Patent Description:
Some light receiving apparatuses use, as light receiving elements, elements generating signals in response to reception of photons (see, for example, PTL <NUM>). Light receiving apparatuses of this type adopt, as a measurement method for measuring a distance to a measurement target, a TOF (Time Of Flight) method for measuring the time from radiation of light toward the measurement target until the light returns after being reflected by the measurement target. In a direct TOF method, which is one type of the TOF method and involves directly calculating the distance from a difference in time of flight of light, the time of flight of photons needs to be accurately determined.

In a light receiving apparatuses in which pixels are arranged in a two-dimensional shape and each include a light receiving element, the light receiving apparatus acquiring a three-dimensional depth map (depthmap), a length of a path from each pixel to a time-to-digital converter (TDC) varies, disadvantageously leading to a propagation delay skew (hereinafter referred to as an "in-plane delay skew") in a two dimensional plane.

To eliminate the in-plane delay skew, a possible technique involves directly adding buffers for delay adjustment to wiring in paths from a plurality of light receiving elements (pixels) to the time to digital converter (TDC). However, a variation in characteristics among the added buffers may further deteriorate the in-plane delay skew. Consequently, correcting the in-plane delay skew using the technique for adding the buffers is difficult.

Additionally, correction of the in-plane delay skew can be performed using an application processor provided in a later stage of the light receiving apparatus. However, in a case where the application processor is used to correct the in-plane delay skew, the processing delay in the system as a whole occurs in units of frames in which all signals from the plurality of pixels are acquired. Thus, the processing delay becomes significant and as a result, adversely affects applications requiring immediate responses.

Thus, an object of the present disclosure is to provide a light receiving apparatus that can implement excellent correction processing on the in-plane delay skew and a distance measuring apparatus using the light receiving apparatus.

Embodiments for implementing techniques of the present disclosure (hereinafter referred to as "embodiments") will be described below in detail using the drawings. The techniques of the present disclosure are not limited to the embodiments, and various numerical values and the like in the embodiments are illustrative. In the following description, the same elements or elements with the same functions are denoted by the same reference signs, and duplicate descriptions are omitted. Note that descriptions will be given in the following order.

A light receiving apparatus and a distance measuring apparatus in the present disclosure can be configured such that a correction value is a value based on a distance from a pixel to a time measuring section. The light receiving apparatus and a distance measuring apparatus in the present disclosure can be configured such that, on the basis of a correction value for a pixel at an end in a light receiving section, correction values for other pixels can be calculated by linear interpolation.

The light receiving apparatus and the distance measuring apparatus of the present disclosure including the above-described preferred embodiments and configurations can be configured such that a plurality of histogram creating sections is provided corresponding to pixel rows in the light receiving section. In this case, the light receiving apparatus and the distance measuring apparatus can be configured such that a correction processing section executes correction processing for each of histograms created by each of the plurality of histogram creating sections. Additionally, the light receiving apparatus and the distance measuring apparatus can be configured such that the correction processing section executes correction processing in units of bins in the histogram.

Further, the light receiving apparatus and the distance measuring apparatus of the present disclosure including the above-described preferred embodiments and configurations can be configured such that the correction processing section executes correction processing using a system correction value common to all the histograms created by each of the plurality of histogram creating sections. The light receiving apparatus and the distance measuring apparatus of the present disclosure can be configured such that the system correction value is a value corresponding to a delay common to all the histograms created by each of the plurality of histogram creating sections.

Furthermore, the light receiving apparatus and the distance measuring apparatus including the above-described preferred embodiments and configurations can be configured such that the storage section includes a group of correction registers in which the correction value is set for each histogram. Further, the light receiving apparatus and the distance measuring apparatus can be configured such that the correction processing section is provided in a later stage of the histogram creating section and executes correction processing by adding the correction value to a bin value for the histogram created by each of the histogram creating sections. Alternatively, but outside the claimed subject-matter, the light receiving apparatus and the distance measuring apparatus can be configured such that the correction processing section is provided in a former stage of the histogram creating section and executes correction processing by adding the correction value to each of the measured values measured by the time measuring section.

Additionally, the light receiving apparatus and the distance measuring apparatus including the above-described preferred embodiments and configurations can be configured such that the light receiving element in each of the pixels includes an element generating a signal in response to reception of photons.

Additionally, the light receiving apparatus and the distance measuring apparatus including the above-described preferred embodiments and configurations can be configured such that the light receiving section includes a group of pixels in units of a plurality of pixels, such that the signal lines include a group of signal lines in units of a plurality of signal lines, and such that each of a plurality of the pixels included in the group of pixels is connected to each of a plurality of the signal lines included in the group of signal lines, on a one-to-one basis.

<FIG> is a schematic configuration diagram depicting a distance measuring apparatus according to an embodiment of the present disclosure. A distance measuring apparatus <NUM> according to the present embodiment adopts, as a measurement method for measuring a distance to a subject <NUM> corresponding to a measurement target, a TOF (time of flight) method for measuring the time from radiation of light (for example, laser light with a peak wavelength in an infrared wavelength region) toward the subject <NUM> until the light returns after being reflected by the subject <NUM>. To implement distance measurement according to the TOF method, the distance measuring apparatus <NUM> according to the present embodiment includes a light source <NUM> and a light receiving apparatus <NUM>. As the light receiving apparatus <NUM>, a light receiving apparatus according to an embodiment of the present disclosure described below is used.

<FIG> depict a specific configuration of the distance measuring apparatus <NUM> according to the present embodiment. The light source <NUM> includes, for example, a laser driver <NUM>, a laser light source <NUM>, and a diffusing lens <NUM> to irradiate the subject <NUM> with laser light. The laser driver <NUM> drives the laser light source <NUM> under the control of a control section <NUM>. The laser light source <NUM> includes, for example, a semiconductor laser to emit laser light by being driven by the laser driver <NUM>. The diffusing lens <NUM> diffuses laser light emitted from the laser light source <NUM> to irradiate the subject <NUM> with the laser light.

The light receiving apparatus <NUM> includes a light receiving lens <NUM>, an optical sensor <NUM> that is a light receiving section, and a logic circuit <NUM> and receives reflected laser light corresponding to radiated laser light reflected by the subject <NUM> after being emitted from a laser irradiation section <NUM>. The light receiving lens <NUM> focuses the reflected laser light from the subject <NUM> on a light receiving surface of the optical sensor <NUM>. The optical sensor <NUM> receives the reflected laser light from the subject <NUM> in units of pixels, the reflected laser light having passed through the light receiving lens <NUM>, and then performs photoelectric conversion.

An output signal from the optical sensor <NUM> is fed to the control section <NUM> via the logic circuit <NUM>. The optical sensor <NUM> will be described below in detail. The control section <NUM> includes, for example, a CPU (Central Processing Unit) and the like, and controls the light source <NUM> and the light receiving apparatus <NUM> and measures a time t from radiation of laser light from the light source <NUM> toward the subject <NUM> until the laser light returns after being reflected by the subject <NUM>. On the basis of the time t, a distance L to the subject <NUM> can be obtained.

A method for time measurement involves starting a timer at a timing when pulsed light is radiated from the light source <NUM>, stopping the timer at a timing when the light receiving apparatus <NUM> receives the pulsed light, and measuring the time t. Another method for time measurement may involve radiating pulsed light from the light source <NUM> with a predetermined period, detecting the period when the light receiving apparatus <NUM> receives the pulsed light, and measuring the time t from a phase difference between the period of light emission and the period of light reception. The time measurement is performed a plurality of times to measure the time t by detecting a peak of a histogram created by accumulating up times measured a plurality of times.

As the optical sensor <NUM>, a two-dimensional array sensor (what is called an area sensor) in which pixels each including a light receiving element are two-dimensionally arranged in a matrix (array) may also be used, or a one-dimensional array sensor (what is called a line sensor) in which pixels each including a light receiving element are linearly arranged may also be used.

In the present embodiment, as the optical sensor <NUM>, a sensor in which the light receiving element of each of the pixels includes an element generating a signal in response to reception of photons, for example, an SPAD (Signal Photon Avalanche Diode) element, is used. Specifically, the light receiving apparatus <NUM> according to the present embodiment is configured such that the light receiving element of each pixel includes an SPAD element. Note that the light receiving element is not limited to the SPAD element and may be any of various elements such as an APD (Avalanche Photo Diode) and a CAPD (Current Assisted Photonic Demodulator).

<FIG> depicts a circuit diagram of a basic pixel circuit of the light receiving apparatus <NUM> using SPAD elements. Here, the basic configuration for one pixel is depicted.

A pixel circuit in a pixel <NUM> according to the present embodiment is configured such that a cathode electrode of an SPAD element <NUM> that is connected, via a P-type MOS transistor QL that is a load, to a terminal <NUM> to which a power supply voltage VDD is provided and such that an anode electrode is connected to a terminal <NUM> to which an anode voltage Vbd is provided. As the anode voltage Vbd, a large negative voltage at which avalanche multiplication occurs is applied. A capacitive element C is connected between the anode electrode and a ground. A cathode voltage VCA of the SPAD element <NUM> is derived as an SPAD output (pixel output) via a CMOS inverter <NUM> including a P-type MOS transistor Qp and an N-type MOS transistor Qn connected in series.

A voltage equal to or higher than a breakdown voltage VBD is applied to the SPAD element <NUM>. An excess voltage equal to or higher than the breakdown voltage VBD is referred to as an excess bias voltage VEX and is typically approximately <NUM> to <NUM> V. The SPAD element <NUM> operates in a region referred to as a Geiger mode in a region with no DC stability point. <FIG> depicts an I (current) - V (voltage) characteristic of the PN junction of the SPAD element <NUM>.

Now, circuit operations of the pixel circuit in the pixel <NUM> configured as described above will be described using a waveform diagram in <FIG>.

With no current flowing through the SPAD element <NUM>, a voltage VDD - Vbd is applied to the SPAD element <NUM>. The voltage value (VDD - Vbd) is (VDD + VEX). In addition, avalanche multiplication is caused by electrons generated at the PN junction of the SPAD element <NUM> due to a generation rate of dark current DCR (Dark Count Rate) or light irradiation. Then, an avalanche current is generated. This phenomenon stochastically occurs in a light blocked state (that is, the state in which no light is incident). This is the generation rate of dark current DCR.

When the cathode voltage VCA decreases to make the voltage across terminals of the SPAD element <NUM> equal to the breakdown voltage VBD of an PN diode, the avalanche current is stopped. Then, electrons generated and accumulated by avalanche multiplication are discharged by a resistance element R (or a P-type MOS transistor QL), and the cathode voltage VCA increases up to the power supply voltage VDD, thus returning to an initial state again.

When light enters the SPAD element <NUM> to generate at least one electron-hole pair, an avalanche current is generated using the electron-hole pair as a seed. Thus, incidence of even one photon can be detected at a certain probability PDE (Photon Detection Efficiency). The probability PDE at which the photon can be detected is normally approximately several percent to <NUM>%, in many cases.

The above-described operations are repeated. Then, in the series of operations, the cathode voltage VCA has the waveform thereof shaped by a CMOS inverter <NUM>, and an SPAD output (pixel output) is a pulse signal with a pulse width T for which a start point corresponds to an arrival time of one photon.

An example of a configuration of the light receiving section of the light receiving apparatus <NUM> in which the pixels <NUM> configured as described above are two-dimensionally arranged in a matrix will be described with reference to <FIG> illustrates a light receiving section <NUM> including a set of the pixels <NUM> two-dimensionally arranged in n rows and m columns.

The light receiving section <NUM> includes a plurality of signal lines <NUM> for the respective pixel rows in a pixel arrangement of n rows and m columns. For the pixels <NUM> provided in units of the number of the signal lines <NUM>, one pixel is connected to the signal line <NUM> for each unit. Specifically, x pixels <NUM> are defined as a unit and are sequentially connected to the x signal lines <NUM> in a manner in which a first pixel within the unit is connected to a first one of x signal lines <NUM>, a second pixel within the unit is connected to a second one of x signal lines <NUM>,. , and so on. Note that the "group of pixels" described in the claims is an example of the unit of x pixels <NUM>. The "group of signal lines" described in the claims is an example of the unit of x signal lines <NUM>.

Thus, in one pixel row, signals from every x pixels <NUM> are transmitted to the succeeding distance measurement control section <NUM> through the same signal line <NUM> shared by the signals (see <FIG>). However, timing control for each pixel <NUM> is performed such that every x pixels <NUM> sharing the same signal line <NUM> are not simultaneously active, that is, such that every x pixels <NUM> use the same signal line <NUM> in a time division manner.

With such a configuration adopted, even in a case where pulse signals are substantially simultaneously output from adjacent pixels, the pulse signals are output through the different signal lines <NUM>, enabling prevention of interference in the plurality of pulse signals. Note that the number x of the pixels <NUM> defined as the unit is desirably as large as possible but that an excessively large x requires a larger space in which the signal lines <NUM> are arranged and is not desirable in terms of layout. The number x of pixels <NUM>, defined as the unit, may range from <NUM> to <NUM> and may further desirably range from <NUM> to <NUM>.

<FIG> depicts a basic configuration of a distance measurement control section of the light receiving apparatus <NUM>. The light receiving apparatus <NUM> includes the light receiving section <NUM> corresponding to the optical sensor <NUM> in <FIG> and a distance measurement control section <NUM> corresponding to the logic circuit <NUM> in <FIG>. The distance measurement control section <NUM> processes signals of the pixels <NUM> fed from the light receiving section <NUM> through the signal lines <NUM>.

The distance measurement control section <NUM> includes a multiplexer (MUX) <NUM>, a time measuring section (TDC) <NUM>, a histogram creating section (Hist) <NUM>, and an output section <NUM>. Provided are n time measuring sections <NUM> and n histogram creating sections <NUM> (<NUM><NUM> to <NUM>n-<NUM> and <NUM><NUM> to <NUM>n-<NUM>) corresponding to pixel rows <NUM> to n-<NUM> of the light receiving section <NUM>.

For each pixel row of the light receiving section <NUM>, the multiplexer <NUM> sequentially selects signals of the pixels <NUM> fed through the x signal lines <NUM> and feeds the signals to the time measuring sections <NUM><NUM> to <NUM>n-<NUM>. The time measuring sections <NUM><NUM> to <NUM>n-<NUM> measure, for each of the pixel rows in the light receiving section <NUM>, the time from a timing for giving light emission instruction to the laser light source <NUM> to a timing for light reception at the light receiving element of the pixel <NUM>. Specifically, the time measuring sections <NUM><NUM> to <NUM>n-<NUM> use a well-known TOF method to measure the time from radiation of laser light from the laser light source <NUM> toward a subject that is a measurement target until the laser light is received by the light receiving element of the pixel <NUM> after being reflected by the subject.

The distance measurement control section <NUM> performs measurement, for example, dozens of times or several hundreds of times during one measurement sequence. Then, each of the histogram creating sections <NUM><NUM> to <NUM>n-<NUM> creates a histogram of measured values (time) repeatedly measured by a corresponding one of the time measuring sections <NUM><NUM> to <NUM>n-<NUM>, specifically, a histogram indicating time on a horizontal axis and a measurement frequency on a vertical axis.

The output section <NUM> sequentially outputs, for each pixel row, data related to the histogram created by each of the histogram creating sections <NUM><NUM> to <NUM>n-<NUM>, to an application processor <NUM> provided outside the light receiving apparatus <NUM>, as information regarding the time of flight (TOF) of laser light from the light emission instruction timing to the light reception timing.

The application processor <NUM> corresponds to the control section <NUM> in <FIG> and extracts the maximum value of the histogram on the basis of the data related to the histogram output through the output section <NUM>. Then, the application processor <NUM> calculates, as a distance to the subject, the distance corresponding to the maximum value of the extracted histogram.

As described above, a histogram of the measured values (time) measured by each of the time measuring sections <NUM><NUM> to <NUM>n-<NUM> is created, and the maximum value of the histogram is extracted as the time of flight of laser light from the light emission instruction timing to the light reception timing. This allows the time of flight to be accurately measured without being affected by ambient light and the like.

As described above, in the light receiving apparatus <NUM> in which the plurality of pixels <NUM> is two-dimensionally arranged, the pixels <NUM> and the distance measurement control section <NUM> are connected together through the signal lines <NUM> provided for the respective pixel rows. Thus, the lengths of paths from the pixels <NUM> to the time measuring sections <NUM><NUM> to <NUM>n-<NUM> vary. In this manner, in a case where the lengths of the paths from the pixels <NUM> to the time measuring sections <NUM><NUM> to <NUM>n-<NUM> vary, wiring delay in the signal lines <NUM> disadvantageously lead to two-dimensional in-plane delay skew.

For example, in <FIG>, when the pixel <NUM> in 0th row and 0th column is defined as a pixel <NUM> and the pixel <NUM> in n-1th row and m-1th column is defined as a pixel N, in-plane delay skew occurs between the maximum value of the histogram for the pixel <NUM> and the maximum value of the histogram for the pixel N as depicted in <FIG>. In the histogram in <FIG>, the horizontal axis indicates time, whereas the vertical axis indicates measurement frequency.

When the application processor <NUM> provided in a later stage of the light receiving apparatus <NUM> is used to correct the in-plane delay skew, the application processor <NUM> executes processing with the data related to the histogram accumulated in a memory, thus causing the processing delay in the system as a whole to occur in units of frames. Consequently, the processing delay is significant, thereby adversely affecting applications requiring immediate responses. Incidentally, the light receiving apparatus <NUM> with a driving frequency of <NUM> fps has a processing delay of approximately <NUM> milliseconds.

An example of the application requiring an immediate response may be cooperative control intended for automatic driving operation or the like in which a vehicle is caused to travel autonomously without depending on operation of a driver by controlling a drive force generating apparatus, a steering mechanism, a brake apparatus, or the like on the basis of information regarding surroundings of a vehicle acquired by the distance measuring apparatus <NUM> including the present light receiving apparatus <NUM>.

In the present embodiment, correction of the in-plane delay skew is performed in the light receiving apparatus <NUM> to implement high-speed correction processing for the in-plane delay skew. More specifically, the histograms created by the histogram creating sections <NUM><NUM> to <NUM>n-<NUM> are generally shifted in the time axis direction to implement the correction of the in-plane delay skew. As described above, the light receiving apparatus <NUM> according to the present embodiment can implement high-speed correction processing for the in-plane delay skew and can thus be used for applications requiring immediate responses (high-speed responses), such as automatic driving operation and distance measurement for a measurement target corresponding to a moving subject.

A specific example of the present embodiment in which, in the light receiving apparatus <NUM>, histograms are generally shifted in the time axis direction to perform correction of the in-plane delay skew, will be described.

Example <NUM> is an example in which the correction processing for the in-plane delay skew is executed when respective pieces of data related to histograms are read out from the histogram creating sections <NUM><NUM> to <NUM>n-<NUM>. <FIG> depicts a configuration of the light receiving apparatus <NUM> according to Example <NUM>.

As depicted in <FIG>, the light receiving apparatus <NUM> according to Example <NUM> includes an in-plane delay correcting section <NUM> in a later stage of the histogram creating section <NUM>, that is, in a former stage of the output section <NUM>, and the in-plane delay correcting section <NUM> executing the correction processing for the in-plane delay skew.

In the light receiving apparatus <NUM> according to Example <NUM>, the processing speed at which respective pieces of data related to measured values from the time measuring sections (TDC) <NUM><NUM> to <NUM>n-<NUM> are written to the histogram creating sections <NUM><NUM> to <NUM>n-<NUM> is high and approximately several hundred MHz. Additionally, the processing speed at which respective pieces of data related to histograms are read out from the histogram creating sections <NUM><NUM> to <NUM>n-<NUM> is low and approximately several dozen MHz.

<FIG> depicts an example of a configuration of the in-plane delay correcting section <NUM> in the light receiving apparatus <NUM> according to Example <NUM>. Here, a configuration is illustrated in which the in-plane delay correcting section <NUM> is built in the output section <NUM>. However, the present example is not limited to the built-in configuration.

The output section <NUM> includes a multiplexer (MUP) <NUM> and a control counter <NUM>. The multiplexer <NUM> receives, as input, respective pieces of data related to histograms provided by the histogram creating sections <NUM><NUM> to <NUM>n-<NUM>, and under the control of the control counter <NUM>, sequentially selects the pieces of data and outputs the selected pieces of data to the succeeding application processor <NUM> as data DATA related to corresponding one of the histograms.

The in-plane delay correcting section <NUM> includes an address counter <NUM>, a storage section <NUM>, a multiplexer (MUP) <NUM>, and an adder <NUM>. The address counter <NUM> controls addresses ADDR of histograms created by the histogram creating sections <NUM><NUM> to <NUM>n-<NUM>. The address ADDR is a bin value that is a unit of histograms and is provided to the adder <NUM> with two inputs, as one of the inputs to the adder <NUM>.

The storage section <NUM> includes n correction registers reg<NUM> to regn-<NUM> (correction register group) corresponding to the histogram creating sections <NUM><NUM> to <NUM>n-<NUM> (that is, pixel rows in the light receiving section <NUM>). The correction registers reg<NUM> to regn-<NUM> store correction values (correction amounts) corresponding to the positions of the pixels <NUM> in the light receiving section <NUM>. The correction values are values for correcting the in-plane delay skew, specifically, values based on the distances from the pixels <NUM> to the time measuring sections <NUM><NUM> to <NUM>n-<NUM>.

The correction values (correction amounts) stored in the correction registers reg<NUM> to regn-<NUM> are specific to the light receiving apparatus <NUM> and can thus pre-acquired in pre-shipment verification, evaluation measurement, or the like for the light receiving apparatus <NUM>, by using a predetermined method, as values for correcting the in-plane delay skew. However, the present example is not limited to the acquisition through pre-shipment verification, evaluation measurement, or the like. For example, when the light receiving apparatus <NUM> is activated, the correction values can also be acquired using a predetermined technique and stored in the correction registers reg<NUM> to regn-<NUM> of the storage section <NUM>.

Under the control of the control counter <NUM>, the multiplexer <NUM> sequentially selects the respective correction values in the correction registers reg<NUM> to regn-<NUM> in synchronism with the multiplexer <NUM> and outputs a correction value OFST for generally shifting each of the histograms in the time axis direction. The correction value OFST corresponds to the other input of the adder <NUM> with two inputs.

For each histogram, the adder <NUM> adds, to the bin value BIN that is one of inputs of the adder <NUM>, the correction value OFST that is the other input, to generally shift each histogram in the time axis direction. Thus, each histogram is generally shifted in the time axis direction to implement the correction processing for the in-plane delay skew.

As is apparent from the above description, the in-plane delay correcting section <NUM> is a correction processing section which executes correction processing on the histograms created by the histogram creating sections <NUM><NUM> to <NUM>n-<NUM>, on the basis of the correction values stored in the storage section <NUM>. <FIG> illustrates a timing chart for the data DATA related to each of the histograms, the address ADDR of the histogram, the correction value OFST, and the bin value BIN for each histogram subjected to correction.

Now, a flow of the correction processing for the in-plane delay skew in the light receiving apparatus <NUM> according to Example <NUM> will be described using a flowchart in <FIG>.

For correction of the in-plane delay skew, first, the correction values for correcting the in-plane delay skew are pre-acquired (step S11). The correction values specific to the light receiving apparatus <NUM> can be acquired, for example, during evaluation measurement by the light receiving apparatus <NUM> or during activation of the light receiving apparatus <NUM> by using the predetermined technique as described above.

Then, the pre-acquired correction values are set in the correction registers reg<NUM> to regn-<NUM> of the storage section <NUM> (step S12). Then, the correction processing for the in-plane delay skew is executed by using, as the correction value OFST for generally shifting the histograms in the time axis direction, each of the correction values set (stored) in the correction registers reg<NUM> to regn-<NUM> of the storage section <NUM>, and adding the correction value OFST to the bin value BIN for the corresponding histogram to (step S13). This addition processing implements the correction of the in-plane delay skew to center each histogram.

With the above-described correction processing for the in-plane delay skew, when the respective pieces of data related to the histograms are read out from the histogram creating sections <NUM><NUM> to <NUM>n-<NUM>, for each histogram, the correction processing can be executed on the in-plane delay skew at high speed by the simple addition processing of adding the correction value OFST to the bin value BIN for each histogram. This processing is approximately one cycle of an operation clock and is a processing delay of approximately several dozen nanoseconds.

Consequently, compared to a case where the correction processing is executed by the succeeding application processor <NUM>, the present example enables a significant reduction in processing delay. Incidentally, in a case where the succeeding application processor <NUM> executes the correction processing, the respective pieces of data related to the histograms are accumulated in the memory for processing. Thus, the processing delay in the system as a whole occurs in units of frames, and in a light receiving apparatus with a drive frequency of <NUM> fps, the processing delay is approximately <NUM> milliseconds.

<FIG> illustrates a positional relation between data related to an uncorrected histogram and data related to a corrected histogram in the time axis direction (BIN direction). Here, a case is illustrated where a histogram with three bins is generally shifted by one BIN in the BIN direction (time axis direction). As is apparent from <FIG>, correction with the correction value OFST is executed in units of bins. Note that, here, the correction with the correction value OFST is executed in units of bins.

Example <NUM> is a modified example of Example <NUM> and corresponds to a case where the delays from the pixels <NUM> to the time measuring sections (TDC) <NUM><NUM> to <NUM>n-<NUM> exhibit a linear tendency within the plane of the light receiving section <NUM>.

Here, in a pixel arrangement of n rows and m columns in the light receiving section <NUM> illustrated in <FIG>, the amount of delay for the pixels is linear between the pixels <NUM> in the m-1th column, which is closest to the time measuring sections <NUM><NUM> to <NUM>n-<NUM>, and the pixels <NUM> in the 0th column, which is farthest from the time measuring sections <NUM><NUM> to <NUM>n-<NUM>, as illustrated in <FIG>.

In this manner, in a case where the delays from the pixels <NUM> to the time measuring sections <NUM><NUM> to <NUM>n-<NUM> exhibit a linear tendency within the plane, in Example <NUM>, from the correction value for the delay from the pixels <NUM> at an end of the light receiving section <NUM>, that is, the pixels <NUM> in the first column, which is farthest from the time measuring sections <NUM><NUM> to <NUM>n-<NUM>, the correction values for the other pixels <NUM>, that is, the pixels <NUM> between the pixel column <NUM> and the pixel column m-<NUM>, are calculated by linear interpolation.

In the flowchart in <FIG> illustrating a flow of the correction processing for the in-plane delay skew, Example <NUM> in which the correction value is obtained by linear interpolation can shorten the time required for acquiring the correction values in step S11, compared to Example <NUM>.

Example <NUM> is a modified example of Example <NUM>, and in Example <NUM>, the correction processing is also executed on a delay common to all the histograms. Here, examples of the "delay common to all the histograms" include a processing delay in the circuit, a delay outside the light receiving apparatus <NUM>, specifically, a delay in wiring through which a trigger signal for causing the laser light source <NUM> of the light source <NUM> illustrated in <FIG> to emit light is transmitted.

In Example <NUM>, different delay corrections are performed for the respective histograms. However, besides the in-plane delay, the above-described delay common to all the histograms is present. The presence of the delay common to all the histograms leads to an error between a distance measured by the light receiving apparatus <NUM> and the actual distance, the error corresponding to the delay common to all the histograms.

Thus, in Example <NUM>, different delay corrections are performed for the respective histograms, and the correction processing is executed also on the delay common to all the histograms by using a system correction value that is common to all the histogram and that corresponds to the delay common to all the histograms. The system correction value can be precalculated by, for example, dividing the difference (error) between the distance measured by the light receiving apparatus <NUM> and the actual difference by a light speed.

<FIG> illustrates a positional relation between data related to an uncorrected histogram and data related to a corrected histogram in the time axis direction (BIN direction). Here, a histogram Hist<NUM> and a histogram Histn-<NUM> are illustrated; the histogram Hist<NUM> is created by the histogram creating sections <NUM><NUM> corresponding to the pixel row <NUM>, and the histogram Histn-<NUM> is created by the histogram creating section <NUM>n-<NUM> corresponding to the pixel row n-<NUM>.

In <FIG>, a solid arrow represents a skew correction value for a case where each histogram is individually corrected, and a dashed arrow represents a system correction value for a case where all the histograms are corrected in common. In the present example, the delay correction is performed in units of bins.

According to Example <NUM>, in addition to different delay corrections for the respective histograms, a correction can be performed on the delay common to all the histograms. Thus, even with the presence of the delay common to all the histograms, the actual distance can be accurately measured.

Example <NUM> is an example outside the claimed subject-matter in which the correction processing for the in-plane delay skew is executed when the respective pieces of data related to the histograms are written to the histogram creating sections <NUM><NUM> to <NUM>n-<NUM>. <FIG> illustrates a configuration of the light receiving apparatus <NUM> according to Example <NUM>.

As illustrated in <FIG>, the light receiving apparatus <NUM> according to Example <NUM> includes the in-plane delay correcting section <NUM> in a former stage of the histogram creating sections <NUM><NUM> to <NUM>n-<NUM>, the in-plane delay correcting section <NUM> executing the correction processing for the in-plane delay skew. The in-plane delay correcting section <NUM> includes a storage section <NUM> storing correction values corresponding to the positions of the pixels <NUM> within the light receiving section <NUM>, and n adders <NUM><NUM> to <NUM>n-<NUM> provided in respective former stages of the histogram creating sections <NUM><NUM> to <NUM>n-<NUM>.

The storage section <NUM> includes n correction registers reg<NUM> to regn-<NUM> (correction register group) corresponding to n time measuring sections <NUM><NUM> to <NUM>n-<NUM>. In the correction registers reg<NUM> to regn-<NUM>, correction values for correcting the in-plane delay skew, specifically, correction values based on the distances from the pixels <NUM> to the time measuring sections <NUM><NUM> to <NUM>n-<NUM>, are set as is the case with Example <NUM>.

Each of the n adders <NUM><NUM> to <NUM>n-<NUM> has, as one of the inputs, a measured value from the corresponding one of the time measuring sections <NUM><NUM> to <NUM>n-<NUM> and has, as the other input, the correction value set in the corresponding one of the correction registers reg<NUM> to regn-<NUM>. Each of the adders <NUM><NUM> to <NUM>n-<NUM> can execute the correction processing for the in-plane delay skew by adding the correction value from the corresponding one of the correction registers reg<NUM> to regn-<NUM> for each histogram to the measured value from the corresponding one of the time measuring sections <NUM><NUM> to <NUM>n-<NUM>.

As described above, Example <NUM> in which the correction processing is executed when the respective pieces of data related to the histograms are written to the histogram creating sections <NUM><NUM> to <NUM>n-<NUM> can execute the correction processing for the in-plane delay skew like Example <NUM> in which the correction processing is executed when the respective pieces of data related to the histograms are read out from the histogram creating sections <NUM><NUM> to <NUM>n-<NUM>. Further, as is the case with Example <NUM>, the present example can substantially reduce the processing delay compared to the case where the correction processing is executed by the succeeding application processor <NUM>.

Note that the technique in Example <NUM> and the technique in Example <NUM> can also be applied to Example <NUM>; the technique in Example <NUM> involves calculating, by linear interpolation, the correction values for the pixels <NUM> between the 0th column and the m-1th column from the correction value for the delay from the pixels <NUM> in the 0th column, which is farthest from the time measuring sections <NUM><NUM> to <NUM>n-<NUM>, and the technique in Example <NUM> involves correcting the delay common to all the histograms.

The techniques according to the present disclosure can be applied to various products. More specific applied examples will be described below. For example, the techniques according to the present disclosure may be implemented as a distance measuring apparatus mounted in any of various types of moving bodies such as an automobile, an electric car, a hybrid electric car, a motorcycle, a bicycle, a personal mobility, an airplane, a drone, a ship, a robot, a construction machine, and an agricultural machine (tractor).

<FIG> is a block diagram depicting an example of schematic configuration of a vehicle control system <NUM> as an example of a mobile body control system to which the technology according to an embodiment of the present disclosure can be applied. The vehicle control system <NUM> includes a plurality of electronic control units connected to each other via a communication network <NUM>. In the example depicted in <FIG>, the vehicle control system <NUM> includes a driving system control unit <NUM>, a body system control unit <NUM>, a battery control unit <NUM>, an outside-vehicle information detecting unit <NUM>, an in-vehicle information detecting unit <NUM>, and an integrated control unit <NUM>. The communication network <NUM> connecting the plurality of control units to each other may, for example, be a vehicle-mounted communication network compliant with an arbitrary standard such as controller area network (CAN), local interconnect network (LIN), local area network (LAN), FlexRay (registered trademark), or the like.

Each of the control units includes: a microcomputer that performs arithmetic processing according to various kinds of programs; a storage section that stores the programs executed by the microcomputer, parameters used for various kinds of operations, or the like; and a driving circuit that drives various kinds of control target devices. Each of the control units further includes: a network interface (I/F) for performing communication with other control units via the communication network <NUM>; and a communication I/F for performing communication with a device, a sensor, or the like within and without the vehicle by wire communication or radio communication. A functional configuration of the integrated control unit <NUM> illustrated in <FIG> includes a microcomputer <NUM>, a general-purpose communication I/F <NUM>, a dedicated communication I/F <NUM>, a positioning section <NUM>, a beacon receiving section <NUM>, an in-vehicle device I/F <NUM>, a sound/image output section <NUM>, a vehicle-mounted network I/F <NUM>, and a storage section <NUM>. The other control units similarly include a microcomputer, a communication I/F, a storage section, and the like.

The driving system control unit <NUM> may have a function as a control device of an antilock brake system (ABS), electronic stability control (ESC), or the like.

The driving system control unit <NUM> is connected with a vehicle state detecting section <NUM>. The vehicle state detecting section <NUM>, for example, includes at least one of a gyro sensor that detects the angular velocity of axial rotational movement of a vehicle body, an acceleration sensor that detects the acceleration of the vehicle, and sensors for detecting an amount of operation of an accelerator pedal, an amount of operation of a brake pedal, the steering angle of a steering wheel, an engine speed or the rotational speed of wheels, and the like. The driving system control unit <NUM> performs arithmetic processing using a signal input from the vehicle state detecting section <NUM>, and controls the internal combustion engine, the driving motor, an electric power steering device, the brake device, and the like.

The body system control unit <NUM> controls the operation of various kinds of devices provided to the vehicle body in accordance with various kinds of programs.

The battery control unit <NUM> controls a secondary battery <NUM>, which is a power supply source for the driving motor, in accordance with various kinds of programs. For example, the battery control unit <NUM> is supplied with information about a battery temperature, a battery output voltage, an amount of charge remaining in the battery, or the like from a battery device including the secondary battery <NUM>. The battery control unit <NUM> performs arithmetic processing using these signals, and performs control for regulating the temperature of the secondary battery <NUM> or controls a cooling device provided to the battery device or the like.

The outside-vehicle information detecting unit <NUM> detects information about the outside of the vehicle including the vehicle control system <NUM>. For example, the outside-vehicle information detecting unit <NUM> is connected with at least one of an imaging section <NUM> and an outside-vehicle information detecting section <NUM>. The imaging section <NUM> includes at least one of a time-of-flight (ToF) camera, a stereo camera, a monocular camera, an infrared camera, and other cameras. The outside-vehicle information detecting section <NUM>, for example, includes at least one of an environmental sensor for detecting current atmospheric conditions or weather conditions and a peripheral information detecting sensor for detecting another vehicle, an obstacle, a pedestrian, or the like on the periphery of the vehicle including the vehicle control system <NUM>.

The environmental sensor, for example, may be at least one of a rain drop sensor detecting rain, a fog sensor detecting a fog, a sunshine sensor detecting a degree of sunshine, and a snow sensor detecting a snowfall. The peripheral information detecting sensor may be at least one of an ultrasonic sensor, a radar device, and a LIDAR device (Light detection and Ranging device, or Laser imaging detection and ranging device). Each of the imaging section <NUM> and the outside-vehicle information detecting section <NUM> may be provided as an independent sensor or device, or may be provided as a device in which a plurality of sensors or devices are integrated.

<FIG> depicts an example of installation positions of the imaging section <NUM> and the outside-vehicle information detecting section <NUM>. Imaging sections <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> are, for example, disposed at at least one of positions on a front nose, sideview mirrors, a rear bumper, and a back door of the vehicle <NUM> and a position on an upper portion of a windshield within the interior of the vehicle. The imaging section <NUM> provided to the front nose and the imaging section <NUM> provided to the upper portion of the windshield within the interior of the vehicle obtain mainly an image of the front of the vehicle <NUM>. The imaging sections <NUM> and <NUM> provided to the sideview mirrors obtain mainly an image of the sides of the vehicle <NUM>. The imaging section <NUM> provided to the rear bumper or the back door obtains mainly an image of the rear of the vehicle <NUM>. The imaging section <NUM> provided to the upper portion of the windshield within the interior of the vehicle is used mainly to detect a preceding vehicle, a pedestrian, an obstacle, a signal, a traffic sign, a lane, or the like.

Incidentally, <FIG> depicts an example of photographing ranges of the respective imaging sections <NUM>, <NUM>, <NUM>, and <NUM>. An imaging range a represents the imaging range of the imaging section <NUM> provided to the front nose. Imaging ranges b and c respectively represent the imaging ranges of the imaging sections <NUM> and <NUM> provided to the sideview mirrors. An imaging range d represents the imaging range of the imaging section <NUM> provided to the rear bumper or the back door. A bird's-eye image of the vehicle <NUM> as viewed from above can be obtained by superimposing image data imaged by the imaging sections <NUM>, <NUM>, <NUM>, and <NUM>, for example.

Outside-vehicle information detecting sections <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> provided to the front, rear, sides, and corners of the vehicle <NUM> and the upper portion of the windshield within the interior of the vehicle may be, for example, an ultrasonic sensor or a radar device. The outside-vehicle information detecting sections <NUM>, <NUM>, and <NUM> provided to the front nose of the vehicle <NUM>, the rear bumper, the back door of the vehicle <NUM>, and the upper portion of the windshield within the interior of the vehicle may be a LIDAR device, for example. These outside-vehicle information detecting sections <NUM> to <NUM> are used mainly to detect a preceding vehicle, a pedestrian, an obstacle, or the like.

Returning to <FIG>, the description will be continued. The outside-vehicle information detecting unit <NUM> makes the imaging section <NUM> image an image of the outside of the vehicle, and receives imaged image data. In addition, the outside-vehicle information detecting unit <NUM> receives detection information from the outside-vehicle information detecting section <NUM> connected to the outside-vehicle information detecting unit <NUM>. In a case where the outside-vehicle information detecting section <NUM> is an ultrasonic sensor, a radar device, or a LIDAR device, the outside-vehicle information detecting unit <NUM> transmits an ultrasonic wave, an electromagnetic wave, or the like, and receives information of a received reflected wave. On the basis of the received information, the outside-vehicle information detecting unit <NUM> may perform processing of detecting an object such as a human, a vehicle, an obstacle, a sign, a character on a road surface, or the like, or processing of detecting a distance thereto. The outside-vehicle information detecting unit <NUM> may perform environment recognition processing of recognizing a rainfall, a fog, road surface conditions, or the like on the basis of the received information. The outside-vehicle information detecting unit <NUM> may calculate a distance to an object outside the vehicle on the basis of the received information.

In addition, on the basis of the received image data, the outside-vehicle information detecting unit <NUM> may perform image recognition processing of recognizing a human, a vehicle, an obstacle, a sign, a character on a road surface, or the like, or processing of detecting a distance thereto. The outside-vehicle information detecting unit <NUM> may subject the received image data to processing such as distortion correction, alignment, or the like, and combine the image data imaged by a plurality of different imaging sections <NUM> to generate a bird's-eye image or a panoramic image. The outside-vehicle information detecting unit <NUM> may perform viewpoint conversion processing using the image data imaged by the imaging section <NUM> including the different imaging parts.

The driver state detecting section <NUM> may include a camera that images the driver, a biosensor that detects biological information of the driver, a microphone that collects sound within the interior of the vehicle, or the like. The biosensor is, for example, disposed in a seat surface, the steering wheel, or the like, and detects biological information of an occupant sitting in a seat or the driver holding the steering wheel. The in-vehicle information detecting unit <NUM> may subject an audio signal obtained by the collection of the sound to processing such as noise canceling processing or the like.

The integrated control unit <NUM> controls general operation within the vehicle control system <NUM> in accordance with various kinds of programs. The integrated control unit <NUM> is connected with an input section <NUM>. The input section <NUM> is implemented by a device capable of input operation by an occupant, such, for example, as a touch panel, a button, a microphone, a switch, a lever, or the like. The integrated control unit <NUM> may be supplied with data obtained by voice recognition of voice input through the microphone. The input section <NUM> may, for example, be a remote control device using infrared rays or other radio waves, or an external connecting device such as a mobile telephone, a personal digital assistant (PDA), or the like that supports operation of the vehicle control system <NUM>. The input section <NUM> may be, for example, a camera. In that case, an occupant can input information by gesture. Alternatively, data may be input which is obtained by detecting the movement of a wearable device that an occupant wears. Further, the input section <NUM> may, for example, include an input control circuit or the like that generates an input signal on the basis of information input by an occupant or the like using the above-described input section <NUM>, and which outputs the generated input signal to the integrated control unit <NUM>. An occupant or the like inputs various kinds of data or gives an instruction for processing operation to the vehicle control system <NUM> by operating the input section <NUM>.

The storage section <NUM> may include a read only memory (ROM) that stores various kinds of programs executed by the microcomputer and a random access memory (RAM) that stores various kinds of parameters, operation results, sensor values, or the like. In addition, the storage section <NUM> may be implemented by a magnetic storage device such as a hard disc drive (HDD) or the like, a semiconductor storage device, an optical storage device, a magneto-optical storage device, or the like.

The general-purpose communication I/F <NUM> is a communication I/F used widely, which communication I/F mediates communication with various apparatuses present in an external environment <NUM>. The general-purpose communication I/F <NUM> may implement a cellular communication protocol such as global system for mobile communications (GSM) (registered trademark), worldwide interoperability for microwave access (WiMAX), long term evolution (LTE)), LTE-advanced (LTE-A), or the like, or another wireless communication protocol such as wireless LAN (referred to also as wireless fidelity (Wi-Fi) (registered trademark), Bluetooth (registered trademark), or the like. The general-purpose communication I/F <NUM> may, for example, connect to an apparatus (for example, an application server or a control server) present on an external network (for example, the Internet, a cloud network, or a company-specific network) via a base station or an access point. In addition, the general-purpose communication I/F <NUM> may connect to a terminal present in the vicinity of the vehicle (which terminal is, for example, a terminal of the driver, a pedestrian, or a store, or a machine type communication (MTC) terminal) using a peer to peer (P2P) technology, for example.

The dedicated communication I/F <NUM> is a communication I/F that supports a communication protocol developed for use in vehicles. The dedicated communication I/F <NUM> may implement a standard protocol such, for example, as wireless access in vehicle environment (WAVE), which is a combination of institute of electrical and electronic engineers (IEEE) <NUM>. 11p as a lower layer and IEEE <NUM> as a higher layer, dedicated short range communications (DSRC), or a cellular communication protocol. The dedicated communication I/F <NUM> typically carries out V2X communication as a concept including one or more of communication between a vehicle and a vehicle (Vehicle to Vehicle), communication between a road and a vehicle (Vehicle to Infrastructure), communication between a vehicle and a home (Vehicle to Home), and communication between a pedestrian and a vehicle (Vehicle to Pedestrian).

The positioning section <NUM>, for example, performs positioning by receiving a global navigation satellite system (GNSS) signal from a GNSS satellite (for example, a GPS signal from a global positioning system (GPS) satellite), and generates positional information including the latitude, longitude, and altitude of the vehicle. Incidentally, the positioning section <NUM> may identify a current position by exchanging signals with a wireless access point, or may obtain the positional information from a terminal such as a mobile telephone, a personal handyphone system (PHS), or a smart phone that has a positioning function.

The beacon receiving section <NUM>, for example, receives a radio wave or an electromagnetic wave transmitted from a radio station installed on a road or the like, and thereby obtains information about the current position, congestion, a closed road, a necessary time, or the like. Incidentally, the function of the beacon receiving section <NUM> may be included in the dedicated communication I/F <NUM> described above.

The in-vehicle device I/F <NUM> is a communication interface that mediates connection between the microcomputer <NUM> and various in-vehicle devices <NUM> present within the vehicle. The in-vehicle device I/F <NUM> may establish wireless connection using a wireless communication protocol such as wireless LAN, Bluetooth (registered trademark), near field communication (NFC), or wireless universal serial bus (WUSB). In addition, the in-vehicle device I/F <NUM> may establish wired connection by universal serial bus (USB), high-definition multimedia interface (HDMI) (registered trademark), mobile high-definition link (MHL), or the like via a connection terminal (and a cable if necessary) not depicted in the figures. The in-vehicle devices <NUM> may, for example, include at least one of a mobile device and a wearable device possessed by an occupant and an information device carried into or attached to the vehicle. The in-vehicle devices <NUM> may also include a navigation device that searches for a path to an arbitrary destination. The in-vehicle device I/F <NUM> exchanges control signals or data signals with these in-vehicle devices <NUM>.

The vehicle-mounted network I/F <NUM> is an interface that mediates communication between the microcomputer <NUM> and the communication network <NUM>. The vehicle-mounted network I/F <NUM> transmits and receives signals or the like in conformity with a predetermined protocol supported by the communication network <NUM>.

The microcomputer <NUM> of the integrated control unit <NUM> controls the vehicle control system <NUM> in accordance with various kinds of programs on the basis of information obtained via at least one of the general-purpose communication I/F <NUM>, the dedicated communication I/F <NUM>, the positioning section <NUM>, the beacon receiving section <NUM>, the in-vehicle device I/F <NUM>, and the vehicle-mounted network I/F <NUM>. For example, the microcomputer <NUM> may calculate a control target value for the driving force generating device, the steering mechanism, or the braking device on the basis of the obtained information about the inside and outside of the vehicle, and output a control command to the driving system control unit <NUM>. For example, the microcomputer <NUM> may perform cooperative control intended to implement functions of an advanced driver assistance system (ADAS) which functions include collision avoidance or shock mitigation for the vehicle, following driving based on a following distance, vehicle speed maintaining driving, a warning of collision of the vehicle, a warning of deviation of the vehicle from a lane, or the like. In addition, the microcomputer <NUM> may perform cooperative control intended for automatic driving, which makes the vehicle to travel autonomously without depending on the operation of the driver, or the like, by controlling the driving force generating device, the steering mechanism, the braking device, or the like on the basis of the obtained information about the surroundings of the vehicle.

The microcomputer <NUM> may generate three-dimensional distance information between the vehicle and an object such as a surrounding structure, a person, or the like, and generate local map information including information about the surroundings of the current position of the vehicle, on the basis of information obtained via at least one of the general-purpose communication I/F <NUM>, the dedicated communication I/F <NUM>, the positioning section <NUM>, the beacon receiving section <NUM>, the in-vehicle device I/F <NUM>, and the vehicle-mounted network I/F <NUM>. In addition, the microcomputer <NUM> may predict danger such as collision of the vehicle, approaching of a pedestrian or the like, an entry to a closed road, or the like on the basis of the obtained information, and generate a warning signal. The warning signal may, for example, be a signal for producing a warning sound or lighting a warning lamp.

The sound/image output section <NUM> transmits an output signal of at least one of a sound and an image to an output device capable of visually or auditorily notifying information to an occupant of the vehicle or the outside of the vehicle. In the example of <FIG>, an audio speaker <NUM>, a display section <NUM>, and an instrument panel <NUM> are illustrated as the output device. The display section <NUM> may, for example, include at least one of an on-board display and a head-up display. The display section <NUM> may have an augmented reality (AR) display function. The output device may be other than these devices, and may be another device such as headphones, a wearable device such as an eyeglass type display worn by an occupant or the like, a projector, a lamp, or the like. In a case where the output device is a display device, the display device visually displays results obtained by various kinds of processing performed by the microcomputer <NUM> or information received from another control unit in various forms such as text, an image, a table, a graph, or the like. In addition, in a case where the output device is an audio output device, the audio output device converts an audio signal constituted of reproduced audio data or sound data or the like into an analog signal, and auditorily outputs the analog signal.

Incidentally, at least two control units connected to each other via the communication network <NUM> in the example depicted in <FIG> may be integrated into one control unit. Alternatively, each individual control unit may include a plurality of control units. Further, the vehicle control system <NUM> may include another control unit not depicted in the figures. In addition, part or the whole of the functions performed by one of the control units in the above description may be assigned to another control unit. That is, predetermined arithmetic processing may be performed by any of the control units as long as information is transmitted and received via the communication network <NUM>. Similarly, a sensor or a device connected to one of the control units may be connected to another control unit, and a plurality of control units may mutually transmit and receive detection information via the communication network <NUM>.

An example of the vehicle control system to which the techniques according to the present disclosure are applied have been described. The techniques according to the present disclosure may be applied to, among the above-described configurations, for example, the imaging sections <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, outside-vehicle information detecting sections <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, a driver state detecting section <NUM>, and the like. Then, application of the techniques according to the present disclosure enables implementation of excellent correction processing for the in-plane delay skew in the light receiving apparatus, thus allowing construction of a vehicle control system with high-speed response. More specifically, application of the techniques according to the present disclosure allows suppression of a variation in distance measurement result depending on the position of the pixel within the same plane, enabling accurate distance measurement. As a result, distance measurement errors in detection of an oncoming vehicle or a pedestrian are reduced, enabling safe vehicle traveling to be achieved.

Claim 1:
A light receiving apparatus (<NUM>) comprising:
a light receiving section (<NUM>) with a plurality of pixels (<NUM>) two-dimensionally arranged in n pixel rows and m columns, wherein the pixels (<NUM>) of each pixel row are grouped into units of x pixels (<NUM>);
a plurality of signal lines (<NUM>) for the respective pixel rows in the pixel arrangement of n pixel rows and m columns,
wherein x pixels (<NUM>) of a unit of x pixels (<NUM>) are sequentially connected to x signal lines (<NUM>) of the plurality of the signal lines (<NUM>);
a plurality of time measuring sections (<NUM>)provided corresponding to the pixel rows in the light receiving section (<NUM>) and connected to the plurality of the signal lines (<NUM>) for the respective pixel rows, the plurality of the time measuring sections (<NUM>) configured to measure, for each of the pixel rows, a time from a light emission instruction timing to a light reception timing;
a plurality of histogram creating sections (<NUM>) provided corresponding to the pixel rows in the light receiving section (<NUM>) and configured to create, for each of the pixel rows, a histogram of measured values measured by a corresponding one of the plurality of the time measuring sections (<NUM>);
a storage section (<NUM>) storing correction values corresponding to positions of the pixels (<NUM>) in the light receiving section (<NUM>);
a correction processing section (<NUM>) configured to execute correction processing on each of the histograms created by each of the plurality of the histogram creating sections (<NUM>), on a basis of the correction values stored in the storage section (<NUM>), wherein the correction processing section is further configured to execute correction processing in units of bins in each of the histograms; and
an output section (<NUM>) configured to output a signal subjected to the correction processing by the correction processing section (<NUM>).