Object detection device

Abstract

The present application relates to an object detection device that improves the detection accuracy of an object based on triangulation. The object detection device includes a triangulation operation section that performs a triangulation operation for detecting the position of an object based on first distance information and second distance information, the first distance information being calculated based on a direct wave that is reflected by an object and received by a first transceiving section from a transmission wave transmitted from the first transceiving section, the second distance information being calculated based on an indirect wave that is reflected by an object and received by the first transceiving section from a transmission wave transmitted from a second transceiving section disposed at a position different from the first transceiving section; and a prohibition processing section that prohibits the triangulation operation when the difference between first speed information representing the speed of the object calculated based on the direct wave and second speed information representing the speed of the object calculated based on the indirect wave exceeds a prescribed range.

Description

Technical Field

[0001] This disclosure relates to an object detection device. Background Technology

[0002] The following technique is used: In a device that detects an object by sending waves such as ultrasonic waves or millimeter waves and receiving reflected waves from the object, the position of the object is detected by using triangulation.

[0003] For example, the following structure is disclosed: In a system utilizing a long-range sensor, in order to prevent the detection of the position (virtual image) of an object that does not actually exist, a combination of two sensors is set multiple times, and triangulation is performed on each combination (Patent Document 1).

[0004] Patent Document 1: Japanese Patent Application Publication No. 2015-4562

[0005] The triangulation described above can be performed using direct and indirect waves acquired by multiple sensors (transceivers) positioned at different locations. A direct wave is a reflected wave from a transmitted wave sent by the first transceiver, reflected by an object and received by the first transceiver. An indirect wave is a reflected wave from a transmitted wave sent by a second transceiver, positioned at a different location than the first transceiver, reflected by an object and received by the first transceiver. However, in cases where multiple objects are present, or where the objects are moving relative to each other, the objects corresponding to the direct wave and the objects corresponding to the indirect wave may differ, increasing the likelihood of detecting a virtual image as a result of the triangulation. Summary of the Invention

[0006] Therefore, one of the objectives of this disclosure is to improve the detection accuracy of objects based on triangulation.

[0007] An object detection apparatus, as an example of this disclosure, includes: a triangulation calculation unit that performs triangulation calculations for detecting the position of an object based on first distance information and second distance information, wherein the first distance information is calculated based on a direct wave from a first transceiver unit that is reflected by the object and received by the first transceiver unit, and the second distance information is calculated based on an indirect wave from a second transceiver unit located at a different position from the first transceiver unit that is reflected by the object and received by the first transceiver unit; and an inhibition processing unit that inhibits the triangulation calculations when the difference between first velocity information representing the velocity of the object calculated based on the direct wave and second velocity information representing the velocity of the object calculated based on the indirect wave exceeds a predetermined range.

[0008] Based on the above structure, when the difference between the first velocity information based on the direct wave and the second velocity information based on the indirect wave is large, triangulation calculations based on the first distance information based on the direct wave and the second distance information based on the indirect wave are not performed. Therefore, triangulation calculations can be performed using only the more reliable distance information, thus suppressing the detection of virtual images and improving the accuracy of object detection.

[0009] Alternatively, in the object detection device described above, the first velocity information can be a Doppler frequency shift calculated based on a direct wave, and the second velocity information can be a Doppler frequency shift calculated based on an indirect wave.

[0010] Alternatively, the object detection device described above can be configured such that the first velocity information is a relative velocity based on a Doppler frequency shift calculated from a direct wave, and the second velocity information is a relative velocity based on a Doppler frequency shift calculated from an indirect wave.

[0011] Alternatively, the object detection device may further include: an acquisition unit that acquires first distance information or second distance information by detecting a direct wave or indirect wave with a signal level exceeding a threshold; a sorting processing unit that, when multiple pieces of first distance information or second distance information are acquired within a specified period, sets the priority of the first distance information or second distance information to a higher level if the difference between the signal level corresponding to the first distance information or second distance information and the threshold is greater; and an output control unit that outputs multiple pieces of first distance information or second distance information in descending order of priority.

[0012] The greater the difference between the signal level corresponding to the first or second distance information and the threshold, the higher the reliability of the first or second distance information. Therefore, based on the above structure, the first or second distance information with higher reliability can be preferentially used for triangulation calculations. Attached Figure Description

[0013] Figure 1 This is a top view showing an example of the appearance of a vehicle equipped with the vehicle control system according to the first embodiment.

[0014] Figure 2 This is a block diagram illustrating an example of the hardware structure of the vehicle control system according to the first embodiment.

[0015] Figure 3 This is a block diagram illustrating an example of the functional structure of the object detection device according to the first embodiment.

[0016] Figure 4This is a diagram used to illustrate the outline of the TOF method involved in the first embodiment.

[0017] Figure 5 This diagram illustrates an example of the processing based on the sorting processing unit according to the first embodiment.

[0018] Figure 6 This diagram illustrates another example of the processing based on the sorting processing unit according to the first embodiment.

[0019] Figure 7 This is a flowchart illustrating an example of the processing of the distance information acquisition unit and the output control unit based on the first embodiment.

[0020] Figure 8 This is a diagram illustrating an example of the Doppler shift generated between a transmitted wave sent from the transceiver unit according to the first embodiment and a reflected wave from an object.

[0021] Figure 9 This is a flowchart illustrating an example of processing based on the arithmetic unit involved in this embodiment.

[0022] Figure 10 This is a block diagram illustrating an example of the functional structure of the object detection device according to the second embodiment.

[0023] Explanation of reference numerals in the attached figures

[0024] 1…Vehicle; 2…Body; 10…Vehicle control system; 11…Object detection device; 12…ECU; 21, 21A~21L…Transceiver unit; 22…Control unit; 25A, 25B…Transmitting wave; 26A…Direct wave; 26B…Indirect wave; 31…Oscillator; 41…Input / output device; 42…Storage device; 43…Processor; 51…Input / output device; 52…Storage device; 53…Processor; 101…Distance information acquisition unit; 102…Output control unit; 103…Calculation unit; 111…Sorting processing unit; 121…Triangulation calculation unit; 122…Vehicle information acquisition unit; 123…Prohibition processing unit; L, L′…Envelope; Lth, Lth′…Threshold line; P1~P4…Peak value; ΔA…Difference. Detailed Implementation

[0025] Hereinafter, embodiments of the present disclosure will be described based on the accompanying drawings. The structure of the embodiments described below, as well as the functions and effects brought about by the structure, are merely examples and are not limited to the following description.

[0026] (First Implementation)

[0027] Figure 1This is a top view showing an example of the appearance of a vehicle 1 equipped with the vehicle control system according to the first embodiment. The vehicle control system is a system that includes an object detection device that detects objects present around the vehicle 1, and an ECU (Electronic Control Unit) that controls the vehicle 1 based on the detection results of the object detection device.

[0028] The object detection device described in this embodiment is a device that detects information (the presence or absence of an object, the position of an object, etc.) related to objects (other vehicles, obstacles, people, etc.) existing around the vehicle 1 by acquiring TOF (Time of Flight) information, Doppler shift information, etc., by transmitting waves such as ultrasonic waves from the vehicle 1 and receiving reflected waves from objects.

[0029] The object detection device according to this embodiment has multiple transceiver units 21A to 21L (hereinafter, as a collective term, sometimes referred to as transceiver unit 21). Each transceiver unit 21 is provided on the vehicle body 2, which is the exterior of the vehicle 1, and transmits transmitted waves toward the outside of the vehicle body 2, and receives reflected waves from objects located on the outside of the vehicle body 2. Figure 1 In the example shown, four transceivers 21A to 21D are arranged at the front end of the vehicle body 2, four transceivers 21E to 21H are arranged at the rear end, two transceivers 21I and 21J are arranged on the right side, and two transceivers 21K and 21L are arranged on the left side. Furthermore, the number and location of the transceivers 21 are not limited to the example described above.

[0030] Figure 2 This is a block diagram illustrating an example of the hardware structure of the vehicle control system 10 according to the first embodiment. The vehicle control system 10 according to this embodiment includes an object detection device 11 and an ECU 12.

[0031] The object detection device 11 has multiple transceiver units 21 and a control unit 22.

[0032] Figure 2 Each transceiver unit 21 illustrated has an oscillator 31 constructed using a piezoelectric element or the like, and ultrasonic waves are transmitted and received through the vibration of the oscillator 31. Specifically, each transceiver unit 21 transmits ultrasonic waves generated by the vibration of the oscillator 31 as transmitted waves, and detects the vibration of the oscillator 31 caused by the reflected waves from the object X.

[0033] Each transceiver unit 21 can receive not only reflected waves corresponding to its own transmitted waves, but also reflected waves corresponding to transmitted waves from other transceiver units 21. For example, as Figure 2As shown, the first transceiver unit 21A receives the reflected wave 26A (direct wave) of the transmitted wave 25A transmitted from the first transceiver unit 21A and reflected by the object X, and the reflected wave 26B (indirect wave) of the transmitted wave 25B transmitted from the second transceiver unit 21B and reflected by the object X. In order to identify the direct wave 26A and the indirect wave 26B, appropriate identification processing (e.g., frequency modulation, phase modulation, etc.) is performed on each transmitted wave. Based on each direct wave 26A and indirect wave 26B, TOF information representing the distance to the object X, Doppler shift information representing the velocity (relative velocity) of the object X, etc., can be obtained.

[0034] Furthermore, the relationship between direct and indirect waves is not limited to the examples described above. The first transceiver unit 21A can also receive indirect waves from other transceivers 21 (e.g., the third transceiver unit 21C, the ninth transceiver unit 21I, etc.) that are physically positioned to receive indirect waves. Moreover, the ability to receive indirect waves is not limited to the first transceiver unit 21A; other transceivers 21B to 21L can also receive indirect waves. Figure 2 The example shown illustrates a structure in which both the transmission of the transmitted wave and the reception of the reflected wave (direct wave and indirect wave) utilize a single transducer 31, but the structure of the transceiver unit 21 is not limited to this. For example, it could be a structure where the first transducer for transmitting the transmitted wave and the second transducer for receiving the reflected wave are separately provided, or it could be a structure where the transmitting side and the receiving side are separated.

[0035] The control unit 22 includes an input / output device 41, a storage device 42, and a processor 43. The input / output device 41 is an interface device used to transmit and receive information between the control unit 22 and external devices (such as the transceiver unit 21 and ECU 12). The storage device 42 includes main storage devices such as ROM (Read Only Memory) and RAM (Random Access Memory), and auxiliary storage devices such as HDD (Hard Disk Drive) and SSD (Solid State Drive). The processor 43 is an integrated circuit that performs various processes to implement the functions of the control unit 22, including, for example, a CPU (Central Processing Unit) that operates according to a program, and an ASIC (Application Specific Integrated Circuit) designed for a specific purpose. The processor 43 performs various arithmetic and control processes by reading and executing programs stored in the storage device 42.

[0036] ECU 12 is a unit that performs various processes for controlling vehicle 1 based on information obtained from object detection device 11, etc. ECU 12 includes an input / output device 51, a storage device 52, and a processor 53. The input / output device 51 is an interface device for transmitting and receiving information between ECU 12 and external devices (object detection device 11, drive mechanism, braking mechanism, steering mechanism, etc.). The storage device 52 includes main storage devices such as ROM and RAM, and auxiliary storage devices such as HDD and SSD. The processor 53 is an integrated circuit that executes various processes to implement the functions of ECU 12, including, for example, a CPU and an ASIC. The processor 53 reads the program stored in the storage device 52 to perform various arithmetic and control processes.

[0037] Figure 3 This is a block diagram illustrating an example of the functional structure of the object detection device 11 according to the first embodiment. The object detection device 11 includes a distance information acquisition unit 101, an output control unit 102, and a calculation unit 103. These functional units 101 to 103 are connected via... Figure 2 The object detection device 11 shown is achieved through the collaboration of its hardware components and software components such as programs.

[0038] The distance information acquisition unit 101 acquires distance information representing the distance from the transceiver unit 21 to the object X based on the time-varying changes in the signal level (received strength) of the reflected waves (direct waves and indirect waves) received by each transceiver unit 21. The distance information may be, for example, Time-of-Flight (TOF) or the distance calculated based on TOF. For instance, the distance information acquisition unit 101 acquires the TOF calculated based on the direct waves received by each transceiver unit 21 (direct TOF) and the TOF calculated based on the indirect waves received by each transceiver unit 21 (indirect TOF).

[0039] The output control unit 102 controls the output of distance information acquired by the distance information acquisition unit 101. In this embodiment, the output control unit 102 performs processing to output multiple distance information items in descending order of priority (reliability). The output control unit 102 includes a sorting processing unit 111.

[0040] When multiple distance information pieces are acquired within a specified period, the sorting processing unit 111 sets the priority of the distance information to be as high as the difference between the signal level of the reflected wave (direct wave or indirect wave) corresponding to the distance information and a specified threshold. The output control unit 102 outputs multiple distance information pieces to the calculation unit 103 in descending order of priority. The specified period may be, for example, the period from the transmission of a wave until the transmission of the next wave (one detection cycle). The specified threshold may be, for example, a threshold set to distinguish between the object to be detected (e.g., other vehicles, people, etc.) and objects other than the object to be detected (e.g., road surface, etc.).

[0041] The greater the difference between the signal level that can be identified as a reflected wave and the threshold, the higher the reliability of the detected distance information. Therefore, by setting the priority order (output order) of multiple distance information based on the above difference, the distance information with high reliability can be output first.

[0042] The calculation unit 103 uses the distance information output from the output control unit 102 to perform calculations to generate information related to objects existing around the vehicle 1. The calculation unit 103 according to this embodiment includes a triangulation calculation unit 121, a speed information acquisition unit 122, and a prohibition processing unit 123.

[0043] The triangulation calculation unit 121 performs triangulation calculations for detecting the position of an object based on first distance information calculated based on direct waves and second distance information calculated based on indirect waves. The first distance information is the aforementioned direct TOF (Time-of-Flight) method. The second distance information is the aforementioned indirect TOF (Time-of-Flight) method.

[0044] The velocity information acquisition unit 122 acquires first velocity information based on direct waves and second velocity information based on indirect waves. The first velocity information may be a Doppler frequency shift calculated based on the direct wave, a relative velocity calculated based on the Doppler frequency shift, etc. The second velocity information may be a Doppler frequency shift calculated based on the indirect wave, a relative velocity calculated based on the Doppler frequency shift, etc.

[0045] If the difference between the first speed information and the second speed information exceeds a specified range, the prohibition processing unit 123 prohibits the execution of triangulation calculation based on the first distance information and the second distance information performed by the triangulation calculation unit 121.

[0046] When the error between the first velocity information based on the direct wave and the second velocity information based on the indirect wave is large, there is a high probability that the object captured by the direct wave and the object captured by the indirect wave are different. In such cases, the accuracy of triangulation calculations performed using the first distance information based on the direct wave and the second distance information based on the indirect wave is low. Therefore, by performing processing based on the prohibition processing unit 123 as described above, the implementation of low-accuracy triangulation calculations can be suppressed.

[0047] The object detection device 11 according to this embodiment detects objects using the TOF method of ultrasonic waves. The TOF method is a technique that calculates the distance to an object based on the difference between the time when the transmitted wave is sent (more specifically, the start of transmission) and the time when the reflected wave is received (more specifically, the start of reception).

[0048] Figure 4 This is a diagram used to illustrate the outline of the TOF method involved in the first embodiment. Figure 4 The image shows the time-varying envelope of the ultrasonic signal level transmitted and received by the transceiver unit 21. Figure 4 In the coordinate graph shown, the horizontal axis corresponds to time, and the vertical axis corresponds to signal level.

[0049] The solid line L11 represents an example of an envelope, which indicates the time-varying change in the signal level of the signals transmitted and received by the transceiver unit 21, i.e., the amplitude of the oscillation of the oscillator 31. From this solid line L11, it can be seen that the oscillator 31 is driven to oscillate for a time Ta starting from time t0. Therefore, during the time Tb from the completion of wave transmission at time t1 to time t2, the oscillation of the oscillator 31 caused by inertia continues while simultaneously decaying. Thus, in Figure 4 In the coordinate graph shown, time Tb corresponds to the so-called reverberation time.

[0050] The solid line L11 marks the point at time t4, after time Tp from the start of the transmitted wave, where the amplitude of the oscillator 31 exceeds (or becomes higher than) a predetermined threshold value represented by the dashed line L21. This threshold value is a preset value used to distinguish whether the vibration of the oscillator 31 is caused by receiving reflected waves from an object being detected or by receiving reflected waves from an object outside the object being detected. Furthermore, an example is shown here where the threshold value represented by the dashed line L21 is set to a constant value that does not change over time; however, this threshold value can also be set to a value that changes over time.

[0051] Vibrations with peak values ​​exceeding (or higher than) the threshold indicated by the dashed line L21 can be considered as vibrations resulting from receiving reflected waves from an object being detected. Conversely, vibrations with peak values ​​below (or less than) the threshold can be considered as vibrations resulting from receiving reflected waves from an object outside the detection target. Therefore, it can be seen from the solid line L11 that the vibration of oscillator 31 at time t4 is a vibration resulting from receiving reflected waves from an object being detected.

[0052] Furthermore, in solid line L11, the vibration of oscillator 31 decays after time t4. Therefore, time t4 corresponds to the moment when the reception of the reflected wave from the object being detected is completed, in other words, it corresponds to the moment when the transmitted wave last sent at time t1 returns as a reflected wave.

[0053] Furthermore, in solid line L11, time t3, which is the starting point of the peak at time t4, corresponds to the moment when the reception of the reflected wave from the object being detected begins; in other words, it corresponds to the moment when the transmitted wave initially sent at time t0 returns as a reflected wave. Therefore, the time ΔT between time t3 and time t4 is equal to the time Ta, which is the transmission time of the transmitted wave.

[0054] Based on the above, in order to determine the distance to the object being detected using the Time-of-Flight (TOF) method, it is necessary to calculate the time Tf between the moment t0 when the transmitted wave begins to be sent and the moment t3 when the reflected wave begins to be received. This time Tf can be obtained by subtracting the time ΔT, which is equal to the transmission time Ta, from the time Tp, which is the difference between moment t0 and the moment t4 when the signal level of the received reflected wave exceeds the threshold peak.

[0055] The moment t0 when the transmitted wave begins can be easily determined as the moment when the object detection device 11 starts operating, and the transmission time Ta of the transmitted wave is predetermined by settings, etc. Therefore, by determining the moment t4 when the signal level of the received reflected wave exceeds the threshold peak, the distance to the object being detected can be calculated.

[0056] The distance information acquisition unit 101 of this embodiment performs the aforementioned processing on each of the direct and indirect waves acquired from each transceiver unit 21, acquiring direct TOF (first distance information) based on the direct wave and indirect TOF (second distance information) based on the indirect wave. Furthermore, when the sorting processing unit 111 of this embodiment acquires multiple TOFs (direct or indirect TOFs) within a specified period, it sets the priority order of each TOF to be higher if the difference between the signal level corresponding to the TOF and a threshold is greater. Moreover, the output control unit 102 of this embodiment outputs the multiple TOFs to the calculation unit 103 in descending order of the set priority.

[0057] Figure 5 This diagram illustrates an example of the processing performed by the sorting processing unit 111 according to the first embodiment. Figure 5 The diagram shows the time-varying envelope L representing the signal level of the reflected wave (direct or indirect) during a single detection cycle, and the threshold line Lth representing the threshold used for detecting TOF (direct or indirect TOF). Figure 5 The example shown illustrates the detection of four peaks P1 to P4 corresponding to the four TOF1 to TOF4 peaks in a single detection cycle.

[0058] like Figure 5 As shown, the priority order of TOF1 to TOF4 is determined by the shortest elapsed time from the moment the transmitted wave was sent to the moment the corresponding peak values ​​P1 to P4 were detected, i.e., the moment when the peak values ​​P1 to P4 were detected. In this case, the four TOF1 to TOF4 are output to the arithmetic unit 103 in the order of TOF1→TOF2→TOF3→TOF4.

[0059] In contrast, the priority order of TOF1 to TOF4 after sorting is determined by the descending order of the difference ΔA between the signal levels of each peak P1 to P4 on the envelope L and the threshold represented by the threshold line Lth. In this case, the four TOF1 to TOF4 are output to the arithmetic unit 103 in the order of TOF3→TOF1→TOF4→TOF2.

[0060] It can be determined that the larger the difference ΔA, the higher the probability that the detected peak corresponds to the object being detected (the probability that it is caused by noise such as road clutter is low). Therefore, by setting the priority order (output order) of each TOF1 to TOF4 according to the difference ΔA as described above, it is possible to prioritize the output of highly reliable TOFs to the arithmetic unit 103.

[0061] Figure 6 This diagram illustrates another example of the processing based on the sorting processing unit 111 according to the first embodiment. Figure 6 The diagram shows the envelope L′ representing the time-varying signal level of the reflected wave (direct wave or indirect wave) in one detection cycle, and the threshold line Lth′ representing the threshold used for detecting TOF (direct TOF or indirect TOF). Figure 6 In the example shown, the threshold line Lth′ is a processed value obtained by using the moving average of the envelope L′. This processed value only needs to be a TOF value that can detect the object being detected; for example, it could be a value obtained by adding or subtracting a threshold based on a specified reference (e.g., a threshold used to remove road clutter) from the moving average. The method for setting the priority order of each TOF1 to TOF4 (each peak P1 to P4) is as follows... Figure 5 The example shown is similar. By setting the threshold used for TOF detection to a value processed using a moving average, the effectiveness of removing noise such as road clutter can be improved.

[0062] Figure 7 This is a flowchart illustrating an example of the processing of the distance information acquisition unit 101 and the output control unit 102 according to the first embodiment. The distance information acquisition unit 101 generates the envelope of the reflected wave (direct wave and / or indirect wave) received by the transceiver unit 21 (S101), and sets a threshold for detecting TOF (S102). At this time, the distance information acquisition unit 101 can also generate the envelope and set the threshold based on data processed by CFAR (Constant False Alarm Rate). CFAR processing involves acquiring a differential signal obtained by subtracting the moving average from the signal level of the reflected wave being processed. By utilizing CFAR processing, the effects of noise caused by road clutter, etc., can be mitigated. Then, the distance information acquisition unit 101 detects TOF based on the reflected wave with a signal level exceeding the threshold (S103).

[0063] The sorting processing unit 111 of the output control unit 102 calculates the difference ΔA (the difference between the signal level of each peak P1 to P4 and the threshold represented by the threshold lines Lth and Lth′) for each detected TOF (S104), and sorts the multiple TOFs in descending order of the difference ΔA (S105). The output control unit 102 outputs the multiple TOFs to the arithmetic unit 103 according to the sorting order (S106).

[0064] Through the processing described above, the TOF with high reliability can be output to the arithmetic unit 103 with priority.

[0065] The triangulation calculation unit 121 of the calculation unit 103 performs triangulation calculations for detecting the position of an object based on the sorted distance information output from the output control unit 102 as described above, namely, the first distance information (direct TOF) with higher priority (reliability) and the second distance information (indirect TOF). Additionally, the velocity information acquisition unit 122 acquires first velocity information (Doppler frequency shift or relative velocity) based on the first distance information and second velocity information (Doppler frequency shift or relative velocity) based on the second distance information. Furthermore, the prohibition processing unit 123 prohibits the execution of triangulation calculations based on the first and second distance information if the difference between the first and second velocity information exceeds a predetermined range.

[0066] Here, we will explain the Doppler frequency shift. Figure 8This is a diagram illustrating an example of the Doppler frequency shift generated between the transmitted wave from the transceiver unit 21 according to the first embodiment and the reflected wave from an object. In this diagram, a case is illustrated where frequency modulation is applied to the transmitted wave to cause a sawtooth-like frequency variation. The horizontal axis in this diagram corresponds to time, and the vertical axis corresponds to the frequencies of the transmitted and reflected waves.

[0067] Waveform W1 represents the frequency characteristics of the transmitted wave, and waveform W2 represents the frequency characteristics of the reflected wave. The transmitted wave waveform W1 corresponds to a linear frequency modulated signal whose instantaneous frequency varies in the range from fc-Δf to fc+Δf.

[0068] When the relative distance between the object and the transceiver unit 21 decreases (as in cases where the vehicle 1 or / and the object moves closer to each other), the frequency band of the received wave shown in waveform W2 shifts to a higher frequency side than the frequency band of the transmitted wave shown in waveform W1 due to the Doppler effect. At this time, although the frequency bands differ between waveforms W1 and W2, a common waveform characteristic of sawtooth-like frequency changes over time occurs. Therefore, by extracting a signal with the same waveform characteristics as waveform W1 from the signal acquired after transmitting the transmitted wave, the waveform W2 of the reflected wave corresponding to that transmitted wave can be determined. Furthermore, when the relative distance increases (as in cases where the vehicle 1 or / and the object moves further apart), the frequency band shown in waveform W2 shifts to a lower frequency side than the frequency band shown in waveform W1.

[0069] As described above, by determining the correspondence between waveforms W1 and W2, the TOF corresponding to the distance from the object and the Doppler frequency shift (frequency difference) fd generated between the transmitted and reflected waves can be obtained. Furthermore, the relative velocity of the object with respect to vehicle 1 (transceiver unit 21) can be calculated based on the Doppler frequency shift fd.

[0070] Figure 9 This is a flowchart illustrating an example of the processing performed by the arithmetic unit 103 according to this embodiment. First, the velocity information acquisition unit 122 determines whether direct TOF (first distance information) has been acquired from the output control unit 102 (S201). If direct TOF has not been acquired (S201: No), the process ends. On the other hand, if direct TOF has been acquired (S201: Yes), the velocity information acquisition unit 122 acquires first velocity information (Doppler frequency shift or relative velocity) based on the direct wave (S202).

[0071] Then, the velocity information acquisition unit 122 determines whether indirect TOF (second distance information) has been acquired from the output control unit 102 (S203). If indirect TOF has not been acquired (S203: No), the calculation unit 103 outputs the position information generated using only direct TOF to the ECU 12 (S209). On the other hand, if indirect TOF has been acquired (S203: Yes), the velocity information acquisition unit 122 acquires second velocity information (Doppler frequency shift or relative velocity) based on the indirect wave (S204).

[0072] The prohibition processing unit 123 determines whether the difference between the first speed information and the second speed information is within a specified range (S205). If the difference is not within the specified range (S205: No), the triangulation calculation based on the triangulation calculation unit 121 is prohibited (S208). In this case, the calculation unit 103 outputs the position information generated using only direct TOF to the ECU 12 (S209). On the other hand, if the difference between the first speed information and the second speed information is within the specified range (S205: Yes), the triangulation calculation unit 121 performs triangulation calculations based on direct TOF and indirect TOF (S206), and the calculation unit 102 outputs the position information based on the triangulation calculation result to the ECU 12 (S207).

[0073] Based on the above processing, when the error between the first velocity information and the second velocity information is large, triangulation calculations based on the first distance information (direct TOF) and the second distance information (indirect TOF) are prohibited. This suppresses the implementation of low-precision triangulation calculations.

[0074] The program that enables the processor 43 and other components to perform processing for implementing the various functions described above can be provided as an installable or executable file on a computer-readable recording medium such as a CD (Compact Disc)-ROM, floppy disk (FD), CD-R (Recordable), or DVD (Digital Versatile Disk). Alternatively, the program can also be provided or distributed via a network such as the Internet.

[0075] According to the above implementation method, the detection accuracy of objects can be improved.

[0076] Hereinafter, other embodiments will be described with reference to the accompanying drawings. There are cases where parts that have the same or similar effects as those in the first embodiment are marked with the same reference numerals and their descriptions are omitted.

[0077] (Second Implementation)

[0078] Figure 10This is a block diagram illustrating an example of the functional structure of the object detection device 61 according to the second embodiment. The object detection device 61 according to this embodiment differs from the object detection device 11 according to the first embodiment in that it does not have the output control unit 102 and the sorting processing unit 111 described above.

[0079] In this embodiment, the multiple first distance information (direct TOF) or multiple second distance information (indirect TOF) acquired by the distance information acquisition unit 101 are output to the calculation unit 103 without a set priority order. For example, the first distance information or second distance information involved in this embodiment may also be... Figure 5 or Figure 6 The order before sorting (based on the order in which the peak corresponding to TOF was detected) is output.

[0080] Even with the structure described above, the accuracy of triangulation calculations can be improved through the function of the prohibition processing unit 123, enabling the detection of objects with high precision.

[0081] The embodiments of this disclosure have been described above, but these embodiments are merely examples and are not intended to limit the scope of the invention. The new embodiments described above can be implemented in various ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The embodiments described above are included within the scope and spirit of the invention, and are included within the scope of the invention as described in the claims and their equivalents.

Claims

1. An object detection device, characterized in that, have: The triangulation unit performs triangulation calculations for detecting the position of an object based on first distance information and second distance information. The first distance information is calculated based on a direct wave that is reflected by the object and received by the first transceiver unit from a transmitted wave sent from the first transceiver unit. The second distance information is calculated based on an indirect wave that is reflected by the object and received by the first transceiver unit from a transmitted wave sent from a second transceiver unit located at a different position than the first transceiver unit. The velocity information acquisition unit calculates first velocity information representing the velocity or relative velocity of an object calculated based on the direct wave and second velocity information representing the velocity or relative velocity of an object calculated based on the indirect wave; as well as The prohibition processing unit prohibits the triangulation calculation when the difference between the first speed information and the second speed information exceeds a specified range.

2. The object detection device according to claim 1, characterized in that, The first velocity information is the Doppler frequency shift calculated based on the direct wave. The second velocity information is the Doppler frequency shift calculated based on the indirect wave.

3. The object detection device according to claim 1, characterized in that, The first velocity information is a relative velocity based on a Doppler frequency shift, which is calculated based on the direct wave. The second velocity information is a relative velocity based on a Doppler frequency shift, which is calculated based on the indirect wave.

4. The object detection device according to any one of claims 1 to 3, characterized in that, It also has: The acquisition unit acquires the first distance information or the second distance information by detecting the direct wave or the indirect wave whose signal level exceeds a threshold. In the case where multiple pieces of the first distance information or the second distance information are acquired within a specified period, the greater the difference between the signal level corresponding to the first distance information or the second distance information and the threshold, the higher the priority order of the first distance information or the second distance information is set. as well as The output control unit outputs multiple sets of the first distance information or the second distance information in descending order of priority.

Images