Object detection device

Abstract

To reduce the influence of a multipath and improve obstacle detection accuracy.SOLUTION: An object detection device of an embodiment includes: a transmitting unit that transmits transmission waves in which a plurality of ultrasonic waves having different frequencies are multiplexed; a receiving unit that receives reflected waves generated when the transmission waves are reflected by an object; a frequency analysis unit that generates separation echo information indicating a change in amplitude value over time for each of a plurality of frequency components included in the reflected waves; and a calculation unit that generates distance information about the distance to the object based on the maximum amplitude value, which is the largest among a plurality of amplitude values detected for each frequency component at the same time, which is obtained from the separation echo information.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to an object detection device. [Background technology]

[0002] 2. Description of the Related Art In a system for assisting a moving body such as a vehicle in traveling, an object detection device is used that detects obstacles present around the moving body by transmitting and receiving ultrasonic waves. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 141370 Summary of the Invention [Problem to be solved by the invention]

[0004] In an object detection device that uses ultrasonic waves, multipath waves may occur, whereby reflected waves from the same obstacle travel different paths and are received by the receiver, due to the shape of the obstacle and the surrounding environment. When such multipath waves occur, the accuracy of obstacle detection may be reduced due to phenomena such as a decrease in amplitude value caused by anti-phase waves.

[0005] Therefore, one of the problems to be solved by the embodiments of the present invention is to provide an object detection device that can reduce the influence of multipath and improve the accuracy of obstacle detection. [Means for solving the problem]

[0006] An object detection device according to one embodiment of the present invention comprises a transmitting unit that transmits a transmission wave in which multiple ultrasonic waves of different frequencies are multiplexed; a receiving unit that receives a reflected wave generated when the transmission wave is reflected by an object; a frequency analysis unit that generates separated echo information indicating changes in amplitude values ​​over time for each of multiple frequency components contained in the reflected wave; and a calculation unit that generates distance information regarding the distance to the object based on the largest maximum amplitude value among multiple amplitude values ​​detected for each frequency component at the same time, which is obtained from the separated echo information.

[0007] According to the above configuration, distance information is generated based on the largest maximum amplitude value among multiple amplitude values ​​detected for each frequency component at the same time. As a result, even if some of the multiple frequency components are affected by multipath (for example, a decrease in amplitude value due to an anti-phase wave), obstacles can be detected with high accuracy using the maximum amplitude value.

[0008] The calculation unit may also generate distance information based on corrected echo information that indicates changes over time in the maximum amplitude value.

[0009] By using the corrected echo information as described above, it is possible to effectively reduce the influence of multipath and improve the accuracy of obstacle detection.

[0010] The calculation unit may also generate distance information based on corrected echo information that indicates the change over time in the root mean square of multiple top amplitude values ​​selected in descending order from multiple amplitude values ​​detected for each frequency component at the same time.

[0011] As described above, by using corrected echo information generated using the root mean square of multiple higher amplitude values ​​including the maximum amplitude value, the effects of multipath can be effectively reduced and the accuracy of obstacle detection can be improved.

[0012] Furthermore, a common oscillator may be used to transmit the transmitted wave and receive the reflected wave.

[0013] According to the above configuration, the paths of the transmitted and received waves are minimized, thereby reducing the possibility of multipath occurrence. Furthermore, since there is no need to provide individual transducers for each frequency component, costs can be reduced. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a top view showing an example of the configuration of a vehicle according to the first embodiment. [Figure 2] FIG. 2 is a block diagram showing an example of a hardware configuration of the vehicle control system according to the first embodiment. [Figure 3] FIG. 3 is a perspective view showing an example of the configuration of the vibrator according to the first embodiment. [Figure 4] FIG. 4 is a diagram showing an example of a method for calculating distance using the TOF method. [Figure 5] FIG. 5 is a block diagram illustrating an example of the functional configuration of the object detection device according to the first embodiment. [Figure 6] FIG. 6 is a diagram showing an example of separated echo information according to the first embodiment. [Figure 7] FIG. 7 is a diagram showing an example of corrected echo information according to the first embodiment. [Figure 8] FIG. 8 is a flowchart showing an example of processing in the object detection device according to the first embodiment. [Figure 9] FIG. 9 is a diagram showing an example of corrected echo information according to the second embodiment. [Figure 10] FIG. 10 is a perspective view showing an example of the configuration of a vibrator according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The configurations of the embodiments described below and the actions and effects brought about by the configurations are merely examples, and the present invention is not limited to the following description.

[0016] (First embodiment) 1 is a top view showing an example of the configuration of a vehicle 1 according to the first embodiment. The vehicle 1 is an example of a moving body on which an object detection device according to the present embodiment is mounted. The object detection device according to the present embodiment is a device that detects obstacles present around the vehicle 1 based on information such as TOF (Time Of Flight) and Doppler shift acquired by transmitting a transmission wave (ultrasound wave) from the vehicle 1 and receiving a reflected wave generated when the transmission wave is reflected by an object.

[0017] The object detection device of this embodiment includes a plurality of transceivers 21A to 21L (hereinafter, abbreviated to transceivers 21 when there is no need to distinguish between the plurality of transceivers 21A to 21L). Each transceiver 21 is installed on a vehicle body 2 that serves as the exterior of a vehicle 1, transmits a transmission wave toward the outside of the vehicle body 2, and receives a reflected wave from an object present outside the vehicle body 2. In the example shown in FIG. 1, 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. Note that the number and installation locations of the transceivers 21 are not limited to this example.

[0018] 2 is a block diagram showing an example of the hardware configuration of a vehicle control system 50 according to the first embodiment. The vehicle control system 50 performs processing for controlling the vehicle 1 based on information output from an object detection device 200. The vehicle control system 50 of this embodiment includes an ECU 100 and an object detection device 200.

[0019] The object detection device 200 includes multiple transmitter / receivers 21 and a control unit 220. Each transmitter / receiver 21 includes a vibrator 511 configured using a piezoelectric element or the like, an amplifier, etc., and realizes transmission and reception of ultrasonic waves by the vibration of the vibrator 511. Specifically, each transmitter / receiver 21 transmits ultrasonic waves generated in response to the vibration of the vibrator 511 as a transmission wave Wt, and detects the vibration of the vibrator 511 caused by a reflected wave Wr generated when the transmission wave Wt is reflected by an object such as an obstacle O or a road surface RS. The vibration of the vibrator 511 is converted into an electrical signal, and based on the electrical signal, it is possible to obtain information such as a time of flight (TOF) corresponding to the distance from the transmitter / receiver 21 to the obstacle O and Doppler shift information corresponding to the relative speed of the obstacle O.

[0020] 2 illustrates a configuration in which a common oscillator 511 is used to transmit the transmission wave Wt and receive the reflected wave Wr, but the configuration of the transmitter / receiver 21 is not limited to this. For example, an oscillator for transmitting the transmission wave Wt and an oscillator for receiving the reflected wave Wr may be provided separately.

[0021] The control unit 220 includes an input / output device 221, a storage device 222, and a processor 223. The input / output device 221 is an interface device that enables transmission and reception of information between the control unit 220 and the outside (such as the transceiver unit 21 and the ECU 100). The storage device 222 includes a main storage device such as a read-only memory (ROM) or a random access memory (RAM), and an auxiliary storage device such as a hard disk drive (HDD) or a solid state drive (SSD). The processor 223 is an integrated circuit that executes various processes to realize the functions of the control unit 220, and may be configured using, for example, a central processing unit (CPU) that operates according to a program, an application-specific integrated circuit (ASIC) designed for a specific application, or the like. The processor 223 executes various arithmetic and control processes by reading and executing programs stored in the storage device 222.

[0022] The ECU 100 is a unit that executes various processes for controlling the vehicle 1 based on various information acquired from the object detection device 200 and the like. The ECU 100 has an input / output device 110, a storage device 120, and a processor 130. The input / output device 110 is an interface device that enables transmission and reception of information between the ECU 100 and external mechanisms (such as the object detection device 200, drive mechanism, braking mechanism, steering mechanism, transmission mechanism, in-vehicle display, speakers, and various sensors). The storage device 120 includes a main storage device such as a ROM or RAM, and an auxiliary storage device such as an HDD or SSD. The processor 130 is an integrated circuit that executes various processes for realizing the functions of the ECU 100, and may be configured using, for example, a CPU, an ASIC, or the like. The processor 130 reads programs stored in the storage device 120 and executes various arithmetic and control processes.

[0023] 3 is a perspective view showing an example of the configuration of a vibrator 511 according to the first embodiment. The vibrator 511 has an upper electrode 521, an upper wiring 522, a piezoelectric body 523, a lower electrode 524, and a lower wiring 525.

[0024] Upper electrode 521 is provided on the upper surface of piezoelectric body 523 and is used as an electrode for applying voltage. Upper wiring 522 is connected to upper electrode 521 and a predetermined AC power supply. Lower electrode 524 is provided on the lower surface of piezoelectric body 523 and is used as a ground electrode. Lower wiring 525 is connected to lower electrode 524 and a predetermined ground electrode. When AC voltage is applied, piezoelectric body 523 vibrates due to the piezoelectric effect, generating an ultrasonic wave (transmission wave) that travels in the direction shown by the arrow in the figure.

[0025] The above configuration is an example, and is not limited to this configuration of the vibrator 511. For example, the upper electrode 521 may be a ground electrode, and the lower electrode 524 may be an electrode for applying a voltage.

[0026] Fig. 4 is a diagram showing an example of a distance calculation method using the TOF method. Fig. 4 illustrates an envelope L11 that indicates changes over time in the amplitude value (signal strength) of ultrasonic waves transmitted and received by the transmitting and receiving unit 210. In the graph shown in Fig. 4, the horizontal axis corresponds to time (TOF), and the vertical axis corresponds to the amplitude value (the magnitude of vibration of the transducer 511) of the ultrasonic waves transmitted and received by the transmitting and receiving unit 210.

[0027] Envelope L11 shows the change over time in amplitude values ​​indicating the magnitude of vibration of oscillator 511. From envelope L11 shown in Fig. 4, it can be seen that oscillator 511 is driven to vibrate for time Ta from time t0, completing transmission of the transmission wave at time t1, and then the vibration of oscillator 511 due to inertia continues while attenuating for time Tb until time t2. Therefore, in the graph shown in Fig. 4, time Tb corresponds to the so-called reverberation time.

[0028] The envelope L11 reaches a peak at time t4, which is a time Tp after time t0 when the transmission of the transmission wave starts, at which time the magnitude of the vibration of the vibrator 511 reaches or exceeds the detection threshold Ith. This detection threshold Ith is a value set to distinguish whether the vibration of the vibrator 511 is caused by the reception of a reflected wave from an obstacle O (another vehicle, a structure, a pedestrian, etc.) or by the reception of a reflected wave from an object other than the obstacle O (for example, a road surface RS, etc.). Note that although the detection threshold Ith is shown as a constant value here, the detection threshold Ith may also be a variable value that changes depending on the situation. Vibrations having a peak equal to or greater than the detection threshold Ith can be considered to be caused by the reception of a reflected wave from the obstacle O.

[0029] The envelope L11 in this example shows that the vibration of the vibrator 511 is attenuated after timing t4. Therefore, timing t4 corresponds to the timing at which reception of the reflected wave from the obstacle O is completed, in other words, the timing at which the transmitted wave last transmitted at timing t1 returns as a reflected wave.

[0030] Furthermore, in envelope L11, timing t3, which is the start point of the peak at timing t4, corresponds to the timing when reception of the reflected wave from obstacle O begins, in other words, the timing when the transmitted wave first transmitted at timing t0 returns as a reflected wave. Therefore, the time ΔT between timing t3 and timing t4 is equal to the time Ta, which is the transmission time of the transmitted wave.

[0031] From the above, in order to use TOF to find the distance from the source of transmission and reception of ultrasonic waves to the obstacle O, it is necessary to find the time Tf between the time t0 when the transmission wave begins and the time t3 when the reflected wave begins to be received. This time Tf can be found by subtracting the time ΔT, which is equal to the time Ta for transmitting the transmitted wave, from the time Tp, which is the difference between the time t0 and the time t4 when the intensity of the reflected wave exceeds the detection threshold Ith and reaches its peak.

[0032] The time t0 when the transmission wave starts to be transmitted can be easily identified as the time when the object detection device 200 starts to operate, and the time Ta as the transmission time of the transmission wave is determined in advance by settings, etc. Therefore, by identifying the time t4 when the intensity of the reflected wave reaches a peak and becomes equal to or greater than the detection threshold Ith, the distance from the source of transmission and reception to the obstacle O can be obtained.

[0033] 5 is a block diagram showing an example of the functional configuration of object detection device 200 according to the first embodiment. Object detection device 200 of this embodiment includes a transmitter 301, a transmission control unit 302, a receiver 303, a signal processor 304, a frequency analyzer 305, and a calculator 306. These functional components 301 to 306 can be realized, for example, by cooperation between hardware components such as those shown in FIG. 2 and software components such as programs and firmware. Furthermore, at least some of these functional components 301 to 306 may be realized by dedicated hardware (circuits, etc.).

[0034] The transmitting unit 301 transmits a transmission wave Wt in which a plurality of ultrasonic waves with different frequencies are multiplexed. That is, the transmission wave Wt is an ultrasonic wave containing a plurality of frequency components. The transmission wave Wt may be, for example, an ultrasonic wave in which sine waves with different frequencies in a frequency range of 20 kHz or higher are multiplexed. The transmitting unit 301 is configured using the above-described transducer 511, etc.

[0035] The transmission control unit 302 performs processing to cause the transmission unit 301 to transmit the transmission wave Wt including the above-described multiple frequency components. The transmission control unit 302 of this embodiment includes a carrier wave generation unit 311 and a multiplexing processing unit 312.

[0036] The carrier wave generation unit 311 generates a plurality of carrier waves that are the source of the transmission wave Wt. The carrier wave generation unit 311 generates, for example, a plurality of sine waves with different frequencies. The multiplexing processing unit 312 generates an audio signal by multiplexing a plurality of carrier waves (sine waves) with different frequencies. The multiplexing method is not particularly limited, but methods such as OFDM (Orthogonal Frequency Division Multiplexing) and FDM (Frequency Division Multiplexing) can be used. The transmission unit 301 outputs a transmission wave Wt that includes a plurality of frequency components in accordance with the audio signal thus generated.

[0037] The receiving unit 303 receives a reflected wave Wr generated when the transmitted wave Wt is reflected by an object. The reflected wave Wr is an ultrasonic wave containing multiple frequency components, just like the transmitted wave Wt. The receiving unit 303 is configured using a vibrator 511, an AD conversion circuit, etc., and generates an audio signal of the received reflected wave Wr.

[0038] The transmitting unit 301 and receiving unit 303 of this embodiment are configured using a common oscillator 511. That is, the transmission of the transmission wave Wt and the reception of the reflected wave Wr in each transmitting / receiving unit 21 (each of the transmitting / receiving units 21A to 21L) are performed using the common oscillator 511. This minimizes the paths of the transmission wave Wt and the reception wave Wr, thereby reducing the possibility of multipath occurrence compared to when multiple oscillators are used. Furthermore, since there is no need to provide an oscillator for each frequency component, an increase in costs can be suppressed.

[0039] The signal processing unit 304 performs predetermined signal processing on the audio signal of the reflected wave Wr. The signal processing may include filtering for noise removal, correlation processing for determining the similarity between the transmitted wave Wt and the received wave Wr, and the like.

[0040] The frequency analysis unit 305 performs frequency analysis processing on the audio signal of the reflected wave Wr after signal processing, and generates separated echo information indicating changes over time in amplitude value for each of the multiple frequency components included in the reflected wave Wr. The frequency analysis processing may be, for example, FFT (Fast Fourier Transform) or the like.

[0041] Fig. 6 is a diagram showing an example of separated echo information 411 according to the first embodiment. Fig. 6 illustrates an audio signal 401 of the transmitted wave Wt, an audio signal 402 of the reflected wave Wr, and separated echo information 411. Here, an example is shown in which the reflected wave Wr includes four types of frequency components (A to D).

[0042] The separated echo information 411 is generated based on the results of FFT analysis of the audio signal 402 of the reflected wave Wr. In the graph of the separated echo information 411, the horizontal axis corresponds to the time elapsed since the transmission wave Wt was transmitted, and the vertical axis corresponds to the amplitude value of the reflected wave Wr. The separated echo information 411 shows the change over time in the amplitude value for each of the four frequency components (A to D) contained in the reflected wave Wr.

[0043] The separated echo information 411 shows that there is variation in the amplitude values ​​of each frequency component. Such variation in amplitude values ​​is thought to be due to the influence of multipath of the reflected wave Wr (for example, cancellation of amplitudes due to opposite phase waves). The object detection device 200 of this embodiment is provided with means for reducing such influence of multipath.

[0044] 5, the calculation unit 306 generates distance information relating to the distance from a reference position (for example, the installation position of the transceiver unit 21) to an object (obstacle O) based on the largest amplitude value among multiple amplitude values ​​detected for each frequency component at the same time, which is acquired from the separated echo information 411. The distance information is output to, for example, the ECU 100 (see FIG. 2) and used for automatic driving control, danger avoidance control, etc. of the vehicle 1.

[0045] The calculation unit 306 of this embodiment includes a corrected echo information generation unit 321 and a distance information generation unit 322. The corrected echo information generation unit 321 of this embodiment generates corrected echo information that indicates changes in the maximum amplitude value over time. The distance information generation unit 322 generates distance information based on the corrected echo information.

[0046] 7 is a diagram showing an example of corrected echo information 421 according to the first embodiment. The corrected echo information 421 is generated by generating a maximum value line L1 that indicates changes over time in a plurality of maximum amplitude values ​​(amplitude values ​​corresponding to the positions of dots in FIG. 7) acquired from the separated echo information 411. For example, the maximum amplitude value corresponding to time t1 is the amplitude value A (solid line), and the maximum amplitude value corresponding to time t2 is the amplitude value C (dash-dotted line). The maximum value line L1 can be generated by acquiring a plurality of such maximum amplitude values ​​at predetermined time intervals.

[0047] In the corrected echo information 421 shown in Fig. 7, the maximum value line L1 is compared with a reference line Lref (the line corresponding to frequency component B in this example) which shows the change over time in the amplitude value of a single frequency component. As shown in the reference line Lref, with a single frequency component, there is a time period in which the amplitude value drops significantly due to the influence of multipath, but such a time period does not exist with the maximum value line L1. By using this maximum value line L1 to calculate the TOF corresponding to the obstacle O (the TOF corresponding to the peak exceeding the threshold value Ith) using, for example, the method shown in Fig. 4, the distance to the obstacle O can be calculated with high accuracy.

[0048] 8 is a flowchart showing an example of processing in the object detection device 200 according to the first embodiment. When execution of the object detection processing is started, the transmitter 301 transmits a transmission wave Wt (S101), and the receiver 303 receives a reflected wave Wr (S102). At this time, the transmission of the transmission wave Wt and the reception of the received wave Wr are preferably performed by a common oscillator 511 (one transmitter / receiver 21).

[0049] The signal processing unit 304 performs filtering on the audio signal 402 of the received wave Wr (S103). The frequency analysis unit 305 performs frequency analysis on the filtered received wave Wr to generate separated echo information 411 indicating changes in amplitude over time for each frequency component contained in the received wave Wr (S104). The calculation unit 306 (corrected echo information generation unit 321) generates corrected echo information 421 indicating changes in maximum amplitude over time based on the separated echo information 411 (S105). Then, the calculation unit 306 (distance information generation unit 322) generates distance information relating to the distance to the obstacle O based on the corrected echo information 421 (S106).

[0050] According to the above embodiment, distance information is generated based on corrected echo information that indicates a time-varying maximum amplitude value among multiple amplitude values ​​detected for each frequency component at the same time, thereby reducing the effects of multipath and improving the accuracy of obstacle detection.

[0051] Other embodiments will be described below, but descriptions of parts that are the same as or similar to the first embodiment will be omitted as appropriate.

[0052] (Second embodiment) The object detection device 200 according to the second embodiment generates distance information using corrected echo information that is different from the corrected echo information 421 according to the first embodiment.

[0053] 9 is a diagram showing an example of corrected echo information 431 according to the second embodiment. The corrected echo information 431 according to this embodiment is information indicating changes over time in the root mean square (RMS) of multiple higher-order amplitude values ​​(amplitude values ​​corresponding to the positions of dots in FIG. 9) acquired from the separated echo information 411. The multiple higher-order amplitude values ​​are multiple (e.g., three) amplitude values ​​selected in descending order from multiple amplitude values ​​detected for each frequency component at the same time (e.g., t3), and include the maximum amplitude value. The number of higher-order amplitude values ​​may be two or more.

[0054] In the corrected echo information 431 shown in Fig. 9, an RMS line L2 showing the time-dependent change in the RMS of multiple higher amplitude values ​​is compared with a reference line Lref showing the time-dependent change in the amplitude value of a single frequency component. The RMS line L2 does not show the large drop in amplitude value seen in the reference line Lref. By using this RMS line L2, the distance to the obstacle O can be accurately calculated, similar to the maximum value line L1 (see Fig. 7) in the first embodiment.

[0055] As described above, by using the corrected echo information 431 that indicates the change over time in the RMS of multiple higher amplitude values ​​including the maximum amplitude value, it is possible to reduce the influence of multipath and the like, and improve the accuracy of obstacle detection, as in the first embodiment.

[0056] (Variation) 10 is a perspective view showing an example of the configuration of a vibrator 551 according to a modified example. The vibrator 551 of this modified example has nine (3×3) upper electrodes 521a-521i, nine upper wires 522a-522i, a piezoelectric body 523, a lower electrode 524, and a lower wire 525. The nine upper electrodes 521a-521i are provided in different regions on the surface of the upper side of the piezoelectric body 523 and are electrically insulated from each other. The nine upper wires 522a-522i are connected to the upper electrodes 521a-521i, respectively.

[0057] With the above configuration, by applying different voltages to the nine upper electrodes 521a-521i, ultrasonic waves of different frequencies can be output from each of the upper electrodes 521a-521i. That is, with the transducer 551 configured as above, by inputting an audio signal of a single frequency to each of the upper electrodes 521a-521i, it is possible to generate the transmission wave Wt containing the above-mentioned multiple frequency components. This makes it possible to omit a mechanism for generating a multiplexed signal in which multiple frequencies are multiplexed.

[0058] The program that causes a computer (e.g., processor 223, etc.) to execute processes for realizing the various functions in the above-described embodiments can be provided by being recorded in an installable or executable file format on a computer-readable recording medium such as a CD (Compact Disc)-ROM, a flexible disk (FD), a CD-R (Recordable), a DVD (Digital Versatile Disk), etc. The program may also be provided or distributed via a network such as the Internet.

[0059] Although the embodiments of the present disclosure have been described above, the above-described embodiments and their modifications are merely examples and are not intended to limit the scope of the invention. The novel embodiments and modifications described above can be implemented in various forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The above-described embodiments and modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as defined in the claims. [Explanation of symbols]

[0060] 1...vehicle, 2...vehicle body, 21, 21A to 21L...transmitter / receiver unit, 50...vehicle control system, 100...ECU, 110...input / output device, 120...storage device, 130...processor, 200...object detection device, 220...control unit, 221...input / output device, 222...storage device, 223...processor, 301...transmitter unit, 302...transmission control unit, 303...receiver unit, 304...signal processing unit, 305...frequency analysis unit, 306...arithmetic unit, 311...carrier wave generator generation unit, 312... multiplexing processing unit, 321... corrected echo information generation unit, 322... distance information generation unit, 411... separated echo information, 421, 431... corrected echo information, 511, 551... transducer, 521, 521a to 521i... upper electrodes, 522, 522a to 522i... upper wiring, 523... piezoelectric element, 524... lower electrode, 525... lower wiring, L1... maximum value line, L2... RMS line, O... obstacle, RS... road surface, Wt... transmitted wave, Wr... reflected wave

Claims

1. a transmitting unit that transmits a transmission wave in which a plurality of ultrasonic waves having different frequencies are multiplexed; a receiving unit that receives a reflected wave generated when the transmitted wave is reflected by an object; a frequency analysis unit that generates separated echo information indicating a change over time in amplitude value for each of a plurality of frequency components included in the reflected wave; a calculation unit that generates distance information regarding a distance to the object based on a maximum amplitude value among a plurality of amplitude values ​​detected for each of the frequency components at the same time, the maximum amplitude value being acquired from the separated echo information; and Equipped with The calculation unit generates the distance information based on corrected echo information indicating a change over time in the maximum amplitude value.

2. a transmitting unit that transmits a transmission wave in which a plurality of ultrasonic waves having different frequencies are multiplexed; a receiving unit that receives a reflected wave generated when the transmitted wave is reflected by an object; a frequency analysis unit that generates separated echo information indicating a change over time in amplitude value for each of a plurality of frequency components included in the reflected wave; a calculation unit that generates distance information regarding a distance to the object based on a maximum amplitude value among a plurality of amplitude values ​​detected for each of the frequency components at the same time, the maximum amplitude value being acquired from the separated echo information; and Equipped with The object detection device, wherein the calculation unit generates the distance information based on corrected echo information that indicates a change over time in the root mean square of a plurality of higher amplitude values ​​selected in descending order from a plurality of the amplitude values ​​detected for each of the frequency components at the same time.

3. The transmission of the transmission wave and the reception of the reflected wave are performed using a common oscillator. The object detection device according to claim 1 or 2.

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