Distance measuring device and distance measuring method

Abstract

A distance measuring device is provided that can improve measurement accuracy while reducing power consumption. A variation amplification unit amplifies a variation in the time relative relationship between an electric signal output from a light receiving element and a clock signal generated by a clock generation unit. Next, a synchronization unit generates a synchronization signal by synchronizing the electric signal with the clock signal based on the electric signal and the clock signal after the variation amplification by the variation amplification unit. Next, a histogram creation unit creates a histogram based on the time from when a light source emits light to when a light receiving element receives reflected light based on the synchronization signal generated by the synchronization unit. Next, a distance calculation unit calculates the distance to an object based on the histogram created by the histogram creation unit.

Description

Technical Field

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

[0002] In recent years, a distance measuring device that directly measures the distance to an object using time of flight (ToF) has been proposed (for example, see Patent Document 1). In the distance measuring device disclosed in Patent Document 1, the time period from when a light source emits light to when a light receiving element receives reflected light is measured multiple times, and a histogram based on the multiple measured time periods is used to improve the accuracy of distance measurement.

[0003] Reference List

[0004] Patent Literature

[0005] Patent document 1: JP 2014-081254 A. Summary of the invention

[0006] Technical issues

[0007] However, in such a distance measurement device, it is necessary to reduce power consumption and improve the accuracy of distance measurement.

[0008] An object of the present disclosure is to provide a distance measurement device and a distance measurement method that can reduce power consumption while improving measurement accuracy.

[0009] Solution to the problem

[0010] The distance measuring device of the present disclosure includes: (a) a light source configured to emit light; (b) a light receiving element configured to receive light reflected from an object reflecting light; (c) a change amplifying section configured to amplify a change in the time relative relationship between an electric signal output from the light receiving element and a clock signal; (d) a synchronizing section configured to generate a synchronizing signal by synchronizing the electric signal with the clock signal based on the electric signal and the clock signal after the change is amplified by the change amplifying section; (e) a histogram creating section configured to create a histogram based on a time period from when the light source emits light to when the light receiving element receives reflected light based on the synchronizing signal generated by the synchronizing section; and (f) a distance calculating section configured to calculate the distance to the object based on the histogram created by the histogram creating section.

[0011] The distance measurement method disclosed in the present invention includes: (a) receiving, by a light receiving element, light reflected from an object reflecting light received from a light source, and outputting an electric signal; (b) amplifying a change in the temporal relative relationship between the output electric signal and a clock signal; (c) generating a synchronization signal by synchronizing the electric signal with the clock signal based on the electric signal and the clock signal after the amplification change; (d) creating, based on the generated synchronization signal, a histogram based on a time period from when the light source emits light to when the light receiving element receives reflected light; and (e) calculating the distance to the object based on the created histogram. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] [ Figure 1 ] is a diagram showing the overall configuration of a distance measurement device according to a first embodiment of the present disclosure.

[0013] [ Figure 2 ] is a diagram showing the configuration of the light projection section.

[0014] [ Figure 3A ] is a diagram illustrating a method of setting the period of a CLK signal.

[0015] [ Figure 3B ] is a diagram illustrating a method of setting the period of a CLK signal.

[0016] [ Figure 3C ] is a diagram illustrating a method of setting the period of a CLK signal.

[0017] [ Figure 4A ] is a diagram illustrating a method of setting the period of a CLK signal.

[0018] [ Figure 4B ] is a diagram illustrating a method of setting the period of a CLK signal.

[0019] [ Figure 5A ] is a diagram showing a histogram when the cycle of the CLK signal is short.

[0020] [ Figure 5B ] is a diagram showing a histogram without amplifying the changes.

[0021] [ Figure 5C ] is a diagram showing a histogram when the cycle of the CLK signal is long.

[0022] [ Figure 6 ] is a diagram showing the configuration of the variation amplification section.

[0023] [ Figure 7 ] is a diagram showing the electrical signal before and after jitter is added.

[0024] [ Fig. 8A ] is a diagram showing a NOT gate.

[0025] [ Figure 8B ] is a diagram showing a NOR gate.

[0026] [ Figure 8C ] is a diagram showing an AND gate.

[0027] [ Fig.8D ] is a diagram showing an exclusive OR (XOR) gate.

[0028] [ Fig. 9 ] is a diagram showing the configuration of a first adding section and a second adding section.

[0029] [ Fig. 10A ] is a diagram showing an RC circuit.

[0030] [ Fig. 10B ] is a diagram showing an RC circuit including a variable resistor.

[0031] [ Fig. 10C ] is a diagram showing an RC circuit including a variable capacitor.

[0032] [ Fig. 10D ] is a diagram showing an RC circuit including a variable resistor and a variable capacitor.

[0033] [ Fig.11A ] is a diagram showing a variable amplification section in the case of using an RC circuit including a variable capacitor.

[0034] [ Fig. 11B ] is a diagram showing a variable amplification section in the case of using an RC circuit including a variable resistor and a variable capacitor.

[0035] [ Fig. 12A ] is a diagram showing an NMOS switch.

[0036] [ Fig. 12B ] is a diagram showing a PMOS switch.

[0037] [ Fig. 12C ] is a diagram showing a CMOS switch.

[0038] [ Fig.13A ] is a diagram showing a NAND gate.

[0039] [ Fig. 13B ] is a diagram showing a NOR gate.

[0040] [ Fig.14 ] is a diagram showing the CLK signal before and after jitter addition.

[0041] [ Fig.15] is a sequence diagram showing the operation of the distance measurement device according to the first embodiment of the present disclosure.

[0042] [ Fig.16 ] is a diagram showing the overall configuration of a distance measuring device according to a modified example.

[0043] [ Fig.17 ] is a diagram showing the potential of SPAD.

[0044] [ Fig.18 ] is a diagram showing the overall configuration of a distance measuring device according to a modified example.

[0045] [ Fig.19 ] is a diagram showing the overall configuration of a distance measuring device according to a modified example.

[0046] [ Fig. 20 ] is a diagram showing the overall configuration of a moving body control system according to an application example.

[0047] [ Fig.21 ] is a diagram showing the installation positions of the imaging unit and the vehicle exterior information detection unit. DETAILED DESCRIPTION

[0048] The inventors have considered increasing the internal frequency when high-precision distance measurement is required in the distance measuring device, and reducing the internal frequency when high-precision distance measurement is not required. However, when the internal frequency is too low, the distance measurement results may be collected in one bin in a histogram based on the time period from emission of light to reception of reflected light, and there is a problem of reduced accuracy of position estimation by fitting of a probability density function.

[0049] In the following, reference will be made to Figures 1 to 21 An example of a distance measuring device and a distance measuring method according to an embodiment of the present disclosure is described. The embodiments of the present disclosure will be described in the following order. Meanwhile, the present disclosure is not limited to the following examples. In addition, the effects described in this specification are only examples and are not limited, and there may be other effects.

[0050] 1. First embodiment: distance measuring device

[0051] 1-1 Overall configuration of the distance measuring device

[0052] 1-2 Operation of distance measuring device

[0053] 1-3 Modification Example

[0054] 2. Application example: mobile control system

[0055] <1. First Embodiment>

[0056] [1-1 Overall configuration of distance measuring device]

[0057] Figure 1 : is a schematic configuration diagram showing the entirety of a distance measurement device according to a first embodiment of the present disclosure. Figure 1 The distance measuring device is a ToF distance measuring sensor. Figure 1 As shown, the distance measuring device according to the first embodiment includes components such as a light projection section 1, a light receiving section 2, a clock signal generating section 3, a distance measurement processing section 4, and a control section 5. These components may be integrated and configured as a system on a chip (SoC) such as complementary MOS (CMOS) or large-scale integration (LSI), or some components such as the light projection section 1 and the light receiving section 2 may be configured as separate LSIs. The distance measuring device operates in response to a clock signal output from the clock signal generating section 3. The distance measuring device includes a communication IF section 6 for outputting distance measurement data according to the distance calculated by the distance measurement processing section 4 to the outside. Although not shown in the figure, the distance measuring device is configured to be able to communicate with an external host IC through the communication IF section 6.

[0058] like Figure 2 As shown, the light projection section 1 includes a light source 8 that emits light 7 for ToF distance measurement. For example, a laser beam can be used as the light 7. The light source 8 can be, for example, an edge-emitting semiconductor laser or can be a surface-emitting semiconductor laser. The light source 8 is driven by a trigger pulse applied from the control section 5. The trigger pulse is a pulse-shaped signal with a predetermined frequency. In addition, the light projection section 1 includes a scanning mechanism for performing raster scanning on the light 7. Figure 2 In FIG. 1 , a mirror scanning type scanning mechanism including an emission lens 9, a light projection mirror 10, and a micromirror 11 is shown as the scanning mechanism.

[0059] The micromirror 11 changes the orientation of the reflection surface in response to a control signal applied from the control section 5. In addition, the light 7 emitted by the light source 8 is emitted in a direction corresponding to the orientation of the reflection surface of the micromirror 11 through the emission lens 9, the light projection mirror 10, and the micromirror 11. The emitted light 7 is reflected by the object 12, and the reflected light 7 (hereinafter, also referred to as "reflected light 13") is incident on the light receiving section 2 through the micromirror 11 and the light projection mirror 10. In this case, since the trigger pulse has a predetermined frequency and the light source 8 periodically emits light, the light 7 emitted from the light source 8 irradiates the same part of the object 12 multiple times, and the reflected light 13 reflected from the position irradiated by the light 7 is incident on the same part (light receiving element 15) of the light receiving section 2 multiple times. Examples of the object 12 include a vehicle ahead of the vehicle in the case where the distance measuring device is mounted on the vehicle, etc.

[0060] The light receiving unit 2 includes a receiving lens 14 and a plurality of light receiving elements 15. The plurality of light receiving elements 15 are arranged in a two-dimensional array. As the light receiving element 15, for example, a single photon avalanche diode (SPAD) that responds to the received light and outputs an electrical signal can be used. In addition, the light receiving unit 2 collects the reflected light 13 incident through the micromirror 11 and the light projection mirror 10 through the receiving lens 14, and causes the light receiving element 15 to receive the light according to the scanning direction of the light 7. The electrical signal received from the light receiving element 15 is output to the distance measurement processing unit 4.

[0061] The clock signal generating unit 3 generates a clock signal (hereinafter also referred to as a "CLK signal") in response to a control signal received from the control unit 5. The CLK signal is output to the distance measurement processing unit 4. For example, in the case where the distance measurement device is installed on a vehicle, Figure 3A and Figure 3B As shown in FIG. 1 , when it is determined that there is no obstacle within a predetermined distance from the vehicle, the frequency of the CLK signal is set to a relatively small value, thereby reducing power consumption. Figure 3C As shown, when it is determined that there is an obstacle within a predetermined distance from the vehicle, the frequency of the CLK signal is set to a relatively large value so that the areas α, β, and γ where the obstacle exists on the road are checked in detail. In addition, for example, low power consumption can be achieved by lowering the frequency of the CLK signal to investigate all areas, and then by increasing the frequency of the CLK signal to check only the areas α, β, and γ where the obstacle is determined to exist.

[0062] In addition, for example, in the case where the distance measuring device is mounted on a drone, such as Figure 4A and Figure 4B As shown, when it is determined that there is no obstacle within a predetermined distance from the drone, the frequency of the CLK signal is set to a relatively small value to reduce power consumption. On the other hand, when it is determined that there is an obstacle, the frequency of the CLK signal is set to a relatively large value to allow for a detailed inspection of the area where the obstacle exists.

[0063] The distance measurement processing unit 4 is a component that calculates the distance to the object 12 based on the timing of the light source 8 emitting the light 7 and the timing of the light receiving unit 2 receiving the reflected light 13. The distance measurement processing unit 4 is composed of, for example, a signal processing processor. The distance measurement processing unit 4 is configured to include a time digital converter (TDC) 16, a histogram creation unit 17, and a distance calculation unit 18.

[0064] The TDC 16 is a component that converts a time period (hereinafter also referred to as "arrival time") from the emission of the light 7 from the light source 8 to the reception of the reflected light 13 by the light receiving element 15 into a digital value based on a trigger pulse (a trigger pulse for driving the light source 8) applied from the control section 5 and a synchronization signal generated by the synchronization section 20. As the digital value, for example, a numerical value in the range of 0 to 255 can be used. The obtained digital value is output to the histogram creation section 17.

[0065] More specifically, the TDC 16 constitutes a variation amplifying section 19 and a synchronizing section 20. The variation amplifying section 19 is a component that amplifies a variation in the temporal relative relationship between the electrical signal output from the light receiving element 15 and the CLK signal output from the clock signal generating section 3. Preferably, the magnitude of the variation is equal to or greater than the magnitude of the histogram created by the histogram creating section 17. Figure 5A , Figure 5B and Figure 5C The width of the interval of the histogram shown is 1 / 3 of the width of the interval of the histogram created by the histogram creation unit 17 and is equal to or smaller than Figure 5A , Figure 5B and Figure 5C The width of the bins of the histogram shown is 1 / 2, which reduces the frequency of a certain bin and increases the frequency of the adjacent bins. Figure 6 As shown, the variation amplification section 19 is configured to include a first electrical path 21, a plurality of first adding sections 221 to 22 n (n is a natural number of 2 or more) and a first mutually exclusive operation switch 23. In addition, the variation amplification section 19 is configured to include a second electrical path 24, a plurality of second adding sections 251 to 25 n and a second mutually exclusive operation switch 26.

[0066] The first electrical path 21 is a signal line, one end of which is connected to the input terminal 27, receives input of an electrical signal from the light receiving element 15, and the other end is connected to one end of a first switch 280 included in the first mutually exclusive operation switch 23. In addition, the electrical signal input from the light receiving element 15 is output to one end of the first switch 280 included in the first mutually exclusive operation switch 23 through the first electrical path 21.

[0067] Each first adding portion 22 i (i is any one of 1 to n) is a signal path provided in parallel with the first electrical path 21, one end of which is connected to the input terminal 27, receives input of the electrical signal from the light receiving element 15, and the other end is connected to the first switch 28 included in the first exclusive operation switch 23 i In addition, the electrical signal output from the light receiving element 15 is output to the first switch 28 included in the first exclusive operation switch 23. iOne end of the electrical signal, wherein jitter is added to the electrical signal. Jitter is a change component generated along the time axis direction in the signal waveform and is extremely short in time. Figure 7 As shown, in this way, jitter is added to the electric signal, and thus the electric signal after the jitter is added varies according to the probability density function of the variation due to the jitter.

[0068] First adding part 221 to 22 n Each of these can use one or more logic gates (such as Fig. 8A The NOT gate shown, Figure 8B The NOR gate shown, Figure 8C The AND gate and Fig.8D For example, Fig. 9 As shown, the first adding part 221 to 22 n Each of them can be a multi-stage delay circuit with multiple NOT gates connected in series. The logic gate is composed of multiple transistors, for example. Fig. 9 , a configuration having only the first adding portion 221 is shown as the first adding portion 221 to 22 n .

[0069] In addition, if Fig. 10A As shown, the first adding part 221 to 22 n Each of the first adding sections 221 to 222 can be configured using one or more RC circuits. By using RC circuits, the signal edge can be blunted and the jitter can be increased. n Each of the RC circuits may be a multi-stage circuit in which a plurality of RC circuits are connected in series. The multi-stage circuit may be configured to include a parallel path, etc. In addition, the logic gate and the RC circuit may be combined and connected in series with each other. In the case of using the RC circuit, the on resistance of the MOS may be used as a resistor, the parasitic capacitance of the MOS may be used as a capacitor, and as Fig. 10B , Fig. 10C and Fig. 10D As shown, the RC circuit may be configured so that one or both of the resistance value of the resistor and the capacitance value of the capacitor can be changed. That is, the RC circuit may be configured to include one or both of a variable resistor and a variable capacitor.

[0070] Fig.11A As shown in FIG. 22 , the first adding part 221 to 22 n Only the configuration of the capacitance value of the capacitor can be changed. Fig.11A It is shown that only the first adding part 221 is provided as the first adding part 221 to 22 n In addition, Fig. 11B As shown in FIG. 22 , the first adding part 221 to 22 nThe configuration of both the resistance value of the resistor and the capacitance value of the capacitor can be changed. Fig. 11B The configuration in which 0 "Ω" can be selected as the resistance value of the resistor and 0 "F" can be selected as the capacitance value of the capacitor is shown, and the Fig.11A The configuration of the first mutually exclusive operation switch 23 and the second mutually exclusive operation switch 26 is shown. Fig. 11B It is shown that only the first adding part 221 is provided as the first adding part 221 to 22 n Configuration.

[0071] The first mutually exclusive operation switch 23 is configured to include a plurality of first switches 280 to 28 n , wherein a first switch 28 j (j is any one of 0 to n) is set to the on state, and the remaining first switches 280 to 28 j-1 and 28 j+1 to 28 n When the first switch 280 is in the on state, the first switch 280 sets the electrical conduction state between the other end of the first electrical path 21 and the output terminal 29 connected to the synchronization unit 20. When the first switch 280 is in the off state, the first switch 280 sets the cutoff state between the other end of the first electrical path 21 and the output terminal 29 connected to the synchronization unit 20. In addition, when the first switch 280 is in the off state, the first switch 280 sets the electrical conduction state between the other end of the first electrical path 21 and the output terminal 29 connected to the synchronization unit 20. i When the first switch 28 is in the on state, i Setting the first adding part 22 i The other end of the first switch 28 is electrically connected to the output terminal 29 connected to the synchronization unit 20. i When the first switch 28 is in the off state, i Setting the first adding part 22 i The other end of the first switch 280 to the output terminal 29 connected to the synchronization unit 20 is in an off state. In addition, the first exclusive operation switch 23 responds to the path selection signal received from the control unit 5, and the first switches 280 to 28 n Any one of the first addition parts 221 to 22 is set to a conductive state, and the electrical signal passing through the first electrical path 21 or the electrical signal from the first addition part 221 to 22 n The electrical signal with jitter added thereto is output to the synchronization section 20. For example, in the case where the histogram created by the histogram creating section 17 Figure 5A , Figure 5B and Figure 5CWhen the width of the interval of the histogram shown is equal to or less than a predetermined width determined in advance, the first exclusive operation switch 23 sets the first switch 280 to the on state and outputs the electrical signal through the first electrical path 21 to the synchronization section 20. On the other hand, when the width of the interval is greater than the predetermined width, the first exclusive operation switch 23 sets the first switches 281 to 28 n any one of which is set to the on state, and the first adding portion 221 to 22 n Any one of the electrical signals output and added with jitter is output to the synchronization section 20 .

[0072] The first switches 280 and 281 to 28 n Each of these can be represented by Fig. 12A The NMOS switch shown, Fig. 12B The PMOS switch and Fig. 12C Meanwhile, when the analog method is used, the jitter of the electrical signal passing through the first electrical path 21 may increase the on-resistance of the MOS.

[0073] In addition, the first switches 280 and 281 to 28 n Each of these can be represented by Fig.13A The NAND gate and Fig. 13B Since the electrical signal output from the light receiving element 15 is already operated with a logic amplitude, it is preferred to use an element with a driving force such as a NAND gate or a NOR gate in terms of characteristics, rather than using an NMOS switch or the like. Fig.13A and Fig. 13B Logic gates with 2 inputs (NAND gate, NOR gate) are shown in FIG, but logic gates with 3 or more inputs may be used.

[0074] The second electrical path 24 is a signal line, one end of which is connected to the input terminal 30, receives the input of the CLK signal output from the clock signal generating section, and the other end is connected to one end of the second switch 310 included in the second mutually exclusive operation switch 26. In addition, the CLK signal is output to one end of the second switch 310 included in the second mutually exclusive operation switch 26 through the second electrical path 24.

[0075] Each second adding portion 25 i The second electrical path 24 is a signal path provided in parallel with the second electrical path 24, one end of which is connected to the input terminal 30, receives the input of the CLK signal from the clock signal generating section 3, and the other end is connected to the second switch 31 included in the second exclusive operation switch 26. i In addition, the CLK signal is output to the second switch 31 included in the second exclusive operation switch 26.i One end of the CLK signal, wherein jitter (a short change component generated along the time axis direction) is added to the CLK signal. Fig.14 As shown, in this way, jitter is added to the CLK signal, and thus the CLK signal after the jitter is added varies in the time axis direction according to the probability density function of the variation due to the jitter.

[0076] Similar to the first adding parts 221 to 22 n , the second adding part 251 to 25 n Each of these can be used as Fig. 8A The NOT gate shown, Figure 8B The NOR gate shown, Figure 8C The AND gate shown and Fig.8D One or more of the XOR gates shown are configured. Fig. 9 As shown, the second adding part 251 to 25 n Each of them can be a multi-stage delay circuit with multiple NOT gates connected in series. Fig. 9 , a configuration having only the second adding portion 251 is shown as the second adding portion 251 to 25 n .

[0077] In addition, if Fig. 10A As shown, the second adding part 251 to 25 n Each of the second adding sections 251 to 252 can be configured using one or more RC circuits. By using RC circuits, the signal edge can be blunted and the jitter can be increased. n Each of the RC circuits may be a multi-stage circuit in which a plurality of RC circuits are connected in series. The multi-stage circuit may be configured to include parallel paths, etc. In addition, the logic gate and the RC circuit may be combined and connected in series with each other. In the case of using the RC circuit, the on-resistance of the MOS may be used as a resistor, the parasitic capacitance of the MOS may be used as a capacitor, and as Fig. 10B , Fig. 10C and Fig. 10D As shown, the RC circuit may be configured such that one or both of the resistance value of the resistor and the capacitance value of the capacitor may be changed.

[0078] Fig.11A The second adding part 251 to 25 n Only the configuration of the capacitance value of the capacitor can be changed. Fig.11A It is shown that only the second adding part 251 is provided as the second adding part 251 to 25 n In addition, Fig. 11B The second adding part 251 to 25 n The configuration of both the resistance value of the resistor and the capacitance value of the capacitor can be changed. Fig. 11BThe configuration in which 0 "Ω" can be selected as the resistance value of the resistor and 0 "F" can be selected as the capacitance value of the capacitor is shown, and the Fig.11A The configuration of the first mutually exclusive operation switch 23 and the second mutually exclusive operation switch 26 is shown. Fig. 11B It is shown that only the second adding part 251 is provided as the second adding part 251 to 25 n Configuration.

[0079] At the same time, preferably, the second adding parts 251 to 25 n The configuration of the first adding portion 221 to 22 n The configurations of the two devices match, but their configurations do not have to match each other.

[0080] The second mutually exclusive operation switch 26 is configured to include a plurality of second switches 310 to 31 n , wherein a second switch 31 j are set to be in the on state, and the remaining second switches 310 to 31 j-1 and 31 j+1 to 31 n When the second switch 310 is in the on state, the second switch 310 sets the other end of the second electrical path 24 to the output terminal 32 connected to the synchronization unit 20 in an electrically conductive state. When the second switch 310 is in the off state, the second switch 310 sets the other end of the second electrical path 24 to the output terminal 32 connected to the synchronization unit 20 in an electrically conductive state. i When the second switch 31 is in the on state, i Setting the second adding part 25 i The other end of the second switch 31 is electrically connected to the output terminal 32 of the synchronization unit 20. i When the second switch 31 is in the off state, i Setting the second adding part 25 i The other end of the second switch 26 is connected to the output terminal 32 of the synchronization unit 20 in an off state. In addition, the second exclusive operation switch 26 responds to the path selection signal received from the control unit 5, and the second switches 310 to 31 n Any one of them is set to the on state, and the CLK signal passing through the second electrical path 24 or the CLK signal from the second adding section 251 to 25 n The CLK signal with jitter added thereto is output to the synchronization section 20. For example, in the case where the histogram creation section 17 creates Figure 5A , Figure 5B and Figure 5CWhen the width of the interval of the histogram shown is equal to or less than the predetermined width, the second exclusive operation switch 26 sets the second switch 310 to the on state and outputs the CLK signal through the second electrical path 24 to the synchronization section 20. On the other hand, when the width of the interval is greater than the predetermined width, the second exclusive operation switch 26 sets the second switches 311 to 31 n Any one of them is set to the on state, and the second adding portion 251 to 25 n Any one of the CLK signals output and added with jitter is output to the synchronization section 20. Similar to the first switches 280 and 281 to 28 n , as the second switch 310 to 31 n The method can be adopted as FIG. 12A to FIG. 12C The simulation method shown and Fig.13A and Fig. 13B The logical approach shown.

[0081] With this configuration, the variation amplification section 19 can apply variation to one or both of the electric signal output from the light receiving element 15 and the CLK signal output from the clock signal generation section 3 and amplify the variation in the temporal relative relationship between the electric signal and the CLK signal.

[0082] The synchronization section 20 is a component that generates a synchronization signal obtained by synchronizing the amplified and changed electrical signal with the CLK signal based on the electrical signal amplified and changed by the change amplifier 19 and the CLK signal. More specifically, the synchronization section 20 generates a synchronization signal obtained by synchronizing the electrical signal output from the first mutually exclusive operation switch 23 with the CLK signal output from the second mutually exclusive operation switch 26. The synchronization section 20 is composed of, for example, a D flip-flop.

[0083] With this configuration, the TDC 16 can measure a time period (arrival time) from when the light source 8 emits the light 7 to when the light receiving element 15 receives the reflected light 13, based on the trigger pulse applied from the control section 5 and the synchronization signal generated by the synchronization section 20, and can output a digital value corresponding to the measured time period (arrival time). As a method of measuring the arrival time, for example, a method of measuring a time period from when the trigger pulse rises to when the synchronization signal rises can be adopted.

[0084] The histogram creation section 17 creates a histogram by accumulating each digital value (interval) converted by the TDC 16. FIG. 5A to FIG. 5C Components of the histogram shown. Figure 5A The histogram is a histogram when the frequency of the CLK signal is relatively high. In addition, Figure 5B and Figure 5C The histogram is created when the frequency of the CLK signal is used Figure 5AThe histogram is a histogram of the case where the frequency is 1 / 10 of the histogram. Figure 5B It is a histogram of the electrical signal and the CLK signal based on the relative relationship of the unamplified time. In addition, Figure 5C It is a histogram of the electrical signal and the CLK signal based on the changes in the relative relationship of amplified time. Figure 5C As shown, by increasing the change in the relative temporal relationship between the electrical signal output from the light receiving element 15 and the CLK signal, the frequency of a certain segment A in the histogram based on the time period from the emission of light 7 to the reception of reflected light 13 can be prevented from becoming significantly higher than the frequencies of other segments B and C.

[0085] The histogram is stored in a memory not shown in the figure as a data structure or table of some type, for example. A histogram is created for each light receiving element 15. That is, a histogram is created by the number of light receiving elements 15. Whenever a digital value output from the TDC 16 is received, the histogram creation unit 17 updates the histogram by increasing the value of the corresponding interval. The histogram created by the histogram creation unit 17 is referred to by the distance calculation unit 18.

[0086] The distance calculation unit 18 is a component that detects a peak value (digital value) in the histogram with reference to the histogram created by the histogram creation unit 17, and calculates the distance to the object 12 based on the arrival time corresponding to the detected peak value (digital value). As a method of detecting the peak value, for example, a probability density function such as an exponential modified Gaussian distribution (ex-Gaussian distribution) is fitted to the histogram, and the peak value represented by the probability density function obtained by the fitting can be adopted. In addition, when the reflected light 13 (which is the emitted light 7 reflected from the object 12) is received, the arrival time is the round-trip time to the object 12, and therefore by multiplying the arrival time by c / 2 (c is the speed of light), the distance to the object 12 can be calculated for each light receiving element 15. In addition, a distance image can be obtained based on the distance calculated for each of the multiple light receiving elements 15. Data on the distance image (distance measurement data) is output to the communication IF unit 6.

[0087] The control unit 5 is a component that controls the overall operation of the distance measuring device. The control unit 5 is composed of, for example, a microprocessor. Whenever a predetermined light emission period passes, the control unit 5 outputs a trigger pulse for emitting light 7 to the light source 8. In addition, the control unit 5 outputs a control signal for setting the frequency of the CLK signal to the clock signal generating unit 3. Whenever, for example, the presence or absence of an obstacle around a vehicle on which the distance measuring device is installed changes, the control signal is output. In addition, the control unit 5 outputs a path selection signal to the first mutually exclusive operation switch 23 and the second mutually exclusive operation switch 26. For example, when the frequency of the CLK signal is switched, the path selection signal is output.

[0088] The communication IF section 6 is an interface circuit for outputting the distance measurement data calculated by the distance calculation section 18 to an external host IC. The communication IF section 6 may be, for example, an interface circuit based on a mobile industry processor interface (MIPI), a serial peripheral interface (SPI), or an inter-integrated circuit (I2C), or may be configured by installing some of these interface circuits.

[0089] [1-2 Operation of distance measuring device]

[0090] Next, the operation of the distance measurement device (distance measurement method) according to the first embodiment of the present disclosure will be described. Fig.15 is a sequence diagram showing the operation of the distance measurement device according to the first embodiment.

[0091] First, when ToF distance measurement is performed, the light source 8 is driven in response to a trigger pulse applied from the control unit 5, and the light source 8 periodically emits light 7, the light receiving element 15 receives the reflected light 13 which is the emitted light 7 reflected from the object, and outputs electrical signals in sequence (step S101).

[0092] Here, obstacles disappear from the vicinity of the vehicle or the like provided with the distance measuring device, and high-precision distance measurement is not required. Fig.15 As shown, it is assumed that the control unit 5 outputs a control signal that makes the frequency value of the CLK signal low to the clock signal generating unit 3 (step S102). Then, the clock signal generating unit 3 switches the frequency of the CLK signal to a low value in response to the control signal (step S103). In addition, when switching the frequency of the CLK signal, the control unit 5 outputs a path selection signal to the first mutually exclusive operation switch 23 and the second mutually exclusive operation switch 26 (step S104). Then, the first mutually exclusive operation switch 23 sets any one of the first switches 281 to 28n (for example, the first switch 281) to an on state in response to the path selection signal (step S105). Therefore, the electrical signal output from the first adding unit 221 and added with jitter (the electrical signal output from the light receiving element 15) is output to the synchronization unit 20.

[0093] At the same time, the second exclusive operation switch 26 switches the second switches 311 to 31 n Any one of (for example, the second switch 311) is set to the on state (step S106). Therefore, the CLK signal (the CLK signal generated by the clock signal generating section 3) output from the second adding section 251 and added with jitter is output to the synchronization section 20. Therefore, the change in the time relative relationship between the electrical signal and the CLK signal is amplified.

[0094] Subsequently, the synchronization section 20 generates a synchronization signal obtained by synchronizing the electric signal output from the first mutually exclusive operation switch 23 with the CLK signal output from the second mutually exclusive operation switch 26 (step S107). Subsequently, the TDC 16 measures the arrival time from the light source 8 emitting the light 7 to the light receiving element 15 receiving the reflected light 13 based on the trigger pulse applied from the control section 5 and the synchronization signal generated by the synchronization section 20, and generates a digital value corresponding to the measured arrival time (step S108). Therefore, the change in the digital value is amplified.

[0095] Thereafter, the above-described flow of steps S107 to S108 is repeated to sequentially generate a new synchronization signal for each periodically emitted light 7 and each light receiving element 15 , and sequentially generate digital values ​​corresponding to the arrival time based on the generated synchronization signal (step S109 ).

[0096] Then, the histogram creation section 17 creates a histogram by accumulating each digital value (interval) converted by the TDC 16 (step S110). Figure 5C As shown, in the histogram, the frequency of segment A to which the true value of the distance belongs is reduced, and the frequency of segment B, which is closer to the actual distance among segments B and C adjacent to segment A, is further increased.

[0097] Subsequently, the distance calculation section 18 refers to the created histogram to detect a peak value (digital value) in the histogram, and calculates the distance to the object 12 based on the arrival time corresponding to the detected peak value (digital value) (step S111). Figure 5C As shown, the distance to object 12 can be measured with a higher resolution than the width of segment A by fitting a probability density function such as an exponentially modified Gaussian distribution to the histogram and using the peak of the exponentially modified Gaussian distribution represented by the function obtained by the fitting as the result of the distance measurement.

[0098] In addition, by operating the scanning mechanism or the like, the above-described flow of steps S107 to S109 is repeated for all the light receiving elements 15 , thereby obtaining a distance image of the object 12 .

[0099] As described above, the distance measuring device according to the first embodiment includes the change amplifying section 19, which amplifies the change in the time relative relationship between the electric signal output from the light receiving element 15 and the CLK signal. In addition, first, the synchronization section 20 generates a synchronization signal by synchronizing the electric signal with the CLK signal based on the electric signal and the CLK signal after the change is amplified by the change amplifying section 19. Subsequently, the histogram creating section 17 creates a histogram based on the time period from the light source 8 emitting the light 7 to the light receiving element 15 receiving the reflected light 13 based on the synchronization signal generated by the synchronization section 20. Subsequently, the distance calculating section 18 calculates the distance to the object 12 based on the histogram created by the histogram creating section 17. Therefore, as Figure 5C As shown, when the internal frequency is lowered, that is, the frequency of the CLK signal is lowered to reduce power consumption, the change in the relative time relationship between the electrical signal output from the light receiving element 15 and the CLK signal is increased, and therefore, the frequency of a certain segment A in the histogram based on the time period from the emission of light 7 to the reception of reflected light 13 can be prevented from becoming significantly higher than the frequencies of other segments B and C.

[0100] That is, in Figure 5B Compared with the histogram of the change in the time relative relationship between the unamplified electric signal and the CLK signal shown in FIG. 1 , the frequency of a certain segment A can be reduced, and the frequency of the segment B closer to the actual distance among the segments B and C adjacent to the segment A can be further increased. Therefore, for example, by fitting a probability density function such as an exponentially modified Gaussian distribution to the histogram, and using the peak of the exponentially modified Gaussian distribution represented by the function obtained by the fitting as the result of the distance measurement, the distance to the object 12 can be measured with a higher resolution than the width of the segment A. Therefore, a distance measurement device capable of improving the measurement accuracy while reducing power consumption can be provided.

[0101] Meanwhile, the effects described in this specification are merely examples and are not limited, and there may be other effects.

[0102] Furthermore, in the distance measuring device according to the first embodiment, the variation amplifying section 19 adds jitter to at least one of the electric signal and the CLK signal output from the light receiving element 15. Therefore, the variation in the temporal relative relationship between the electric signal and the CLK signal can be easily amplified.

[0103] Furthermore, the distance measuring device according to the first embodiment includes: first adding parts 221 to 22 n , which receives an input of an electrical signal and outputs an electrical signal to which jitter is added; and a second adding section 251 to 25 n , which receives the input of the CLK signal and outputs the CLK signal with jitter added. Figure 7 As shown, when the first adding part 221 to 22 nWhen jitter is added to the electrical signal output from the light receiving element 15, the electrical signal after the jitter is added changes along the time axis direction according to the probability density function of the change caused by the added jitter. Fig.14 As shown, when the second adding part 251 to 25 n When jitter is added to the CLK signal, the CLK signal after the jitter is added varies according to a probability density function of the variation due to the added jitter.

[0104] Furthermore, in the distance measuring device according to the first embodiment, the first adding sections 221 to 22 n and the second adding parts 251 to 25 n Each of the first adding parts 221 to 22 includes at least one or more of a logic gate and an RC circuit. n and the second adding parts 251 to 25 n .

[0105] Furthermore, in the distance measuring device according to the first embodiment, logic gates are connected in series to configure a multi-stage delay circuit. Therefore, jitter can be further increased.

[0106] Furthermore, in the distance measuring device according to the first embodiment, the resistor of the RC circuit is configured as a variable resistor. Therefore, it is not necessary to prepare a plurality of first adding portions 221 to 22 n and a plurality of second adding parts 251 to 25 n .

[0107] Furthermore, in the distance measuring device according to the first embodiment, the capacitor of the RC circuit is configured as a variable capacitor. Therefore, it is not necessary to prepare a plurality of first adding portions 221 to 22 n and a plurality of second adding parts 251 to 25 n .

[0108] Furthermore, the distance measuring device according to the first embodiment includes a first electrical path 21 connected to first adding portions 221 to 22 n are arranged in parallel, and transmit the electrical signal output from the light receiving element 15; and a first exclusive operation switch 23, which will be from the first adding portion 221 to 22 n The distance measuring device includes: a second electrical path 24, which is connected to the second adding parts 251 to 25 n and a second mutually exclusive operation switch 26, which will be from the second adding portion 251 to 25 nAny one of the CLK signal to which the jitter is output and added and the CLK signal passing through the second electrical path 24 is output to the synchronization section 20. In addition, the synchronization section 20 generates a synchronization signal by synchronizing the electric signal output from the first mutually exclusive operation switch 23 with the CLK signal output from the second mutually exclusive operation switch 26. Therefore, various synchronization signals such as a synchronization signal obtained by adding jitter only to the electric signal, a synchronization signal obtained by adding jitter only to the CLK signal, and a synchronization signal obtained by adding jitter to both the electric signal and the CLK signal can be easily generated.

[0109] Furthermore, in the distance measuring device according to the first embodiment, in the case where the width of the interval of the histogram is equal to or less than the predetermined width determined in advance, the first exclusive operation switch 23 outputs the electric signal through the first electric path 21 to the synchronization section 20. In addition, in the case where the width of the interval of the histogram is equal to or less than the predetermined width determined in advance, the second exclusive operation switch 26 outputs the CLK signal through the second electric path 24 to the synchronization section 20. Therefore, in the case where the width of the interval of the histogram is small and the measurement accuracy is high, there is no need to amplify the variation, and the reduction in measurement accuracy can be prevented.

[0110] In addition, in the distance measuring device according to the first embodiment, each of the first exclusive operation switch 23 and the second exclusive operation switch 26 includes any one of an NMOS switch, a PMOS switch, a CMOS switch, a NAND gate, and a NOR gate. Therefore, the first exclusive operation switch 23 and the second exclusive operation switch 26 can be easily configured.

[0111] In addition, in the distance measurement device according to the first embodiment, the change amplification unit 19 sets the amplitude of the change to 1 / 3 or more and 1 / 2 or less of the width of the interval of the histogram. Therefore, the frequency of a certain segment A of the histogram can be reduced, and the frequencies of segments B and C adjacent to segment A can be increased.

[0112] [1-3 Modification Example]

[0113] Meanwhile, in the distance measuring device according to the first embodiment, the first adding parts 221 to 22 n An example is used as the variation amplification section 19 to add jitter to the electrical signal output from the light receiving element 15, but other configurations may also be adopted. Fig.16 As shown, the voltage control section 33 that controls the voltage between the anode and cathode of the SPAD as the light receiving element 15 so as to add jitter to the electric signal can be used as the variation amplification section 19. Fig.17As shown, by controlling the voltage between the anode and the cathode, the tilt angle "b" can be adjusted, at which the electrons emitted by the received reflected light 13 roll to the region "a", in which an avalanche is generated in the potential of the SPAD. For example, as the tilt angle "b" becomes smaller, the time period until the avalanche is generated can be increased and the jitter can be increased, and as the tilt angle "b" becomes larger, the time period until the avalanche is generated can be reduced and the jitter can be reduced.

[0114] In addition, for example, Fig.18 As shown, the wavelength control section 34 that controls the wavelength of the light 7 emitted by the light source 8 so as to add jitter to the electric signal can be used as the variation amplification section 19. In addition, for example, Fig.19 As shown, the temperature control section 35 that controls the temperature of the light receiving element 15 so as to add jitter to the electric signal can function as the variation amplification section 19 .

[0115] <2. Application Examples>

[0116] The technology according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure can be implemented as a device installed on any type of mobile body such as a car, an electric car, a hybrid electric car, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, a robot, a construction machine, or an agricultural machine (tractor).

[0117] Fig. 20 7000 is a block diagram showing a schematic configuration example of a vehicle control system 7000, which is an example of a mobile body control system to which the technology according to the present disclosure can be applied. The vehicle control system 7000 includes a plurality of electronic control units connected to each other via a communication network 7010. Fig. 20 In the example shown, 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 internal information detection unit 7500, and an integrated control unit 7600. The communication network 7010 for connecting the plurality of control units may be an in-vehicle communication network based on any standard, such as a controller area network (CAN), a local interconnect network (LIN), a local area network (LAN), or FlexRay (registered trademark).

[0118] The control unit includes a microcomputer that performs calculations according to various programs; a storage unit that stores programs executed by the microcomputer, parameters for various operations, etc.; and a drive circuit that drives various devices to be controlled. The control unit includes a network I / F for communicating with other control units via the communication network 7010, and includes a communication I / F for communicating with devices, sensors, etc. inside and outside the vehicle in a wired or wireless manner. Fig. 20, a microcomputer 7610, a general communication I / F 7620, a dedicated communication I / F 7630, a positioning unit 7640, a beacon receiving unit 7650, an in-vehicle device I / F 7660, a sound image output unit 7670, an in-vehicle network I / F 7680, and a storage unit 7690 are shown as functional components of the integrated control unit 7600. Similarly, other control units also include a microcomputer, a communication I / F, a storage unit, and the like.

[0119] The drive system control unit 7100 controls the operation of devices related to the drive system of the vehicle according to various programs. For example, the drive system control unit 7100 is used as a control device such as a drive force generator for generating a drive force of the vehicle such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle. The drive system control unit 7100 may have the function of a control device such as an anti-lock braking system (ABS) or an electronic stability control (ESC).

[0120] The vehicle state detection unit 7110 is connected to the drive system control unit 7100. The vehicle state detection unit 7110 includes, for example, at least one of the following items: a gyro sensor for detecting the angular velocity of the axial rotation of the vehicle body, an acceleration sensor for detecting the acceleration of the vehicle, and a sensor for detecting the operation amount of the accelerator pedal, the operation amount of the brake pedal, the steering angle of the steering wheel, the engine speed, or the wheel rotation speed. The drive system control unit 7100 performs arithmetic processing using the signal input from the vehicle state detection unit 7110 to control the internal combustion engine, the drive motor, the electric power steering device, the brake device, etc.

[0121] The body system control unit 7200 controls the operation of various devices installed on the vehicle body according to various programs. For example, the body system control unit 7200 is used as a keyless entry system, a smart key system, a power window device, or a control device for various lights (such as headlights, reverse lights, brake lights, turn signals, and fog lights). In this case, a radio wave sent from a portable device that replaces the key or a signal of various switches may be input to the body system control unit 7200. The body system control unit 7200 receives the input of the radio wave or the signal, and controls the door lock device, power window device, lights, etc. of the vehicle.

[0122] The battery control unit 7300 controls the secondary battery 7310 as a power source for driving the motor according to various programs. For example, information such as battery temperature, battery output voltage, or remaining capacity of the battery is input to the battery control unit 7300 from a battery device including the secondary battery 7310. The battery control unit 7300 performs arithmetic processing using these signals to perform temperature adjustment control of the secondary battery 7310 or control of a cooling device included in the battery device, etc.

[0123] The vehicle exterior information detection unit 7400 detects information about the exterior of the vehicle in which the vehicle control system 7000 is provided. For example, at least one of the imaging 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 time-of-flight (ToF) camera, a stereo camera, a monocular camera, an infrared camera, and other cameras. The vehicle exterior information detection unit 7420 includes, for example, at least one of the following items: an environmental sensor for detecting current atmospheric conditions or weather conditions and a peripheral information detection sensor for detecting other vehicles, obstacles, or pedestrians around the vehicle in which the vehicle control system 7000 is provided.

[0124] The environmental sensor may be, for example, at least one of the following: a raindrop sensor for detecting rainy days, a fog sensor for detecting fog, a sunshine sensor for detecting the degree of sunshine, and a snow sensor for detecting snowfall. The peripheral information detection sensor may be at least one of the following: an ultrasonic sensor, a radar device, and a light detection and ranging, laser imaging detection and ranging (LIDAR) device. The imaging unit 7410 and the vehicle exterior information detection unit 7420 may be configured as independent sensors or devices, or may be configured as a device in which a plurality of sensors or devices are integrated.

[0125] here, Fig.21 An example of the installation position of the imaging unit 7410 and the vehicle exterior information detection unit 7420 is shown. The imaging units 7910, 7912, 7914, 7916, and 7918 are arranged at least one of the front nose, side mirrors, rear bumper, rear door, and upper portion of the windshield inside the vehicle 7900. The imaging unit 7910 arranged at the front nose and the imaging unit 7918 arranged at the upper portion of the windshield inside the vehicle mainly acquire images in front of the vehicle 7900. The imaging units 7912 and 7914 included in the side mirrors mainly acquire images of the sides of the vehicle 7900. The imaging unit 7916 included in the rear bumper or rear door mainly acquires images of the rear of the vehicle 7900. The imaging unit 7918 included in the upper portion of the windshield inside the vehicle is mainly used to detect front vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0126] at the same time, Fig.21An example of the imaging ranges of the respective imaging units 7910, 7912, 7914, and 7916 is shown. Imaging range "a" represents the imaging range of the imaging unit 7910 disposed at the front nose, imaging ranges "b" and "c" respectively represent the imaging ranges of the imaging units 7912 and 7914 disposed at the side mirrors, and imaging range "d" represents the imaging range of the imaging unit 7916 disposed at the rear bumper or rear door. For example, by superimposing the image data captured by the imaging units 7910, 7912, 7914, and 7916, a bird's-eye view image of the vehicle 7900 observed from above is obtained.

[0127] The vehicle exterior information detection units 7920, 7922, 7924, 7926, 7928, and 7930 respectively disposed at the front, rear, side, and corner of the vehicle 7900 and the upper portion of the windshield inside the vehicle may be, for example, ultrasonic sensors or radar devices. The vehicle exterior information detection units 7920, 7926, and 7930 respectively disposed at the front nose, rear bumper, rear door, and the upper portion of the windshield inside the vehicle 7900 may be, for example, LIDAR devices. These vehicle exterior information detection units 7920 to 7930 are mainly used to detect vehicles ahead, pedestrians, obstacles, and the like.

[0128] Back to Fig. 20 , continue to describe. The vehicle exterior information detection unit 7400 enables the imaging unit 7410 to capture an image of the outside of the vehicle and receive the captured image data. In addition, the vehicle exterior information detection unit 7400 receives detection information from the vehicle exterior information detection unit 7420 connected thereto. In the case where 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 sends ultrasonic waves, electromagnetic waves, etc., and receives information about the received reflected waves. The vehicle exterior information detection unit 7400 can perform object detection processing or distance detection processing for detecting people, vehicles, obstacles, signs, or characters on the road surface based on the received information. The vehicle exterior information detection unit 7400 can perform environmental recognition processing for identifying rainfall, fog, road conditions, etc. based on the received information. The vehicle exterior information detection unit 7400 can calculate the distance to an object outside the vehicle based on the received information.

[0129] In addition, the vehicle exterior information detection unit 7400 can perform image recognition processing or distance detection processing for identifying people, vehicles, obstacles, signs, characters, etc. on the road based on the received information. The vehicle exterior information detection unit 7400 can perform processing such as distortion correction or alignment on the received image data, and synthesize the image data captured by the different imaging units 7410 to generate a bird's-eye view image or a panoramic image. The vehicle exterior information detection unit 7400 can use the image data captured by the different imaging units 7410 to perform viewpoint conversion processing.

[0130] The in-vehicle information detection unit 7500 detects information about the interior of the vehicle. For example, a driver state detection unit 7510 that detects the state of the driver is connected to the in-vehicle information detection unit 7500. The driver state detection unit 7510 may include a camera that captures an image of the driver, a biosensor that detects the driver's biometric information, a microphone that collects sounds inside the vehicle, and the like. The biosensor is disposed on, for example, a seat surface, a steering wheel, and the like, and detects biometric information of an occupant sitting on a seat or a driver holding the steering wheel. The in-vehicle information detection unit 7500 can calculate the driver's fatigue or concentration based on the detection information input from the driver state detection unit 7510, and can determine whether the driver is dozing off. The in-vehicle information detection unit 7500 can perform processing such as noise elimination processing on the collected sound signals.

[0131] The integrated control unit 7600 controls the overall operation inside the vehicle control system 7000 according to various programs. The input unit 7800 is connected to the integrated control unit 7600. The input unit 7800 is implemented by a device (such as a touch panel, a button, a microphone, a switch or a joystick) through which the occupant can perform input operations. Data obtained by recognizing the sound input through the microphone can be input to the integrated control unit 7600. The input unit 7800 can be a remote controller device using, for example, infrared or other radio waves, or can be an external connection device such as a mobile phone or a personal digital assistant (PDA) corresponding to the operation of the vehicle control system 7000. The input unit 7800 can be, for example, a camera. In this case, the occupant can input information through gestures. Alternatively, data obtained by detecting the movement of a wearable device worn by the occupant can be input. In addition, the input unit 7800 may include an input control circuit that generates an input signal based on information input by, for example, the occupant, etc. using the input unit 7800, and outputs the generated input signal to the integrated control unit 7600, etc. An occupant or the like operates input portion 7800 to input various data to vehicle control system 7000 or give instructions for processing operations.

[0132] The storage unit 7690 may include a read-only memory (ROM) storing various programs executed by the microcomputer and a random access memory (RAM) storing various parameters, arithmetic operation results, sensor values, etc. In addition, the storage unit 7690 may be implemented by a magnetic storage device such as a hard disk drive (HDD), a semiconductor storage device, an optical storage device, an optical magnetic storage device, or the like.

[0133] The general communication I / F 7620 is a general communication I / F that mediates communication between various devices present in the external environment 7750. The general communication I / F 7620 may be provided with a cellular communication protocol such as Global System for Mobile Communications (GSM) (registered trademark), WiMAX (registered trademark), Long Term Evolution (LTE) (registered trademark), or LTE Advanced (LTE-A), or other wireless communication protocols such as wireless LAN (also known as Wi-Fi (registered trademark)) or Bluetooth (registered trademark). The general communication I / F 7620 may be connected to a device (e.g., an application server or a control server) present on an external network (e.g., the Internet, a cloud network, or an operator-specific network) through, for example, a base station or an access point. In addition, the general communication I / F 7620 may be connected to a terminal (e.g., a terminal of a driver, a pedestrian, or a store, or a machine type communication (MTC) terminal) present near the vehicle using, for example, a peer-to-peer (P2P) technology.

[0134] The dedicated communication I / F 7630 is a communication I / F that supports a communication protocol designed for a vehicle. The dedicated communication I / F 7630 may be provided with a standard protocol such as Wireless Access in Vehicular Environments (WAVE) (which is a combination of IEEE 802.11p at the lower layer and IEEE 1609 at the upper layer), Dedicated Short Range Communication (DSRC), or a cellular communication protocol. The dedicated communication I / F 7630 generally performs V2X communication, which is a concept including one or more of vehicle-to-vehicle communication, vehicle-to-infrastructure communication, vehicle-to-home communication, and vehicle-to-pedestrian communication.

[0135] The positioning unit 7640 performs positioning by, for example, receiving a GNSS signal from a global navigation satellite system (GNSS) satellite (e.g., a GPS signal from a global positioning system (GPS) satellite), and generates position information including the latitude, longitude, and altitude of the vehicle. At the same time, the positioning unit 7640 may specify the current position by exchanging signals with a wireless access point, or may acquire position information from a terminal such as a mobile phone, a PHS, or a smart phone having a positioning function.

[0136] The beacon receiving unit 7650 receives, for example, radio waves or electromagnetic waves transmitted from a radio station installed on a road, and obtains information such as the current position, traffic congestion, road closure, or required time. Meanwhile, the function of the beacon receiving unit 7650 may be included in the above-mentioned dedicated communication I / F 7630.

[0137] 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 present inside the vehicle. The in-vehicle device I / F 7660 can establish a wireless connection using a wireless communication protocol such as wireless LAN, Bluetooth (registered trademark), near field communication (NFC), or wireless USB (WUSB). In addition, the in-vehicle device I / F 7660 can establish a wired connection such as a universal serial bus (USB), a high-definition multimedia interface (HDMI) (registered trademark), or a mobile high-definition link (MHL) through a connection terminal (and a cable if necessary) not shown in the figure. The in-vehicle device 7760 may include, for example, at least one of a mobile device and a wearable device carried by an occupant and an information device carried or attached to the vehicle. In addition, the in-vehicle device 7760 may include a navigation device that performs a path search to any destination. The in-vehicle device I / F 7660 exchanges a control signal or a data signal with the in-vehicle device 7760.

[0138] The in-vehicle network I / F 7680 is an interface that mediates communication between the microcomputer 7610 and the communication network 7010. The in-vehicle network I / F 7680 transmits and receives signals and the like according to a predetermined protocol supported by the communication network 7010.

[0139] The microcomputer 7610 of the integrated control unit 7600 controls the vehicle control system 7000 according to various programs based on information acquired through at least one of the general communication I / F 7620, the dedicated communication I / F 7630, the positioning unit 7640, the beacon receiving unit 7650, the in-vehicle device I / F 7660, and the vehicle network I / F 7680. For example, the microcomputer 7610 can perform arithmetic operations on control target values ​​of a driving force generation device, a steering mechanism, or a braking device based on the acquired information about the inside and outside of the vehicle, and can output a control instruction to the drive system control unit 7100. For example, the microcomputer 7610 can perform cooperative control to realize the functions of an advanced driver assistance system (ADAS), including avoiding or mitigating a collision with a vehicle, following driving based on the distance between vehicles, speed-maintaining driving, an alarm for collision with a vehicle, an alarm for vehicle deviation from a lane, and the like. In addition, the microcomputer 7610 can control the driving force generating device, steering mechanism, braking device, etc. based on the information acquired about the vehicle's surroundings, thereby performing cooperative control aimed at performing autonomous operations that enable the vehicle to travel autonomously without relying on the driver's operation.

[0140] The microcomputer 7610 can generate three-dimensional distance information between the vehicle and objects such as surrounding structures or people based on information acquired through at least one of the general communication I / F 7620, the dedicated communication I / F 7630, the positioning unit 7640, the beacon receiving unit 7650, the in-vehicle device I / F 7660, and the vehicle network I / F 7680, and create local map information including information about the surrounding environment of the current position of the vehicle. In addition, the microcomputer 7610 can predict dangers such as collision with a vehicle, approach of a pedestrian, or entry into a closed road based on the acquired information, and generate an alarm signal. The alarm signal may be, for example, a signal for generating an alarm sound or turning on an alarm light.

[0141] The audio and video output unit 7670 transmits an output signal of at least one of audio and video to an output device capable of visually or audibly notifying an occupant in or outside the vehicle of information. Fig. 20 In the example of , an audio speaker 7710, a display unit 7720, and an instrument panel 7730 are shown as output devices. The display unit 7720 may include, for example, at least one of an on-board display and a head-up display. The display unit 7720 may have an augmented reality (AR) display function. In addition to these devices, the output device may also be a wearable device such as a headset, a glasses-type display worn by an occupant, or other devices such as a projector or a lamp. In the case where the output device is a display device, the display device visually displays the results obtained by various processes performed by the microcomputer 7610 or information received from other control units in various forms such as text, images, tables, or graphs. In addition, in the case where the output device is a sound output device, the sound output device converts an audio signal consisting of reproduced sound data, acoustic data, etc. into an analog signal, and audibly outputs the analog signal.

[0142] At the same time, Fig. 20 In the example shown, at least two control units connected via the communication network 7010 can be integrated into one control unit. Optionally, a separate control unit can be composed of multiple control units. In addition, the vehicle control system 7000 may include another control unit not shown in the figure. In addition, in the above description, some or all of the functions of any one control unit can be provided to other control units. That is, as long as information is sent and received via the communication network 7010, a predetermined operation process can be performed by any one control unit. Similarly, a sensor or device connected to any one control unit can be connected to another control unit, and multiple control units can send and receive detection information to each other via the communication network 7010.

[0143] In the vehicle control system 7000, the Fig.21 The distance measuring device according to the present embodiment described can be applied to Fig. 20 The vehicle exterior information detection unit 7420 according to the application example is shown. For example, the distance to the obstacle in front of the vehicle 7900 can be calculated by a distance measurement device.

[0144] Meanwhile, the present technology may adopt the following configurations.

[0145] (1) A distance measuring device comprising:

[0146] a light source configured to emit light;

[0147] a light receiving element configured to receive light reflected from an object reflecting the light;

[0148] a variation amplifying section configured to amplify a variation in a temporal relative relationship between an electrical signal output from the light receiving element and a clock signal;

[0149] a synchronization section configured to generate a synchronization signal by synchronizing the electric signal with the clock signal based on the electric signal after the variation is amplified by the variation amplification section and the clock signal;

[0150] a histogram creating section configured to create a histogram based on a time period from when the light source emits light to when the light receiving element receives reflected light, based on the synchronization signal generated by the synchronization section; and

[0151] A distance calculation section is configured to calculate a distance to the object based on the histogram created by the histogram creation section.

[0152] (2) The distance measuring device according to (1), wherein:

[0153] The variation amplifying section adds jitter to at least one of the clock signal and the electrical signal output from the light receiving element.

[0154] (3) The distance measuring device according to (2), wherein:

[0155] The change amplification unit includes:

[0156] a first adding section configured to receive an input of an electrical signal and output the electrical signal to which jitter is added, and

[0157] The second adding section is configured to receive an input of a clock signal and output the clock signal to which jitter is added.

[0158] (4) The distance measuring device according to (3), wherein:

[0159] Each of the first adding section and the second adding section includes at least one or more of a logic gate and an RC circuit.

[0160] (5) The distance measuring device according to (4), wherein:

[0161] The logic gates form a multi-stage delay circuit connected in series.

[0162] (6) The distance measuring device according to (4), wherein:

[0163] The resistor of an RC circuit is a variable resistor.

[0164] (7) The distance measuring device according to (4) or (6), wherein:

[0165] The capacitor of the RC circuit is a variable capacitor.

[0166] (8) The distance measuring device according to any one of (3) to (7), further comprising:

[0167] a first electrical path disposed in parallel with the first added portion and configured to transmit an electrical signal output from the light receiving element;

[0168] a first mutually exclusive operation switch configured to output, to the synchronization section, any one of the electrical signal output from the first adding section and to which the jitter is added and the electrical signal passing through the first electrical path;

[0169] a second electrical path disposed in parallel with the second added portion and configured to transmit a clock signal; and

[0170] a second mutually exclusive operation switch configured to output any one of the clock signal output from the second adding section and to which the jitter is added and the clock signal passing through the second electrical path to the synchronization section, wherein,

[0171] The synchronization section generates a synchronization signal by synchronizing the electrical signal output from the first mutually exclusive operation switch with the clock signal output from the second mutually exclusive operation switch.

[0172] (9) The distance measuring device according to (8), wherein:

[0173] When the width of the interval of the histogram is equal to or smaller than a predetermined width determined in advance, the first mutually exclusive operation switch outputs the electric signal through the first electric path to the synchronization section, and

[0174] The second exclusive operation switch outputs the clock signal through the second electrical path to the synchronization section when the width of the interval of the histogram is equal to or smaller than a predetermined width determined in advance.

[0175] (10) The distance measuring device according to (8) or (9), wherein:

[0176] Each of the first mutually exclusive operation switch and the second mutually exclusive operation switch includes any one of an NMOS switch, a PMOS switch, a CMOS switch, a NAND gate, and a NOR gate.

[0177] (11) The distance measuring device according to any one of (1) to (10), wherein:

[0178] The variation amplification section is configured so that the amplitude amount of the variation is equal to or greater than 1 / 3 of the width of the bin of the histogram and less than or equal to 1 / 2 of the width of the bin of the histogram.

[0179] (12) The distance measuring device according to (1), wherein:

[0180] The light receiving element is a single photon avalanche diode, and

[0181] The variation amplification section controls the voltage between the anode and cathode of the single photon avalanche diode, thereby adding jitter to the electrical signal.

[0182] (13) The distance measuring device according to (1), wherein:

[0183] The variation amplification section controls the wavelength of light emitted by the light source, thereby adding jitter to the electrical signal.

[0184] (14) The distance measuring device according to (1), wherein:

[0185] The variation amplification section controls the temperature of the light receiving element, thereby adding jitter to the electrical signal.

[0186] (15) A distance measurement method, comprising:

[0187] Light reflected from an object reflecting light periodically emitted by a light source is received by a light receiving element, and an electric signal is sequentially output; a change in the relative time relationship between the output electric signal and a clock signal is amplified; based on the electric signal and the clock signal after the amplified change, a synchronization signal is sequentially generated by synchronizing the electric signal with the clock signal; a histogram based on a time period from when the light source emits light to when the light receiving element receives reflected light is created based on the generated synchronization signal; and a distance to the object is calculated based on the created histogram.

[0188] Reference Mark List

[0189] 1 Light projection unit

[0190] 2 Light receiving unit

[0191] 3 Clock signal generation unit

[0192] 4 Distance measurement processing unit

[0193] 5. Control Unit

[0194] 6 Communications IF Department

[0195] 7 Light

[0196] 8 Light Source

[0197] 9 Emission lens

[0198] 10 Light Projection Mirror

[0199] 11 Microscope

[0200] 12 Objects

[0201] 13 Reflected Light

[0202] 14 Receiving lens

[0203] 16 TDC

[0204] 15 Light receiving element

[0205] 17 Histogram Creation Section

[0206] 18 Distance calculation unit

[0207] 19 Change Amplification Department

[0208] 20 Synchronization Department

[0209] 21 First electrical path

[0210] 221 to 22 n First adding part

[0211] 23 First mutually exclusive operation switch

[0212] 24 Second electrical path

[0213] 251 to 25 n Second Adding Section

[0214] 26 Second mutually exclusive operation switch

[0215] 27 Input terminals

[0216] 280 to 28 n First switch

[0217] 29 Output terminals

[0218] 30 Input terminals

[0219] 310 to 31 n Second switch

[0220] 32 Output terminals

[0221] 33 Voltage control unit

[0222] 34. Wavelength Control Unit

[0223] 35 Temperature Control Unit

[0224] 7000 Vehicle Control Systems

[0225] 7010 Communication Networks

[0226] 7100 Drive system control unit

[0227] 7110 Vehicle Status Detection Unit

[0228] 7200 Body system control unit

[0229] 7300 Battery Control Unit

[0230] 7310 Secondary Battery

[0231] 7400 External vehicle information detection unit

[0232] 7410 Imaging Department

[0233] 7420 External vehicle information detection department

[0234] 7500 In-vehicle information detection unit

[0235] 7510 Driver Status Detection Unit

[0236] 7600 Integrated Control Unit

[0237] 7610 Microcomputer

[0238] 7620 General communication I / F

[0239] 7630 Dedicated Communication I / F

[0240] 7640 Positioning Department

[0241] 7650 Beacon receiving unit

[0242] 7660 In-vehicle equipment I / F

[0243] 7670 Audio and video output unit

[0244] 7680 In-vehicle Network I / F

[0245] 7690 Storage Department

[0246] 7710 Audio Speaker

[0247] 7720 Display unit

[0248] 7730 Instrument Panel

[0249] 7750 External Environment

[0250] 7760 In-vehicle equipment

[0251] 7800 Input

[0252] 7900 vehicles

[0253] 7910, 7912, 7914, 7916, 7918 Imaging Department

[0254] 7920, 7921, 7922, 7923, 7924, 7925, 7926, 7927, 7928, 7929, 7930: External vehicle information detection unit.

Claims

1. A distance measuring device, comprising: a light source configured to emit light; a light receiving element configured to receive light reflected from an object reflecting the light; a variation amplifying section configured to amplify a variation in a temporal relative relationship between an electrical signal output from the light receiving element and a clock signal; a synchronization section configured to generate a synchronization signal by synchronizing the electrical signal with the clock signal based on the electrical signal after the variation is amplified by the variation amplification section and the clock signal; a histogram creating section configured to create a histogram based on a time period from when the light source emits light to when the light receiving element receives reflected light, based on the synchronization signal generated by the synchronization section; as well as a distance calculation unit configured to calculate a distance to the object based on the histogram created by the histogram creation unit, wherein the variation amplification section adds jitter to at least one of the clock signal and the electrical signal output from the light receiving element, Wherein, the change amplification unit comprises: a first adding section configured to receive an input of the electrical signal and output the electrical signal to which jitter is added, and a second adding section configured to receive an input of the clock signal and output the clock signal to which jitter is added, And wherein, the distance measuring device further comprises: a first electrical path disposed in parallel with the first adding portion and configured to transmit the electrical signal output from the light receiving element; a first mutually exclusive operation switch configured to output, to the synchronization section, any one of the electrical signal output from the first adding section and to which jitter is added and the electrical signal passing through the first electrical path; a second electrical path disposed in parallel with the second adding portion and configured to transmit the clock signal; and a second mutually exclusive operation switch configured to output any one of the clock signal output from the second adding section and to which jitter is added and the clock signal passing through the second electrical path to the synchronization section, wherein: The synchronization section generates a synchronization signal by synchronizing the electrical signal output from the first mutually exclusive operation switch with the clock signal output from the second mutually exclusive operation switch.

2. The distance measuring device according to claim 1, wherein: Each of the first adding section and the second adding section includes at least one or more of a logic gate and an RC circuit.

3. The distance measuring device according to claim 2, wherein: The logic gates constitute a multi-stage delay circuit connected in series.

4. The distance measuring device according to claim 2, wherein: The resistor of the RC circuit is a variable resistor.

5. The distance measuring device according to claim 2, wherein: The capacitor of the RC circuit is a variable capacitor.

6. The distance measuring device according to claim 1, wherein: When the width of the interval of the histogram is equal to or smaller than a predetermined width determined in advance, the first exclusive operation switch outputs the electrical signal passing through the first electrical path to the synchronization section, and The second exclusive operation switch outputs the clock signal passing through the second electrical path to the synchronization section when the width of the interval of the histogram is equal to or smaller than the predetermined width determined in advance.

7. The distance measuring device according to claim 1, wherein: Each of the first mutually exclusive operation switch and the second mutually exclusive operation switch includes any one of an NMOS switch, a PMOS switch, a CMOS switch, a NAND gate, and a NOR gate.

8. The distance measuring device according to claim 1, wherein: The change amplification section is configured to make the magnitude of the change equal to or greater than 1 / 3 of the width of the bin of the histogram and less than or equal to 1 / 2 of the width of the bin of the histogram.

9. The distance measuring device according to claim 1, wherein: The light receiving element is a single photon avalanche diode, and The variation amplification section controls a voltage between an anode and a cathode of the single photon avalanche diode, thereby adding jitter to the electrical signal.

10. The distance measuring device according to claim 1, wherein: The variation amplification section controls the wavelength of light emitted by the light source, thereby adding jitter to the electrical signal.

11. The distance measuring device according to claim 1, wherein: The variation amplifying section controls the temperature of the light receiving element, thereby adding jitter to the electric signal.

12. A distance measurement method, comprising: receiving, by a light receiving element, light reflected from an object reflecting light periodically emitted by a light source, and sequentially outputting electrical signals; amplifying, by a variation amplifying unit, a variation in the relative temporal relationship between an output electric signal and a clock signal; and generating, by a synchronizing unit, sequentially a synchronization signal by synchronizing the electric signal with the clock signal based on the electric signal and the clock signal after amplifying the variation; A histogram creation unit creates a histogram based on a time period from when the light source emits light to when the light receiving element receives reflected light based on the generated synchronization signal; and a distance calculation unit calculates a distance to the object based on the created histogram, wherein the variation amplification section adds jitter to at least one of the clock signal and the electrical signal output from the light receiving element, Wherein, the change amplification unit comprises: a first adding section configured to receive an input of the electrical signal and output the electrical signal to which jitter is added, and a second adding section configured to receive an input of the clock signal and output the clock signal to which jitter is added, Wherein, the distance measurement method further comprises: transmitting the electrical signal output from the light receiving element through a first electrical path provided in parallel with the first adding portion; outputting, by a first mutually exclusive operation switch, to the synchronization section any one of the electrical signal output from the first adding section and to which jitter is added and the electrical signal passing through the first electrical path; transmitting the clock signal via a second electrical path arranged in parallel with the second adding portion; and Any one of the clock signal output from the second adding section and to which jitter is added and the clock signal passing through the second electrical path is output to the synchronization section by a second mutually exclusive operation switch, wherein, The synchronization section generates a synchronization signal by synchronizing the electrical signal output from the first mutually exclusive operation switch with the clock signal output from the second mutually exclusive operation switch.

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