Distance detection device and object detection device

Abstract

To acquire an accurate correlation value between a transmission wave and a reception wave by a simpler circuit configuration.SOLUTION: A distance detector as one example of the present disclosure comprises: a wave transmitter for transmitting a transmission wave that corresponds to a transmission signal; a wave receiver for receiving the transmission wave reflected by an object as a reception wave; a storage unit for storing the transmission signal; a correlation processing unit for acquiring a correlation value between the transmission signal read from the storage unit and a reception signal that corresponds to the reception wave; and a detection unit which, when the correlation value indicates that the transmission signal and the reception signal are similar at a prescribed or higher level, detects a distance to the object on the basis of a difference between a timing at which the transmission wave is transmitted and a timing at which the reception wave is received.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a distance detection device and an object detection device. [Background technology]

[0002] Conventionally, a technique is known in which a correlation value between a transmitted wave and a received wave that is the transmitted wave reflected by an object and returned is obtained (calculated), and based on the correlation value, a determination is made as to whether or not the similarity between the transmitted wave and the received wave is at a predetermined level or higher, and based on the determination result, a technique is known in which the distance to an object is detected as one piece of information about the object, using a TOF (Time Of Flight) method or the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-249770 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional techniques described above, it is generally necessary to provide a tuning circuit for tuning the transmitted wave and the received wave in order to obtain an accurate correlation value, which can result in a complex circuit configuration.

[0005] Therefore, one object of the present disclosure is to provide a distance detection device and an object detection device that are capable of acquiring an accurate correlation value between a transmitted wave and a received wave with a simpler circuit configuration. [Means for solving the problem]

[0006] A distance detection device according to an example of the present disclosure transmits a transmission wave in response to a transmission signal. Multiple Transmitter and ,before Store the transmitted signal Multiple A storage unit; a plurality of receiving units, the number of which is equal to the number of the plurality of wave transmitters, a receiver that receives the transmission wave reflected by the body as a received wave;、 The transmission signal is read from the storage unit, and a correlation value between the read transmission signal itself and a reception signal corresponding to the reception wave is obtained. Multiple a correlation processing unit, and when the correlation value indicates that the transmission signal and the reception signal are similar to each other at a predetermined level or more, detecting a distance to the object based on a difference between a timing at which the transmission wave is transmitted and a timing at which the reception wave is received. Multiple A detection unit, Multiple Correlation Processor and the plurality of detection units. teeth , respectively, of the plurality of transmitters The same number of units will be provided as the number of units.

[0007] According to the above-mentioned configuration, by storing the transmission signal in the storage unit, it is possible to obtain an accurate correlation value by directly using the transmission signal read from the storage unit and the reception signal input according to the reception wave without having to consider the synchronization between the transmission signal and the reception signal. Therefore, since there is no need to provide a tuning circuit for synchronizing the transmission signal and the reception signal, it is possible to simplify the circuit configuration.

[0008] The distance detection device further includes an amplifier circuit that amplifies the transmission signal and outputs it to the wave transmitter, and the memory unit stores the transmission signal amplified by the amplifier circuit. With this configuration, unlike a case where the transmission signal before being amplified is stored, the transmission signal before being transmitted as a transmission wave can be stored more accurately.

[0009] In this case, the distance detection device further includes a transmission signal output unit that outputs the transmission signal to the transmitter side, and the memory unit stores the amplified transmission signal for the output time of the transmission signal based on information regarding the timing of output of the transmission signal acquired from the transmission signal output unit. With this configuration, even in a case where amplified noise is added to the transmission signal, the transmission signal stored in the memory unit as the basis of the correlation value does not include a section corresponding to the amplified noise, and only a section corresponding to the output time is included, so that the correlation value can be acquired more accurately.

[0010] The distance detection device further includes a transmission signal output unit that outputs a transmission signal to the transmitter side, and the transmission signal output unit outputs, as a transmission signal, a coded signal generated by adding identification information of a predetermined code length to a carrier wave. With this configuration, the identification information can improve the identifiability of the transmission signal.

[0011] In this case, a plurality of combinations of transmission signal output units and wave transmitters with different identification information are provided, and the same number of storage units are provided as the number of combinations. With this configuration, in a configuration for transmitting a plurality of transmission waves with different identification information, a plurality of transmission signals that are the source of the plurality of transmission waves can be stored separately.

[0012] In the above-mentioned distance detection device, the transmitter and the receiver are integrally configured as a transmitting / receiving unit including a single transducer capable of transmitting and receiving ultrasonic waves. With this configuration, the configuration of the distance detection device can be simplified.

[0013] In the distance detection device described above, the storage unit is configured as a buffer that temporarily stores the transmission signal. With this configuration, it is possible to reduce the storage capacity compared to a case in which the transmission signal is non-temporarily stored.

[0014] An object detection device as another example of the present disclosure transmits a transmission wave in response to a transmission signal. Multiple Transmitter and ,before Store the transmitted signal Multiple A storage unit; a plurality of receiving units, the number of which is equal to the number of the plurality of wave transmitters, a receiver that receives the transmission wave reflected by the body as a received wave; 、 The transmission signal is read from the storage unit, and a correlation value between the read transmission signal itself and a reception signal corresponding to the reception wave is obtained. Multiple a correlation processing unit, and when the correlation value indicates that the transmission signal and the reception signal are similar to each other at a predetermined level or more, detecting a distance to the object based on a difference between a timing at which the transmission wave is transmitted and a timing at which the reception wave is received. MultipleA detection unit, Multiple Correlation Processor and the plurality of detection units. teeth , respectively, of the plurality of transmitters The same number of units will be provided as the number of units.

[0015] According to the above-mentioned configuration, by storing the transmission signal in the storage unit, it is possible to obtain an accurate correlation value by directly using the transmission signal read from the storage unit and the reception signal input according to the reception wave without having to consider the synchronization between the transmission signal and the reception signal. Therefore, since there is no need to provide a tuning circuit for synchronizing the transmission signal and the reception signal, it is possible to simplify the circuit configuration. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is an exemplary schematic diagram showing the external appearance of a vehicle equipped with an object detection system according to an embodiment, as viewed from above. [Diagram 2] FIG. 2 is an exemplary schematic block diagram showing a general hardware configuration of an ECU (electronic control unit) and a distance detection device according to the embodiment. [Diagram 3] FIG. 3 is an exemplary schematic diagram for explaining an overview of a technique used by the distance detection device according to the embodiment to detect the distance to an object. [Figure 4] FIG. 4 is an exemplary schematic block diagram showing a detailed configuration of a distance detection device according to an embodiment. [Diagram 5] FIG. 5 is an exemplary schematic flowchart showing the flow of operations of the distance detection device according to the embodiment. [Figure 6] FIG. 6 is an exemplary schematic block diagram showing a detailed configuration of a distance detection system according to a first modified example of the embodiment. [Figure 7] FIG. 7 is an exemplary schematic block diagram showing a detailed configuration of a distance detection device according to a second modified example of the embodiment. [Figure 8] FIG. 8 is an exemplary schematic block diagram showing a detailed configuration of a distance detection system according to a third modified example of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment will be described with reference to the drawings. The configuration of the embodiment described below, and the actions and results (effects) brought about by the configuration are merely examples, and are not limited to the following description.

[0018] <Embodiment> 1 is an exemplary schematic diagram showing the external appearance of a vehicle 1 equipped with an object detection system according to an embodiment, as seen from above. Although details will be described later, the object detection system according to the embodiment is a sensor system that transmits and receives ultrasonic waves and obtains a time difference between the transmission and reception, thereby detecting information about objects (for example, an obstacle O shown in FIG. 2, which will be described later) including humans that exist in the vicinity.

[0019] As shown in FIG. 1, the object detection system includes an ECU (electronic control unit) 100 (see also FIG. 2 described later) mounted inside a four-wheeled vehicle 1 including a pair of front wheels 3F and a pair of rear wheels 3R, and distance detection devices 201-204 mounted on the exterior of the vehicle 1.

[0020] In the example shown in FIG. 1, distance detection devices 201 to 204 are installed at different positions on the rear end of a vehicle body 2 serving as the exterior of a vehicle 1, for example, on a rear bumper.

[0021] In the embodiment, the distance detection devices 201 to 204 have the same hardware configuration and functions. Therefore, in the following, for simplicity, the distance detection devices 201 to 204 may be collectively referred to as the distance detection device 200.

[0022] In the embodiment, the installation position of the distance detection device 200 is not limited to the example shown in Fig. 1. The distance detection device 200 may be installed on the front end of the vehicle body 2, for example, on the front bumper, or on a side of the vehicle body 2, or on two or more of the rear bumper, the front bumper, and the side. In the embodiment, the number of distance detection devices 200 is also not limited to the example shown in Fig. 1.

[0023] FIG. 2 is an exemplary schematic block diagram showing a hardware configuration of the ECU 100 and the distance detection device 200 according to the embodiment.

[0024] 2, the ECU 100 has a hardware configuration similar to that of a typical computer. More specifically, the ECU 100 has an input / output device 110, a storage device 120, and a processor .

[0025] The input / output device 110 is an interface for implementing transmission and reception of information between the ECU 100 and the outside (the distance detection device 200 in the example shown in FIG. 1).

[0026] The storage device 120 includes a primary storage device such as a Read Only Memory (ROM) or a Random Access Memory (RAM), and / or an auxiliary storage device such as a Hard Disk Drive (HDD) or a Solid State Drive (SSD).

[0027] The processor 130 controls various processes executed in the ECU 100. The processor 130 includes an arithmetic device such as a CPU (Central Processing Unit). The processor 130 reads and executes computer programs stored in the storage device 120 to realize various functions such as automatic parking.

[0028] On the other hand, as shown in FIG. 2, the distance detection device 200 includes a transmitting / receiving unit 210 and a control unit 220.

[0029] The transmitting / receiving unit 210 has a transducer 211 such as a piezoelectric element, and the transducer 211 realizes transmission and reception of ultrasonic waves.

[0030] More specifically, the transmitting / receiving unit 210 transmits ultrasonic waves generated in response to the vibration of the transducer 211 as a transmission wave, and receives, as a reception wave, the vibration of the transducer 211 caused by the ultrasonic waves transmitted as the transmission wave being reflected by an object present outside and returning. In the example shown in Fig. 2, an obstacle O placed on the road surface RS is illustrated as an object that reflects ultrasonic waves from the transmitting / receiving unit 210.

[0031] 2 illustrates a configuration in which both transmission of transmission waves and reception of reception waves are achieved by a single transmitting / receiving unit 210 having a single transducer 211. However, the technology of the embodiment can also be naturally applied to a configuration in which the transmission side configuration and the reception side configuration are separated, such as a configuration in which a first transducer for transmitting transmission waves and a second transducer for receiving reception waves are separately provided.

[0032] The control unit 220 has a hardware configuration similar to that of a typical computer. More specifically, the control unit 220 has an input / output device 221, a storage device 222, and a processor 223.

[0033] The input / output device 221 is an interface for implementing transmission and reception of information between the control unit 220 and the outside (the ECU 100 and the transmission / reception unit 210 in the example shown in FIG. 1).

[0034] The storage device 222 includes a main storage device such as a ROM or a RAM, and / or a secondary storage device such as a HDD or an SSD.

[0035] The processor 223 controls various processes executed in the control unit 220. The processor 223 includes an arithmetic unit such as a CPU. The processor 223 reads out and executes computer programs stored in the storage device 333 to realize various functions.

[0036] Here, the distance detection device 200 according to the embodiment detects the distance to the object by a technique called the TOF (Time Of Flight) method. As described in detail below, the TOF method is a technique for calculating the distance to the object by considering the difference between the timing when the transmission wave is transmitted (more specifically, the transmission starts) and the timing when the reception wave is received (more specifically, the reception starts).

[0037] Fig. 3 is an exemplary and schematic diagram for explaining an overview of a technique used by the distance detection device 200 according to the embodiment to detect the distance to an object. More specifically, Fig. 3 is an exemplary and schematic diagram showing, in a graph form, a change over time in the signal level (e.g., amplitude) of an ultrasonic wave transmitted and received by the distance detection device 200 according to the embodiment. In the graph shown in Fig. 3, the horizontal axis corresponds to time, and the vertical axis corresponds to the signal level of a signal transmitted and received by the distance detection device 200 via the transmission / reception unit 210 (transducer 211).

[0038] In the graph shown in Fig. 3, solid line L11 represents an example of an envelope curve representing the signal level of a signal transmitted and received by distance detection device 200, that is, the change over time in the degree of vibration of oscillator 211. From this solid line L11, it can be seen that oscillator 211 is driven to vibrate for time Ta from timing t0, completing the transmission of the transmission wave at timing t1, and then the vibration of oscillator 211 due to inertia continues while attenuating for time Tb until timing t2. Therefore, in the graph shown in Fig. 3, time T2 corresponds to the so-called reverberation time.

[0039] The solid line L11 indicates that the degree of vibration of the transducer 211 reaches a peak exceeding (or exceeding) a predetermined threshold value Th1 represented by the dashed-dotted line L21 at a timing t4, which is a time Tp after the timing t0 when the transmission of the transmission wave starts. This threshold value Th1 is a value that is set in advance to distinguish whether the vibration of the transducer 211 is caused by the reception of a received wave as a transmission wave reflected and returned by an object to be detected (for example, an obstacle O shown in FIG. 2), or whether the vibration is caused by the reception of a received wave as a transmission wave reflected and returned by an object other than the object to be detected (for example, a road surface RS shown in FIG. 2).

[0040] Although FIG. 3 shows an example in which the threshold value Th1 is set as a constant value that does not change over time, in an embodiment, the threshold value Th1 may be set as a value that changes over time.

[0041] Here, vibrations having a peak that exceeds (or is equal to or greater than) threshold Th1 can be considered to be caused by reception of a transmitted wave reflected and returned by an object to be detected, whereas vibrations having a peak that is equal to or less than threshold Th1 can be considered to be caused by reception of a transmitted wave reflected and returned by an object that is not to be detected.

[0042] Therefore, it can be seen from the solid line L11 that the vibration of the transducer 211 at the timing t4 is caused by the reception of a received wave that is a transmitted wave that has been reflected by the object to be detected and returned.

[0043] In the solid line L11, the vibration of the transducer 211 attenuates after timing t4. Therefore, timing t4 corresponds to the timing at which reception of the received wave as the transmitted wave reflected by the object to be detected is completed, in other words, the timing at which the transmitted wave finally transmitted at timing t1 returns as the received wave.

[0044] In addition, in the solid line L11, the timing t3 as the start point of the peak at the timing t4 corresponds to the timing at which reception of the received wave as the transmitted wave reflected by the object to be detected starts, in other words, the timing at which the transmitted wave initially transmitted at the timing t0 returns as the received wave. Therefore, in the solid line L11, the time ΔT between the timing t3 and the timing t4 is equal to the time Ta as the transmission time of the transmitted wave.

[0045] Based on the above, in order to calculate the distance to a detection target object using the TOF method, it is necessary to calculate the time Tf between the timing t0 when the transmission wave starts to be transmitted and the timing t3 when the reception wave starts to be received. This time Tf can be calculated by subtracting the time ΔT, which is equal to the transmission time Ta of the transmission wave, from the time Tp, which is the difference between the timing t0 and the timing t4 when the signal level of the reception wave reaches a peak and exceeds the threshold value Th1.

[0046] Here, the timing t0 when the transmission wave starts to be transmitted can be easily identified as the timing when the distance detection device 200 starts to operate, and the time Ta as the transmission time of the transmission wave is predetermined by settings, etc. Therefore, in order to obtain the distance to the object to be detected by the TOF method, it is ultimately important to identify the timing t4 when the signal level of the received wave reaches a peak and exceeds the threshold value Th1.

[0047] In view of this, a conventional technique is known in which a correlation value corresponding to the similarity between a transmitted wave and a received wave is acquired (calculated), and based on a result of comparing the correlation value with a predetermined threshold, it is determined whether the similarity is at a predetermined level or higher, and the timing at which it is determined that the similarity is at a predetermined level or higher is specified as the timing t4 at which the received wave reaches a peak exceeding the threshold Th1. The correlation value is a value calculated based on a generally well-known autocorrelation function or the like, and reaches a peak when the waveforms of the transmitted wave and the received wave are similar (match) at a predetermined level or higher.

[0048] In the conventional techniques described above, it is generally necessary to provide a tuning circuit for tuning the transmitted wave and the received wave in the distance detection device 200 in order to obtain an accurate correlation value, which can result in a complex circuit configuration.

[0049] Therefore, in the embodiment, by configuring the distance detection device 200 as follows, it is possible to obtain an accurate correlation value between a transmitted wave and a received wave with a simpler circuit configuration.

[0050] Fig. 4 is an exemplary schematic block diagram showing a detailed configuration of a distance detection device 200 according to an embodiment. In the example shown in Fig. 4, the configuration on the transmission side and the configuration on the reception side are separated, but such an illustrated form is merely for convenience of explanation. In the embodiment, as described above, both the transmission of the transmission wave and the reception of the reception wave are realized by a (single) transmission / reception unit 210 having a (single) transducer 211. However, to repeat the above, the technology of the embodiment is naturally applicable to a configuration in which the configuration on the transmission side and the configuration on the reception side are separated.

[0051] 4, the distance detection device 200 has, as a transmitting side configuration, a wave transmitter 311, a code generation unit 312, a carrier wave output unit 313, a multiplier 314, an amplifier circuit 315, and a buffer 316. The distance detection device 200 has, as a receiving side configuration, a wave receiver 321, an amplifier circuit 322, a filter processing unit 323, a correlation processing unit 324, an envelope processing unit 325, a threshold processing unit 326, and a detection unit 327.

[0052] In the example shown in Fig. 4, the buffer 316 may be provided on the receiving side instead of the transmitting side. Also, a part of the configuration shown in Fig. 4 may be realized by dedicated hardware (analog circuit), and the remaining part may be realized as a result of cooperation between hardware and software, more specifically, as a result of the processor 223 of the control unit 220 reading and executing a computer program from the storage device 222.

[0053] First, the configuration on the transmitting side will be briefly described.

[0054] The wave transmitter 311 is configured with the above-mentioned transducer 211, and the transducer 211 transmits a transmission wave corresponding to the (amplified) transmission signal output from the amplifier circuit 315. As described below, in the embodiment, a coded signal generated by adding identification information of a predetermined code length to a carrier wave is output as a transmission signal that is the basis of the transmission wave.

[0055] The code generator 312 generates a signal (pulse signal) corresponding to a code of a bit string consisting of a succession of bits of, for example, 0 or 1. The length of this bit string corresponds to the code length of the identification information added to the transmission signal.

[0056] The carrier wave output unit 313 outputs a carrier wave as a signal to which identification information is to be added. The carrier wave is configured as, for example, a sine wave of an arbitrary frequency.

[0057] The multiplier 314 multiplies the output from the code generation unit 312 by the output from the carrier wave output unit 313, thereby modulating the carrier wave to add identification information. Then, the multiplier 314 outputs the modulated carrier wave to which the identification information has been added, to the amplifier circuit 315, as a transmission signal that is the basis of the transmission wave. Note that the modulation method may be a single modulation method or a combination of two or more generally well-known modulation methods such as an amplitude modulation method, a phase modulation method, a frequency modulation method, or the like.

[0058] Thus, in the embodiment, the combination of the code generating unit 312, the carrier wave output unit 313, and the multiplier 314 functions as a transmission signal output unit that outputs, to the wave transmitter 311, a coded signal that is generated by adding identification information of a predetermined code length to a carrier wave as a transmission signal that is the basis of a transmission wave. Since the identification information is not basically lost due to reflection, it is possible to more easily or more reliably determine the similarity between a transmission signal and a received signal that corresponds to a reception wave that is received when a transmission wave corresponding to the transmission signal is reflected back, based on the identification information.

[0059] The amplifier circuit 315 amplifies the transmission signal output from the multiplier 314 , and outputs the amplified transmission signal to the wave transmitter 311 .

[0060] The buffer 316 temporarily stores (at least a part of) the transmission signal amplified by the amplifier circuit 315. The role of the buffer 316 will be described in detail later, and therefore further description will be omitted here; however, in the embodiment, as long as it is a storage unit capable of storing the transmission signal, a configuration for non-temporarily storing the transmission signal may be provided instead of the buffer 316 that temporarily stores the transmission signal.

[0061] Next, the configuration of the receiving side will be briefly described.

[0062] The wave receiver 321 is composed of the above-mentioned transducer 211, and receives the transmitted wave reflected by an object as a received wave by the transducer 211. As described above, the transmitted wave contains identification information, and therefore the received wave also contains similar identification information.

[0063] The amplifier circuit 322 amplifies a received signal that corresponds to the wave received by the wave receiver 321 .

[0064] The filter processing unit 323 suppresses noise by performing filtering processing on the received signal amplified by the amplifier circuit 322. In the embodiment, the filter processing unit 323 may obtain information on the frequency of the transmission signal stored in the buffer 316, and further perform frequency correction on the received signal so as to match the frequency of the transmission signal.

[0065] The correlation processing unit 324 obtains the above-mentioned correlation value corresponding to the similarity between the transmitted wave and the received wave. More specifically, the correlation processing unit 324 obtains the correlation value between the transmitted signal read from the buffer 316 and the received signal output via the filter processing unit 323. As described above, the correlation value is calculated based on a generally well-known correlation function or the like.

[0066] Here, consider a configuration in which the buffer 316 is removed from the configuration shown in Fig. 4. In order to obtain an accurate correlation value in this configuration, as in the conventional technology described above, it is necessary to separately provide a tuning circuit for tuning the transmission signal and the reception signal, such as a multiplier that tunes the transmission signal and the reception signal by multiplying each of the transmission signal and the reception signal by a carrier wave of the same frequency, in the stage preceding the correlation processing unit 324.

[0067] In contrast to this, in the embodiment, by storing the transmission signal in the buffer 316, it is possible to obtain an accurate correlation value by directly using the transmission signal read from the buffer 316 and the reception signal input according to the received wave, without having to consider the synchronization between the transmission signal and the reception signal. Therefore, in the embodiment, it is not necessary to provide a tuning circuit or the like for synchronizing the transmission signal and the reception signal, and therefore the circuit configuration can be simplified.

[0068] The envelope processor 325 obtains the envelope of the signal waveform corresponding to the correlation value acquired by the correlation processor 324 .

[0069] The threshold processing unit 326 compares the value of the envelope calculated by the envelope processing unit 325 with a predetermined threshold value.

[0070] Based on the comparison result by threshold processing unit 326, detection unit 327 identifies the timing (timing t4 shown in FIG. 3) at which the signal level of the received wave reaches a peak and exceeds the threshold, and detects the distance to the object using the TOF method.

[0071] As described above, in the embodiment, the buffer 316 stores the transmission signal after amplification by the amplifier circuit 315. However, the amplified transmission signal may contain amplification noise. For example, in the example shown in FIG. 4, the amplified transmission signal includes a section X1 corresponding to the amplification noise after a section X0 corresponding to the output time of the transmission signal, as shown in the signal waveform SW1 in the balloon B1. This section X1 becomes noise in acquiring (calculating) the correlation value, so it is preferable to exclude it from the transmission signal that may be input to the correlation processing unit 324 as a basis for the correlation value.

[0072] Therefore, in an embodiment, buffer 316 stores the amplified transmission signal for the output time of the transmission signal based on information about the timing at which the transmission signal is output, which is acquired from, for example, code generation unit 312 as a transmission signal output unit. For example, in the example shown in Fig. 4, buffer 316 stores a transmission signal such as signal waveform SW2 in speech bubble B2 by extracting only section X0 corresponding to the output time of the transmission signal from signal waveform SW1 in speech bubble B1, based on information acquired from code generation unit 312.

[0073] Thus, in the embodiment, even in a case where amplified noise is added to the transmission signal, the transmission signal that can be input to the correlation processing unit 324 as the basis for the correlation value is only the section X0 corresponding to the output time, and does not include the section X1 corresponding to the amplified noise.

[0074] In the embodiment, each of the above-mentioned components in the distance detection device 200 may operate under the control of the control unit 220 of the distance detection device 200 itself, or may operate under the control of the external ECU 100.

[0075] The distance detection device 200 according to the embodiment operates according to the flow shown in FIG.

[0076] FIG. 5 is an exemplary schematic flowchart showing the flow of operations of the distance detection device 200 according to the embodiment.

[0077] 5, in the embodiment, first, in S501, the transmission signal output unit (code generating unit 312, carrier wave output unit 313, and multiplier 314) outputs an encoded signal generated by adding identification information of a predetermined code length to a carrier wave as a transmission signal that is the basis of a transmission wave. This transmission signal is amplified by amplifier circuit 315 and then output to wave transmitter 311.

[0078] Then, in S502, the buffer 616 temporarily stores the amplified transmission signal that is generated by being amplified by the amplifier circuit 315 after being output in S501. At this time, as described above, the buffer 616 temporarily stores the amplified transmission signal for the output time of the transmission signal based on information acquired from, for example, the code generation unit 312 of the transmission signal output unit.

[0079] Then, in S503, the wave transmitter 311 transmits, to the outside of the vehicle 1, a transmission wave corresponding to the transmission signal output in S501.

[0080] Then, in S504, the wave receiver 321 receives the received wave as the transmitted wave that has been reflected by an object outside the vehicle 1 and returned to the vehicle 1 side.

[0081] Then, in S505, the correlation processing unit 324 acquires (calculates) a correlation value between the transmission signal read out from the buffer 316 (the transmission signal stored in the buffer 316 in S502) and the received signal corresponding to the received wave received in S504 (the received signal that has been amplified by the amplifier circuit 322 and has had noise suppressed by the filter processing unit 323).

[0082] Then, in S506, the detection unit 327 detects the distance to the object that reflected the transmission wave based on the correlation value acquired in S505. More specifically, the detection unit 327 first acquires from the threshold processing unit 326 the result of comparing the correlation value processed by the envelope processing unit 325 with the threshold. Then, based on the information acquired from the threshold processing unit 326, the detection unit 327 identifies the timing at which the transmission wave was transmitted and the timing at which a reception wave similar (matching) to the transmission wave at a level equal to or higher than a predetermined level was received. Then, based on the difference between the two timings, the detection unit 327 acquires (calculates) the distance to the object that reflected the transmission signal by the TOF method. Then, the processing ends.

[0083] As described above, the distance detection device 200 according to the embodiment includes at least the code generation unit 312, the carrier wave output unit 313, the multiplier 314, the transmitter 311, the receiver 321, the buffer 316, the correlation processing unit 324, and the detection unit 327. The code generation unit 312, the carrier wave output unit 313, and the multiplier 314 function as a transmission signal output unit that outputs a transmission signal to the transmitter 311 side. The transmitter 311 transmits a transmission wave corresponding to the transmission signal. The receiver 321 receives the transmission wave reflected by an object as a received wave. The buffer 316 functions as a storage unit that stores the transmission signal. The correlation processing unit 324 obtains a correlation value between the transmission signal read from the buffer 316 and the received signal corresponding to the received wave. When the correlation value indicates that the transmitted signal and the received signal are similar at a predetermined level or above, the detection unit 327 detects the distance to the object based on the difference between the timing when the transmitted wave is transmitted and the timing when the received wave is received.

[0084] According to the above-mentioned configuration, by storing the transmission signal in the buffer 316, it is possible to obtain an accurate correlation value by directly using the transmission signal read from the buffer 316 and the reception signal input according to the received wave, without having to consider the synchronization between the transmission signal and the reception signal. Therefore, since there is no need to provide a tuning circuit for synchronizing the transmission signal and the reception signal, the circuit configuration can be simplified.

[0085] In the embodiment, the distance detection device 200 further includes an amplifier circuit 315 that amplifies the transmission signal and outputs it to the transmitter, and the buffer 316 stores the transmission signal amplified by the amplifier circuit 315. According to such a configuration, unlike a case where the transmission signal before being amplified is stored, the transmission signal before being transmitted as a transmission wave can be more accurately stored.

[0086] Furthermore, in the embodiment, the buffer 316 stores the amplified transmission signal for the output time of the transmission signal based on information on the timing at which the transmission signal is output, which is acquired from, for example, the code generating unit 312 of the transmission signal output unit. With this configuration, even in a case where an amplified noise is added to the transmission signal, the transmission signal stored in the buffer 316 as the basis for the correlation value is only the section X0 (see FIG. 4) corresponding to the output time, not including the section X1 (see FIG. 4) corresponding to the amplified noise, so that the correlation value can be acquired more accurately.

[0087] In the embodiment, the transmission signal output unit, which is a combination of the code generation unit 312, the carrier wave output unit 313, and the multiplier 314, outputs, as a transmission signal, a coded signal generated by adding identification information of a predetermined code length to a carrier wave. With this configuration, it is possible to improve the identifiability of the transmission signal by the identification information.

[0088] In the embodiment, the wave transmitter 311 and the wave receiver 321 are integrally configured as a transmitting / receiving unit 210 including a single transducer 211 capable of transmitting and receiving ultrasonic waves. With this configuration, the configuration of the distance detection device 200 can be simplified.

[0089] In the embodiment, the transmission signal is stored by the buffer 316 that temporarily stores the transmission signal. According to such a configuration, it is possible to reduce the storage capacity, for example, compared to a case where the transmission signal is non-temporarily stored.

[0090] <Modification> In the above-described embodiment, a distance detection device that detects the distance to an object is exemplified as an object to which the technology of the present disclosure is applied, but the technology of the present disclosure can be widely applied to object detection devices other than distance detection devices as long as the object detection device detects information about an object based on a correlation value between a transmission signal and a reception signal. For example, the technology of the present disclosure can be applied to an object detection device that detects only the presence or absence of an object as information about the object.

[0091] In other words, the technology disclosed herein can also be applied to an object detection device that includes a transmitter that transmits a transmission wave in response to a transmission signal, a receiver that receives the transmission wave reflected by an object as a received wave, a memory unit that stores the transmission signal, a correlation processing unit that obtains a correlation value between the transmission signal read from the memory unit and a received signal in response to the received wave, and a detection unit that detects information about an object based on the correlation value.

[0092] Furthermore, in the above-described embodiment, the transmission signal is configured as a coded signal, but the technology of the present disclosure is also applicable to cases where the transmission signal is configured as an uncoded signal.

[0093] In addition, in the above-described embodiment, the technology of the present disclosure is applied to a configuration for transmitting and receiving ultrasonic waves, but the technology of the present disclosure can also be applied to a configuration for transmitting and receiving waves other than ultrasonic waves, such as sound waves, millimeter waves, and electromagnetic waves.

[0094] In addition, in the above-described embodiment, a distance detection device (see FIG. 4) having one transmitting side configuration and one receiving side configuration is exemplified, but the technology of the present disclosure also contemplates a distance detection system 600 having multiple transmitting side configurations and multiple receiving side configurations, as shown in the following FIG. 6.

[0095] Fig. 6 is an exemplary schematic block diagram showing a detailed configuration of a distance detection system 600 according to a first modified example of the embodiment. As shown in Fig. 6, the distance detection system 600 according to the first modified example has three transmitting units 610, 630, and 650 as a transmitting side configuration, and has three receiving units 620, 640, and 660 as a receiving side configuration. The distance detection system 600 is an example of a "distance detection device".

[0096] In the first modified example, the transmission section 610 has a wave transmitter 611, a transmission signal output section (a combination of a code generation section 612, a carrier wave output section 613, and a multiplier 614), an amplifier circuit 615, and a buffer 616. The functions and operations of these components are substantially similar to the functions and operations of the components on the transmission side of the distance detection device 200 according to the above-described embodiment (see FIG. 4, etc.), so further explanation will be omitted here.

[0097] Due to space constraints, components other than the transmitters 631 and 651 and the buffers 636 and 656 are omitted from the illustration, but in addition to these, the transmitting units 630 and 650 each have the same configuration as the transmitting unit 610, such as a transmission signal output unit.

[0098] Here, in the first modification, the transmitting units 610, 630, and 650 are configured to transmit transmission waves corresponding to transmission signals as coded signals to which different identification information is added, thereby avoiding confusion of the transmission waves. The transmitting units 610, 630, and 650 each have buffers 616, 636, and 656 as storage units for temporarily storing the transmission signals.

[0099] That is, in the first modified example, a plurality of (three) combinations of transmission signal output units and wave transmitters having different identification information are provided, and the same number of storage units for temporarily storing transmission signals are provided as the number of combinations. With this configuration, in a configuration for transmitting a plurality of transmission waves having different identification information, the plurality of transmission signals that are the source of the plurality of transmission waves can be stored separately.

[0100] Meanwhile, in the first modified example, the receiving section 620 has a receiver 621, an amplifier circuit 622, and a filter processing section 623. The functions and operations of these components are substantially similar to the functions and operations of the receiver 321, the amplifier circuit 322, and the filter processing section 323 according to the above-described embodiment (see FIG. 4, etc.), and therefore further explanation will be omitted here.

[0101] Here, the receiving unit 620 in the first variant has the same number (i.e., three) of configurations (hereinafter referred to as signal processing systems) as the transmitting units 610, 630, and 650, which are similar to the configuration consisting of a combination of the correlation processing unit 324, envelope processing unit 325, threshold processing unit 326, and detection unit 327 in the above-mentioned embodiment (see Figure 4, etc.).

[0102] That is, the receiving unit 620 in the first modified example has a signal processing system A which is a combination of a correlation processing unit 624A, an envelope processing unit 625A, a threshold processing unit 626A, and a detection unit 627A, a signal processing system B which is a combination of a correlation processing unit 624B, an envelope processing unit 625B, a threshold processing unit 626B, and a detection unit 627B, and a signal processing system C which is a combination of a correlation processing unit 624C, an envelope processing unit 625C, a threshold processing unit 626C, and a detection unit 627C.

[0103] The signal processing system A (correlation processing unit 624A) realizes various functions and operations based on the transmission signal read from the buffer 616 of the transmitter 610. Similarly, the signal processing system B (correlation processing unit 624B) realizes various functions and operations based on the transmission signal read from the buffer 636 of the transmitter 630, and the signal processing system C (correlation processing unit 624C) realizes various functions and operations based on the transmission signal read from the buffer 656 of the transmitter 650.

[0104] In addition, the specific functions and operations of the signal processing systems A to C are substantially the same as those of the signal processing systems according to the above-mentioned embodiment (see FIG. 4, etc.), and therefore will not be described further here. In addition, although the illustration of the configuration other than the receivers 641 and 661 is omitted due to space limitations, the receiving units 640 and 660 each have the same configuration as the receiving unit 620.

[0105] In this way, in the first modification, the receiver 620 can simultaneously obtain three correlation values ​​between the transmission signals that are the source of the transmission waves transmitted from the three transmitters 610, 630, and 650, and the reception signals that correspond to the reception waves that are reflected waves of the transmission waves. Similarly, the receivers 640 and 660 can each simultaneously obtain three correlation values. Therefore, according to the first modification, the distance to the object can be detected in more detail by considering three different types of information simultaneously.

[0106] 6, the combination of the wave transmitter 611 and the wave receiver 621 may be configured with the same transducer or may be configured with separate transducers, as in the above-mentioned embodiment. The same can be said for the combination of the wave transmitter 631 and the wave receiver 641, and the combination of the wave transmitter 651 and the wave receiver 661.

[0107] In the first modification shown in Fig. 6, three transmitting and receiving components are provided, and each receiving component also has three signal processing systems, but the number "3" itself has no special technical meaning. Therefore, the number of each of these components may be two, or four or more.

[0108] Furthermore, the number of components on the transmitting side and the number of components on the receiving side do not necessarily have to match, and the number of components on the transmitting side and the number of signal processing systems provided in each of the components on the receiving side do not necessarily have to match.

[0109] Furthermore, in the above-described embodiment, a configuration is exemplified in which a combination of a code generating unit, a carrier wave output unit, and a multiplier functions as a transmission signal output unit that outputs a transmission signal that is the source of a transmission wave to a transmitter side. However, the technology of the present disclosure is also applicable to a configuration in which the transmission signal output unit does not have a carrier wave output unit and a multiplier, as shown in the following FIG. 7.

[0110] Fig. 7 is an exemplary schematic block diagram showing a detailed configuration of a distance detection device 700 according to a second modified example of the embodiment. As shown in Fig. 7, the distance detection device 700 according to the second modified example corresponds to a configuration obtained by removing the carrier wave output unit 313 and the multiplier 314 from the distance detection device 200 according to the above-mentioned embodiment (see Fig. 4).

[0111] 7, distance detection device 700 according to the second modification has, as a transmission side configuration, wave transmitter 311, code generation unit 312, amplifier circuit 315, and buffer 316. With this configuration, in the second modification, the pulse signal output from code generation unit 312 is input directly to amplifier circuit 315 as a transmission signal. Then, the transmission signal amplified by amplifier circuit 315 is stored in buffer 316 and input to wave transmitter 311, and a transmission wave corresponding to the amplified transmission signal is transmitted from wave transmitter 311.

[0112] Since the other configuration of the distance detection device 700 according to the second modified example is similar to that of the embodiment described above (see FIG. 4), further explanation of the configuration of the distance detection device 700 will be omitted here.

[0113] A variant based on the same concept as the above-mentioned second variant can also be provided for the above-mentioned first variant (see FIG. 6) in which multiple transmitting side configurations and multiple receiving side configurations are provided, in the form shown in the following FIG. 8.

[0114] Fig. 8 is an exemplary schematic block diagram showing a detailed configuration of a distance detection system 800 according to a third modified example of the embodiment. As shown in Fig. 8, the distance detection system 800 according to the third modified example corresponds to a configuration obtained by removing the carrier wave output unit 613 and the multiplier 614 from the distance detection system 600 according to the above-mentioned first modified example (see Fig. 6). Note that the distance detection system 800 is an example of a "distance detection device".

[0115] 8, one transmission unit 810 in a distance detection system 800 according to the third modified example includes a wave transmitter 611, a code generator 612, an amplifier circuit 615, and a buffer 616. With this configuration, in the third modified example as well, as in the above-described second modified example, a pulse signal output from the code generator 612 is input directly to the amplifier circuit 615 as a transmission signal. Then, the transmission signal amplified by the amplifier circuit 615 is stored in the buffer 616 and input to the wave transmitter 611, and a transmission wave corresponding to the amplified transmission signal is transmitted from the wave transmitter 611.

[0116] Thus, in the transmitting section 810 according to the third modified example, the transmission signal output section is made up of only the code generating section 612. The same is true for the other transmitting sections 830 and 850.

[0117] Since the other configurations of the distance detection system 800 according to the third modified example are similar to those of the above-described first modified example (see FIG. 6), further explanation of the configuration of the distance detection system 800 will be omitted here.

[0118] In this way, in the technology disclosed herein, the transmission signal output section may be configured only by the code generation section, rather than by a combination of a code generation section, a carrier wave output section, and a multiplier.

[0119] Although the embodiment and the modified examples of the present disclosure have been described above, the above-mentioned embodiment and the modified examples are merely examples and are not intended to limit the scope of the invention. The above-mentioned novel embodiment and modified examples can be implemented in various forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. The above-mentioned embodiment and modified examples are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0120] 200, 201, 202, 203, 204, 700 Distance detection device 210 Transmitter / receiver 211 Transducer 311, 611, 631, 651 transmitter 312, 612 Code generation unit (transmission signal output unit) 313, 613 Carrier wave output section (transmission signal output section) 314, 614 multiplier (transmit signal output section) 315, 615 amplifier circuit 316, 616, 636, 656 Buffer (storage section) 321, 621, 641, 661 receiver 324, 624A, 624B, 624C Correlation Processing Unit 327, 627A, 627B, 627C Detector 600, 800 Distance detection system (distance detection device)

Claims

1. a plurality of wave transmitters that transmit transmission waves in response to transmission signals; A plurality of storage units for storing the transmission signals; a plurality of receiving units, the number of which is equal to the number of the plurality of wave transmitters; Each of the plurality of receiving units is a receiver that receives the transmission wave reflected by an object as a received wave; a plurality of correlation processing units that read out the transmission signal from the storage unit and obtain a correlation value between the read out transmission signal itself and a reception signal corresponding to the reception wave; a plurality of detection units that detect a distance to the object based on a difference between a timing at which the transmission wave is transmitted and a timing at which the reception wave is received when the correlation value indicates that the transmission signal and the reception signal are similar to each other at a predetermined level or more; The plurality of correlation processing units and the plurality of detection units are provided in the same number as the number of the plurality of wave transmitters, Distance detection device.

2. an amplifier circuit for amplifying the transmission signal and outputting the signal to the transmitter; The storage unit stores the transmission signal amplified by the amplifier circuit.

2. The distance detection device according to claim 1.

3. a transmission signal output unit that outputs the transmission signal to the transmitter side, the storage unit stores the amplified transmission signal for an output time of the transmission signal based on information regarding a timing at which the transmission signal is output, the information being acquired from the transmission signal output unit.

3. The distance detection device according to claim 2.

4. a transmission signal output unit that outputs the transmission signal to the transmitter side, the transmission signal output unit outputs, as the transmission signal, a coded signal generated by adding identification information of a predetermined code length to a carrier wave; The distance detection device according to any one of claims 1 to 3.

5. a plurality of combinations of the transmission signal output unit and the wave transmitter, each of which has different identification information; The number of the storage units is the same as the number of the combinations.

5. A distance detection device according to claim 4.

6. The transmitter and the receiver are integrally configured as a transceiver unit including a single transducer capable of transmitting and receiving ultrasonic waves. The distance detection device according to any one of claims 1 to 5.

7. The storage unit is configured as a buffer that temporarily stores the transmission signal. The distance detection device according to any one of claims 1 to 6.

8. a plurality of wave transmitters that transmit transmission waves in response to transmission signals; A plurality of storage units for storing the transmission signals; a plurality of receiving units, the number of which is equal to the number of the plurality of wave transmitters; Each of the plurality of receiving units is a receiver that receives the transmission wave reflected by an object as a received wave; a plurality of correlation processing units that read out the transmission signal from the storage unit and obtain a correlation value between the read out transmission signal itself and a reception signal corresponding to the reception wave; a plurality of detection units that detect a distance to the object based on a difference between a timing at which the transmission wave is transmitted and a timing at which the reception wave is received when the correlation value indicates that the transmission signal and the reception signal are similar to each other at a predetermined level or more; The plurality of correlation processing units and the plurality of detection units are provided in the same number as the number of the plurality of wave transmitters, Object detection device.

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