Sensor control system and sensor

Abstract

Provided is a sensor control system that can reduce the load on an application system during the processing of a synchronization signal and can perform flexible synchronization control according to a system change even when there is a change in the system such as an increased number of sensors. The sensor control system comprises: a light emitting unit; a sensor having a signal processing unit that performs signal processing on the basis of electrical signals output from a plurality of pixels; and a control device that controls the execution of the signal processing performed by the sensor. The sensor comprises: a communication interface processing unit that receives a communication interface signal; a synchronization signal generation unit that generates a synchronization signal; a light emitting trigger output unit that transmits a light emission trigger on the basis of the synchronization signal; a synchronization signal processing unit that controls the signal processing unit on the basis of the synchronization signal and transmits the synchronization signal; and a feedback signal processing unit that receives a feedback signal and transmits predetermined signal processing data including the reception result to the control device.

Description

Technical Field

[0001] The technology related to the present disclosure (this technology) relates to a sensor control system and a sensor.

Background Art

[0002] In recent years, a technology for recognizing an object in an image detected by a sensor has been known. In such an object recognition technology, generally, an image sensor, a millimeter wave radar, or a lidar is used (for example, Patent Document 1). Furthermore, in recent years, a Time of Flight (ToF) sensor that measures the distance to an object (target object) based on the time of flight of light has been used.

[0003] As the ToF sensor, there are known a direct ToF (dToF) type distance measurement sensor that measures the distance from the time of flight of light directly measured using a pulse wave, and an indirect ToF (iToF) type distance measurement sensor that measures the distance from the time of flight of light indirectly calculated using the phase of modulated light.

[0004] By the way, in the above ToF sensor, it is necessary to synchronize with the light emitting unit in units of ps / ns, and in addition to the light emitting unit, it is also necessary to synchronize with an external device such as a scanning device. In such a ToF sensor, the upper application system generates a synchronization signal for the light emitting unit and the external device including the ToF sensor, and manages the synchronization signal.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] As described above, in a ToF sensor, with regard to the processing of the synchronization signal, much of the processing is performed by the application system, and the application system is required to perform high-speed processing in real time. In the future, it is assumed that the processing of the synchronization signal will become more complex with the addition of multiple sensors. In such a case, if there are many synchronization signals generated and managed by the application system, it will be difficult to manage and difficult to handle errors such as noise.

[0007] In view of such circumstances, the present disclosure has been made, and in the processing of the synchronization signal, it is an object to provide a sensor control system and a sensor that can reduce the burden on the application system and perform flexible synchronization control in accordance with system changes such as the addition of multiple sensors.

Means for Solving the Problems

[0008] One aspect of the present disclosure includes a sensor having a light emitting unit that irradiates light onto a target area, a plurality of pixels that receive reflected light from the target area and convert it into an electrical signal, and a signal processing unit that performs signal processing based on the electrical signal output for each pixel, and a control device that can be connected to the sensor and controls the execution of signal processing of the sensor. The sensor includes a communication interface processing unit that receives a communication interface signal necessary for control related to the signal processing from an external device, a synchronization signal generation unit that generates a synchronization signal for synchronizing the signal processing based on the communication interface signal, a light emission trigger output unit that transmits a light emission trigger for irradiating the light emitting unit based on the synchronization signal, a synchronization signal processing unit that controls the signal processing unit based on the synchronization signal and transmits the synchronization signal to a connectable external device, and a feedback signal processing unit that receives a feedback signal returned from the light emitting unit in response to the light emission trigger and a feedback signal returned from the external device in response to the synchronization signal, and transmits predetermined signal processing data including the reception result to the control device.

[0009] Another aspect of the present disclosure is a sensor including: a plurality of pixels that irradiate light from a light emitting unit to a target area, receive reflected light from the target area, and convert the received reflected light into an electrical signal; a signal processing unit that performs signal processing based on the electrical signal output for each pixel; a communication interface processing unit that receives a communication interface signal necessary for control related to the signal processing from an external device; a synchronization signal generation unit that receives a synchronization signal for synchronizing with the signal processing based on the communication interface signal; a light emission trigger output unit that transmits a light emission trigger for irradiating the light emitting unit with light based on the synchronization signal; a synchronization signal processing unit that controls the signal processing unit based on the synchronization signal and transmits the synchronization signal to a connectable external device; and a feedback signal processing unit that receives a feedback signal returned from the light emitting unit in response to the light emission trigger and a feedback signal returned from the external device in response to the synchronization signal, includes the received result in predetermined signal processing data, and transmits the data to a control device that controls execution of the signal processing.

[0010] Furthermore, another aspect of the present disclosure is a sensor including: a plurality of pixels that irradiate light from a light emitting unit to a target area, receive reflected light from the target area, and convert the received reflected light into an electrical signal; a signal processing unit that performs signal processing based on the electrical signal output for each pixel; a communication interface processing unit that receives a communication interface signal necessary for control related to the signal processing; a synchronization signal receiving unit that receives a synchronization signal for synchronizing with the signal processing from an external device; a light emission trigger output unit that transmits a light emission trigger for irradiating the light emitting unit with light based on the synchronization signal; and a synchronization signal processing unit that controls the signal processing unit based on the synchronization signal and transmits the synchronization signal to a connectable external device.

Brief Description of the Drawings

[0011]

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Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the description of the drawings referred to below, the same or similar parts are denoted by the same or similar reference numerals, and duplicate descriptions are omitted. Note that the effects described in this specification are merely examples and are not limiting, and there may be other effects.

[0013] <First Embodiment> <Configuration of the Distance Measuring Sensor> FIG. 1 is a block diagram showing an example of the configuration of a distance measuring sensor 1 according to the first embodiment of the present technology. In the first embodiment of the present technology, the distance measuring sensor 1 is, for example, a dToF sensor. The distance measuring sensor 1 is a distance measuring sensor that measures the distance to an object OBJ (target object or subject) based on an electrical signal obtained by emitting pulsed light from a light emitting element and receiving reflected light from the object OBJ irradiated with the pulsed light by a light receiving element.

[0014] As shown in the figure, the distance measuring sensor 1 includes components such as, for example, a system control unit 10, a light emitting unit 20, a light emission timing adjustment unit 30, a light receiving unit 40, and a distance measurement processing unit 50. These components can be integrally configured as a system-on-chip (SoC) such as a CMOS LSI, for example, but some components such as the light emitting unit 20 and the light receiving unit 40 may be configured as separate LSIs. The distance measuring sensor 1 operates according to an operation clock (not shown). The distance measuring sensor 1 also includes a communication interface unit 60 for outputting data related to the distance calculated by the distance measurement processing unit 50 (distance measurement data) to the outside. Although not shown, the distance measuring sensor 1 is configured to be communicable with a host IC arranged outside via the communication interface unit 60. The system control unit 10 is a component that comprehensively controls the operation of the distance measurement sensor 1. Typically, the system control unit 10 includes a microprocessor and is configured.

[0015] The light emitting unit 20 emits pulsed light such as infrared light (IR) toward the target area. The light emission timing adjustment unit 30 is a circuit that adjusts the light emission timing of the light emitting unit 20. For example, the light emission timing adjustment unit 30 outputs a trigger pulse to synchronize with the read timing for each line from the light receiving unit 40 described later, and drives the light emitting unit 20.

[0016] The light receiving unit 40 is a sensor that outputs an electrical signal in response to light incident from the target area. The incident light includes reflected light from the object OBJ. In the present disclosure, the light receiving unit 40 is a CMOS image sensor composed of a plurality of pixels including a plurality of light receiving elements arranged in a two-dimensional matrix. In the present disclosure, for example, under the control of the system control unit 10, a specific pixel group (for example, a pixel group in one line direction in the imaging frame) is activated, and thereby an electrical signal is read out. Also, in one frame time, the pixel groups of each line are sequentially activated, and an imaging frame for the target area is formed by the electrical signals output from each of the activated pixel groups.

[0017] The distance measurement processing unit 50 is a component that calculates the distance to the object OBJ based on the pulsed light emitted by the light emitting unit 20 and the reflected light received by the light receiving unit 40. The distance measurement processing unit 50 is typically composed of a signal processing processor. In the present disclosure, the distance measurement processing unit 50 includes a sampling circuit 51, a histogram generation circuit 52, and a distance calculation circuit 53.

[0018] The sampling circuit 51 is a component that samples the electrical signal output from a specific pixel group in response to the emission of pulsed light at a predetermined sampling frequency. The sampling circuit 51 outputs a High or Low value (sampling value) according to the value of the electrical signal output from each of the activated pixel groups, for example.

[0019] The histogram generation circuit 52 is a component that generates a histogram indicating the intensity of the reflected light for each time based on the total value of the sampling values for each sampling time output by the sampling circuit 51. The histogram is held, for example, as a certain data structure or table on a memory (not shown). The histogram is generated in a number corresponding to the number of pixels based on the pulsed light emitted for each read line in the imaging frame. The histogram generated by the histogram generation circuit 52 is referred to by the distance calculation circuit 53.

[0020] The distance calculation circuit 53 is a component that refers to the generated histogram, detects the peak value in the histogram, and calculates the distance from the time corresponding to the peak value (i.e., the arrival time). That is, assuming that the reflected light when the emitted pulsed light irradiates the object OBJ is received, this time is the round-trip time to the object OBJ, so by multiplying this by c / 2 (c is the speed of light), the distance to the object OBJ can be calculated for each pixel. Therefore, a distance image can be obtained from the distances calculated for all the pixels constituting the imaging frame. The distance calculation circuit 53 outputs data (distance measurement data) related to the distances calculated for each pixel in each imaging frame to the communication interface unit 60.

[0021] The communication interface unit 60 is an interface circuit for outputting the calculated distance measurement data to an external host IC. For example, the communication interface unit 60 is an interface circuit compliant with MIPI (Mobile Industry Processor Interface), but is not limited to this. For example, it may be SPI (Serial Peripheral Interface), LVDS, SLVS-EC, etc., or some of these interface circuits may be implemented.

[0022] Incidentally, in the first embodiment, the system control unit 10 includes a communication interface signal processing unit 10a, a frame synchronization signal receiving unit 10b, and a frame synchronization signal processing unit 10c. Furthermore, it includes a master synchronization signal generation unit 81, a slave signal receiving unit 82, a synchronization signal selection unit 83, a delay adjustment unit 84, and an error determination unit 85.

[0023] The communication interface signal processing unit 10a receives from the application system (details will be described later) the communication interface signals necessary for the distance measurement processing by the distance measurement processing unit 50. The frame synchronization signal receiving unit 10b receives from the application system a frame synchronization signal synchronized with an imaging frame formed by a plurality of pixels. If the distance measurement sensor 1 is set as the master, the frame synchronization signal processing unit 10c outputs the frame synchronization signal to the master synchronization signal generation unit 81.

[0024] The master synchronization signal generation unit 81 generates a line synchronization signal having a shorter period than the frame synchronization signal from the frame synchronization signal. This line synchronization signal is transmitted to an external distance measurement sensor or an imaging position changing device (details will be described later) via the synchronization signal selection unit 83 and the delay adjustment unit 84. Also, the master synchronization signal generation unit 81 may generate a frame synchronization signal even when the frame synchronization signal is not transmitted from the application system. If the distance measurement sensor 1 is set as the slave, the slave signal receiving unit 82 receives the frame synchronization signal from the master, outputs the received frame synchronization signal to the system control unit 10, and when there is a next connected slave, transmits the received frame synchronization signal to the next slave via the synchronization signal selection unit 83 and the delay adjustment unit 84. If the next is the master, a feedback signal for the received frame synchronization signal is transmitted to the master via the synchronization signal selection unit 83 and the delay adjustment unit 84. The synchronization signal selection unit 83 selectively derives the output of the master synchronization signal generation unit 81 and the output of the slave signal receiving unit 82 under the control of the system control unit 10. The delay adjustment unit 84 can adjust the delay time, for example, under the control of the system control unit 10 or manually.

[0025] When the distance measuring sensor 1 is set as the master, the error determination unit 85 receives the feedback signal returned from the light emitting unit 20 and the feedback signal returned from the imaging position changing device, performs error determination, and outputs the error determination result to the system control unit 10. Then, the system control unit 10 transmits the error determination result to the application system.

[0026] Also, the error determination unit 85 receives the feedback signal from the slave, performs error determination by comparing the frame synchronization signal and the feedback signal, and outputs the error determination result to the system control unit 10. Then, the system control unit 10 transmits the error determination result to the application system. As the error determination method, if the feedback signal does not return within a range considering the exposure time, wiring delay, etc. from the rising edge of the frame synchronization signal, an error notification is issued. Also, the time required from the transmission of the light emission request to the reception of the feedback signal for the light emission request is measured, and if the feedback signal is not received within a predetermined time, an error notification is issued.

[0027] Also, a buffer 90 is connected to the system control unit 10. The buffer 90 stores a value that can be rewritten from the outside for communication data. The system control unit 10 has a function of being able to transmit the stored content of the buffer 90 in a master operation such as SPI / I2C, and a function of writing the received content to the buffer 90 during the read operation. Also, the system control unit 10 can select the timing for transmitting / receiving the stored content of the buffer 90 from each synchronization signal. Further, the system control unit 10 outputs the set value stored in the buffer 90 to the error determination unit 85 to cause an expected value determination with the received feedback signal.

[0028] <Configuration of the light receiving unit> FIG. 2 illustrates one pixel 41 among a plurality of pixels arranged in a two-dimensional matrix in the light receiving unit 40. The pixel 41 has a photoelectric conversion element that photoelectrically converts the received light and generates electric charges according to the amount of light. The light-receiving unit 40 is connected to a pixel driving unit 70 via a pixel driving line 43. The pixel driving unit 70 drives each pixel of the light-receiving unit 40 either simultaneously for all pixels or in units of rows. Pixel signals output from each pixel of the pixel line (pixel row) selectively scanned by the pixel driving unit 70 are supplied to a sampling circuit 51 through respective ones of the vertical signal lines 44.

[0029] The sampling circuit 51 samples, at a predetermined sampling frequency, the pixel signals output through the vertical signal lines 44 from each pixel unit of the selection line (selection row) for each pixel column of the light-receiving unit 40. In this way, as shown in FIG. 3, the distance measuring sensor 1 can, for example, in a scene in front of a vehicle, more accurately avoid collisions and the like by measuring the distance to nearby obstacles (e.g., other vehicles) with higher distance measurement accuracy. On the other hand, as a result of distance measurement, when there is no nearby obstacle (e.g., other vehicle), by turning off the power supply that supplies power to the pixel 41 or masking the pixel signal output from the pixel 41, the driving voltage of the pixel and the arithmetic load on the processor can be reduced, and the power consumption can be suppressed.

[0030] <Configuration of the Sensor Control System> FIG. 4 is a block diagram showing an example of the configuration of a sensor control system 100 according to the first embodiment of the present technology. In the sensor control system 100, the distance measuring sensor 1 can be connected to an application system 200 and an imaging position changing device 300. The application system controls the execution of the distance measurement process of the distance measuring sensor 1. The distance measuring sensor 1 and the light emitting unit 20 are rotatably supported about the arrow Z axis in FIG. 5 by the imaging position changing device 300 as shown in FIG. 5. The imaging position changing device 300 has a rotation axis about the arrow Z axis in FIG. 5 and is controlled by the distance measuring sensor 1. Note that the imaging position changing device 300 may have, for example, a rotation axis about the arrow Y axis in FIG. 5. Further, for example, a rate gyro is attached to each rotation axis.

[0031] Returning to FIG. 4, the distance measurement sensor 1 receives a communication interface signal from the application system 200. This communication interface signal includes identification information for identifying the application system 200, command information for outputting distance measurement data, the amount of movement with respect to the imaging position changing device 300, and the like.

[0032] Subsequently, the distance measurement sensor 1 receives the frame synchronization signal shown in FIG. 6(a) from the application system 200. Then, the distance measurement sensor 1 generates the line synchronization signal shown in FIG. 6(b) from the frame synchronization signal and transmits it to the imaging position changing device 300. Further, the distance measurement sensor 1 controls the imaging position changing device 300 based on the target direction obtained by the distance measurement processing unit 50 from the command information included in the communication interface signal and the angle information obtained by the rate gyroscopes provided on each rotation axis. Furthermore, the distance measurement sensor 1 generates another synchronization signal shown in FIG. 6(c) from the frame synchronization signal, generates a light emission trigger (light emission request) shown in FIG. 6(d), and transmits it to the light emitting unit 20.

[0033] Thereafter, the distance measurement sensor 1 receives a feedback signal for the transmission of the line synchronization signal from the imaging position changing device 300 and a feedback signal for the light emission trigger from the light emitting unit 20. When each feedback signal is received, the distance measurement sensor 1 makes an error determination as to whether the feedback signal is returned within a predetermined time from the rising edge of the line synchronization signal, and includes this error determination result in the predetermined distance measurement data shown in FIG. 6(e) and transmits it to the application system 200.

[0034] The distance measurement data shown in FIG. 6(e) is configured as, for example, a data sequence for each imaging frame. Such a data sequence includes, for example, a blanking period (BLK) in which no data is inserted, a start code (SOF), a slot in which distance measurement data for each pixel 41 is inserted, and an end code (EOF), synchronized with the line synchronization signal. The slot number corresponds to the number of the pixel 41 according to the scan.

[0035] <Comparative Example of the Embodiment> FIG. 7 is a block diagram showing a sensor control system as a comparative example. In FIG. 7, the same parts as those in FIG. 4 are denoted by the same reference numerals, and detailed description thereof is omitted. In the comparative example, the application system 200 not only transmits a synchronization signal to the distance measuring sensor 1 but also transmits a synchronization signal to the imaging position changing device 300. Further, the application system 200 not only receives distance measurement data from the distance measuring sensor 1 but also receives feedback signals from the light emitting unit 20 and the imaging position changing device 300. Therefore, the synchronization signals generated and managed by the application system 200 increase. In addition, when the same synchronization signal is output to the distance measuring sensor 1 and two other devices other than the distance measuring sensor 1, the wiring to be cared for doubles.

[0036] <Solution means of the first embodiment> Therefore, in the first embodiment, as shown in FIG. 4, the transmission of the light emission trigger to the light emitting unit 20, the reception of the feedback signal for the light emission trigger, the transmission of the line synchronization signal to the imaging position changing device 300, and the reception of the feedback signal for the line synchronization signal are executed by the distance measuring sensor 1.

[0037] <Operational effects according to the first embodiment> As described above, according to the first embodiment, when the application system 200 communicatively connects to the distance measuring sensor 1, it is only when transmitting a communication interface signal, transmitting a frame synchronization signal, and receiving distance measurement data including an error determination result from the distance measuring sensor 1. Since the transmission of the light emission trigger to the light emitting unit 20, the reception of the feedback signal for the light emission trigger, the transmission of the line synchronization signal to the imaging position changing device 300, and the reception of the feedback signal for the line synchronization signal are executed by the distance measuring sensor 1, the processing amount of the application system 200 is reduced, and further, the number of target signals to which noise should be cared for can be reduced, and efficient synchronization control can be performed in real time.

[0038] Also, according to the first embodiment, the application system 200 only needs to transmit a frame synchronization signal to the distance measurement sensor 1, and by generating a line synchronization signal with a period shorter than that of the frame synchronization signal at the distance measurement sensor 1 and transmitting it to the imaging position changing device 300, efficient synchronization control can be performed.

[0039] Furthermore, according to the first embodiment, by performing error determination on the synchronization signal by the distance measurement sensor 1, it is no longer necessary for the application system 200 to perform error determination on the synchronization signal, and the processing amount of the application system 200 can be reduced accordingly.

[0040] <Second Embodiment> Next, the second embodiment will be described. The second embodiment is a modification of the first embodiment. FIG. 8 is a block configuration diagram showing a sensor control system 100A according to the second embodiment. In FIG. 8, the same parts as those in FIG. 4 are denoted by the same reference numerals and detailed description thereof is omitted.

[0041] The distance measurement sensors 1A operating as a master and 2a, 2b operating as slaves are connected to the application system 200. When the distance measurement sensor 1A receives a communication interface signal from the application system 200, it generates a frame synchronization signal based on the communication interface signal, controls the distance measurement processing unit 50 based on the frame synchronization signal, transmits a light emission trigger to the light emission unit 20, and transmits the frame synchronization signal to the slave distance measurement sensor 2a.

[0042] The distance measurement sensor 2a controls the distance measurement processing unit based on the received frame synchronization signal, transmits a light emission trigger to the light emission unit 3a, and transmits the frame synchronization signal to the subsequent distance measurement sensor 2b if there is a distance measurement sensor 2b in the subsequent stage. The distance measurement sensor 2b controls the distance measurement processing unit based on the received frame synchronization signal, transmits a light emission trigger to the light emission unit 3b, and transmits a feedback signal to the master distance measurement sensor 1A if there is no distance measurement sensor in the subsequent stage.

[0043] When the distance measurement sensor 1A receives the feedback signal, it performs an error determination as to whether the feedback signal is returned within a predetermined time from the rising edge of the frame synchronization signal, and includes the error determination result in the distance measurement data and transmits it to the application system 200.

[0044] <Operational effects according to the second embodiment> As described above, according to the second embodiment, the same operational effects as those of the first embodiment can be obtained. In addition, the distance measurement sensor 1A becomes the master and passes the frame synchronization signal to a plurality of distance measurement sensors 2a and 2b in series, so that synchronization can be achieved among the distance measurement sensors 1A, 2a, and 2b. The distance measurement sensor 1A only needs to receive the feedback signal from the distance measurement sensor 2b that finally receives the frame synchronization signal and perform an error determination, so that flexible synchronization control can be performed according to the system. Further, even if there is a distance measurement sensor 2a that does not require synchronization while being partially synchronized with the distance measurement sensor 1A, a flexible system design is possible.

[0045] Further, according to the second embodiment, the application system 200 only needs to transmit a communication interface signal to each of the distance measurement sensors 1A, 2a, and 2b, so that it can easily cope with an increase in the distance measurement sensors.

[0046] <Third embodiment> Next, the third embodiment will be described. The third embodiment is a modification of the second embodiment. FIG. 9 is a block configuration diagram showing a sensor control system 100B according to the third embodiment. In FIG. 9, the same parts as those in FIG. 8 are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0047] In the sensor control system 100B, instead of the application system 200, the host device 400 transmits a communication interface signal to each of the distance measurement sensors 1B, 2a, and 2b. When the distance measurement sensor 1B receives the feedback signal, it performs an error determination on whether the feedback signal is returned within a predetermined time from the rising edge of the frame synchronization signal, and includes the error determination result in the distance measurement data and transmits it to the application system 200.

[0048] <Operational effects according to the third embodiment> As described above, according to the third embodiment, the same operational effects as those of the second embodiment can be obtained, and the application system 200 only needs to receive the distance measurement data from each of the distance measurement sensors 1B, 2a, and 2b, and the processing load is reduced accordingly.

[0049] <Fourth embodiment> Next, the fourth embodiment will be described. The fourth embodiment is a modification of the second embodiment. FIG. 10 is a block configuration diagram showing a sensor control system 100C according to the fourth embodiment. In FIG. 10, the same parts as those in FIG. 8 are denoted by the same reference numerals and detailed descriptions thereof are omitted.

[0050] The application system 200 is connected to a distance measurement sensor 1C that functions as a master, distance measurement sensors 2a and 2b that operate as slaves, and an image sensor 4. When the distance measurement sensor 1C receives a communication interface signal from the application system 200, it generates a frame synchronization signal based on the communication interface signal, controls the distance measurement processing unit 50 based on the frame synchronization signal, transmits a light emission trigger to the light emission unit 20, and transmits the frame synchronization signal and the communication interface signal to the slave distance measurement sensor 2a.

[0051] The distance measurement sensor 2a controls the distance measurement processing unit based on the received frame synchronization signal, transmits a light emission trigger to the light emission unit 3a, and transmits the distance measurement data to the application system 200 based on the received communication interface signal. Further, when there is a distance measurement sensor 2b in the subsequent stage, the distance measurement sensor 2a transmits the frame synchronization signal and the communication interface signal to the distance measurement sensor 2b in the subsequent stage.

[0052] The distance measurement sensor 2b controls the distance measurement processing unit based on the received frame synchronization signal, transmits a light emission trigger to the light emission unit 3b, and transmits distance measurement data to the application system 200 based on the received communication interface signal. Further, when the image sensor 4 exists in the subsequent stage, the distance measurement sensor 2b transmits a frame synchronization signal and a communication interface signal to the subsequent image sensor 4.

[0053] The image sensor 4 generates and accumulates electric charges according to the amount of light received from a predetermined imaging field of view, and generates an image signal of the imaging field of view at, for example, 30 frames per second according to the accumulation amount of the electric charges. The image sensor 4 controls the image processing unit based on the received frame synchronization signal, and transmits the image signal to the application system 200 based on the received communication interface signal. Further, when there is no slave in the subsequent stage, the image sensor 4 transmits a feedback signal or readout information for the communication interface signal to the master distance measurement sensor 1C.

[0054] When the distance measurement sensor 1C receives the feedback signal or the readout information for the communication interface signal, it makes an error determination as to whether the feedback signal is returned within a predetermined time from the rising edge of the frame synchronization signal, and includes the error determination result in the distance measurement data and transmits it to the application system 200.

[0055] <Operational Effects According to the Fourth Embodiment> As described above, according to the fourth embodiment, the same operational effects as those of the second embodiment can be obtained, and even if the image sensor 4 that does not have a mechanism for transmitting a feedback signal to the frame synchronization signal is included, the master distance measurement sensor 1C can read the frame count number of the image sensor 4 and use it as a feedback signal for the frame synchronization signal, enabling a flexible system design.

[0056] <Fifth Embodiment> Next, the fifth embodiment will be described. The fifth embodiment is a modification of the fourth embodiment. FIG. 11 is a block configuration diagram showing a sensor control system 100D according to a fifth embodiment. In FIG. 11, the same parts as those in FIG. 10 are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0057] A light emitting unit 5 that emits IR light is connected to the image sensor 4. When the distance measurement sensor 1D receives a communication interface signal from the application system 200, based on the communication interface signal, it generates a frame synchronization signal, controls the distance measurement processing unit 50 based on the frame synchronization signal, transmits a light emission trigger to the light emitting unit 20, and transmits the frame synchronization signal and the communication interface signal to the slave distance measurement sensor 2a.

[0058] Based on the received frame synchronization signal, the distance measurement sensor 2a controls the distance measurement processing unit, transmits a light emission trigger to the light emitting unit 3a, and transmits distance measurement data to the application system 200 based on the received communication interface signal. Further, when there is a distance measurement sensor 2b in the subsequent stage, the distance measurement sensor 2a transmits the frame synchronization signal and the communication interface signal to the distance measurement sensor 2b in the subsequent stage.

[0059] Based on the received frame synchronization signal, the distance measurement sensor 2b controls the distance measurement processing unit, transmits a light emission trigger to the light emitting unit 3b, and transmits distance measurement data to the application system 200 based on the received communication interface signal. Further, when there is an image sensor 4 in the subsequent stage, the distance measurement sensor 2b transmits the frame synchronization signal and the communication interface signal to the image sensor 4 in the subsequent stage.

[0060] Based on the received frame synchronization signal, the image sensor 4 controls the image processing unit, transmits a light emission trigger to the light emitting unit 5, and transmits an image signal to the application system 200 based on the received communication interface signal. Further, when there is no slave in the subsequent stage, the image sensor 4 transmits a feedback signal or readout information for the communication interface signal to the master distance measurement sensor 1D.

[0061] When the ranging sensor 1D receives the read information for the feedback signal or the communication interface signal, it determines whether there is an error in whether the feedback signal is returned within a predetermined time from the rising edge of the frame synchronization signal, and includes the error determination result in the ranging data and transmits it to the application system 200.

[0062] <Operation and Effect according to the Fifth Embodiment> As described above, according to the fifth embodiment, the same operation and effect as those of the fourth embodiment can be obtained, and exclusive control between sensors becomes easier.

[0063] <Sixth Embodiment> Next, the sixth embodiment will be described. The sixth embodiment is a modification of the second embodiment. FIG. 12 is a block configuration diagram showing a sensor control system 100E according to the sixth embodiment. In FIG. 12, the same parts as those in FIG. 8 are denoted by the same reference numerals, and detailed description thereof is omitted.

[0064] Ranging sensors 2a, 2b, and 2c that operate as slaves are connected to the application system 200. When the ranging sensors 2a, 2b, and 2c receive a light emission request from the application system 200, based on the received light emission request, they transmit a light emission trigger to the light emission units 3a, 3b, and 3c, and include a light emission request transmission unit 6 that transmits the light emission request to the ranging sensor with the last connection order sequentially via the ranging sensors.

[0065] When the ranging sensor 2a receives the light emission request shown in FIG. 13(a) from the application system 200, it transmits a light emission trigger to the light emission unit 3a to cause light emission, and transmits a light emission request to the ranging sensor 2b of the slave.

[0066] The ranging sensor 2b transmits a light emission trigger to the light emitting unit 3b based on the received light emission request shown in Fig. 13(b), causing it to emit light at a timing shifted from the light emitting unit 3a. When there is a ranging sensor 2c in the subsequent stage, a light emission request is transmitted to the ranging sensor 2c in the subsequent stage.

[0067] The ranging sensor 2c transmits a light emission trigger to the light emitting unit 3c based on the received light emission request shown in Fig. 13(c), causing it to emit light at a timing shifted from the light emitting unit 3b. When there is no slave in the subsequent stage, an error notification or the like is sent to the application system 200.

[0068] <Operation and Effect of the Sixth Embodiment> As described above, according to the sixth embodiment, if the plurality of ranging sensors 2a, 2b, and 2c are sensors of different types, since the frame rate and the light emission pattern are different, the application system 200 performs light emission control, and uses the delay amounts of the respective ranging sensors 2a, 2b, and 2c to shift the light emission timing to prevent interference.

[0069] <Seventh Embodiment> Next, the seventh embodiment will be described. The seventh embodiment is a modification of the second embodiment. Fig. 14 is a block configuration diagram showing a sensor control system 100E according to the seventh embodiment. In Fig. 12, the same parts as those in Fig. 12 are denoted by the same reference numerals and detailed description thereof is omitted.

[0070] The ranging sensor 1F functioning as a master includes the above-described light emission request transmission unit 6. The ranging sensor 1F transmits a light emission trigger to the light emitting unit 20 to cause it to emit light, and transmits a light emission request to the slave ranging sensor 2a. The ranging sensor 2a transmits a light emission trigger to the light emitting unit 3a based on the received light emission request shown in Fig. 15(a), causing it to emit light at a timing shifted from the light emitting unit 20. When there is a ranging sensor 2b in the subsequent stage, a light emission request is transmitted to the ranging sensor 2b in the subsequent stage.

[0071] The ranging sensor 2b transmits a light emission trigger to the light emitting unit 3b based on the received light emission request shown in Fig. 15(b), causing it to emit light at a timing shifted from that of the light emitting unit 3a. When there is no ranging sensor in the subsequent stage, it transmits a feedback signal to the master ranging sensor 1F.

[0072] When the ranging sensor 1F receives the feedback signal, as shown in Fig. 15(c), it performs an error determination on whether the feedback signal is returned within a predetermined time from the transmission of the light emission request, and includes the error determination result in the ranging data and transmits it to the application system 200. In addition, the ranging sensor 1F measures the time required from the transmission of the light emission request to the ranging sensor 2a to the reception of the feedback signal for the light emission request, and when the feedback signal is not received within a predetermined time, it transmits error information to the application system 200.

[0073] <Operation and effect according to the seventh embodiment> As described above, according to the seventh embodiment, the master ranging sensor 1F can notify the application system 200 of an error if the feedback signal does not return within a range taking into account the exposure time, wiring delay, etc.

[0074] Also, according to the seventh embodiment, the time required from the transmission of the light emission request by the master ranging sensor 1F to the reception of the feedback signal for the light emission request can be measured.

[0075] <Eighth embodiment> Next, the eighth embodiment will be described. The eighth embodiment is an embodiment that performs error detection of the feedback signal with respect to the synchronization signal. Figs. 16 and 17 are timing charts for receiving a feedback signal and performing an error determination at the master in the eighth embodiment. Fig. 16 is an example of performing an error determination when there is sufficient space in the frame synchronization signal. After the error determination unit 85 of the distance measurement sensor 1 transmits the frame synchronization signal generated by the master synchronization signal generation unit 81 to the slave, as shown in Fig. 16(a), if the feedback signal is received within a certain period of time, it is considered OK, and if it cannot be received, it is determined as an error.

[0076] Also, after the error determination unit 85 transmits the frame synchronization signal generated by the master synchronization signal generation unit 81 to the slave, as shown in Fig. 16(b), if the feedback signal is received two or more times, it is determined as an error. Furthermore, when the frame synchronization signal is not pulsing and a feedback signal is received, it is determined as an error.

[0077] Fig. 17 shows an example of error determination when overtaking occurs if delay processing is added due to pulses output in a short period. As shown in Fig. 17(a), at the time when one unit of pulse output is completed, the error determination unit 85 compares the number of pulses of the frame synchronization signal with the number of pulses of the feedback signal. If they are the same, it is considered OK, and if they are different, it is determined as an error. Also, as shown in Fig. 17(b), when the frame synchronization signal is not pulsing and a feedback signal is received, it is determined as an error.

[0078] Fig. 18 shows an example of error determination during slave operation. The error determination unit 85 has the expected value of the number of pulses output per unit, compares it with the number of input pulses at the time when one unit of pulse output is completed, and if they are the same, it is considered OK, and if they are different, it is determined as an error.

[0079] <The Ninth Embodiment> Next, the ninth embodiment will be described. The ninth embodiment is an embodiment of I2C / SPI communication. Fig. 19 is a timing chart showing the I2C / SPI communication operation as the ninth embodiment. Since the distance measurement sensor 1 grasps the timing of the synchronization signal, I2C / SPI communication control can be performed in accordance with the synchronization signal.

[0080] Also, when internal adjustment is performed during master or slave operation, communication is possible even before the synchronization signal. When communication is desired before the start of line synchronization operation, communication is enabled at the end of the previous line operation (Fig. 19(1)) or by going back from the next synchronization to the time in Fig. 19(2). With this configuration, it becomes possible to efficiently control peripheral devices during the blanking period before or after the sensor operation.

[0081] <Other Embodiments> As described above, the present technology has been described by the first to ninth embodiments, but it should not be understood that the discussions and drawings forming part of this disclosure limit the present technology. For those skilled in the art, it will be apparent that various alternative embodiments, examples, and operation techniques can be included in the present technology if they understand the gist of the technical content disclosed by the above embodiments. Also, the configurations disclosed by the first to ninth embodiments and the modified examples of the first to ninth embodiments can be appropriately combined within a range where no contradiction occurs. For example, the configurations disclosed by a plurality of different embodiments may be combined, or the configurations disclosed by a plurality of different modified examples of the same embodiment may be combined.

[0082] Note that the present disclosure can also adopt the following configuration. (1) A light emitting unit that irradiates light onto a target area, A sensor having a plurality of pixels that receive reflected light from the target area and convert it into an electrical signal, and a signal processing unit that performs signal processing based on the electrical signal output for each pixel, A control device that can be connected to the sensor and controls the execution of signal processing of the sensor and the sensor includes a communication interface processing unit that receives a communication interface signal necessary for control related to the signal processing from an external device, a synchronization signal generation unit that generates a synchronization signal for synchronizing with the signal processing based on the communication interface signal, A light emission trigger output unit that transmits a light emission trigger for irradiating the light emitting unit with light based on the synchronization signal; A synchronization signal processing unit that controls the signal processing unit based on the synchronization signal and transmits the synchronization signal to an external device that can be connected; A feedback signal processing unit that receives a feedback signal returned from the light emitting unit in response to the light emission trigger, receives a feedback signal returned from the external device in response to the synchronization signal, and transmits predetermined signal processing data including the reception result to the control device A sensor control system comprising: (2) The synchronization signal generation unit generates a frame synchronization signal synchronized with an imaging frame formed by the plurality of pixels, The synchronization signal processing unit generates a line synchronization signal having a shorter period than the frame synchronization signal from the frame synchronization signal, and transmits the line synchronization signal to the external device The sensor control system according to (1) above. (3) The synchronization signal processing unit transmits the line synchronization signal to an imaging position changing device capable of changing the imaging position of the sensor The sensor control system according to (2) above. (4) The feedback signal processing unit performs an error determination by comparing the synchronization signal and the feedback signal, and transmits the error determination result to the control device The sensor control system according to (1) above. (5) A plurality of the sensors are provided, In the first sensor among the plurality of sensors, the synchronization signal processing unit controls the signal processing unit based on the frame synchronization signal, and outputs the frame synchronization signal to another second sensor. In the second sensor, the signal processing unit is controlled based on the frame synchronization signal, and when there is a second sensor in the subsequent stage, the frame synchronization signal is output to the second sensor in the subsequent stage. The feedback signal processing unit receives, at the first sensor, a feedback signal transmitted from the second sensor that is the last stage, and transmits the reception result to the control device. The sensor control system according to (2) above. (6) The communication interface processing unit receives, at each of the plurality of sensors, the communication interface signal from the control device. The sensor control system according to (5) above. (7) The communication interface processing unit receives, at the first sensor, the communication interface signal from the control device, and transmits the communication interface signal from the first sensor to the second sensor that is the last in the connection order via the plurality of second sensors in sequence. The sensor control system according to (5) above. (8) The second sensor that is the last in the connection order is an image sensor. The sensor control system according to (5) above. (9) When each of the plurality of sensors receives a light emission request from the control device, based on the received light emission request, it transmits the light emission trigger to the light emitting unit and transmits the light emission request to the sensor that is the last in the connection order via the plurality of sensors in sequence. Each is provided with a light emission request transmission unit. The sensor control system according to (5) above. (10) The feedback signal processing unit receives, at the first sensor, a feedback signal for the transmission of the light emission request from the second sensor that is the last stage, and transmits predetermined signal processing data including the reception result to the control device. The sensor control system according to (9) above. (11) The feedback signal processing unit performs an error determination by comparing the frame synchronization signal with the feedback signal output from the second sensor that is the last stage at the first sensor, and transmits the error determination result to the control device. The sensor control system described in (5) above. (12) The feedback signal processing unit measures the time required from the transmission of the light emission request to the second sensor to the reception of the feedback signal for the light emission request in the first sensor, and when the feedback signal is not received within a predetermined time, it transmits error information to the control device. The sensor control system described in (10) above. (13) The synchronization signal generation unit receives the synchronization signal from the control device. The sensor control system described in (1) above. (14) The communication interface processing unit receives a communication interface signal from the control device. The sensor control system described in (1) above. (15) A plurality of pixels that are irradiated with light to a target area from a light emitting unit, receive reflected light from the target area, and convert it into an electrical signal, A signal processing unit that performs signal processing based on the electrical signal output for each pixel, A communication interface processing unit that receives a communication interface signal necessary for control related to the signal processing from an external device, A synchronization signal generation unit that receives a synchronization signal for synchronizing the signal processing based on the communication interface signal, A light emission trigger output unit that transmits a light emission trigger for irradiating the light emitting unit with light based on the synchronization signal, A synchronization signal processing unit that controls the signal processing unit based on the synchronization signal and transmits the synchronization signal to a connectable external device, A feedback signal processing unit that receives a feedback signal returned from the light emitting unit in response to the light emission trigger, receives a feedback signal returned from the external device in response to the synchronization signal, includes the reception result in predetermined signal processing data, and transmits it to a control device that controls the execution of the signal processing A sensor comprising: (16) A plurality of pixels that are irradiated with light from a light emitting unit to a target area, receive reflected light from the target area, and convert it into an electrical signal, A signal processing unit that performs signal processing based on the electrical signal output for each pixel, A communication interface processing unit that receives a communication interface signal necessary for control related to the signal processing, A synchronization signal receiving unit that receives a synchronization signal for synchronizing with the signal processing from an external device, A light emission trigger output unit that transmits a light emission trigger for irradiating the light emitting unit with light based on the synchronization signal, A synchronization signal processing unit that controls the signal processing unit based on the synchronization signal and transmits the synchronization signal to a connectable external device, A sensor comprising: (17) The sensor according to (16), further comprising a feedback signal processing unit that receives a feedback signal returned from the light emitting unit in response to the light emission trigger and includes the reception result in a feedback signal to an external device and transmits it. (18) The sensor according to (16), wherein the communication interface processing unit receives the communication interface signal from a control device that controls execution of the signal processing. (19) The sensor according to (16), wherein the communication interface processing unit receives the communication interface signal from an external device.

Explanation of Reference Numerals

[0083] 1, 1A, 1B, 1C, 1D, 1F, 2a, 2b, 2c... distance measurement sensors, 3a, 3b, 3c, 5, 20... light emitting units, 4... image sensors, 6... light emission request transmission unit, 10... system control unit, 10a... communication interface signal processing unit, 10b... frame synchronization signal receiving unit, 10c... frame synchronization signal processing unit, 30... light emission timing adjustment unit, 40... light receiving unit, 41... pixels, 43... pixel drive lines, 44... vertical signal lines, 50... distance measurement processing unit, 51... sampling circuit, 52... histogram generation circuit, 53... distance calculation circuit, 60... communication interface unit, 70... pixel drive unit, 81... master synchronization signal generation unit, 82... slave signal receiving unit, 83... synchronization signal selection unit, 84... delay adjustment unit, 85... error determination unit, 90... buffer, 100, 100A, 100B, 100C, 100D, 100E... sensor control systems, 200... application system, 300... imaging position changing device, 400... host device

Claims

1. A light-emitting unit that irradiates light onto a target area, a plurality of pixels that receive reflected light from the target area and convert it into an electrical signal, and a signal processing unit that performs signal processing based on the electrical signal output for each pixel, and a sensor having the same, a control device that can be connected to the sensor and controls the execution of signal processing of the sensor comprising, the sensor is, a communication interface processing unit that receives a communication interface signal necessary for control related to the signal processing from an external device, a synchronization signal generation unit that generates a synchronization signal for synchronization with the signal processing based on the communication interface signal, a light emission trigger output unit that transmits a light emission trigger for causing the light-emitting unit to irradiate light based on the synchronization signal, a synchronization signal processing unit that controls the signal processing unit based on the synchronization signal and transmits the synchronization signal to a connectable external device, a feedback signal processing unit that receives a feedback signal returned from the light-emitting unit in response to the light emission trigger, receives a feedback signal returned from the external device in response to the synchronization signal, and transmits predetermined signal processing data including the reception result to the control device A sensor control system comprising.

2. The synchronization signal generation unit generates a frame synchronization signal synchronized with an imaging frame formed by the plurality of pixels, The synchronization signal processing unit generates a line synchronization signal having a shorter period than the frame synchronization signal from the frame synchronization signal and transmits the line synchronization signal to the external device The sensor control system according to claim 1.

3. The synchronization signal processing unit transmits the line synchronization signal to an imaging position changing device capable of changing the imaging position of the sensor The sensor control system according to claim 2.

4. The feedback signal processing unit performs an error determination by comparing the synchronization signal and the feedback signal, and transmits the error determination result to the control device The sensor control system according to claim 1.

5. A plurality of the sensors are provided, The synchronization signal processing unit controls the signal processing unit based on the frame synchronization signal in the first sensor among the plurality of sensors, and outputs the frame synchronization signal to other second sensors. In the second sensor, the signal processing unit is controlled based on the frame synchronization signal, and when there is a second sensor in the subsequent stage, the frame synchronization signal is output to the second sensor in the subsequent stage. The feedback signal processing unit receives a feedback signal transmitted from the second sensor that is the last stage in the first sensor, and transmits the reception result to the control device. The sensor control system according to claim 2.

6. The communication interface processing unit receives the communication interface signal from the control device in each of the plurality of sensors. The sensor control system according to claim 5.

7. The communication interface processing unit receives the communication interface signal from the control device in the first sensor, and transmits the communication interface signal from the first sensor to the second sensor whose connection order is the last via the plurality of second sensors in sequence. The sensor control system according to claim 5.

8. The second sensor whose connection order is the last is an image sensor. The sensor control system according to claim 5.

9. When each of the plurality of sensors receives a light emission request from the control device, based on the received light emission request, it transmits the light emission trigger to the light emitting unit and includes a light emission request transmission unit that transmits the light emission request to the sensor whose connection order is the last via the plurality of sensors in sequence. The sensor control system according to claim 5.

10. The feedback signal processing unit receives a feedback signal for the transmission of the light emission request from the second sensor that is the last stage in the first sensor, and transmits predetermined signal processing data including the reception result to the control device. The sensor control system according to claim 9.

11. The feedback signal processing unit performs an error determination by comparing the frame synchronization signal with the feedback signal output from the second sensor that is the last stage in the first sensor, and transmits the error determination result to the control device. The sensor control system according to claim 5.

12. The feedback signal processing unit measures, in the first sensor, the time required from the transmission of the light emission request to the second sensor to the reception of the feedback signal for the light emission request, and transmits error information to the control device when the feedback signal is not received within a predetermined time. The sensor control system according to claim 10.

13. The synchronization signal generation unit receives the synchronization signal from the control device. The sensor control system according to claim 1.

14. The communication interface processing unit receives a communication interface signal from the control device. The sensor control system according to claim 1.

15. A plurality of pixels that irradiate light to a target area from a light emitting unit, receive reflected light from the target area, and convert it into an electrical signal, A signal processing unit that performs signal processing based on the electrical signal output for each pixel, A communication interface processing unit that receives a communication interface signal necessary for control related to the signal processing from an external device, A synchronization signal generation unit that receives a synchronization signal for synchronizing the signal processing based on the communication interface signal, A light emission trigger output unit that transmits a light emission trigger for irradiating the light emitting unit with light based on the synchronization signal, A synchronization signal processing unit that controls the signal processing unit based on the synchronization signal and transmits the synchronization signal to an external device that can be connected, A feedback signal processing unit that receives a feedback signal returned from the light emitting unit in response to the light emission trigger, receives a feedback signal returned from the external device in response to the synchronization signal, includes the reception result in predetermined signal processing data, and transmits it to a control device that controls the execution of the signal processing A sensor comprising:

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