example, an application server or a control server) existing on an external network (for example, the Internet, a cloud network, or a business-specific network) via, for example, a base station or an access point. You may. Further, the general-purpose communication I / F7620 uses, for example, P2P (Peer To Peer) technology, and is a terminal existing in the vicinity of the vehicle (for example, a terminal of a driver, a pedestrian, or a store, or an MTC (Machine Type Communication) terminal). May be connected with.

The dedicated communication I / F 7630 is a communication I / F that supports a communication protocol formulated for use in a vehicle. The dedicated communication I / F7630 uses a standard protocol such as WAVE (Wireless Access in Vehicle Environment), DSRC (Dedicated Short Range Communications), or cellular communication protocol, which is a combination of lower layer IEEE802.11p and upper layer IEEE1609. May be implemented. Dedicated communication I / F7630 typically includes vehicle-to-vehicle (Vehicle to Vehicle) communication, road-to-vehicle (Vehicle to Infrastructure) communication, vehicle-to-home (Vehicle to Home) communication, and pedestrian-to-pedestrian (Vehicle to Pedestrian) communication. ) Carry out V2X communication, a concept that includes one or more of the communications.

The positioning unit 7640 receives, for example, a GNSS signal from a GNSS (Global Navigation Satellite System) satellite (for example, a GPS signal from a GPS (Global Positioning System) satellite), executes positioning, and executes positioning, and the latitude, longitude, and altitude of the vehicle. Generate location information including. The positioning unit 7640 may specify the current position by exchanging signals with the wireless access point, or may acquire position information from a terminal such as a mobile phone, PHS, or smartphone having a positioning function.

The beacon receiving unit 7650 receives radio waves or electromagnetic waves transmitted from a radio station or the like installed on the road, and acquires information such as the current position, traffic jam, road closure, or required time. The function of the beacon receiving unit 7650 may be included in the above-mentioned dedicated communication I / F 7630.

The in-vehicle device I / F 7660 is a communication interface that mediates the connection between the microcomputer 7610 and various in-vehicle devices 7760 existing in the vehicle. The in-vehicle device I / F7660 may establish a wireless connection using a wireless communication protocol such as wireless LAN, Bluetooth (registered trademark), NFC (Near Field Communication) or WUSB (Wireless USB). In addition, the in-vehicle device I / F7660 is connected via a connection terminal (and a cable if necessary) (not shown), USB (Universal Serial Bus), HDMI (registered trademark) (High-Definition Multimedia Interface, or MHL (Mobile High)). A wired connection such as -definition Link) may be established. The in-vehicle device 7760 includes, for example, at least one of a mobile device or a wearable device owned by a passenger, or an information device carried in or attached to a vehicle. In addition, the in-vehicle device 7760 may include a navigation device that searches for a route to an arbitrary destination. The in-vehicle device I / F 7660 is a control signal to and from these in-vehicle devices 7760. Or exchange the data signal.

The in-vehicle network I / F7680 is an interface that mediates communication between the microcomputer 7610 and the communication network 7010. The vehicle-mounted network I / F7680 transmits and receives signals and the like according to a predetermined protocol supported by the communication network 7010.

The microcomputer 7610 of the integrated control unit 7600 is via at least one of general-purpose communication I / F7620, dedicated communication I / F7630, positioning unit 7640, beacon receiving unit 7650, in-vehicle device I / F7660, and in-vehicle network I / F7680. Based on the information acquired in the above, the vehicle control system 7000 is controlled according to various programs. For example, the microcomputer 7610 calculates the control target value of the driving force generator, the steering mechanism, or the braking device based on the acquired information inside and outside the vehicle, and outputs a control command to the drive system control unit 7100. May be good. For example, the microcomputer 7610 realizes ADAS (Advanced Driver Assistance System) functions including vehicle collision avoidance or impact mitigation, follow-up driving based on inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane deviation warning, and the like. Cooperative control may be performed for the purpose of. In addition, the microcomputer 7610 automatically travels autonomously without relying on the driver's operation by controlling the driving force generator, steering mechanism, braking device, etc. based on the acquired information on the surroundings of the vehicle. Coordinated control for the purpose of driving or the like may be performed.

The microcomputer 7610 has information acquired via at least one of a general-purpose communication I / F7620, a dedicated communication I / F7630, a positioning unit 7640, a beacon receiving unit 7650, an in-vehicle device I / F7660, and an in-vehicle network I / F7680. Based on the above, three-dimensional distance information between the vehicle and an object such as a surrounding structure or a person may be generated, and local map information including the peripheral information of the current position of the vehicle may be created. Further, the microcomputer 7610 may predict a danger such as a vehicle collision, a pedestrian or the like approaching or entering a closed road based on the acquired information, and may generate a warning signal. The warning signal may be, for example, a signal for generating a warning sound or turning on a warning lamp.

The audio image output unit 7670 transmits an output signal of at least one of audio and image to an output device capable of visually or audibly notifying information to the passengers of the vehicle or outside the vehicle. In the example of FIG. 20, an audio speaker 7710, a display unit 7720, and an instrument panel 7730 are exemplified as output devices. The display unit 7720 may include, for example, at least one of an onboard display and a heads-up display. The display unit 7720 may have an AR (Augmented Reality) display function. The output device may be other devices other than these devices, such as headphones, wearable devices such as eyeglass-type displays worn by passengers, and projectors or lamps. When the output device is a display device, the display device displays the results obtained by various processes performed by the microcomputer 7610 or the information received from other control units in various formats such as texts, images, tables, and graphs. Display visually. When the output device is an audio output device, the audio output device converts an audio signal composed of reproduced audio data, acoustic data, or the like into an analog signal and outputs it audibly.

In the example shown in FIG. 20, at least two control units connected via the communication network 7010 may be integrated as one control unit. Alternatively, each control unit may be composed of a plurality of control units. Further, the vehicle control system 7000 may include another control unit (not shown). Further, in the above description, the other control unit may have a part or all of the functions carried out by any of the control units. That is, as long as information is transmitted and received via the communication network 7010, predetermined arithmetic processing may be performed by any control unit. Similarly, a sensor or device connected to one of the control units may be connected to the other control unit, and the plurality of control units may send and receive detection information to and from each other via the communication network 7010. ..

Note that a computer program for realizing each function of the ToF sensor 1 according to the present embodiment described with reference to FIG. 1 can be mounted on any control unit or the like. It is also possible to provide a computer-readable recording medium in which such a computer program is stored. The recording medium is, for example, a magnetic disk, an optical disk, a magneto-optical disk, a flash memory, or the like. Further, the above computer program may be distributed via, for example, a network without using a recording medium.

In the vehicle control system 7000 described above, the ToF sensor 1 according to the present embodiment described with reference to FIG. 1 can be applied to the integrated control unit 7600 of the application example shown in FIG. 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, the present invention is not limited to this, and the vehicle control system 7000 may correspond to the host 80 in FIG.

Further, at least a part of the components of the ToF sensor 1 according to the present embodiment described with reference to FIG. 1 is a module for the integrated control unit 7600 shown in FIG. 20 (for example, an integrated configuration composed of one die). It may be realized in a circuit module). Alternatively, the ToF sensor 1 according to the present embodiment described with reference to FIG. 1 may be realized by a plurality of control units of the vehicle control system 7000 shown in FIG.

3. 3. Summary As described above, according to one embodiment of the present disclosure, the distance measuring device (ToF sensor 1) according to the present embodiment includes a light emitting unit 13, a light receiving unit 14, and a control unit 11. In the light receiving unit 14, a plurality of light receiving elements (SPAD pixels 20) that receive the reflected light L2 reflected by the light (laser light L1) of the light emitting unit 13 are arranged two-dimensionally. The control unit 11 controls to read out detection signals from a plurality of light receiving elements for each of a predetermined number of light receiving elements and measure the distance. The control unit 11 detects an abnormality in the light emitting unit 13 based on calculated values (pixel values, cumulative pixel values) calculated based on the detection signals of a predetermined number of light receiving elements. As a result, the abnormality of the light emitting unit 13 can be detected with high accuracy at low cost.

Further, according to one embodiment of the present disclosure, the distance measuring device (ToF sensor 1) according to the present embodiment includes a light emitting unit 13, a light receiving unit 14, and a control unit 11. The light emitting unit 13 emits light (laser beam L1) that scans a predetermined ranging range. In the light receiving unit 14, a plurality of light receiving elements (SPAD pixels 20) that receive the reflected light L2 reflected by the light emitting unit 13 are arranged two-dimensionally. The control unit 11 controls to read a detection signal from the light receiving element at a position corresponding to the scanning position of the light emitting unit 13 among the plurality of light receiving elements and measure the distance. As a result, light can be efficiently received.

Further, according to one embodiment of the present disclosure, the distance measuring device (ToF sensor 1) according to the present embodiment includes a light emitting unit 13, a light receiving unit 14, and a control unit 11. The light receiving unit 14 detects the incident of light (laser beam L1). The control unit 11 controls the distance measurement based on the time from when the light emitting unit 13 emits light until the light receiving unit 14 detects the incident of light. The control unit 11 generates a histogram of the calculated value based on the detection signal output from the light receiving unit 14, and from among the plurality of peaks included in the generated histogram, the calculated value and the peak width are peaks having a predetermined threshold value or more. Is detected. As a result, distance measurement can be performed with high accuracy even in an environment with strong ambient light.

Although each embodiment of the present disclosure has been described above, the technical scope of the present disclosure is not limited to each of the above-described embodiments as it is, and various changes can be made without departing from the gist of the present disclosure. be. In addition, components covering different embodiments and modifications may be combined as appropriate.

Further, the effects in each embodiment described in the present specification are merely examples and are not limited, and other effects may be obtained.

The present technology can also have the following configurations.
(1)
Light emitting part and
A light receiving unit in which a plurality of light receiving elements that receive the reflected light reflected by the light emitting unit are arranged in a two-dimensional manner, and a light receiving unit.
A control unit that reads a detection signal from the plurality of light receiving elements for each of a predetermined number of the light receiving elements and controls distance measurement.
With
The control unit
A distance measuring device that detects an abnormality in the light emitting unit based on an calculated value calculated based on the detection signals of the predetermined number of light receiving elements.
(2)
The control unit
The distance measuring device according to (1), wherein a histogram of the calculated values is generated, and an abnormality in the light emitting unit is detected based on the histogram.
(3)
The control unit
The distance measuring device according to (2) above, wherein when the plurality of peaks included in the histogram include a peak whose calculated value and peak width satisfy a predetermined condition, an abnormality in the light emitting unit is detected.
(4)
The control unit
The distance measuring device according to (3) above, wherein when the calculated value includes a peak having a predetermined threshold value or more and the peak width has a predetermined threshold value or more, an abnormality in the light emitting unit is detected.
(5)
The distance measuring device according to (4), wherein the threshold value of the peak width is a value corresponding to the pulse width of the light of the light emitting unit.
(6)
The calculated value is
The distance measuring device according to any one of (1) to (5) above, which is a pixel value obtained by totaling the number of detection signals output from the light receiving unit for each of a plurality of light receiving elements.
(7)
The light receiving element is
The distance measuring device according to any one of (1) to (6) above, which is a SPAD pixel.
(8)
The control unit
Among the calculated values of the light receiving element for each row or column, when the calculated value of a specific row or column is equal to or higher than a predetermined threshold value, an abnormality of the light emitting unit is detected, according to (1) to (7). The distance measuring device according to any one of the above.
(9)
Light emitting part and
It is a distance measuring method executed by a distance measuring device including a light receiving unit in which a plurality of light receiving elements for receiving the reflected light reflected by the light of the light emitting unit are arranged in a two-dimensional manner.
It includes a control step of reading a detection signal from each of a predetermined number of the light receiving elements from the plurality of light receiving elements and controlling the distance measurement.
The control step is
A distance measuring method for detecting an abnormality in the light emitting unit based on an calculated value calculated based on the detection signals of the predetermined number of light receiving elements.
(10)
A light emitting unit that emits light that scans a predetermined ranging range,
A light receiving unit in which a plurality of light receiving elements that receive the reflected light reflected by the light emitting unit are arranged in a two-dimensional manner, and a light receiving unit.
Among the plurality of light receiving elements, a control unit that controls to read a detection signal from the light receiving element at a position corresponding to the scanning position of the light emitting unit and measure the distance.
A distance measuring device equipped with.
(11)
The control unit
The distance measuring device according to (10), wherein the scanning position of the light emitting unit is gradually changed, and the scanning position of the light receiving unit is changed in predetermined angle units.
(12)
The control unit
The distance measuring device according to (11), wherein the scanning start position of the light emitting unit and the scanning start position of the light receiving unit are aligned.
(13)
The control unit
The distance measuring device according to (11) or (12), wherein the scanning start position of the light emitting unit and the scanning start position of the light receiving unit are different from each other.
(14)
The control unit
The distance measurement according to any one of (11) to (13) above, wherein the region corresponding to the scanning position of the light receiving unit is divided into a plurality of regions, and the scanning timing is different for each of the divided regions. Device.
(15)
The control unit
The distance measuring device according to any one of (10) to (14), wherein the scanning position of the light emitting unit is changed in a predetermined angle unit, and the scanning position of the light receiving unit is changed in a predetermined angle unit.
(16)
A light emitting unit that emits light that scans a predetermined ranging range,
It is a distance measuring method executed by a distance measuring device including a light receiving unit in which a plurality of light receiving elements for receiving the reflected light reflected by the light of the light emitting unit are arranged in a two-dimensional manner.
A control step for controlling distance measurement by reading a detection signal from the light receiving element at a position corresponding to the scanning position of the light emitting unit among the plurality of light receiving elements.
Distance measurement method including.
(17)
Light emitting part and
A light receiving part that detects the incident of light and
A control unit that controls distance measurement based on the time from when the light emitting unit emits light until the light receiving unit detects an incident of light is provided.
The control unit
A histogram of the calculated value based on the detection signal output from the light receiving unit is generated, and a peak in which the calculated value and the peak width are each equal to or more than a predetermined threshold value is detected from a plurality of peaks included in the generated histogram. , Distance measuring device.
(18)
The peak width is
The distance measuring device according to (17), which is the peak width of the threshold value in the calculated value.
(19)
The peak width is
The distance measuring device according to (17) or (18), which is a peak width at a half value of the calculated value of the peak value and the threshold value in the calculated value.
(20)
The control unit
Any of the above (17) to (19), among the plurality of peaks included in the histogram, a peak whose calculated value is less than a predetermined threshold value or whose peak width is less than a predetermined threshold value is detected as a peak of ambient light. The distance measuring device according to one.
(21)
The control unit
Among the plurality of peaks included in the histogram, the peaks satisfying the predetermined conditions are extracted as the target of the reflected light from the plurality of peaks whose calculated values are equal to or higher than the predetermined threshold values (17) to (20). ). The distance measuring device according to any one of.
(22)
The control unit
The distance measuring device according to (21), wherein a predetermined number of peaks are extracted from a plurality of peaks whose calculated values are equal to or higher than a predetermined threshold value in descending order of the calculated values.
(23)
The control unit
The distance measuring device according to (21) or (22), wherein a predetermined number of peaks are extracted in ascending order of flight time from a plurality of peaks whose calculated values are equal to or higher than a predetermined threshold value.
(24)
The control unit
The measurement according to any one of (19) to (23) above, wherein among the plurality of peaks included in the histogram, a peak having a flight time within a predetermined time and having a shape similar to that of the peak is detected as reflected light. Distance device.
(25)
Light emitting part and
It is a distance measuring method performed by a distance measuring device including a light receiving unit for detecting the incident of light.
A control step of controlling the distance measurement based on the time from when the light emitting unit emits light until the light receiving unit detects the incident of light is included.
The control step is
A histogram of the calculated value based on the detection signal output from the light receiving unit is generated, and a peak in which the calculated value and the peak width are each equal to or more than a predetermined threshold value is detected from a plurality of peaks included in the generated histogram. , Distance measurement method.

1 ToF sensor (distance measuring device)
11 Control unit 13 Light emitting unit 14 Light receiving unit 15 Calculation unit 20 SPAD pixel 30 Macro pixel 80 Host 90 Object

Claims (7)

1. A light emitting unit that emits light that scans a predetermined ranging range,
   A light receiving unit in which a plurality of light receiving elements that receive the reflected light reflected by the light emitting unit are arranged in a two-dimensional manner, and a light receiving unit.
   Among the plurality of light receiving elements, a control unit that controls to read a detection signal from the light receiving element at a position corresponding to the scanning position of the light emitting unit and measure the distance.
   A distance measuring device equipped with.
2. The control unit
   The distance measuring device according to claim 1, wherein the scanning position of the light emitting unit is gradually changed, and the scanning position of the light receiving unit is changed in predetermined angle units.
3. The control unit
   The distance measuring device according to claim 2, wherein the scanning start position of the light emitting unit and the scanning start position of the light receiving unit are aligned.
4. The control unit
   The distance measuring device according to claim 2, wherein the scanning start position of the light emitting unit and the scanning start position of the light receiving unit are different from each other.
5. The control unit
   The distance measuring device according to claim 2, wherein a region corresponding to a scanning position of the light receiving unit is divided into a plurality of regions, and the scanning timing is different for each of the divided regions.
6. The control unit
   The distance measuring device according to claim 1, wherein the scanning position of the light emitting unit is changed in a predetermined angle unit, and the scanning position of the light receiving unit is changed in the predetermined angle unit.
7. A light emitting unit that emits light that scans a predetermined ranging range,
   It is a distance measuring method executed by a distance measuring device including a light receiving unit in which a plurality of light receiving elements for receiving the reflected light reflected by the light of the light emitting unit are arranged in a two-dimensional manner.
   A control step for controlling distance measurement by reading a detection signal from the light receiving element at a position corresponding to the scanning position of the light emitting unit among the plurality of light receiving elements.
   Distance measurement method including.

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