Object sensing device and object sensing method

Abstract

A processing unit, which is an object sensing device, irradiates irradiation light toward a measurement region, and senses an object on the basis of information acquired from a LiDAR that detects reflected light of the object from the measurement region. The processing unit is provided with: a waveform detection unit that detects a plurality of signal waveforms (S1, S2) that reach the LiDAR with a time difference; and a false object determination unit that determines whether or not the object indicated by the signal waveform (S2) is a false object on the basis of the magnitude relationship between the amplitudes (W1, W2) of the plurality of signal waveforms (S1, S2).

Description

[0001] Cross - reference to related applications

[0002] This application is based on Japanese Patent Application No. 2022 - 182746 filed on November 15, 2022, and the entire content of the basic application is incorporated herein by reference in its entirety. Technical field

[0003] The disclosure of this specification relates to a technique for sensing an object. Background art

[0004] In Patent Document 1, a signal waveform of reflected light of a sensor that detects reflected light of an object is obtained, and a plurality of signal waveforms that arrive at the sensor with a time difference are generated. Then, the magnitude relationship of the peak intensities of the plurality of signal waveforms is compared to determine whether the object indicated by the signal waveform is a pseudo - object.

[0005] Prior art documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2021 - 169944 Summary of the invention

[0008] However, in the configuration of Patent Document 1, when the peak intensity in the signal waveform saturates, etc., the comparison of the magnitude relationship itself becomes impossible. That is, for the determination of a pseudo - object, it cannot be said that the versatility is high enough.

[0009] One of the purposes of the disclosure of this specification is to provide an object sensing device and an object sensing method with improved versatility in the determination of a pseudo - object.

[0010] A method disclosed herein is an object sensing device that irradiates an irradiation light toward a measurement area and senses an object based on information obtained from a sensor that detects reflected light from an object in the measurement area, and includes:

[0011] A waveform detection unit that detects a signal waveform of reflected light and a plurality of signal waveforms that arrive at the sensor with a time difference; and

[0012] A pseudo - object determination unit that determines whether the object indicated by the signal waveform is a pseudo - object based on the magnitude relationship of the amplitudes of the plurality of signal waveforms.

[0013] Another method disclosed herein is an object sensing method executed by at least one processor for sensing an object, including:

[0014] Causing the sensor to irradiate light toward the measurement area;

[0015] Causing the sensor to detect reflected light from an object in the measurement area;

[0016] The signal waveforms of the reflected light are detected, and there are a plurality of signal waveforms that reach the sensor with a time difference; and

[0017] Based on the magnitude relationship among the amplitudes of the plurality of signal waveforms, it is determined whether the object indicated by the signal waveform is a false object.

[0018] According to these methods, it is determined whether the object indicated by the signal waveform is a false object based on the magnitude relationship of the amplitudes of the signal waveforms. Therefore, for example, the determination is also effective in the case where the peak intensity in the signal waveform is saturated. Therefore, the generality of the determination of false objects is improved.

[0019] In addition, the reference numerals in parentheses included in the claims and the like illustratively indicate the correspondence with parts of the embodiments described later, and are not intended to limit the technical scope. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a configuration diagram showing a schematic configuration of a LiDAR module.

[0021] Figure 2 It is a schematic diagram explaining the mechanical configuration of the LiDAR and the measurement area.

[0022] Figure 3 It is a diagram showing a light receiving element.

[0023] Figure 4 It is a diagram showing a functional configuration of a processing unit.

[0024] Figure 5 It is a diagram explaining an assumed measurement situation.

[0025] Figure 6 It is a graph explaining the amplitude of the signal waveform corresponding to a reflector.

[0026] Figure 7 It is a graph explaining the amplitude of the signal waveform corresponding to raindrops.

[0027] Figure 8 It is a graph explaining the magnitude relationship of amplitudes.

[0028] Figure 9 It is a graph explaining the magnitude relationship of amplitudes.

[0029] Figure 10 It is a graph explaining the peak intensity of the signal waveform corresponding to a reflector.

[0030] Figure 11 It is a graph explaining the peak intensity of the signal waveform corresponding to raindrops.

[0031] Figure 12It is a flowchart showing an example of object sensing processing.

[0032] Figure 13 It is a diagram showing the functional configuration of a processing unit.

[0033] Figure 14 It is a diagram explaining the relationship between ROI and intensity saturation.

[0034] Figure 15 It is a diagram explaining the relationship between ROI and intensity saturation.

[0035] Figure 16 It is a diagram showing the functional configuration of a processing unit.

[0036] Figure 17 It is a diagram explaining the sensing of the road surface based on the interference light image.

[0037] Figure 18 It is a diagram explaining the overlap of the distance of the reflector and the signal waveform. Detailed implementation mode

[0038] Hereinafter, a plurality of embodiments will be described based on the drawings. In addition, in each embodiment, the same reference numerals are assigned to corresponding components, and thus repeated explanations may be omitted. When only a part of the configuration is described in each embodiment, for the other parts of the configuration, the configurations of other previously described embodiments can be applied. In addition, not only the combinations of the configurations clearly shown in the description of each embodiment, but also the configurations of the plurality of embodiments can be partially combined with each other as long as the combination does not cause any particular obstacle even if not explicitly stated.

[0039] (First Embodiment)

[0040] As Figure 1 shown, the LiDAR module 1 of the first embodiment of the present disclosure is mounted on a vehicle as a moving body. The LiDAR module 1 senses objects around the vehicle. The LiDAR module 1 is configured to include a LiDAR (Light Detection and Ranging / Laser imaging Detection and Ranging) 2 main body and a processing unit 3. In the present embodiment, the LiDAR 2 main body and the processing unit 3 are integrated, for example, by being housed in a common housing. The processing unit 3 is a dedicated processing device dedicated to the control of the LiDAR 2 main body or object sensing.

[0041] The LiDAR 2 is a vehicle-mounted sensor that irradiates irradiation light IL from a light source 11 toward a measurement area MA and detects reflected light RL from an object, and is a light ranging device. The LiDAR 2 is disposed, for example, on the front grille, the roof of the vehicle, etc. Also as Figure 2As shown, LiDAR2 includes a light-emitting unit 10, a scanning unit 15, and a light-receiving unit 20.

[0042] The light-emitting unit 10 emits irradiation light IL toward the measurement area MA. The light-emitting unit 10 is configured to include, for example, a light source 11 and a light-projecting optical system 12. The light source 11 can be one or more. The light source 11 can be, for example, a laser oscillation element such as a laser diode (LD, Laser Diode). The light source 11 can also be an LED. The wavelength of the light emitted by the light source 11 can be a wavelength other than visible light such as near-infrared light. The light-projecting optical system 12 condenses the light emitted from the light source 11 and projects beam-shaped light toward the measurement area MA. The light-projecting optical system 12 is configured to include one or more lenses.

[0043] The scanning unit 15 scans the light emitted by the light-emitting unit 10 within the range of the measurement area MA. The scanning unit 15 is configured to include a scanning mirror 16. The scanning mirror 16 is configured to include a drive motor and a reflector. The drive motor is, for example, a voice coil motor, a brushed DC motor, a stepper motor, etc. The drive motor drives the rotation axis of the reflector in a manner linked to the light-emitting timing. The reflector is a mirror having a reflecting surface that reflects the irradiation light IL toward the measurement area MA. The reflecting surface is formed, for example, in a planar shape.

[0044] Especially in this embodiment, the reflector faces both the light-projecting optical system 12 of the light-emitting unit 10 and the light-receiving optical system 21 of the light-receiving unit 20. Therefore, the reflector can not only reflect the irradiation light IL, but also reflect the reflected light RL after the light is reflected from an object in the measurement area MA and simultaneously make it incident on the light-receiving unit 20.

[0045] The light-receiving unit 20 receives the reflected light RL. The light-receiving unit 20 is configured to include a light-receiving optical system 21, a light-receiving element 22, and a decoder 23. The light-receiving optical system 21 condenses the reflected light RL and makes it incident on the light-receiving element 22. The light-receiving optical system 21 is configured to include one or more lenses.

[0046] The light-receiving element 22 receives the reflected light RL condensed by the light-receiving optical system 21. The light-receiving element 22 can be, for example, a single photon avalanche photodiode (SPAD, Single Photon Avalanche Diode) sensor. As Figure 3 shown, the light-receiving element 22 is formed by two-dimensionally arranging a plurality of SPADs (hereinafter referred to as sensor pixels 22a) in a highly integrated state on the detection surface 22b.

[0047] When a photon is received, each sensor pixel 22a generates an electrical pulse through an electron multiplication operation by avalanche multiplication (so-called Geiger mode). That is, the sensor pixel 22a can directly generate an electrical pulse as a digital signal without going through an AD conversion circuit from an analog signal to a digital signal. Therefore, the light reception result can be read out at high speed.

[0048] The decoder 23 is provided to output the electrical pulses generated by the sensor pixels 22a, and includes a selection circuit and a clock oscillator. The selection circuit sequentially selects the sensor pixels 22a that are the objects from which the electrical pulses are to be extracted. The selected sensor pixel 22a outputs the electrical pulse to the processing unit 3. When the selection circuit finishes selecting the sensor pixels 22a each time, one sampling ends. This sampling period corresponds to the clock frequency output from the clock circuit.

[0049] In addition, at a timing when the irradiation light IL is not emitted from the light emitting unit 10, that is, when not emitting light, the light receiving unit 20 can receive and detect interference light from a direction corresponding to the angle of the reflector. Moreover, the interference light is imaged on the light receiving element 22, and thus the object in the measurement area MA can also be sensed. The interference light mentioned here is also called background light.

[0050] The processing unit 3 processes the information obtained from the LiDAR2 main body and senses the object in the measurement area MA. The processing unit 3 can be implemented by, for example, a dedicated computer. The processing unit 3 can also have at least one memory 3a and a processor 3b. The memory 3a can be at least one non-transitory physical storage medium such as a semiconductor memory, a magnetic medium, and an optical medium that non-temporarily stores programs and data that can be read by the processor 3b. And, as the memory 3a, for example, a rewritable volatile storage medium such as a RAM (Random Access Memory) can also be provided.

[0051] The processor 3b includes, for example, at least one of a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and a RISC (Reduced Instruction Set Computer)-CPU as a core. In addition, the processing unit 3 can also be configured to further include circuits such as an FPGA (Field-Programmable Gate Array) and an ASIC (Application Specific Integrated Circuit).

[0052] As Figure 4As shown, the processing unit 3 is configured to include a histogram generation unit 31, a distance calculation unit 32, and a pseudo-object determination unit 33 as functional blocks implemented by at least one processor 3b that executes a program.

[0053] The histogram generation unit 31 adds up the electrical pulses corresponding to the reflected light RL output from the light receiving unit 20. The histogram generation unit 31 generates a histogram of the reflected light intensity with respect to the time axis for the addition result. The generated histogram substantially represents the signal waveform of the reflected light RL.

[0054] The histogram generation unit 31 generally generates a histogram obtained by accumulating multiple samplings for the pixels in the opening area (i.e., ROI, Region Of Interest) of the sensor pixel 22a. By accumulating multiple samplings, the S / N ratio can be improved.

[0055] In addition, each sensor pixel 22a substantially outputs a signal of 0 or 1 for one sampling. The number of pixels of one of the sensor pixels 22a that outputs the ROI corresponds to the reflected light intensity. Therefore, when all the sensor pixels 22a in the ROI output 1, the reflected light intensity represents the maximum value in measurement and is saturated. This saturation phenomenon often occurs when an object is present at a short distance or when the object is a reflector RF (also called a strong reflecting object).

[0056] The distance calculation unit 32 calculates the distance at which the object exists based on the histogram generated by the histogram generation unit 31, that is, the signal waveform of the reflected light RL. The time axis corresponds to the time from when the irradiation light IL from the light emitting unit 10 is reflected by the object and returns to the light receiving unit 20, that is, the so-called TOF (Time Of Flight), and this time is proportional to the distance. That is, the distance calculation unit 32 calculates the time representing the peak intensity of the signal waveform and calculates the distance of the object corresponding to the time representing the peak intensity PI.

[0057] Sometimes there is a time difference for one emission of light, and multiple signal waveforms reach the light receiving unit 20. In other words, there are sometimes multiple parts in the histogram that represent the peak intensity PI. In this case, the distance calculation unit 32 can determine that there are multiple objects at different distances.

[0058] The pseudo-object determination unit 33 determines whether an object exists at the distances calculated by the distance calculation unit 32. The pseudo-object determination unit 33 determines whether the signal waveform represents a pseudo-object VO based on whether the signal waveform obtained from the LiDAR 2 satisfies a specified condition.

[0059] As Figure 5 shown, the pseudo-object VO is sometimes, for example, a ghost, virtual image, etc. caused by multiple reflected light resulting from multiple reflections between the LiDAR 2 and the reflector RF located at a distance D1. In this case, asFigure 6 As shown, there is a tendency for a second signal waveform S2 and a third signal waveform to arrive with a time difference relative to the generation time of the first signal waveform S1 representing the reflector RF. The second signal waveform S2 to the third signal waveform correspond to a pseudo-object VO that should not originally exist at the position of distance D2.

[0060] The signal waveform corresponding to the pseudo-object VO should be distinguished from the signal waveform of an object with an entity. For example, as Figure 5 shown, in rainy weather, when there is a normal object RO at the position of distance D2 inside the raindrop RD at distance D1, etc., a signal waveform similar to the pseudo-object VO may sometimes be measured. It is necessary to prevent the object RO inside the raindrop RD from being determined as the pseudo-object VO.

[0061] Here, the conditions for the pseudo-object determination unit 33 to determine the pseudo-object VO when the first signal waveform S1 and the second signal waveform S2 that arrive with a time difference are detected are shown below.

[0062] The first condition is that the distance of the object indicated by the second signal waveform S2 represents a distance that is substantially N times the distance of the object indicated by the first signal waveform S1. The relationship of N times the distance indicates the possibility that the second signal waveform S2 is due to multiple reflections. Here, N can be an integer of 2 or more. On the other hand, it is also possible to only determine the case of N = 2, that is, a two-fold distance.

[0063] The second condition is that the amplitude of the first signal waveform S1 represents above a preset amplitude threshold. The amplitude of the signal waveform mentioned here refers to the width defined in the time region or the distance region. The amplitude refers to the width in the signal waveform that becomes the threshold intensity obtained by multiplying the peak intensity PI of the signal waveform by a preset specified coefficient. The specified coefficient can be set appropriately. Assuming that the coefficient is 0.5, the amplitude W1 can be said to be the half-value width.

[0064] As Figure 6 shown, in the case of a reflector RF where a pseudo-object VO is likely to be generated in the sensing, the amplitude of the first signal waveform S1 corresponding to the reflector RF is relatively large. On the other hand, as Figure 7 shown, in the case where there is an object RO inside the raindrop RD, the amplitude of the first signal waveform S1 corresponding to the raindrop RD is relatively small. Therefore, the amplitude W1 of the first signal waveform S1 representing above the amplitude threshold indicates the possibility that the object indicated by the first signal waveform S1 is a reflector RF where a pseudo-object VO is likely to be generated. The amplitude threshold is set to a value that can distinguish the reflector RF and the raindrop RD. In addition, the amplitude threshold can be appropriately adjusted according to the climate or environment of the region where the vehicle is used (for example, a region where strong winds and heavy rains are likely to occur).

[0065] The third condition is that the difference between the amplitude W1 of the first signal waveform S1 and the amplitude W2 of the second signal waveform S2 is equal to or greater than a preset difference threshold. The difference between the amplitude W1 of the first signal waveform S1 and the amplitude W1 of the second signal waveform S2 is a value obtained by subtracting the amplitude W2 of the second signal waveform S2 from the amplitude W1 of the first signal waveform S1.

[0066] As Figure 8 shown, when the first signal waveform S1 corresponds to the reflector RF and the second signal waveform S2 corresponds to the pseudo object VO, the amplitude W1 of the first signal waveform S1 is larger than the amplitude W2 of the second signal waveform S2. On the other hand, as Figure 9 shown, when the first signal waveform S1 corresponds to the raindrop RD and the second signal waveform S2 corresponds to the object RO, there is a tendency for the difference between the amplitude W1 of the first signal waveform S1 and the amplitude W2 of the second signal waveform S2 to become smaller.

[0067] Here, it is assumed that if the lower limit of the difference is not set for the third condition and only the amplitude W1 of the first signal waveform S1 is larger than the amplitude W2 of the second signal waveform S2, then in the presence of raindrops RD and the object RO, the condition may be accidentally satisfied. Therefore, by setting a difference threshold as the lower limit of the difference, the possibility that the object shown by the second signal waveform S2 is the pseudo object VO is increased. The difference threshold is a value greater than 0, and for example, the optimal value can be set based on insights obtained through experiments and the like.

[0068] The fourth condition is that the peak intensity PI of the second signal waveform S2 is equal to or greater than an intensity threshold. As Figure 10 shown, when the second signal waveform S2 represents the multiple reflection of the reflector RF, due to the high specular reflectivity of the reflector RF, the peak intensity PI of the second signal waveform S2 becomes relatively high. On the other hand, as Figure 11 shown, when the first signal waveform S1 corresponds to the raindrop RD and the second signal waveform S2 corresponds to the object RO, the intensity of the light reciprocating between the LiDAR2 and the object RO is attenuated by the raindrop RD.. Therefore, the peak intensity PI of the second signal waveform S2 becomes relatively low.

[0069] Therefore, the fact that the peak intensity PI of the second signal waveform S2 is equal to or greater than the intensity threshold indicates the possibility that the second signal waveform S2 is due to multiple reflection.

[0070] The pseudo-object determination unit 33 can determine that the object corresponding to the second signal waveform S2 is a pseudo-object VO only when all of the above first to fourth conditions are satisfied. On the other hand, the pseudo-object determination unit 33 can also determine that the object corresponding to the second signal waveform S2 is a pseudo-object VO as long as one, two or more, or three or more of the above first to fourth conditions are satisfied. The pseudo-object determination unit 33 can also comprehensively perform the determination of the pseudo-object VO based on whether each condition is satisfied or each value used thereby.

[0071] When there is no object within the distance calculated by the distance calculation unit 32, that is, when a pseudo-object VO is determined, the pseudo-object determination unit 33 removes the information of the pseudo-object VO. The pseudo-object determination unit 33 can also, when determining the second signal waveform S2 as a pseudo-object VO by a distance that is N times the distance of the object indicated by the first signal waveform S1 by the distance of the object indicated by the second signal waveform S2, regard all candidates of objects detected farther than the pseudo-object VO as noise and remove them. The candidates of objects detected farther than the pseudo-object VO here indicate candidates of objects detected at a distance above the pseudo-object VO with respect to LiDAR2 as a reference. In addition to the pseudo-object VO at N times the distance, noise is generated at points that are not at N times the distance due to unnecessary light emission or the reflection of objects behind the sensor, so they are removed. Alternatively, the pseudo-object determination unit 33 can also add information indicating that the object corresponding to the second signal waveform S2 is a pseudo-object VO instead of removing the information of the pseudo-object VO.

[0072] The information of the objects sensed by the processing unit 3 in this way can be output and provided to a driving assistance system, an autonomous driving system, an HMI, etc. of a vehicle that is external to the processing unit 3.

[0073] Next, Figure 12 An example of the processing particularly for the pseudo-object VO in the object sensing method of the LiDAR module 1 is described using the

[0074] In S11, the light emitting unit 10 emits light in LiDAR2. After S11, the process proceeds to S12.

[0075] In S12, the light receiving unit 20 receives the reflected light RL reflected from the object in the measurement area MA. After S12, the process proceeds to S13.

[0076] In S13, in the processing unit 3, the histogram generation unit 31 acquires information from the light receiving unit 20. The histogram generation unit 31 detects the signal waveform of the reflected light RL by generating a histogram. The detection here includes detecting a plurality of signal waveforms having peak intensities PI at different positions in the histogram, that is, detecting a plurality of signal waveforms S1, S2 that arrive with a time difference. After S13, it proceeds to S14.

[0077] In S14, the distance calculation unit 32 calculates the distance to the object corresponding to the signal waveform. When a plurality of signal waveforms are detected, the distance calculation unit 32 calculates the distance to the object corresponding to each signal waveform separately. After S14, it proceeds to S15.

[0078] In S15, the pseudo object determination unit 33 determines whether the object corresponding to the signal waveform is a pseudo object VO. If an affirmative determination is made in S15, it moves to S16. If a negative determination is made in S15, a series of processes ends.

[0079] In S16, the pseudo object determination unit 33 removes the information of the pseudo object VO determined in S16. A series of processes ends with S16.

[0080] According to the first embodiment described above, whether the objects shown by the signal waveforms S1, S2 are pseudo objects VO is determined based on the magnitude relationship between the amplitudes W1, W2 of the signal waveforms S1, S2. Therefore, for example, when the peak intensity PI in the signal waveform is saturated, the determination is also effective. Therefore, the versatility of the determination of the pseudo object VO is improved.

[0081] In addition, according to the first embodiment, the distance of the object shown by the second signal waveform S2 being substantially N times the distance of the object shown by the first signal waveform S1 is included in the determination condition. The relationship of N times the distance indicates the possibility that the second signal waveform S2 is a signal waveform caused by multiple reflections. Therefore, the determination accuracy of the pseudo object VO caused by multiple reflections can be improved.

[0082] Here, the reflector RF is likely to generate a pseudo object VO, and there is a tendency for the amplitude W1 of the first signal waveform S1 corresponding to the reflector RF to become relatively large. In contrast, according to the first embodiment, the determination condition includes that the amplitude W1 of the first signal waveform S1 represents a value equal to or greater than a preset amplitude threshold. Therefore, the determination accuracy of the pseudo object VO can be improved.

[0083] Here, when the first signal waveform S1 corresponds to a raindrop RD and the second signal waveform S2 corresponds to an object RO, there is a tendency for the difference to become smaller. In contrast, according to the first embodiment, the determination condition includes that the difference between the amplitude W1 of the first signal waveform S1 and the amplitude W2 of the second signal waveform S2 represents a value equal to or greater than a preset difference threshold. That is, the patterns of the raindrop RD and the object RO can be distinguished, so the determination accuracy of the pseudo-object VO can be improved.

[0084] Here, when the second signal waveform S2 represents multiple reflections of a reflector RF, due to the high specular reflectivity of the reflector RF, the peak intensity PI of the second signal waveform S2 becomes relatively high. In contrast, according to the first embodiment, the determination condition includes that the peak intensity PI of the second signal waveform S2 represents a value equal to or greater than an intensity threshold. Therefore, the determination accuracy of the pseudo-object VO caused by multiple reflections can be improved.

[0085] In addition, in the first embodiment, the LiDAR 2 corresponds to the "sensor". The processing unit 3 corresponds to the "object sensing device". The histogram generation unit 31 corresponds to the "waveform detection unit".

[0086] (Second Embodiment)

[0087] As Figures 13 - 15 shown, the second embodiment is a modification of the first embodiment. Regarding the second embodiment, the description will be centered on the points different from the first embodiment.

[0088] As Figure 13 shown, the processing unit 3 of the second embodiment is configured to include a measurement condition changing unit 34 as a functional block implemented by at least one processor 3b that executes a program.

[0089] The measurement condition changing unit 34 changes the measurement conditions based on a specified trigger. The specified trigger may be a plurality of signal waveforms S1, S2 that arrive with a time difference detected by the histogram generation unit 31. Additionally, the specified trigger may be the detection of a plurality of signal waveforms in which the intensity of the first signal waveform S1 and the intensity of the second signal waveform S2 are saturated. Further, the specified trigger may be the detection of a plurality of signal waveforms in which the intensity of the first signal waveform S1 is saturated.

[0090] In addition, the measurement condition changing unit 34 may change the measurement conditions each time a histogram is generated (in other words, for each frame). For example, a first measurement condition and a second measurement condition may be preset, and the measurement condition changing unit 34 alternately sets the first measurement condition and the second measurement condition.

[0091] As a change in the measurement conditions, specifically, it is preferable to implement at least one of the following changes. One of the measurement conditions listed below may be changed only, or two or more may be changed simultaneously.

[0092] As a change in the measurement conditions, the measurement condition changing unit 34 may also reduce the light emission intensity of the light emitting unit 10 so as to be weaker than the light emission intensity of the light emitting unit 10 before the detection trigger.

[0093] As a change in the measurement conditions, the measurement condition changing unit 34 may also reduce the cumulative number of samplings so as to be less than the cumulative number of samplings before the detection trigger.

[0094] As a change in the measurement conditions, the measurement condition changing unit 34 may also change at least one of the position and size of the ROI with respect to the ROI at the time of detecting the trigger.

[0095] Figure 14 、 Figure 15 Examples of changing the ROI are shown in Figure 14 It shows the ROI 220 before the change and the corresponding signal waveforms S1, S2, S3. Figure 14 The ROI 220 shown in the upper section coincides with the region (light receiving point SP) where the received light beam of the reflected light RL is incident on the light receiving element 22. Figure 14 The graph shown in the middle section shows the case where, with respect to the ROI 220 in the upper section, the first signal waveform S1 corresponds to the reflector RF, and the second signal waveform S2 and the third signal waveform S3 correspond to the pseudo object VO. Figure 14 The graph shown in the lower section shows the case where, with respect to the ROI 220 in the upper section, the first signal waveform S1 corresponds to the raindrop RD, and the second signal waveform S2 corresponds to the object RO.

[0096] Figure 15 It shows the ROI 221 after the change and the corresponding signal waveforms S1, S2, S3. Figure 15 The ROI 221 shown in the upper section is offset in position with respect to the light receiving point SP in the light receiving element 22 and is larger in size than before the change. That is, the changed ROI 221 is set to a region where saturation is less likely to occur compared to the ROI 220 before the change.

[0097] Figure 15 The graph shown in the middle section shows the case where, with respect to the ROI 221 in the upper section, the first signal waveform S1 corresponds to the reflector RF, and the second signal waveform S2 and the third signal waveform S3 correspond to the pseudo object VO. Figure 15 The graph shown in the lower section shows the case where, with respect to the ROI 221 in the upper section, the first signal waveform S1 corresponds to the raindrop RD, and the second signal waveform S2 corresponds to the object RO.

[0098] Based on Figure 14 and Figure 15 comparison, when the first signal waveform S1 corresponds to the raindrop RD, there is a tendency that saturation of intensity is easily avoided by changing the ROI. On the other hand, when the first signal waveform S1 corresponds to the reflector RF, there is a tendency that saturation of intensity is difficult to avoid even by changing the ROI. The pseudo-object determination unit 33 can utilize this difference in tendency to determine that the second signal waveform S2 and the third signal waveform S3 correspond to the pseudo-object VO.

[0099] According to the second embodiment described above, the measurement conditions of the reflected light RL are changed in such a way that the saturation state of the intensities of the signal waveforms S1, S2, and S3 corresponding to the type of object changes. By confirming the response of the signal waveforms S1, S2, and S3 before and after the change of the measurement conditions, that is, the change of the saturation state, the determination accuracy of the pseudo-object VO can be significantly improved.

[0100] Here, the type of object can be a type classified based on different reflection characteristics of the reflector RF, raindrop RD, etc.

[0101] (Third Embodiment)

[0102] As Figure 16 and Figure 17 shown, the third embodiment is a modification of the first embodiment. Regarding the third embodiment, the description will be centered on the points different from the first embodiment.

[0103] As Figure 16 shown, the processing unit 3 of the second embodiment is configured to include an interference light image generation unit 35 and a road surface sensing unit 36 as functional blocks implemented by at least one processor 3b that executes a program.

[0104] The interference light image generation unit 35 generates an interference light image IM based on the sampling result of the light receiving element 22 when the light emitting unit 10 does not emit light. Figure 17 The interference light image IM shown is an image that does not include the reflected light RL, and the intensity of the interference light received by the light receiving element 22 is imaged twice. The interference light image IM is sometimes also referred to as a background light image.

[0105] The road surface sensing unit 36 performs image processing on the interference light image IM to sense the road surface RR reflected in the interference light image IM. The road surface sensing unit 36 can extract the area occupied by the road surface RR in the interference light image IM. The sensing of the road surface RR can also be performed using a preset condition for distinguishing the road surface RR. The sensing of the road surface RR can also be performed using a learned road surface sensing model including a neural network.

[0106] The pseudo-object determination unit 33 of the third embodiment determines the pseudo-object VO with reference to the detection result of the road surface detection unit 36. Specifically, even if a signal waveform S2 different from the first signal waveform S1, corresponding to a distance substantially N times the distance of the object shown by the first signal waveform S1, is detected as a candidate for the pseudo-object VO, when the road surface RR is detected at the N-fold distance, the pseudo-object determination unit 33 determines that the different signal waveform S2 does not represent the pseudo-object VO. That is, even when the first condition shown in the first embodiment is satisfied, the pseudo-object determination unit 33 determines that it is not the pseudo-object VO.

[0107] According to the third embodiment described above, when the distance of the object shown by the second signal waveform S2 represents a distance substantially N times the distance of the object shown by the first signal waveform S1 and the road surface RR existing at the N-fold distance is detected, it is determined that the object shown by the second signal waveform S2 is not the pseudo-object VO. The detection result of the road surface RR can be used to improve the determination accuracy of the pseudo-object VO.

[0108] (Fourth Embodiment)

[0109] As Figure 18 shown, the fourth embodiment is a modification of the first embodiment. Regarding the fourth embodiment, the description will be centered on the points different from the first embodiment.

[0110] The fourth embodiment is configured to improve the determination accuracy when the signal waveforms S2R and S3R corresponding to the pseudo-object VO overlap with the signal waveform S1R corresponding to the reflector RF.

[0111] As Figure 18 shown, the overlapping state of the signal waveforms S2R and S3R including the pseudo-object VO changes according to the distance at which the reflector RF exists. For example, when the distance at which the reflector RF exists is smaller than CD1, that is, at a "very close distance", the signal waveforms S2R and S3R based on multiple reflections overlap with the signal waveform S1R based on single reflection. More specifically, since the distance at which the reflector RF exists and its 2-fold distance and 3-fold distance are closer, the signal waveform S2R based on two-way reflections and the signal waveform S3R based on three-way reflections overlap with the amplitude range shown by the signal waveform S1R based on single reflection. That is, the signal waveforms S1R, S2R, and S3R can be detected as a signal waveform S1 concentrated into one. In addition, the "very close distance" is, for example, assumed to be less than 1.5 m.

[0112] However, in this case, the signal waveform S2R based on two-way reflections and the signal waveform S3R based on three-way reflections are not misdetected as objects independent of the reflector RF. Therefore, no problem occurs in the determination of the pseudo-object VO.

[0113] When the distance at which the reflector RF exists is greater than CD2, i.e., in the case of "medium / long distance", the signal waveform S1R based on one reflection, the signal waveform S2R based on two reciprocating reflections, and the signal waveform S3R based on three reciprocating reflections are separated respectively. In addition, CD2 is set to a value greater than CD1. Further, for "medium / long distance", a distance greater than 3.0 m is assumed, for example.

[0114] In the case of this "medium / long distance", it is possible to determine the pseudo-object VO under the same conditions as in the first embodiment. Strictly speaking, under the first condition, it is only necessary to determine that the distance of the object indicated by the second signal waveform S2 represents a substantially two-fold distance of the distance of the object indicated by the first signal waveform S1. For the third signal waveform S3 corresponding to a distance of three times or more, it is only necessary to respond based on the determination result for the second signal waveform S2 corresponding to twice the distance.

[0115] Moreover, when the distance at which the reflector RF exists is greater than CD1 and less than CD2, i.e., in the case of "short distance", although the signal waveform S3R based on three reciprocating reflections is separated, the signal waveform S1R based on one reflection overlaps with the signal waveform S2R based on two reciprocating reflections. That is, the signal waveforms S1R and S2R1 are sensed as the first signal waveform S1 concentrated into one, and the signal waveform S3R is sensed as the second signal waveform S2. In addition, for "short distance", a range of 1.5 to 3.0 m is assumed, for example.

[0116] In the case of this "short distance", even if there is no independent signal waveform at twice the distance, when there is an independent signal waveform S2 at three times the distance, the second signal waveform S2 may be sensed as an object independent of the reflector RF.

[0117] Therefore, when the distance of the object indicated by the first signal waveform S1 is within a preset distance range, the pseudo-object determination unit 33 of the fourth embodiment determines that the distance of the object indicated by the second signal waveform S2 represents a substantially three-fold distance of the distance of the object indicated by the first signal waveform S1. This distance range corresponds to "short distance". The distance range can be set, for example, according to the knowledge obtained through experiments, etc., to be within the range of CD1 to CD2 corresponding to Figure 18 When the second signal waveform S2 represents three times the distance, in combination with other conditions shown in the first embodiment, the object corresponding to the second signal waveform S2 is determined as the pseudo-object VO.

[0118] According to the fourth embodiment described above, when the distance indicated by the first signal waveform S1 is within a specified distance range (a distance range corresponding to "short distance"), the distance of the object indicated by the second signal waveform S2 including a distance substantially three times the distance of the object indicated by the first signal waveform S1 is included in the determination condition. That is, within the distance range corresponding to "short distance", even if a signal corresponding to twice the distance is not confirmed, as long as a signal corresponding to three times the distance is confirmed, it is determined as a pseudo object. That is, it is possible to suppress the misdetection of the pseudo object VO as an object having an entity.

[0119] (Other embodiments)

[0120] As described above, a plurality of embodiments have been described, but the present disclosure is not limited to these embodiments for interpretation, and can be applied to various embodiments and combinations within the scope not departing from the gist of the present disclosure.

[0121] Specifically, the LiDAR2 main body and the processing unit 3 may also be arranged at mutually different positions in the vehicle and connected in a manner capable of communicating with each other through wired communication or wireless communication using an in-vehicle network. The processing unit 3 may also be assembled, for example, as a part of an ADAS domain controller, an autonomous driving system, etc., and shared with these hardware.

[0122] The pseudo object determination unit 33 may also perform the determination described in each embodiment and remove the information of the pseudo object VO when the intensities of the first signal waveform S1 and the second signal waveform S2 are saturated.

[0123] In the third embodiment, the road surface sensing unit 36 may also use the point cloud measured by the LiDAR2 instead of the interference light image IM to detect the road surface RR. The road surface sensing unit 36 may also sense the road surface RR according to the image of the in-vehicle camera instead of the interference light image IM. The road surface sensing unit 36 may also only obtain the sensing result of the road surface RR sensed by other processing devices of the vehicle.

[0124] The control unit and method described in the present disclosure may also be implemented by a dedicated computer, which constitutes a processor programmed to execute one or more functions embodied by a computer program. Alternatively, the device and method described in the present disclosure may also be implemented by dedicated hardware logic circuits. Alternatively, the device and method described in the present disclosure may also be implemented by one or more dedicated computers constituted by a combination of a processor executing a computer program and one or more hardware logic circuits. In addition, the computer program may also be stored as instructions executed by a computer in a computer-readable non-transitory tangible recording medium.

[0125] (Disclosure of technical idea)

[0126] This specification discloses a plurality of technical ideas described in the following listed items. Some items are sometimes described in a multiple dependent form that selectively references multiple preceding items in subsequent items. The items described in these multiple dependent forms define a plurality of technical ideas.

[0127] <Technical idea 1>

[0128] An object sensing device senses an object based on information obtained from a sensor (2). The sensor (2) irradiates irradiation light (IL) toward a measurement area (MA) and detects reflected light (RL) from an object in the measurement area. The object sensing device includes:

[0129] A waveform detection unit (31) that detects a signal waveform of the reflected light and is a plurality of signal waveforms (S1, S2, S3) that arrive at the sensor with a time difference; and

[0130] A pseudo-object determination unit (33) that determines whether the object indicated by the signal waveform is a pseudo-object (VO) based on a magnitude relationship among amplitudes of the plurality of signal waveforms.

[0131] <Technical idea 2>

[0132] The object sensing device according to Technical idea 1,

[0133] The plurality of signal waveforms include a first signal waveform and a second signal waveform that arrives after the first signal waveform,

[0134] If N is set as an integer of 2 or more, the pseudo-object determination unit includes, as a determination condition, a distance in which a distance of the object indicated by the second signal waveform is N times a distance of the object indicated by the first signal waveform.

[0135] <Technical idea 3>

[0136] The object sensing device according to Technical idea 2,

[0137] When the pseudo-object determination unit determines the second signal waveform as the pseudo-object because the distance of the object indicated by the second signal waveform is N times the distance of the object indicated by the first signal waveform, the pseudo-object determination unit removes all candidates of objects detected farther than the pseudo-object as noise.

[0138] <Technical idea 4>

[0139] The object sensing device according to any one of Technical ideas 1 to 3,

[0140] A plurality of the signal waveforms include a first signal waveform and a second signal waveform that arrives after the first signal waveform.

[0141] The pseudo-object determination unit includes a determination condition that an amplitude (W1) of the first signal waveform is equal to or greater than a preset amplitude threshold.

[0142] <Technical idea 5>

[0143] The object sensing device according to any one of Technical ideas 1 to 4.

[0144] A plurality of the signal waveforms include a first signal waveform and a second signal waveform that arrives after the first signal waveform.

[0145] The pseudo-object determination unit includes a determination condition that a difference between an amplitude of the first signal waveform and an amplitude (W2) of the second signal waveform is equal to or greater than a preset difference threshold.

[0146] <Technical idea 6>

[0147] The object sensing device according to any one of Technical ideas 1 to 5.

[0148] A plurality of the signal waveforms include a first signal waveform and a second signal waveform that arrives after the first signal waveform.

[0149] The pseudo-object determination unit includes a determination condition that a peak intensity (PI) of the second signal waveform is equal to or greater than an intensity threshold.

[0150] <Technical idea 7>

[0151] The object sensing device according to any one of Technical ideas 1 to 6.

[0152] The object sensing device further includes a measurement condition changing unit (34) that changes a measurement condition of the reflected light to avoid a saturation state of an intensity of the signal waveform corresponding to a type of an object.

[0153] <Technical idea 8>

[0154] The object sensing device according to Technical idea 7.

[0155] An intensity of the signal waveform is obtained based on the reflected light detected in an opening area of a pixel of the sensor.

[0156] The measurement condition changing unit changes a size of the opening area as a change of the measurement condition.

[0157] <Technical idea 9>

[0158] The object sensing device according to Technical Idea 7 or 8

[0159] The intensity of the signal waveform is based on the reflected light detected in the opening area of the pixels of the sensor.

[0160] The measurement condition changing unit changes the position of the opening area as a change in the measurement condition.

[0161] <Technical Idea 10>

[0162] The object sensing device according to any one of Technical Ideas 7 to 9

[0163] As a change in the measurement condition, the measurement condition changing unit sets the emission intensity of the irradiation light irradiated from the sensor to a lower intensity than before the change.

[0164] <Technical Idea 11>

[0165] The object sensing device according to any one of Technical Ideas 1 to 10

[0166] The object sensing device further includes a road surface sensing unit (36), and the road surface sensing unit (36) senses the road surface (RR) based on the information of the sensor.

[0167] The pseudo-object determination unit includes a determination condition that, when the position of the candidate for the pseudo-object is included in the position of the road surface, determines that the candidate is not the pseudo-object.

[0168] <Technical Idea 12>

[0169] The object sensing device according to Technical Idea 11

[0170] The road surface sensing unit senses the road surface using interfering light.

[0171] <Technical Idea 13>

[0172] The object sensing device according to Technical Idea 11 or 12

[0173] The road surface sensing unit senses the road surface using the point cloud measured by the sensor.

[0174] <Technical Idea 14>

[0175] The object sensing device according to any one of Technical Ideas 11 to 13

[0176] The plurality of signal waveforms include a first signal waveform and a second signal waveform that arrives after the first signal waveform.

[0177] As a determination condition, the pseudo-object determination unit includes: when the distance of the object shown in the second signal waveform represents a distance that is substantially N times the distance of the object shown in the first signal waveform and the road surface exists at the N-fold distance, it is determined that the object shown in the second signal waveform is not the pseudo-object.

[0178] <Technical idea 15>

[0179] The object sensing device according to any one of Technical Ideas 1 to 14,

[0180] A plurality of the signal waveforms include a first signal waveform and a second signal waveform that arrives after the first signal waveform.

[0181] As a determination condition, the pseudo-object determination unit includes: even when no candidate for the pseudo-object is detected at a distance that is twice the distance of the object shown in the first signal waveform, when the distance shown in the first signal waveform is within a preset distance range and the distance of the object shown in the second signal waveform represents a distance that is substantially three times the distance of the object shown in the first signal waveform, it is also determined that the object shown in the second signal waveform is the pseudo-object.

[0182] <Technical idea 16>

[0183] An object sensing device includes at least one processor (3b), irradiates irradiation light (IL) toward a measurement area (MA), and senses an object based on information obtained from a sensor (2) that detects reflected light (RL) from the object in the measurement area. Among them,

[0184] The processor executes:

[0185] Detecting signal waveforms of the reflected light, and a first signal waveform (S1) and a second signal waveform (S2) that arrive at the sensor with a time difference; and

[0186] When the intensities of the first signal waveform and the second signal waveform are saturated and the amplitude of the first signal waveform is larger than the amplitude of the second signal waveform, removing information on the object related to the second signal waveform and outputting it to the outside.

Claims

1. An object sensing device senses an object based on information obtained from a sensor (2), the sensor (2) irradiating irradiation light (IL) toward a measurement area (MA) and detecting reflected light (RL) from an object in the measurement area, characterized in that, The object sensing device includes: a waveform detection unit (31) that detects a plurality of signal waveforms (S1, S2, S3) that reach the sensor as the generation time difference of the signal waveforms of the reflected light; and a pseudo-object determination unit (33) that determines whether the object indicated by the signal waveform is a pseudo-object (VO) based on the magnitude relationship among the amplitudes of the plurality of signal waveforms.

2. The object sensing device according to claim 1, wherein the plurality of signal waveforms include a first signal waveform and a second signal waveform that arrives after the first signal waveform, if N is an integer of 2 or more, the pseudo-object determination unit includes, as a determination condition, a distance in which the distance of the object indicated by the second signal waveform is N times the distance of the object indicated by the first signal waveform.

3. The object sensing device according to claim 2, wherein when the pseudo-object determination unit determines the second signal waveform as the pseudo-object because the distance of the object indicated by the second signal waveform is N times the distance of the object indicated by the first signal waveform, the pseudo-object determination unit removes all candidates of objects detected farther than the pseudo-object as noise.

4. The object sensing device according to claim 1, wherein the plurality of signal waveforms include a first signal waveform and a second signal waveform that arrives after the first signal waveform, the pseudo-object determination unit includes, as a determination condition, that the amplitude (W1) of the first signal waveform represents a value equal to or greater than a preset amplitude threshold.

5. The object sensing device according to claim 1, wherein the plurality of signal waveforms include a first signal waveform and a second signal waveform that arrives after the first signal waveform, the pseudo-object determination unit includes, as a determination condition, that the difference between the amplitude of the first signal waveform and the amplitude (W2) of the second signal waveform represents a value equal to or greater than a preset difference threshold.

6. The object sensing device according to claim 1, wherein the plurality of signal waveforms include a first signal waveform and a second signal waveform that arrives after the first signal waveform, the pseudo-object determination unit includes, as a determination condition, that the peak intensity (PI) of the second signal waveform represents a value equal to or greater than an intensity threshold.

7. The object sensing device according to claim 1, wherein it further includes a measurement condition changing unit (34) that changes the measurement condition of the reflected light to avoid a saturation state of the intensity of the signal waveform corresponding to the type of the object.

8. The object sensing device according to claim 7, wherein the intensity of the signal waveform is obtained based on the reflected light detected in the opening area of the pixel of the sensor, the measurement condition changing unit changes the size of the opening area as the change of the measurement condition.

9. The object sensing device according to claim 7, wherein the intensity of the signal waveform is obtained based on the reflected light detected in the opening area of the pixel of the sensor, The measurement condition changing unit changes the position of the opening area as a change in the measurement conditions.

10. The object sensing device according to claim 7, wherein As a change in the measurement conditions, the measurement condition changing unit sets the emission intensity of the irradiation light irradiated from the sensor to a lower intensity than before the change.

11. The object sensing device according to any one of claims 1 to 10, wherein The object sensing device further includes a road surface sensing unit (36), and the road surface sensing unit (36) senses the road surface (RR) based on information from the sensor. The pseudo-object determination unit includes, as a determination condition, determining that the candidate is not a pseudo-object when the position of the candidate for the pseudo-object is included in the position of the road surface.

12. The object sensing device according to claim 11, wherein The road surface sensing unit senses the road surface using interfering light.

13. The object sensing device according to claim 11, wherein The road surface sensing unit senses the road surface using a point cloud obtained by ranging with the sensor.

14. The object sensing device according to claim 11, wherein The plurality of signal waveforms include a first signal waveform and a second signal waveform that arrives after the first signal waveform. As a determination condition, it includes: when the distance of the object indicated by the second signal waveform represents a distance that is substantially N times the distance of the object indicated by the first signal waveform and the road surface exists at the N-fold distance, the pseudo-object determination unit determines that the object indicated by the second signal waveform is not a pseudo-object.

15. The object sensing device according to claim 1, wherein The plurality of signal waveforms include a first signal waveform and a second signal waveform that arrives after the first signal waveform. As a determination condition, it includes: even when no candidate for the pseudo-object is detected at a distance that is twice the distance of the object indicated by the first signal waveform, when the distance indicated by the first signal waveform is within a preset distance range and the distance of the object indicated by the second signal waveform represents a distance that is substantially three times the distance of the object indicated by the first signal waveform, the pseudo-object determination unit also determines that the object indicated by the second signal waveform is a pseudo-object.

16. An object sensing method, which is an object sensing method executed by at least one processor (3b) for sensing an object, characterized in that, Including the following steps: Causing the sensor (2) to irradiate light toward the measurement area (MA); Causing the sensor to detect reflected light (RL) from an object in the measurement area; Detecting a plurality of signal waveforms (S1, S2, S3) that arrive at the sensor as a time difference in the generation of the signal waveforms of the reflected light; and Based on the magnitude relationship among the amplitudes of the plurality of signal waveforms, determining whether the object indicated by the signal waveform is a pseudo-object.

Images