JP6443132B2 - Arithmetic unit - Google Patents

Description

  The present invention relates to an arithmetic device that generates a histogram to calculate a physical quantity.

  2. Description of the Related Art Conventionally, an arithmetic device that generates a histogram to calculate a physical quantity has been provided. This type of arithmetic device adds measured values obtained at a predetermined detection time by repeating time measurement to a time bin. For example, the horizontal axis is time and the vertical axis is an integrated value that is an integration of measured values. Generate a histogram. Then, the arithmetic device calculates a physical quantity based on the generated histogram.

IEEE Journal of Solid-State Circuits (Impact Factor: 3.06) .01 / 2014; 49 (1): 315-330.,

  In a configuration in which this type of arithmetic device is applied to a radar device in an in-vehicle environment, the radar device has, for example, a light reception integrated value in which the horizontal axis represents the flight time of light measured by time measurement and the vertical axis represents the total number of received light. To generate a histogram. Then, the radar device calculates a distance from the own device to an object around the vehicle based on the generated histogram. Such an in-vehicle environment is affected by disturbance light (background light, noise light), but it is required to calculate the distance with high accuracy even in an environment with strong disturbance light. In order to detect weak reflected light (signal light reflected by an object from a long distance) in an environment with strong disturbance light, data is accumulated by repeating laser light emission to ensure an input dynamic range. By doing so, disturbance light and reflected light are discriminated. However, if an attempt is made to secure the input dynamic range, there is a problem that the amount of data of the histogram increases and the memory capacity for storing (holding) the histogram increases.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to increase the memory capacity for storing a histogram while ensuring an appropriate input dynamic range and calculating a physical quantity appropriately. An object of the present invention is to provide an arithmetic device capable of suppressing the above.

According to the first aspect of the present invention, the histogram generating means adds the measurement value obtained at a predetermined detection time by repeating the time measurement to the time bin, and an integrated value that is an integration of the time and the measured value. Based on the above, a histogram is generated. The physical quantity calculation means calculates the physical quantity based on the histogram generated by the histogram generation means. Here, when the histogram characteristic value at the time when the addition of the measurement value obtained at a predetermined time which is a part of the detection time is over at least the threshold value, the histogram generation means calculates a subtraction value from the measurement value in the histogram. subtracting compressing the integration direction of the data of the measured value, the subtraction data, the memory area for storing a histogram Ru is stored in another memory area as the data of the disturbance light intensity values. Then, the physical quantity calculation means specifies the mode value of time measurement based on the histogram in which the data in the integration direction of the measurement value is compressed by the histogram generation means, and specifies the time corresponding to the specified mode value. Calculate physical quantity.

That is, when the characteristic value of the histogram exceeds at least the threshold value , the subtraction value is subtracted from the measurement value in the histogram to compress the integration direction data of the measurement value, and the measurement value integration direction data is compressed based on the histogram. The physical quantity was calculated by specifying the mode value of time measurement. Thereby, by compressing the data in the integration direction of the measurement values, the amount of data in the integration direction of the measurement values can be reduced, and the input dynamic range can be appropriately ensured even when time measurement is repeated. As a result, it is possible to appropriately secure the input dynamic range and appropriately calculate the physical quantity, and to suppress an increase in memory capacity for storing the histogram. Especially in the in-vehicle environment, by appropriately securing the input dynamic range in this way, even if the reflected light coming from a long distance (signal light reflected by the object) is weak, disturbance light (background light, noise) Light) and reflected light can be discriminated appropriately. As a result, not only the distance to an object at a short distance but also the distance to an object at a long distance can be calculated appropriately.

Functional block diagram showing a first embodiment of the present invention Diagram showing the scanning range of laser light Diagram showing the path of laser light Diagram showing the scanning period of laser light Diagram showing pixel configuration The figure which shows the structure of the light receiving element and the lead-out circuit Functional block diagram showing the configuration of the pixel data processing unit Flow chart showing histogram generation processing Flow chart showing distance calculation processing Flow chart showing SN ratio calculation processing Diagram showing transition of histogram Diagram showing transition of histogram The flowchart which shows the histogram production | generation process of the 2nd Embodiment of this invention. Diagram showing transition of histogram The flowchart which shows the histogram production | generation process of the 3rd Embodiment of this invention. Diagram showing transition of histogram Diagram showing transition of histogram The flowchart which shows the histogram production | generation process of the 4th Embodiment of this invention. Diagram showing transition of histogram

(First embodiment)
A first embodiment in which the present invention is applied to a radar device that can be mounted on a vehicle will be described below with reference to FIGS. A radar device (corresponding to a calculation device) calculates (measures) a distance (physical quantity) from the own device to an object (target) around the vehicle while being mounted on the vehicle. Any mode may be sufficient as a mode with which a radar apparatus is mounted in a vehicle. For example, in a mode in which the radar device is mounted on the front part of the vehicle, the front side of the vehicle is an object detection area, and in a mode in which the radar device is mounted on the rear side of the vehicle, the rear side of the vehicle is an object detection area. Objects around the vehicle are, for example, pedestrians, preceding vehicles, succeeding vehicles, walls, and the like. In the present embodiment, a case will be described in which the front of the vehicle is an object detection area, and a pedestrian or a preceding vehicle in front is the detection target.

  As shown in FIG. 1, the radar apparatus 1 includes a light source 2 (corresponding to a light emitting unit), a one-dimensional scanner 3, a scanning control unit 4, a light detection unit 5, and a data processing unit 6. The light source 2 is composed of, for example, a semiconductor laser diode, and emits (irradiates) pulsed laser light (hereinafter referred to as laser light) as a radar wave. As shown in FIG. 2, the laser light emitted from the light source 2 is shaped in a rectangular shape whose longitudinal direction is the longitudinal direction with respect to the scanning direction SD1 (scanning light SL). The laser light emitted from the light source 2 has, for example, a pulse width of 4 ns and a light emission period of 4 μs.

  As shown in FIG. 3, the one-dimensional scanner 3 is configured to be able to vibrate the mirror 8 with the rotation shaft 7 as the vibration center. When a driving command is input from a driving source (not shown), the one-dimensional scanner 3 vibrates the mirror 8 about the rotation shaft 7 as a vibration center, and performs one-dimensional scanning of the laser light emitted from the light source 2 at a predetermined scanning angle. In the range R1. Note that the scanning mechanism of the one-dimensional scanner 3 is configured by a micro electro mechanical system (MEMS), a micro motor, or the like. The scanning angle range R1 in the one-dimensional scanner 3 is, for example, −27 ° to + 27 ° as shown in FIG. The scanning cycle is, for example, 50 ms, scanning from −27 ° to + 27 ° in a time of 40 ms, and returning from + 27 ° to −27 ° in a time of 10 ms.

  The laser light emitted from the light source 2 passes through the collimating lens 9 and reaches the one-dimensional scanner 3 (light L1). The laser light that has reached the one-dimensional scanner 3 is reflected by the mirror 8 and irradiated as irradiation light in the direction corresponding to the scanning angle of the mirror 8 (light L2). When the laser light reaches an object around the vehicle, it is reflected by the object. To do. The laser light reflected by the object passes through the light receiving lens 10 as reflected light (signal light reflected by the object) and reaches the two-dimensional pixel array 11 of the light detection unit 5 (light L3). As described above, since the laser light is formed in a rectangular shape, on the light receiving surface RP of the two-dimensional pixel array 11, a rectangular shape whose longitudinal direction is the longitudinal direction with respect to the scanning direction SD2 of the reflected light is formed. The shaped reflected light arrives (reflected light RL). Further, the length of the reflected light formed in the rectangular shape in the longitudinal direction is longer than the length in the short direction of the light receiving surface RP formed in the rectangular shape. The length in the longitudinal direction is set.

  The scanning control unit 4 detects the scanning angle of the one-dimensional scanner 3, controls the emission of laser light from the light source 2 based on the detected scanning angle, and controls the scanning of the laser light by the one-dimensional scanner 3. . Further, the scanning control unit 4 inputs a vehicle speed signal (vehicle speed pulse) indicating the traveling speed (vehicle speed) of the vehicle on which the radar device 1 is mounted from the vehicle speed sensor, and specifies the vehicle speed based on the input vehicle speed signal. Then, the scanning control unit 4 controls the operations of the light source 2 and the one-dimensional scanner 3 according to the specified vehicle speed.

  Specifically, the scanning control unit 4 changes the light emission intensity from the light source 2 according to the vehicle speed, relatively reduces the light emission intensity when the vehicle speed is relatively slow, and emits light intensity when the vehicle speed is relatively fast. Is relatively increased. Further, the scanning control unit 4 changes the scanning angle range R1 of the one-dimensional scanner 3 according to the vehicle speed. When the vehicle speed is relatively slow, the scanning angle range R1 is set relatively wide so that the vehicle speed is relatively high. When it is very fast, the scanning angle range R1 is set relatively narrow. If the vehicle speed is relatively slow, there is a high possibility that there are pedestrians around the vehicle, and it is necessary to consider the presence of pedestrians in the vicinity. At this time, by relatively reducing the emission intensity, it is possible to avoid the irradiation of the high-intensity laser light to the pedestrian, and by setting the scanning angle range R1 relatively wide, Presence can be detected quickly. On the other hand, if the vehicle speed is relatively high, it is necessary to consider the presence of a preceding vehicle. At this time, it is possible to detect a distant preceding vehicle by relatively increasing the emission intensity, and by setting the scanning angle range R1 to be relatively narrow, it is highly possible that the preceding vehicle does not exist. Can be excluded from the scanning range, and a distant preceding vehicle can be detected quickly.

The light detection unit 5 includes a two-dimensional pixel array 11 and a decoder 12. The two-dimensional pixel array 11 is configured by arranging a plurality of pixels 13 in a two-dimensional matrix. The decoder 12 has a selection control line 14 connected to each column of a plurality of pixels 13 arranged in a two-dimensional matrix. The decoder 12 receives scan angle information indicating the scan angle of the one-dimensional scanner 3 from the scan control unit 4, and the reflected light is irradiated on the light receiving surface RP of the two-dimensional pixel array 11 based on the input scan angle information. The column of pixels 13 to be identified is specified. Then, the decoder 12 applies the selection control voltage V _SEL to the selection control line 14 corresponding to the identified column, thereby selecting the pixel 13 used for detecting the laser beam in units of columns. In addition, by applying the selection control voltage V _SEL to the corresponding selection control line 14 in this way, the operation of the pixel 13 irradiated with the reflected light is permitted, while the selection control voltage V is applied to the corresponding selection control line 14. _By not applying _SEL , the operation of the pixel 13 irradiated with the reflected light is prohibited, and the output of the detection signal from the pixel 13 not irradiated with the reflected light can be suppressed.

  As will be described later, the data processing unit 6 determines from the own device based on the time (flight time) that is the difference between the time when the laser light is emitted from the light source 2 and the time when the reflected light is received (incident) on the pixel 13. Calculate the distance to the object around the vehicle. The data processing unit 6 includes a plurality of pixel data processing units 15 for each row of the plurality of pixels 13 arranged in a two-dimensional matrix. The plurality of pixel data processing units 15 are each connected to a signal output line 16 for each row of the plurality of pixels 13 and input detection signals from the plurality of pixels 13 arranged in the corresponding rows.

  As shown in FIG. 5, the pixel 13 includes four light receiving elements 17 (corresponding to light receiving means), four lead-out circuits (ROC (Read Out Circuit)) 18 corresponding to the four light receiving elements 17, and Have The light receiving element 17 of the present embodiment is a SPAD (Single Photon Avalanche Diode). The SPAD is an avalanche photodiode that operates in a Geiger mode by applying a reverse bias voltage equal to or higher than a breakdown voltage (breakdown voltage) between its anode and cathode, and can detect light reception of a single photon. In addition, since the pixel 13 has the plurality of light receiving elements 17 as described above, it is detected that the reflected light is received by the pixels 13 that the reflected light is simultaneously received by some of the plurality of light receiving elements 17. The method can be adopted. That is, since the possibility that the plurality of light receiving elements 17 are erroneously detected at the same time is extremely low, the erroneous detection of the pixels 13 can be reduced by employing such a detection method.

  The four light receiving elements 17 are arranged in a two-dimensional matrix so that two light receiving portions 19 are arranged in the column direction and two in the row direction. The four lead-out circuits 18 are arranged on the end side of the pixel 13 adjacent to the corresponding light receiving elements 17 in the row direction D1. That is, the pixel 13 includes four light receiving elements 17 arranged on the center side and four lead-out circuits 18 arranged on the end side. With such a configuration, the possibility that reflected light is simultaneously received by at least two light receiving elements 17 is increased. The light source 2 emits, for example, 16 times of laser light within a time when the reflected light scans the region E1 where the four light receiving elements 17 are arranged along the scanning direction SD2. In addition, the scanning control unit 4 sets the scanning speed at which the reflected light scans along the scanning direction SD2 on the light receiving surface RP of the two-dimensional pixel array 11 to be relatively slow in the region E1, and relatively to other than the region E1. By setting it faster, the number of times the reflected light is received by the light receiving element 17 is increased.

The light receiving element 17 and the lead-out circuit 18 are electrically connected as shown in FIG. When a photon is incident (received) on the light receiving unit 19 in a state where a reverse bias voltage V _SPAD equal to or higher than the breakdown voltage (breakdown voltage) is applied between the anode and the cathode of the light receiving element 17, the avalanche is detected. Generate current. The lead-out circuit 18 includes a quench resistor 20, a digital converter 21, an inverter 22, a buffer 23, and a selector 24. The quench resistor 20 is an N-channel MOSFET (Metal Oxide Semiconductor Field Effect Transistor, N-type transistor) whose drain is connected to the anode of the light receiving element 17 and whose source is grounded via the selector 24. In addition, a quench voltage V _QCH that is set in advance to apply the N-type transistor as a quench resistor is applied to the gate of the N-type transistor that constitutes the quench resistor 20.

The digital converter 21 has a resistor 25 and an N-type transistor 26. The N-type transistor 26 has its drain connected to the power supply voltage V _DD via the resistor 25 and its source grounded. The voltage at the connection point CP 1 between the anode of the light receiving element 17 and the quench resistor 20 is applied to the gate of the N-type transistor 26.

The inverter 22 includes a P-channel MOSFET (P-type transistor) 27 and an N-type transistor 28. The P-type transistor 27 has a drain connected to the power supply voltage V _DD and a source connected to the drain of the N-type transistor 28. The drain of the N-type transistor 28 is connected to the source of the P-type transistor 27, and the source is grounded. A voltage at a connection point CP2 between the resistor 25 and the drain of the N-type transistor 26 is applied to the gate of the P-type transistor 27 and the gate of the N-type transistor 28, respectively. The output signal of the inverter 22 (the voltage at the connection point CP3 between the source of the P-type transistor 27 and the drain of the N-type transistor 28) is input to the buffer 23.

The buffer 23 is a circuit for impedance conversion, and when an output signal is input from the inverter 22, the input output signal is impedance-converted and output. The selector 24 is an N-type transistor, and its drain is connected to the source of the N-type transistor constituting the quench resistor 20, and its source is grounded. The selector 24 is connected to the decoder 12 as described above. When the selection control voltage V _SEL is applied from the decoder 12 to the gate of the N-type transistor, the selector 24 changes from the off state to the on state.

The lead-out circuit 18 operates as follows. First, when the selection control voltage V _SEL is applied from the decoder 12 to the selector 24 and the selector 24 is in the ON state, the reverse bias voltage V _SPAD is applied to the light receiving element 17 and the operation of the light receiving element 17 is permitted. (Becomes ready for operation). On the other hand, when the selection control voltage V _SEL is not applied from the decoder 12 to the selector 24 and the selector 24 is in the OFF state, the reverse bias voltage V _SPAD is not applied to the light receiving element 17 and the operation of the light receiving element 17 is prohibited. (Becomes inoperable).

If the reflected light is received by the light receiving element 17 and the avalanche current is generated when the selector 24 is in the ON state, the avalanche current flows through the quench resistor 20 and the voltage at the connection point CP1 increases. When the voltage at the connection point CP1 becomes higher than the ON voltage of the N-type transistor 26, the N-type transistor 26 is turned on, and the voltage at the connection point CP2 changes from the power supply voltage V _DD to 0V. When the voltage at the connection point CP2 changes from the power supply voltage V _DD to 0 V, the P-type transistor 27 changes from the OFF state to the ON state, and the N-type transistor 28 changes from the ON state to the OFF state. The voltage changes from 0 V to the power supply voltage V _DD . As a result, the output signal of the buffer 23 (the voltage V _{OUT at the} output terminal) becomes high level. Thereafter, when the voltage at the connection point CP1 continues to rise, the voltage applied between the anode and the cathode of the light receiving element 17 becomes smaller than the breakdown voltage, the avalanche current stops, and the voltage at the connection point CP1 decreases. . When the voltage at the connection point CP1 becomes lower than the on-voltage of the N-type transistor 26, the N-type transistor 26 is turned off and the output signal of the buffer 23 becomes low level.

  Thus, when the reflected light is received by the light receiving element 17, the lead-out circuit 18 stops the avalanche current from the timing when the avalanche current is generated and the N-type transistor 26 is turned on, and the N-type transistor 26 is turned off. A digital pulse signal is output as the above-described detection signal in the time until the timing of the state.

  As shown in FIG. 7, the pixel data processing unit 15 includes a pulse shaping unit 29, a received light number specifying unit 30 (corresponding to a received light number specifying unit), a time measuring unit 31 (corresponding to a time measuring unit), and a histogram generation. A unit 32 (corresponding to a histogram generating unit), a distance calculating unit 33 (corresponding to a physical quantity calculating unit), an SN ratio (Signal-Noise Ratio) calculating unit 34 (corresponding to an SN ratio calculating unit), a data storage unit 35, Have

  The pulse shaping unit 29 includes a plurality of D-type flip-flop circuits 36 corresponding to the plurality of light receiving elements 17 and a plurality of delay circuits 37 corresponding to the plurality of D-type flip-flop circuits 36. The D-type flip-flop circuit 36 is applied with a high level at its input terminal D, and inputs the digital pulse signal output from the corresponding readout circuit 18 as a detection signal to the clock terminal CLK. That is, the D-type flip-flop circuit 36 starts outputting a high-level pulse signal from the output terminal Q at the timing when the digital pulse signal is input to the clock terminal CLK.

  The D-type flip-flop circuit 36 inputs the high-level pulse signal output from the output terminal Q to the reset terminal CLR via the delay circuit 37. When receiving a high level pulse signal, the delay circuit 37 delays the input high level pulse signal by a preset delay time and outputs the delayed signal. That is, after the D-type flip-flop circuit 36 starts outputting the high-level pulse signal from the output terminal Q, the delay time elapses from the timing of outputting the high-level pulse signal, and the high-level pulse signal The output of the high-level pulse signal from the output terminal Q is terminated at the timing when is input to the reset terminal CLR. In this way, when the D-type flip-flop circuit 36 inputs a digital pulse signal from the corresponding lead-out circuit 18 to the clock terminal CLK, the D-type flip-flop circuit 36 continues to output a high-level pulse signal as a light reception detection signal for the delay time.

  The received light number identification unit 30 includes an input number determination circuit 38, a plurality of D-type flip-flop circuits 39, and an adder circuit (ADD) 40. The input number determination circuit 38 can receive light reception detection signals from each of the plurality of D-type flip-flop circuits 36, and the number of received light detection signals (number of signals) is equal to or greater than a preset measurement start determination value. In this case, a preset high level pulse signal is continuously output for a predetermined time and output as a measurement start detection signal. In the present embodiment, since one pixel 13 includes four light receiving elements 17, the input number determination circuit 38 sets, for example, a measurement start determination value to “2”, and the received light reception detection When the number of signals is “2” or more, a high-level pulse signal is continuously output as a measurement start detection signal for a predetermined time.

  The plurality of D-type flip-flop circuits 39 correspond to the plurality of D-type flip-flop circuits 36, respectively. In FIG. 7, only one D-type flip-flop circuit 39 is shown in a simplified manner. The D-type flip-flop circuit 39 inputs the light reception detection signal from the corresponding D-type flip-flop circuit 36 to the input terminal D, and inputs the measurement start detection signal from the input number determination circuit 38 to the clock terminal CLK. That is, the D-type flip-flop circuit 39 outputs a high-level pulse signal from the output terminal Q when the light reception detection signal is input to the input terminal D at the timing when the measurement start detection signal is input to the clock terminal CLK. .

  The adder circuit 40 counts (counts) the number of high-level pulse signals input from each of the plurality of D-type flip-flop circuits 39, and reflects the counted value (measured value obtained by time measurement). The number of light receiving elements 17 that have detected the light reception (number of received light) is specified, and a digital signal indicating the counted value is output as a received light number signal. In the present embodiment, since one pixel 13 has four light receiving elements 17, the adder circuit 40 has “0”, “1”, “2”, “3”, “4” as count values. ”Is output. Note that the adder circuit 40 requires 3 bits to represent the numerical values “0” to “4” in digital form, and therefore outputs a digital signal through three signal output lines.

  The time measuring unit 31 includes a TDC (Time to Digital Converter) 41, a plurality of D-type flip-flop circuits 42, a delay circuit 43, and a data generation circuit 44. The TDC 41 inputs a measurement start detection signal from the input number determination circuit 38. The TDC 41 measures the time from the timing when the laser light is emitted from the light source 2 to the timing when the measurement start detection signal is input (time from light emission to light reception, flight time), and a digital signal indicating the measured time is used as the time. Output as measurement signal. In the present embodiment, the TDC 41 outputs an 11-bit digital signal through 11 signal output lines.

  The D-type flip-flop circuit 42 corresponds to three signal output lines from which the adder circuit 40 outputs a digital signal. In FIG. 7, only one D-type flip-flop circuit 42 is shown in a simplified manner. The D-type flip-flop circuit 42 inputs a signal from the corresponding signal output line to the input terminal D, and inputs a measurement start detection signal from the input number determination circuit 38 via the delay circuit 43. When the measurement start detection signal is input, the delay circuit 43 delays the input measurement start detection signal by a preset delay time and outputs the result. The delay time of the delay circuit 43 is set so that the measurement start detection signal is input to the D-type flip-flop circuit 42 immediately after the signal from the adder circuit 40 is input to the D-type flip-flop circuit 42. . That is, when the D-type flip-flop circuit 42 receives the measurement start detection signal from the input number determination circuit 38, the D-type flip-flop circuit 42 outputs the received light number signal input from the addition circuit 40. When the data generation circuit 44 receives the time measurement signal from the TDC 41 and also receives the light reception number signal from the D-type flip-flop circuit 42, the data generation circuit 44 associates the time indicated by the time measurement signal with the count value indicated by the light reception number signal. Generate and output data.

  The histogram generation unit 32 generates a histogram by summing up the data input from the data generation circuit 44 for each time (unit scanning time) in which the reflected light scans on the light receiving surface of one pixel 13 along the scanning direction SD2. To do. That is, the histogram generation unit 32 sets the horizontal axis as time, the vertical axis as the received light integrated value, and adds the count value of the data input from the data generation circuit 44 on the time bin, thereby calculating the time for each resolution time of the TDC 41. The histogram is generated by integrating the numerical values by the number of times of laser light emission.

  The distance calculation unit 33 calculates a distance from the own device to an object around the vehicle based on the histogram generated by the histogram generation unit 32. The SN ratio calculation unit 34 calculates the ratio of the reflected light and disturbance light (background light, noise light) as the SN ratio. The data storage unit 35 uses the data output from the data generation circuit 44 to the histogram generation unit 32, the time until the distance calculation unit 33 calculates the distance from the own device to an object around the vehicle, and the SN ratio calculation unit 34 Temporarily stores the time until the SN ratio is calculated. The histogram generator 32 generates the histogram within the unit scanning time, and therefore discards the data input from the data generation circuit 44 every time the unit scanning time elapses. In other words, the data storage unit 35 may be configured to have a storage capacity capable of storing the data of the image 13 for one column of the two-dimensional pixel array 11 by the number of times of laser emission (integration number) within the unit scanning time. .

  Next, the operation of the above configuration will be described with reference to FIGS. The histogram generation unit 32 generates a histogram by performing the histogram generation processing shown in FIG. The distance calculation unit 33 calculates a distance from the own apparatus to an object around the vehicle by performing a distance calculation process shown in FIG. The SN ratio calculation unit 34 calculates the SN ratio by performing the SN ratio calculation process shown in FIG. Hereinafter, the histogram generation process, the distance calculation process, and the SN ratio calculation process will be described.

(1) Histogram Generation Processing The histogram generation unit 32 sets the horizontal axis as time, sets the maximum value of the time as the bin maximum value (maxbin), and sets the vertical axis as the received light integrated value that is the integrated count value, The maximum value that can store (hold) the accumulated value data is set as the memory maximum value (maxnum). When the histogram generation unit 32 starts the histogram generation processing, each received light integrated value (hist [0: maxbin]) from time (0) to time (maxbin), the sum total value (hist_sum) of the histogram, and the disturbance light amount value (base ), The first threshold value (thre1) and the subtraction value (sub) are initialized (A1). Specifically, the histogram generation unit 32 sets each received light integrated value from time (0) to time (maxbin) to “0”, sets the total value of the histogram to “0”, and sets the disturbance light amount value. A value obtained by multiplying the product of the bin maximum value and the memory maximum value by a constant (for example, 0.4) is set as the first threshold, and the memory maximum value is set to a constant (for example, 0.4). The multiplied value is set as a subtraction value (hist [0: maxbin] = 0, hist_sum = 0, base = 0, thre1 = maxbin * maxnum * 0.4, sub = maxnum * 0.4). The total value of the histogram is the sum of the received light integrated values from time (0) to time (maxbin), and is one of the characteristic values of the histogram. The disturbance light amount value is a value corresponding to the amount of disturbance light received.

  Next, the histogram generation unit 32 determines whether or not an instruction to end the histogram generation process has occurred (A2). If the histogram generation unit 32 determines, for example, that the measurement time has not reached the preset detection time and that an instruction to end the histogram generation processing has not occurred (A2: NO), the final measurement of one measurement is performed. It is determined whether or not the time has been reached and the total value of the histogram exceeds the first threshold (final time && hist_sum> thre1?) (A3). If the histogram generation unit 32 determines that the final time of one measurement has not been reached or the total value of the histogram does not exceed the first threshold (A3: NO), the data generation circuit 44 receives data (time measurement). It is determined whether or not the time (T) indicated by the signal and the count value (D) indicated by the received light number signal are input (A4). If the histogram generation unit 32 determines that data is input from the data generation circuit 44 (A4: YES), the histogram generation unit 32 adds the count value to the light reception integrated value at that timing, and uses the value obtained by adding the count value as a new light reception integration. As a value, a count value is added to the sum total value of the histogram, and a value obtained by adding the count value is set as a new sum value of the histogram (hist [T] + = D, hist_sum + = D) (A5) The process returns to step A2.

  On the other hand, when the histogram generation unit 32 determines that the final time of one measurement has been reached and the total value of the histogram has exceeded the first threshold (A3: YES), the time from time (0) to time (maxbin) The subtraction value is subtracted from each received light integrated value, the subtracted value is added to the disturbance light intensity value, and the sum of the received light integrated values from time (0) to time (maxbin) is defined as the sum total value of the histogram (hist [0: maxbin] − = sub, base + = sub, hist_sum = Σ (hist [0: maxbin])) (A6). Thereafter, the histogram generation unit 32 repeats steps A3 to A6 described above until it is determined that an end command has been generated. If the histogram generation unit 32 determines that, for example, the measurement time has reached the detection time and an instruction to end the histogram generation process has occurred (A2: YES), the histogram generation process ends.

  With the above processing, when the histogram generation unit 32 reaches the final measurement time for one measurement and the total value of the histogram exceeds the first threshold, each received light integrated value from time (0) to time (maxbin) The subtraction value is subtracted from the data to compress the count value integration direction data. At this time, the histogram generation unit 32 stores the data obtained by subtracting the received light integrated values (data corresponding to the subtraction amount) in a memory area different from the memory area for storing (holding) the histogram. Store as data.

  FIG. 11 shows the transition of the histogram generated by the histogram generator 32. FIG. 11 illustrates a case where one measurement time (predetermined time) is 1000 ns. When the total value of the histogram exceeds the first threshold at the time when the first measurement is finished, the histogram generation unit 32 subtracts the subtraction value from each light reception integrated value from time (0) to time (maxbin), Compress the count direction integration data. Then, the histogram generation unit 32 stores data corresponding to the subtraction amount in another memory area, and starts the second measurement (next measurement).

  Note that the histogram generation unit 32 is not limited to comparing the total value of the histogram with the first threshold value, and uses the average value or median value of the histogram as the characteristic value of the histogram, as shown in FIG. A value obtained by multiplying by a constant (for example, 0.4) may be set as the first threshold value, and the average value or median value of the histogram may be compared with the first threshold value. The average value of the histogram is a value obtained by dividing the total value of the histogram by the bin maximum value. The median value of the histogram is the median value among the received light integrated values from time (0) to time (maxbin).

  Further, the histogram generation unit 32 may set the constant as a fixed value or a variable value, and may set the first threshold value as a fixed value or a variable value. In the case where the first threshold value is a variable value, the histogram generation unit 32 may set the first threshold value using the disturbance light quantity value or SN ratio of the previous measurement. That is, when the disturbance light quantity value of the previous measurement is used, the histogram generation unit 32 sets the first threshold value large if the disturbance light quantity value of the previous measurement is relatively large, and first if the disturbance light quantity value of the previous measurement is relatively small. It is sufficient to set a small threshold value. In addition, when the SN ratio of the previous measurement is used, the histogram generation unit 32 sets the first threshold small if the SN ratio of the previous measurement is relatively large, and the first threshold if the SN ratio of the previous measurement is relatively small. Should be set larger.

  The histogram generation unit 32 may calculate the total disturbance light amount value by integrating the disturbance light amount value every time the count value integration direction data is compressed, or may compress the count value integration direction data. The entire disturbance light quantity value may be calculated based on the number of times. The histogram generation unit 32 may subtract the subtraction value from the received light integrated value every time one measurement is completed, or subtract the subtracted value from the received light integrated value when a plurality of measurements are completed. Also good.

(2) Distance calculation process When the distance calculation process is started, the distance calculation unit 33 initializes a time determination value (dist), a detection maximum value (max) that is a mode value, and a determination target time (t) (B1). ). Specifically, the distance calculation unit 33 sets the time determination value to “0”, sets the maximum detection value to “0”, and sets the determination target time to “1” (dist = 0, max = 0, t = 1).

  The distance calculation unit 33 uses the histogram generated by the histogram generation processing by the histogram generation unit 32 to determine whether or not the light reception integrated value at the determination target time exceeds the maximum detection value (max <hist [t]?). (B2). When the distance calculation unit 33 determines that the integrated light reception value at the determination target time exceeds the maximum detection value (B2: YES), the distance calculation unit 33 sets the determination target time as a time determination value, and calculates the integrated light reception value at the determination target time. The maximum detection value is set (dist = t, max = hist [t]) (B3). Next, the distance calculation unit 33 increments the determination target time (t + = 1) (B4), and determines whether or not the determination target time exceeds the bin maximum time (t> maxbin?) (B5).

  On the other hand, when the distance calculation unit 33 determines that the integrated light reception value at the determination target time does not exceed the maximum detection value (B2: NO), the determination target time is not set as the time determination value, and the determination target is set. Without setting the light reception integrated value in time as the detection maximum value, the determination target time is incremented (t + = 1) (B4), and it is determined whether or not the determination target time exceeds the bin maximum value time (t > maxbin?) (B5).

  When determining that the determination target time does not exceed the bin maximum value (B5: NO), the distance calculation unit 33 returns to step B2. Thereafter, the distance calculation unit 33 repeats steps B2 to B5 described above until it is determined that the determination target time has exceeded the bin maximum value time. If the histogram generation unit 32 determines that the determination target time has exceeded the bin maximum value (B5: YES), it outputs the time determination value and the maximum detection value (B6), and ends the distance calculation process.

  Through the above processing, the distance calculation unit 33 specifies the maximum detection value that is the mode of the light reception integrated value based on the histogram in which the count direction integration data is compressed, and corresponds to the specified detection maximum value. The time to perform is specified as a time determination value. And the distance calculation part 33 calculates the distance from the own apparatus to the object around a vehicle using the specified time determination value. Specifically, since the time from light emission to light reception is proportional to the distance from the own device to an object around the vehicle under the condition where there is no influence by disturbance light, the distance calculation unit 33 calculates the time of the time determination value. Assuming that ta, the speed of light is C (C≈300,000 km / s), and the distance from the device to the object around the vehicle is D, D is calculated by the following formula.

D = (ta × C) / 2
For example, if the time determination value is 100 ns, the distance calculation unit 33 calculates the distance from the own device to an object around the vehicle as 15 m. Similarly, the distance calculation unit 33 calculates the distance from the own device to an object around the vehicle as 30 m if the time determination value time is 200 ns, and if the time determination value time is 400 ns, The distance from the vehicle to the object around the vehicle is calculated as 60 m.

  The distance calculation unit 33 compares the detection maximum value with a preset calculation determination value, and calculates the distance if the detection maximum value is equal to or greater than the calculation determination value, and the detection maximum value must be equal to or greater than the calculation determination value. For example, the distance may not be calculated (the object is not detected) (if it is less than the calculated determination value). Also, the distance calculation unit 33 refers to the distance calculated in the past (for example, the result from one cycle before scanning to the current timing) even if the maximum detection value is less than the calculation determination value, and the object exists at the same distance. The distance may be calculated on the condition that it is determined that the user is doing. Further, when there are a plurality of maximum detection values equal to or greater than the calculation determination value, the distance calculation unit 33 may calculate the distance by specifying the minimum time among the times corresponding to the plurality of maximum detection values. .

  In addition, the distance calculation unit 33 may set the calculation determination value as a fixed value or a variable value. When the calculation determination value is a variable value, the distance calculation unit 33 may set the calculation determination value using the disturbance light quantity value or SN ratio of the previous measurement. That is, when the disturbance light quantity value of the previous measurement is used, the histogram generation unit 32 sets the calculation determination value to be large if the disturbance light quantity value of the previous measurement is relatively large, and the calculation determination value if the disturbance light quantity value is relatively small. Should be set small. Further, when using the SN ratio of the previous measurement, the histogram generation unit 32 sets the calculated determination value to be small if the SN ratio of the previous measurement is relatively large, and increases the calculation determination value if the SN ratio is relatively small. Set it.

(3) SN ratio calculation process The SN ratio calculation part 34 will initialize SN ratio (sn), if an SN ratio calculation process is started (C1). Specifically, the SN ratio calculation unit 34 sets the SN ratio to “0” (sn = 0). Next, the SN ratio calculation unit 34 calculates, as the SN ratio, a value obtained by dividing the detected maximum value calculated by the distance calculation unit 33 by the distance calculation process by the disturbance light amount value calculated by the histogram generation unit 32 by the histogram generation process ( sn = max / base) (C2). Then, the SN ratio calculation unit 34 outputs the calculated SN ratio (C3), and ends the SN ratio calculation process. In this case, the SN ratio calculation unit 34 calculates a value obtained by dividing the detection maximum value by the disturbance light amount value as described above as an SN ratio, and thus is relatively relative if the detection maximum value is relatively large with respect to the disturbance light amount value. A relatively high SN ratio is output, and if it is relatively small, a relatively low SN ratio is output.

  As described above, according to the first embodiment, the following operational effects can be obtained. In the radar device 1, when the total value of the histogram exceeds the first threshold value, the data in the integration direction of the count value is compressed, and the maximum detected value is specified based on the histogram in which the data in the integration direction of the measurement value is compressed. The distance from the device to the object around the vehicle was calculated. Thereby, by compressing the data in the integration direction of the count value, the amount of data in the integration direction of the count value can be reduced, and the input dynamic range can be appropriately ensured even when time measurement is repeated. As a result, by appropriately securing the input dynamic range, it is possible to appropriately calculate the distance from the own device to an object around the vehicle, and to suppress an increase in memory capacity for storing the histogram. That is, in the in-vehicle environment, by appropriately securing the input dynamic range in this way, even if the reflected light coming from a long distance is weak, disturbance light and reflected light can be appropriately distinguished, The distance to a far object can be calculated appropriately.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. In addition, description is abbreviate | omitted about the same part as above-mentioned 1st Embodiment, and a different part is demonstrated. In the first embodiment, the total value of the histogram is compared with the first threshold value. In the second embodiment, the maximum value of the histogram is compared with the second threshold value. The maximum value of the histogram is the maximum value among the received light integrated values from time (0) to time (maxbin), and is one of the characteristic values of the histogram.

  When the histogram generation unit 32 starts the histogram generation processing, each received light integrated value (hist [0: maxbin]) from time (0) to time (maxbin), disturbance light amount value (base), and second threshold value (thre2) ), The subtraction value (sub) is initialized (A11). Specifically, the histogram generation unit 32 sets each received light integrated value from time (0) to time (maxbin) to “0”, sets the disturbance light quantity value to “0”, and sets the memory maximum value as a constant. A value obtained by multiplying (for example, 0.7) is set as the second threshold value, and a value obtained by multiplying the memory maximum value by a constant (for example, 0.4) is set as the subtraction value (hist [0: maxbin] = 0, base = 0, thre2 = maxnum * 0.7, sub = maxnum * 0.4).

  Next, when the histogram generation unit 32 determines that an instruction to end the histogram generation process has not occurred (A12: NO), the histogram has reached the final measurement time and the maximum value of the histogram exceeds the second threshold value. (Final time && hist_max> thre2?) (A13). The histogram generation unit 32 determines that the final time of one measurement has not been reached or the maximum value of the histogram does not exceed the second threshold (A13: NO), and data is input from the data generation circuit 44. (A14: YES), the count value is added to the light reception integrated value at that timing, and the added value is set as a new light reception integrated value (hist [T] + = D) (A15). Return to step A12. On the other hand, when the histogram generating unit 32 determines that the final time of one measurement is reached and the maximum value of the histogram exceeds the second threshold (A13: YES), the time from time (0) to time (maxbin) is determined. A subtraction value is subtracted from each received light integrated value, and the subtraction value is added to the disturbance light quantity value (hist [0: maxbin] − = sub, base + = sub) (A16).

  As a result of the above processing, the histogram generation unit 32 reaches each light reception integrated value from time (0) to time (maxbin) when the final time of one measurement is reached and the maximum value of the histogram exceeds the second threshold. The subtraction value is subtracted from the data to compress the count value integration direction data. Also at this time, the histogram generation unit 32 stores the data subtracted from each received light integrated value as data of the disturbance light quantity value in another memory area.

  FIG. 14 shows the transition of the histogram generated by the histogram generator 32. When the maximum value of the histogram exceeds the second threshold at the time when the first measurement is finished, the histogram generation unit 32 subtracts a subtraction value from each light reception integrated value from time (0) to time (maxbin), Compress the count direction integration data. Then, the histogram generation unit 32 stores data corresponding to the subtraction amount in another memory area, and starts the second measurement. Thereafter, the distance calculation unit 33 calculates the distance using the histogram generated by the histogram generation unit 32, as in the first embodiment. Similarly to the first embodiment, the SN ratio calculation unit 34 calculates the SN ratio using the detected maximum value calculated by the distance calculation unit 33 and the disturbance light amount value calculated by the histogram generation unit 32.

  As described above, according to the second embodiment, the following operational effects can be obtained. In the radar apparatus 1, when the maximum value of the histogram exceeds the second threshold value, the histogram in which the count direction integration data is compressed and the measurement value integration direction data is compressed, as in the first embodiment. Based on the above, the maximum detection value is specified, and the distance from the device to the object around the vehicle is calculated. Thereby, the effect similar to 1st Embodiment can be acquired. That is, by appropriately securing the input dynamic range, it is possible to appropriately calculate the distance from the own device to the object around the vehicle, and to suppress an increase in memory capacity for storing the histogram.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. In addition, description is abbreviate | omitted about the same part as above-mentioned 2nd Embodiment, and a different part is demonstrated. In the second embodiment, when the maximum value of the histogram exceeds the second threshold, the data in the counting direction is uniformly compressed. In the third embodiment, the maximum value of the histogram is When the second threshold value is exceeded, the data in the direction of integration of the count values is compressed based on the average value of the histogram, or the process proceeds to the subsequent process without compressing the data (data is output to the distance calculation unit 33). It is the structure which selects.

  When the histogram generation unit 32 starts the histogram generation processing, each received light integrated value (hist [0: maxbin]) from time (0) to time (maxbin), disturbance light amount value (base), and second threshold value (thre2) ), A subtraction value (sub), and a compression determination value (dec) are initialized (A21). Specifically, the histogram generation unit 32 sets each received light integrated value from time (0) to time (maxbin) to “0”, sets the disturbance light quantity value to “0”, and sets the memory maximum value as a constant. A value obtained by multiplying (for example, 0.7) is set as the second threshold value, a value obtained by multiplying the memory maximum value by a constant (for example, 0.4) is set as a subtraction value, and a constant (for example, 0. A value obtained by multiplying 4) is set as a compression determination value (hist [0: maxbin] = 0, base = 0, thre2 = maxnum * 0.7, sub = maxnum * 0.4, dec = maxnum * 0.4).

  Next, when the histogram generation unit 32 determines that an instruction to end the histogram generation processing has not occurred (A22: NO), the histogram has reached the final time of one measurement and the maximum value of the histogram exceeds the second threshold value. (Final time && hist_max> thre2?) (A23). The histogram generation unit 32 determines that the final time of one measurement is not reached or the maximum value of the histogram does not exceed the second threshold (A23: NO), and data is input from the data generation circuit 44. (A24: YES), the count value is added to the integrated light reception value at that timing, and the added value is set as a new integrated light reception value (hist [T] + = D) (A25). Return to step A22.

  On the other hand, when the histogram generation unit 32 determines that the final time of one measurement has been reached and the maximum value of the histogram has exceeded the second threshold (A23: YES), the histogram generation unit 32 compares the average value of the histogram with the compression determination value. Then, it is determined whether or not the average value of the histogram is less than the compression determination value (hist_mean <dec?) (A26). If the histogram generation unit 32 determines that the average value of the histogram is not less than the compression determination value (is greater than or equal to the compression determination value) (A26: NO), the time (0) to the time (maxbin) are the same as in the second embodiment. The subtracted value is subtracted from each received light accumulated value until () and the subtracted value is added to the disturbance light quantity value (hist [0: maxbin] − = sub, base + = sub) (A27). On the other hand, if the histogram generation unit 32 determines that the average value of the histogram is less than the compression determination value (A26: YES), the histogram generation process ends at that point.

  With the above processing, when the histogram generation unit 32 reaches the final measurement time for one measurement and the maximum value of the histogram exceeds the second threshold, whether or not the average value of the histogram is less than the compression determination value is determined. It is selected whether to compress the data in the integration direction of the count value or to shift to subsequent processing without compression. That is, the histogram generation unit 32 specifies that the discrimination between the disturbance light and the reflected light is insufficient when the average value of the histogram is not less than the compression determination value (is greater than or equal to the compression determination value), and the count value integration direction Compress the data. Also at this time, the histogram generation unit 32 stores the data subtracted from the received light integrated value as data of the disturbance light quantity value in another memory area. On the other hand, if the average value of the histogram is less than the compression determination value, the histogram generation unit 32 specifies that the disturbance light and the reflected light are sufficiently distinguished from each other, and does not compress the data in the integration direction of the count value. Move on to processing.

  16 and 17 show the transition of the histogram generated by the histogram generator 32. FIG. As shown in FIG. 16, the histogram generation unit 32 determines that the count value is obtained when the maximum value of the histogram exceeds the second threshold at the time when the first measurement is finished and the average value of the histogram is not less than the compression determination value. Compress the data in the integration direction. Then, the histogram generation unit 32 stores data corresponding to the subtraction amount in another memory area, and starts the second measurement. On the other hand, as shown in FIG. 17, when the first measurement is finished, the histogram generation unit 32 has the maximum value of the histogram that exceeds the second threshold, and the average value of the histogram is less than the compression determination value. The data is output to the distance calculation unit 33 without compressing the data in the integration direction of the count values.

  The histogram generation unit 32 is not limited to comparing the average value of the histogram with the compression determination value, but uses the total value of the histogram as another characteristic value of the histogram, and uses a constant as the product of the bin maximum value and the memory maximum value. A value obtained by multiplying (for example, 0.4) may be set as the compression determination value, and the total value of the histogram may be compared with the compression determination value. That is, if the total value of the histogram is not less than the compression determination value, the histogram generation unit 32 specifies that the discrimination between the disturbance light and the reflected light is insufficient, while the histogram total value is less than the compression determination value. Then, it may be specified that the discrimination between disturbance light and reflected light is sufficient.

  As described above, according to the third embodiment, the following operational effects can be obtained. In the radar apparatus 1, if the maximum value of the histogram exceeds the second threshold and the average value of the histogram is not less than the compression determination value, the count direction integration data is obtained as in the first and second embodiments. The maximum detected value is specified based on a histogram obtained by compressing and compressing the data in the integration direction of the measured value, and the distance from the own device to an object around the vehicle is calculated. Thereby, the same effect as 1st and 2nd embodiment can be acquired. That is, by appropriately securing the input dynamic range, it is possible to appropriately calculate the distance from the own device to the object around the vehicle, and to suppress an increase in memory capacity for storing the histogram.

  Further, in the radar device 1, when the maximum value of the histogram exceeds the second threshold value and the average value of the histogram is less than the compression determination value, the data in the integration direction of the count value is not compressed and the process proceeds to the subsequent process. I tried to do it. As a result, when it is assumed that the discrimination between disturbance light and reflected light is sufficient, the process of compressing the data is omitted, so that the distance from the own device to the object around the vehicle can be appropriately and quickly obtained. Can be calculated.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIGS. In addition, description is abbreviate | omitted about the same part as the above-mentioned 1st-3rd embodiment, and a different part is demonstrated. In the fourth embodiment, the minimum value of the histogram is compared with the third threshold value. The minimum value of the histogram is the minimum value of the integrated values of received light from time (0) to time (maxbin), and is one of the characteristic values of the histogram.

  When the histogram generation unit 32 starts the histogram generation process, each received light integrated value (hist [0: maxbin]) from time (0) to time (maxbin), disturbance light amount value (base), and third threshold value (thre3) ), The subtraction value (sub) is initialized (A31). Specifically, the histogram generation unit 32 sets each received light integrated value from time (0) to time (maxbin) to “0”, sets the disturbance light quantity value to “0”, and sets the memory maximum value as a constant. A value obtained by multiplying (for example, 0.1) is set as a third threshold value, and a value obtained by multiplying a memory maximum value by a constant (for example, 0.1) is set as a subtraction value (hist [0: maxbin-1] = 0, base = 0, thre3 = maxnum * 0.1, sub = maxnum * 0.1).

  Next, when the histogram generation unit 32 determines that an instruction to end the histogram generation processing has not occurred (A32: NO), the histogram reaches the final time of one measurement and the minimum value of the histogram exceeds the third threshold value. (Final time && hist_min> thre3?) (A33). The histogram generation unit 32 determines that the final time of one measurement is not reached or the maximum value of the histogram does not exceed the third threshold (A33: NO), and data is input from the data generation circuit 44. (A34: YES), the count value is added to the received light integrated value at that timing, and the added value is set as a new received light integrated value (hist [T] + = D) (A35). Return to step A32. On the other hand, if the histogram generation unit 32 determines that the final time of one measurement is reached and the minimum value of the histogram exceeds the third threshold (A33: YES), the time from time (0) to time (maxbin) is determined. The subtracted value is subtracted from each received light integrated value, and the subtracted value is added to the disturbance light quantity value (hist [0: maxbin] − = sub, base + = sub) (A36).

  With the above processing, when the histogram generation unit 32 reaches the final time of one measurement and the minimum value of the histogram exceeds the third threshold, each received light integrated value from time (0) to time (maxbin) The subtraction value is subtracted from the data to compress the count value integration direction data. Also at this time, the histogram generation unit 32 stores the data subtracted from the received light integrated value as data of the disturbance light quantity value in another memory area.

  FIG. 19 shows the transition of the histogram generated by the histogram generator 32. When the maximum value of the histogram exceeds the second threshold at the time when the first measurement is finished, the histogram generation unit 32 subtracts a subtraction value from each light reception integrated value from time (0) to time (maxbin), Compress the count direction integration data. Then, the histogram generation unit 32 stores data corresponding to the subtraction amount in another memory area, and starts the second measurement.

  As described above, according to the fourth embodiment, the following operational effects can be obtained. In the radar apparatus 1, when the minimum value of the histogram exceeds the third threshold value, the data in the integration direction of the count value is compressed and the data in the integration direction of the measured value is converted as in the first to third embodiments. The maximum detection value is specified based on the compressed histogram, and the distance from the device to an object around the vehicle is calculated. Thereby, the same effect as the 1st to 3rd embodiment can be acquired. That is, by appropriately securing the input dynamic range, it is possible to appropriately calculate the distance from the own device to the object around the vehicle, and to suppress an increase in memory capacity for storing the histogram.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be modified or expanded as follows.
In the present embodiment, the configuration for calculating the distance from the radar device 1 mounted on the vehicle to the object around the vehicle is exemplified, but the measurement value obtained at a predetermined detection time by repeating the time measurement is displayed on the time bin. As long as the histogram is generated by adding to and the physical quantity is calculated based on the generated histogram, it may be applied to uses other than the vehicle.
In the present embodiment, the configuration is illustrated in which the horizontal axis is time and the vertical axis is the received light integrated value and the histogram is generated. However, the horizontal axis and the vertical axis may be interchanged, and the vertical axis is time and horizontal. A histogram may be generated with the axis as the integrated light reception value.

  In the present embodiment, for example, the measurement time has not reached the preset detection time, and the configuration in which the histogram feature value is compared with the threshold value until the histogram generation processing end command is generated is exemplified. A configuration may be used in which the feature value of the histogram is compared with a threshold value in an arbitrary portion of the above. That is, the process of compressing the data by comparing the histogram feature value according to the present invention with the threshold value at any part of the detection time, and the conventional process (compare the histogram feature value with the threshold value) at the remaining part of the detection time. Without processing the data compression). Even in such a configuration, it is possible to appropriately calculate the distance from the own device to an object around the vehicle while suppressing an increase in memory capacity for storing the histogram. That is, by applying the present invention at least a part of the detection time, not the entire detection time, the above-described effects can be obtained.

In the present embodiment, the configuration in which the subtracted value is subtracted from each received light integrated value to compress the data is exemplified, but each received light integrated value may be divided by a constant to compress the data.
When the scanning speed of the one-dimensional scanner 3 is high and the number of times of laser light emission within the unit scanning time is small, the columns irradiated with the reflected light on the light receiving surface RP of the two-dimensional pixel array 11 are thinned out. It is good also as a structure scanned by an interlace system. By thinning out the columns irradiated with the reflected light, it is not necessary to store data for the thinned columns, and an increase in storage capacity in the data storage unit 35 can be suppressed.

  A part of the elements constituting the lead-out circuit 18 (for example, the inverter 22 and the buffer 23) may be extended by wiring and installed outside the light receiving surface RP of the two-dimensional pixel array 11. In this case, if the wiring is extended, the delay of the signal increases, and transmission of a signal transmitted between the pixels 13 and the pixel data processing unit 15 is also performed between the pixels 13 in the same row connected to the pixel data processing unit 15. Since the time difference may become large, a mechanism for correcting the difference in transmission time between the pixels 13 in the same row may be provided. Furthermore, some of the elements constituting the lead-out circuit 18 may be installed on the back side of the light receiving surface RP of the two-dimensional pixel array 11 by through vias or back surface irradiation.

  In the drawings, 1 is a radar device (arithmetic unit), 2 is a light source (light emitting means), 17 is a light receiving element (light receiving means), 30 is a light receiving number specifying unit (light receiving number specifying unit), and 31 is a time measuring unit (time measuring). Means), 32 is a histogram generator (histogram generator), 33 is a distance calculator (physical quantity calculator), and 34 is an SN ratio calculator (SN ratio calculator).

Claims (14)

A histogram generation means (32) for adding a measurement value obtained at a predetermined detection time by repeating time measurement to a time bin, and generating a histogram based on the time and an integrated value that is an integration of the measured value; ,
Physical quantity calculating means (33) for calculating a physical quantity based on the histogram generated by the histogram generating means,
The histogram generation means subtracts from the measurement value in the histogram when the histogram characteristic value at the time when the addition of the measurement value obtained at a predetermined time which is a part of the detection time is over at least a threshold value The value is subtracted to compress the data in the integration direction of the measurement value , and the subtracted data is stored as disturbance light quantity value data in a memory area different from the memory area for storing the histogram,
The physical quantity calculating means specifies a mode value for time measurement based on a histogram obtained by compressing data in the integration direction of the measurement value by the histogram generation unit, and specifies a time corresponding to the specified mode value. An arithmetic unit (1) characterized in that a physical quantity is calculated. The arithmetic device according to claim 1,
The histogram generating means uses at least one of a total value, an average value, a median value, a maximum value, and a minimum value as a feature value of the histogram. In the arithmetic unit according to claim 1 or 2,
An arithmetic unit comprising an SN ratio calculating means (34) for calculating an SN ratio based on a compression result obtained by compressing the data in the integration direction of the measurement values by the histogram generating means. In the arithmetic unit according to any one of claims 1 to 3,
The calculation device, wherein the histogram generation means uses a value determined based on a maximum value of a memory capacity for storing a histogram as the threshold value. In the arithmetic unit according to any one of claims 1 to 3,
The histogram generating means uses a value determined based on a past compression result as the threshold value. In the arithmetic unit according to any one of claims 1 to 5,
The arithmetic unit characterized in that the histogram generation means compresses data in the integration direction of the measurement values in the histogram by subtraction or division. In the arithmetic unit according to any one of claims 1 to 6,
The calculation device, wherein the histogram generation means compresses data in the integration direction of the measurement values in the histogram in the middle of repetition of time measurement. In the arithmetic unit according to any one of claims 1 to 7,
The histogram generating means has a feature value of the histogram that exceeds the threshold when the addition of the measurement value obtained in a predetermined time that is a part of the detection time is exceeded, and another feature value of the histogram is a compression determination value. When it is above, the arithmetic apparatus which compresses the data of the integration direction of the said measured value in a histogram. In the arithmetic unit according to claim 8,
The histogram generation means has detected that the feature value of the histogram at the time when the addition of the measurement value obtained at a predetermined time which is a part of the detection time has exceeded the threshold value, but another feature value of the histogram is compressed. When the value is less than the value, the calculation device is characterized in that the data in the integration direction of the measurement value in the histogram is not compressed. In the arithmetic unit according to claim 9,
When the histogram generation unit does not compress the integration direction data of the measurement value in the histogram, the physical quantity calculation unit specifies a mode value of time measurement based on the histogram in which the integration direction data is not compressed. And calculating a physical quantity by specifying a time corresponding to the specified mode value. In the arithmetic unit according to any one of claims 1 to 10,
The histogram generating means generates a histogram with the horizontal axis as time and the vertical axis as an integrated value. In the arithmetic unit according to any one of claims 1 to 11,
The arithmetic unit according to claim 1, wherein the physical quantity calculation means calculates the physical quantity on condition that the mode value is equal to or greater than a calculation determination value. In the arithmetic unit according to any one of claims 1 to 11,
The physical quantity calculating means calculates a physical quantity by specifying a minimum time among times corresponding to each of the plurality of mode values when there are a plurality of mode values that are equal to or greater than a calculation determination value. Arithmetic unit. In the arithmetic unit according to any one of claims 1 to 13,
A light emitting means (2) for emitting pulsed light;
A light receiving means (17) for receiving the reflected light reflected from the object by the pulsed light emitted from the light emitting means;
A light receiving number specifying means (30) for specifying the timing at which the reflected light is received by the light receiving means and specifying the number of the light receiving means that has detected the reception of the reflected light as the number of received light;
A time measuring means (31) for measuring the time from the timing when the pulsed light is emitted from the light emitting means to the timing when the reflected light is received by the light receiving means as flight time,
The histogram generating means generates a histogram based on a flight time measured by the time measuring means and a received light integrated value that is an integration of the received light number specified by the received light number specifying means,
The arithmetic apparatus according to claim 1, wherein the physical quantity calculating means calculates a distance from the apparatus to an object around the apparatus as a physical quantity.

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