CN112166344B - Detection device - Google Patents

Abstract

The invention provides a detection device. In the detection device (1), a transmitting antenna (TXANT 1) spatially transmits a modulated signal. The receiving antennas (RXANT 1 to RXANTN) receive reflected waves of the modulated signals transmitted from the transmitting antenna (TXANT 1). The calculation unit is provided with distance peak detection units (31-3N) and an azimuth detection unit (34), obtains the distance and azimuth of the object from the received signals of the reflected waves received by the receiving antennas (RXANT 1-RXANT) at regular intervals, and calculates the time variation of the distance from the obtained distance and azimuth of the object. A corner detection unit (35) detects the corners of the object on the basis of the time-varying amounts calculated by the calculation unit. The corner detection unit compares the time variation calculated by the calculation unit with a preset threshold value, detects a corner of the object when the time variation exceeds the threshold value, and outputs a corner detection signal.

Description

Detection device

technical field

The present invention relates to a detection device, and particularly relates to a technique effective for detection of a corner portion of an object by a radar system.

Background technique

Driving assistance systems are attracting attention as technologies for reducing the load on drivers who drive motor vehicles and reducing accident rates. As one of such driving assistance systems, there is an automatic parking assist system.

The automatic parking assist system detects a parking space and automatically parks a motor vehicle by guiding the vehicle within a dividing line while maintaining an appropriate distance from an adjacent vehicle at a target parking position.

In recent years, with the improvement of the performance of millimeter-wave radar, the application of millimeter-wave radar is not only for long-distance detection originally used, but also for medium-range or short-distance, and millimeter-wave radar is used to realize automatic parking applications And the detection device that detects the corners of the target vehicle during automatic parking.

As a detection technique of a detection device using such a radar device, for example, when an object in front of the own vehicle is detected by a millimeter wave radar, it is known processing, calculate the right end recognition point, left end recognition point, and representative recognition point of a plurality of reflection points, and perform grouping processing using the estimated width of the object calculated based on the respective variation amounts (for example, refer to Patent Document 1).

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2015-132553

Contents of the invention

The problem to be solved by the invention

However, in the technology of the above-mentioned Patent Document 1, although the temporal change amount of the recognition point is used to judge whether the target is the same object, there is no description about the calculation method of the right end recognition point and the left end recognition point of the respective corners of the objects.

In addition, when the automatic parking is used for longitudinal parking or lateral parking, it is necessary to quickly and accurately extract the corners of the target vehicle. In the case of Patent Document 1, regarding the right end recognition point, the reflection point located at the rightmost in the left-right direction among the reflection points within the grouping range is taken as the right end recognition point, but it cannot be judged whether it is a corner of an object or not. In other words, the corners of the target vehicle cannot be detected, and there is a risk that the accuracy of automatic parking may decrease.

In addition, as a technique for detecting corners and the like in the target vehicle using the millimeter-wave radar described above, it is conceivable to detect the corners of the target vehicle by performing beam scanning using transmission beamforming of the millimeter-wave radar.

However, in this case, a phase shifter and the like for performing transmit beamforming are newly required, and the number of transmit antennas also increases. As a result, there is a problem that the cost of the detection device increases.

An object of the present invention is to provide a technology capable of quickly and inexpensively detecting the corners of objects in automatic parking applications.

The above and other objects and novel features of the present invention will be explained by the description of this specification and the accompanying drawings.

method used to solve the problem

Among the inventions disclosed in this application, the summary of representative inventions will be briefly described as follows.

That is, a typical detection device includes a first transmission antenna, a plurality of reception antennas, a calculation unit, and a corner detection unit. The first transmitting antenna transmits the modulated signal to space. The plurality of receiving antennas receive reflected waves of the modulated signal transmitted from the first transmitting antenna.

The calculation unit acquires the distance and direction of the object at regular intervals based on the reception signals of the reflected waves received by the plurality of receiving antennas, and calculates the time change amount of the distance based on the obtained distance and direction of the object.

The corner detection unit detects the corners of the object based on the amount of time change calculated by the calculation unit. The corner detection unit compares the amount of time change calculated by the calculation unit with a preset threshold, detects the corner of the object when the amount of time change exceeds the threshold, and outputs a corner indicating that the corner of the object has been detected. heartbeat.

In particular, the corner detection unit detects, as a corner of the object, a point of the object corresponding to a distance and an orientation calculated by the calculation unit before a time when the amount of time change exceeds the threshold value.

The effect of the invention

Among the inventions disclosed in the present application, effects obtained by typical inventions will be briefly described as follows.

It is possible to provide a low-cost detection device with a short detection time.

Description of drawings

FIG. 1 is an explanatory diagram showing an example of a configuration of a detection device according to Embodiment 1. FIG.

FIG. 2 is an explanatory diagram for explaining the operation performed by the detection device in FIG. 1 .

FIG. 3 is a flowchart showing an example of operation processing performed by the detection device in FIG. 1 .

4 is an explanatory diagram of a strong reflection signal of an object, the signal strength and orientation of a reflection point located between the strong reflection point and the corner of the object.

Fig. 5 is an explanatory diagram showing another example of the detection device of Fig. 1 .

FIG. 6 is a flowchart showing an example of detection processing performed by the detection device in FIG. 5 .

FIG. 7 is an explanatory diagram showing an example of a verification experiment for each scene of longitudinal automatic parking obtained through research by the inventors of the present invention.

FIG. 8 is an explanatory diagram showing an example of reception strength in a millimeter-wave radar having a wide-angle antenna for BSD application obtained through studies by the inventors of the present invention.

FIG. 9 is an explanatory diagram of an FFT spectrum in the verification experiment of FIG. 8 .

FIG. 10 is an explanatory diagram showing the relationship between the amount of spectral leakage power of a reflected signal and the intensity of the reflected signal.

FIG. 11 is an explanatory diagram showing an example of a configuration in a detection device according to Embodiment 2. FIG.

FIG. 12 is an explanatory diagram of operations performed by the detection device of FIG. 11 .

FIG. 13 is a flowchart showing an example of detection processing performed by the detection device in FIG. 11 .

FIG. 14 is a flowchart showing an example of detection processing when a new switch and transmitting antenna are installed in the detection device of FIG. 11 .

FIG. 15 is an explanatory diagram showing an example of a configuration in a detection device according to Embodiment 3. FIG.

FIG. 16 is an explanatory diagram of operations in the detection device of FIG. 15 .

17 is an explanatory diagram showing the relationship between the distance and the azimuth angle at each time between the own vehicle and the target vehicle from the positions R0 and R4.

FIG. 18 is a flowchart showing an example of detection processing performed by the detection device in FIG. 15 .

FIG. 19 is a flowchart showing an example of detection processing when a new switch and transmitting antenna are installed in the detection device of FIG. 15 .

FIG. 20 is an explanatory diagram showing an example of a configuration in a detection device according to Embodiment 4. FIG.

FIG. 21 is a flowchart showing an example of detection processing performed by the detection device in FIG. 20 .

Detailed ways

In all the drawings for explaining the embodiment, the same components are given the same reference numerals in principle, and repeated description thereof will be omitted.

(Embodiment 1)

Embodiments are described in detail below.

<Structure Example of Detection Device>

FIG. 1 is an explanatory diagram showing an example of the configuration of a detection device 1 according to the first embodiment.

As shown in FIG. 1 , the detection device 1 is composed of a transmitting/receiving antenna/analog unit 2 , a digital signal processing unit 3 , and a memory 4 . The transmitting and receiving antenna/analog section 2 has a frequency generator VCO, a transmitting antenna TXANT1, N receiving antennas RXANT1~RXANTN forming N receiving channels, N mixers MIX1~MIXN, and N analog/digital converters ADC1~ ADCN. In addition, the receiving antennas RXANT1 to RXANTN are arranged at intervals at which a phase difference occurs in received signals between the respective receiving channels in order to detect the azimuth of an object.

The modulated signal generated by the frequency generator VCO is respectively distributed to the transmitting antenna TXANT1 and the mixers MIX1˜MIXN. The modulated signal is, for example, a signal in the 79 GHz band in millimeter wave radar.

The transmitting antenna TXANT1 which is the first transmitting antenna transmits the modulated signal output from the frequency generator VCO as an electromagnetic wave to space. The emitted electromagnetic wave hits the object, and part of the reflected electromagnetic wave is received by the receiving antennas RXANT1 to RXANTN of the detection device 1 .

Reception signals received by reception antennas RXANT1 to RXANTN are converted into low frequency signals by mixers MIX1 to MIXN, and sent to analog/digital converters ADC1 to ADCN.

The low-frequency signals converted by the mixers MIX1 to MIXN include frequency components corresponding to the distance between the detection device 1 and the object. The low-frequency signals are converted into digital signals by the analog/digital converters ADC1 to ADCN, respectively, and then sent to the digital signal processing unit 3 .

The digital signal processing unit 3 is composed of distance peak detection units 31 to 3N, an orientation detection unit 34 , and a corner detection unit 35 . The distance peak detection sections 31 to 3N constituting the calculation section process the signals converted to digital signals by the analog/digital converters ADC1 to ADCN of the transmitting and receiving antenna/analog section 2, for example, through FFT (Fast Fourier Transform: Fast Fourier Transform) processing from time to time. domain signal into a frequency domain signal.

Then, extract the power intensity and phase information at the frequency proportional to the distance from the object to the detection device 1 from the converted frequency domain signal, and output the extracted power intensity and phase information at the frequency to the orientation detection unit 34 .

The azimuth detection section 34 constituting the calculation section detects the azimuth where the object exists based on the power intensity and phase information at the frequency generated by the distance peak detection sections 31 to 3N, for example, using signal processing of DBF (Digital Beam Forming). , output the distance and orientation information of the object to the memory 4 and the corner detection unit 35, respectively.

The memory 4 stores the information on the distance and orientation of the object output from the orientation detection unit 34 for each of time t=t1 to t=tN, and outputs the information on the distance and orientation of the object at each time to the edge Angle detection unit 35 . Here, N at time t=tN is different from the number N of reception channels described above.

The corner detection unit 35 determines whether or not there is a corner of the object based on the information on the distance and direction of the object output from the direction detection unit 34 and the information on the distance/direction of the object at each time stored in the memory 4 . It is determined that a corner detection signal is output when a corner of the object is detected.

<Operation principle of detection device 1>

Here, the operation in the detection device 1 will be described.

FIG. 7 is an explanatory diagram showing an example of a verification experiment for each scene of longitudinal automatic parking obtained through research by the inventors of the present invention. FIG. 8 is an explanatory diagram showing an example of reception strength in a millimeter-wave radar having a wide-angle antenna for BSD (Blind Spot Detection) application obtained through research by the present inventors.

First, in order to realize the automatic parking application using the millimeter-wave radar, the inventors conducted a verification experiment for each scene of the longitudinal automatic parking shown in FIG. 7 .

In FIG. 7 , there is a wall 105 on the left side, and a curb 106 is provided on the right side, and the vehicle 101 and the vehicle 102 are parked vertically along the curb 106 with a parking space equivalent to one vehicle. , an example of automatically parking the own vehicle 100 between the vehicle 101 and the vehicle 102 .

In FIG. 7 , when the automatic parking is started, the own vehicle 100 needs to accurately and quickly recognize the rear corner of the vehicle 101 which is the target vehicle parked ahead.

For example, when observing the side of the target vehicle 101 with a millimeter-wave radar having a wide-angle antenna, the signal from the distance position R0 at which the emitted electromagnetic wave is perpendicularly incident on the target vehicle 101 as shown by the solid line in FIG. 8 is received strongly. . On the other hand, the signals from the distance positions R1 to R5 incident from the non-perpendicular angles shown by the dotted line in FIG. 8 are specularly reflected and the reception strength decreases.

In particular, the sharper the incident angle, the stronger the specular reflection. The corner of the target vehicle 101 to be detected, that is, the distance position R5 shown in FIG. It is difficult to detect when the corner of 101 is close to the distance position R0.

FIG. 9 is an explanatory diagram of an FFT spectrum in the verification experiment of FIG. 8 .

As shown in the FFT spectrum of FIG. 9, the received signal from the distance position R0 with strong reflection intensity also affects the received signals at the distance positions R1 to R5 due to the spectral leakage caused by the window function during FFT processing, causing the target vehicle 101 corner detection becomes more difficult. Here, the distance intervals of the distance positions R0 to R1, the distance positions R1 to R2, . . . are determined by the resolving power of the FFT.

As explained above in FIG. 9 , the received signal from the distance position R0 with strong reflection intensity also affects the received signals at the distance positions R1 to R5 due to spectral leakage caused by the window function during FFT processing.

However, as a result of detailed studies by the present inventors, it has been found that there is a spectrum that is not affected by the distance position R0 in the distance between the distance position R0 where the reflection intensity is strong and the distance position where the corner of 101 of the target vehicle exists. Leakage power masks signals at distances greater than the noise floor.

FIG. 10 is an explanatory diagram showing the relationship between the amount of spectral leakage power of a reflected signal and the intensity of the reflected signal. This FIG. 10 shows comparison results regarding the amount of spectral leakage power of the reflected signal from the distance position R0 in FIG. 8 and the intensity of the reflected signal from the distance position R4.

The spectral leakage power from the position R0 decreases as the distance from the bin increases. At the distance bin from the position R4, the spectral leakage power is about 10dB smaller than the spectral leakage power from the position R0. Using DBF to detect the azimuth, it was confirmed that it can detect Out the bearing from position R4. The detection technique in the detection device 1 is based on this conclusion.

<Operation example of detection device 1>

The operation of the detection device 1 will be described in detail below.

FIG. 2 is an explanatory diagram illustrating operations performed by the detection device 1 of FIG. 1 . FIG. 3 is a flowchart showing an example of operation processing performed by the detection device 1 of FIG. 1 . In addition, the flowchart shown in this FIG. 3 shows the process mainly operated by the digital signal processing part 3 with which the detection apparatus 1 is equipped.

First, at time t=t1 shown in FIG. 2 , the parking process by the automatic vehicle 100 starts. At this time t=t1, the detection device 1 transmits, in other words, transmits, electromagnetic waves to the target vehicle 101 , and receives reflected waves from the target vehicle 101 by the receiving antennas RXANT1 - RXANTN of the detection device 1 .

The received reception signal is frequency-converted and converted into a digital signal by the transmission/reception antenna/analog section 2 of the detection device 1 , and output to the digital signal processing section 3 . The digital signal is subjected to FFT processing by the distance peak detectors 31 to 3N of the digital signal processing unit 3 to extract the frequency proportional to the distance from the object to the detection device 1 and the power intensity and phase information at the frequency. The power intensity and phase information at the frequency are output to the azimuth detection section 34 .

Based on the power intensity and phase information at the frequency generated by the distance peak detectors 31 to 3N, the orientation detection unit 34 uses DBF processing to obtain the sum of the distance between the distance position R0 where the reflection intensity is strong and the distance position R4 where the corner of the target vehicle 101 exists. The information of the orientation (step S101). Here, in the case of the example shown in FIG. 2, the angle ∠R4=2°.

The orientation detection unit 34 outputs information on the distance and orientation of the target vehicle 101 from the position R4 to the memory 4 and the corner detection unit 35 , respectively. The memory 4 stores information on the distance and orientation of the target vehicle 101 at time t=t1 from the position R4 output from the orientation detection unit 34 .

The same signal processing is performed for the next time t=t2, and information on the distance and direction of the target vehicle 101 from the position R4 at the time t=t2 is output to the memory 4 and the corner detection unit 35 . In the example shown in FIG. 2, the orientation information is an angle ∠R4=2°.

The corner detection unit 35 compares the information on the distance and orientation from the position R4 at the time t=t1 with the information on the distance and orientation from the position R4 at the time t=t2, and judges whether the amount of variation between the two reaches a certain value. threshold.

The threshold is input from outside such as an ECU (Electronic Control Unit) responsible for automatic driving control in vehicle 100 , for example. Alternatively, a threshold value previously stored in the memory 4 may be acquired.

When the fluctuation amount is smaller than the threshold value, the process returns to step S101 again (step S102). In the case of the example in FIG. 2 , since the fluctuation amount of the angle ∠R4 is equal to or less than the threshold value, the process returns to step S101 again. In addition, the time interval between time t=t1 and time t=t2 depends on the processing time for calculating distance and azimuth, which is on the order of several tens of ms in the case of millimeter wave radar.

The same signal processing is performed at time t=tN, and information on the distance and direction of target vehicle 101 from position R4 at time t=tN is output to memory 4 and corner detection unit 35 . In the case of the example shown in FIG. 2, the angle ∠R4=45°.

The corner detection unit 35 compares the information of the distance and orientation from the position R4 at the time t=t1, t2=, ... tN-1, and the information of the distance and orientation from the position R4 at the time t=tN, It is judged whether the amount of fluctuation between the two exceeds a set threshold value, and if the amount of fluctuation is greater than the threshold value, it is judged that there is a corner at the distance position (step S103). In the case of the example in FIG. 2 , at time t=tN, the amount of variation in the angle ∠R4 is 43°, which exceeds the threshold value.

More precisely, the distance and bearing from position R4 at time t=tN−1 represent the corner position of target vehicle 101 . In addition, at the time t1<t<tN, the object present at the azimuth of 2° calculated as the azimuth of the distance position R4 changes from the corner of the target vehicle 101 to the wall 105, so the distance position R4 of the 2° azimuth changes. for other distances. In the case of FIG. 2 , at time t=tN, the distance position in the 2° azimuth changes from the distance position R4 to the distance position R14. Therefore, the threshold value of the amount of variation may be the amount of variation in the orientation of a certain distance position of interest, the amount of variation in the distance on a certain orientation of interest, or both.

Through the above processing, in the detection device 1 , it is possible to quickly detect the corner of the rear of the target vehicle 101 by making a determination based on the time variation of the distance position and the heading of the target vehicle 101 .

In addition, since the corners of the rear of the target vehicle 101 can be detected with high accuracy without using a transmit beamforming technique or the like, it is possible to provide a low-cost detection device 1 .

<Effectiveness of detection device 1>

4 is an explanatory diagram of a strong reflection signal of an object, the signal strength and orientation of a reflection point located between the strong reflection point and the corner of the object.

This FIG. 4 shows the results of experiments conducted to confirm the effectiveness of the detection device 1 of FIG. 1 .

At the time corresponding to the time t=t2 shown on the left side of FIG. 4 , the calculated azimuth of the distance R4 between the distance position R0 where the reflection intensity is strong and the distance position where the corner of the target vehicle 101 exists is −15°. .

On the other hand, at the time corresponding to the time t=tN when the distance to the corner of the target vehicle 101 shown on the right side of FIG. 4 coincides with the distance position R4, the calculated azimuth from the position R4 is +30°.

That is, it can be confirmed that the azimuth from the position R4 has changed by 45° from the time t=t2 to the time t=tN, and it has been confirmed that the rear corner of the target vehicle 101 can be detected by the detection device 1 .

The reason why the azimuth from the distance position R4 at time t=tN is 30° is that the spectrum leakage from the distance position R0 with strong reflection intensity affects the distance position R4, and the azimuth from the distance position R0 is calculated.

In addition, as a more preferable embodiment, the corner detection unit 35 detects the corner of the target vehicle 101 when it is determined that the threshold value is exceeded twice or more, thereby enabling accurate detection even when there is an influence of noise such as external disturbance. The corners of the target vehicle 101 .

<Other configuration examples and operation examples of the detection device>

FIG. 5 is an explanatory diagram showing another example of the detection device 1 of FIG. 1 . FIG. 6 is a flowchart showing an example of detection processing performed by the detection device in FIG. 5 .

The detection device 1 shown in FIG. 5 differs from the detection device 1 in FIG. 1 in that switches SW1 and SW2 and a transmission antenna TXANT2 are newly installed in the transmission/reception antenna/analog unit 2 .

Switch SW1 switches the connection of frequency generator VCO to transmit antenna TXANT1. Switch SW2 switches the connection of frequency generator VCO to transmit antenna TXANT2. The switches SW1 and SW2 are switch sections.

The switches SW1 and SW2 switch connection destinations based on the corner detection signal output from the corner detection unit 35 . The transmitting antenna TXANT2 that is the second transmitting antenna is, for example, an antenna having a downward depression angle and an inclination characteristic, and is an antenna dedicated to detecting the curb 106 shown in FIG. 7 .

Next, the operation in the detection device 1 of FIG. 5 will be described.

FIG. 6 is a flowchart showing an example of detection processing performed by the detection device in FIG. 5 . Here, the processing of steps S201 to S203 in the flowchart of FIG. 6 is the same processing as that of steps S101 to S103 in the flowchart of FIG. 3 .

In the detecting device 1 shown in FIG. 5, until the corner of the target vehicle 101 is detected (steps S201-S203), that is, until the time t<tN, the transmitting antenna TXANT1 is connected to the frequency generator VCO by the switch SW1.

Then, at time t=tN, when a corner detection signal is output from the corner detection unit 35 when a corner of the target vehicle 101 is detected, the switch SW1 is turned OFF and the switch SW2 is turned ON. As a result, the transmit antenna TXANT2 is connected to the frequency generator VCO.

As mentioned above, the transmitting antenna TXANT2 has, for example, a downward, that is, an inclination characteristic of a depression angle, and is an antenna dedicated to detecting the curb 106 . At time t=tN+1, transmit antenna TXANT2 is used to detect the changed distance in the azimuth of interest, for example, curb 106 arranged at distance position R14 in FIG. 2 (step S204 ). In the process of step S204, when the curb 106 is not detected, it can return to the process of step S201.

In this way, the corner position of the target vehicle 101 can be judged more accurately by detecting the curb 106 after detecting the corner of the target vehicle 101 .

(Embodiment 2)

<Configuration example of detection device 1>

FIG. 11 is an explanatory diagram showing an example of the configuration of the detection device 1 according to the second embodiment.

The detection device 1 shown in FIG. 11 differs from the detection device 1 shown in FIG. 1 of the first embodiment above in the configuration of the digital signal processing unit 3 . About other structures, since it is the same as that of FIG. 1, description is abbreviate|omitted.

The digital signal processing unit 3 is composed of distance peak detection units 31 to 3N, an orientation detection unit 34 , a corner detection unit 35 , and a newly provided surface detection unit 36 . The distance peak detectors 31 to 3N convert the signals converted to digital signals by the analog/digital converters ADC1 to ADCN of the transmitting/receiving antenna/analog unit 2 from time domain signals to frequency domain signals by, for example, FFT processing.

Then, a frequency proportional to the distance from the object to the detection device 1 and power intensity and phase information at the frequency proportional to the distance from the object to the detection device 1 are extracted from the frequency domain signal, and the power intensity and phase information at the frequency are output to the orientation detection unit 34 .

The direction detection unit 34 detects the direction where the object exists based on the power intensity and phase information at the frequency generated by the distance peak detection units 31 to 3N, for example, using DBF signal processing, and outputs the information on the distance and direction of the object to the memory 4 and surface detection unit 36 .

The memory 4 stores the information on the distance and orientation of the object output from the orientation detection unit 34 for each of time t=t1 to t=tN, and outputs the information on the distance and orientation of the object at each time to the edge The corner detection unit 35 and the surface detection unit 36 . Here, N at time t=tN is different from the number N of reception channels described above.

Based on the information on the distance and orientation of the object output from the orientation detecting section 34 and the information on the distance/orientation of the object at each time stored in the memory 4, the surface detection unit 36 determines whether the object constitutes the surface of the same object. If it is judged that the object constitutes the surface of the same object, a judgment result signal is output to the corner detection unit 35 .

When the corner detection unit 35 receives the judgment result signal from the surface detection unit 36, the information based on the distance and direction information of the object output from the direction detection unit 34 and the distance/direction information of the object for each time stored in the memory 4 The information judges whether there is a corner of the object, and outputs a corner detection signal when a corner is detected.

<Operation example of detection device 1>

FIG. 12 is an explanatory diagram of operations performed by the detection device 1 of FIG. 11 . FIG. 13 is a flowchart showing an example of detection processing performed by the detection device 1 of FIG. 11 . In addition, the main body of the processing in the flowchart of FIG. 13 is mainly based on the operation of the digital signal processing unit 3 .

First, automatic parking starts at time t=t1 in FIG. 12 . At time t=t1 , the detection device 1 transmits electromagnetic waves to the target vehicle 101 , and receives reflected waves from the target vehicle 101 with the receiving antennas RXANT1 - RXANTN of the detection device 1 .

The reception signals received by the reception antennas RXANT1 to N are frequency-converted and converted into digital signals by the transmission/reception antenna/analog section 2 constituting the detection device 1 and output to the digital signal processing section 3 .

After the digital signal is subjected to FFT processing by the distance peak detectors 31 to 3N of the digital signal processing unit 3 , the frequency proportional to the distance from the object to the detection device 1 and the power intensity and phase information at the frequency are extracted. The power intensity and phase information at the extracted frequency are output to the azimuth detection unit 34 .

Based on the power intensity and phase information at the frequency generated by the distance peak detection sections 31 to 3N, the azimuth detection unit 34 uses DBF processing to obtain the distance and azimuth information of the distance position R0 with strong reflection intensity, the distance position R0 and the target with strong reflection intensity The information of the distance position R4 and the orientation which is the distance between the distance positions where the corner of the vehicle 101 exists (step S301 ). In the example of FIG. 12, the angle ∠R0=45°, and the angle ∠R4=2°.

Here, if there is no difference between the azimuth of the distance position R0 and the azimuth of the distance position R4 with strong reflection intensity (step S302), it is considered that two or more reflections have not been detected from the target vehicle 101 as the object. point, return to the processing of step S301. Alternatively, the automatic parking sequence may be stopped or restarted.

If there is a certain difference between the azimuth of the distance position R0 with strong reflection intensity and the azimuth of the above-mentioned distance position R4 (step S302), it is considered that two or more reflection points have been successfully detected from the target vehicle 101, and the distance positions R0 and R4 are considered to be successfully detected. The information of the distance and orientation is output to the memory 4 and the corner detection unit 35.

The memory 4 stores the distance and bearing information of the target vehicle 101 from the position R0 at the time t=t1 and the distance and bearing information at the time t=t1 from the position R4 of the target vehicle 101 input from the bearing detector 34 .

The same signal processing is performed for the next time t=t2, and information on the distance and direction of the target vehicle 101 from the positions R0 and R4 at the time t=t2 is output to the memory 4 and the surface detection unit 36 (step S303). In the example of FIG. 12, the angle ∠R0=45°, and the angle ∠R4=2°.

The surface detection unit 36 judges the distance position R0 and the distance position R4 based on the information on the distance and orientation from the positions R0 and R4 at time t=t1 and the information on the distance and orientation from the positions R0 and R4 at time t=t2. Whether or not to constitute the elements of the surface of the same object (step S304).

If the distance position R0 and the distance position R4 are elements constituting the surface of the same object, then as shown in FIG. 12 , the time trajectories of the distance position R0 and the distance position R4 are arranged on a certain straight line.

Corner detection part 35 is to the information (step S305) of the distance and bearing of distance position R0, R4 when time t=tN, and the distance and bearing of distance position R4 when time t=t1, t2, ... tN-1 The information is compared, and it is judged whether the variation of the two exceeds a certain threshold (step S306).

Then, when the fluctuation amount is smaller than the threshold value, the process returns to step S305. In the example of FIG. 12 , since the fluctuation amount of the angle ∠R4 is not more than the threshold value, the process returns to step S305 again.

Here, the threshold value is also input from outside such as an ECU in charge of automatic driving control in vehicle 100 , for example. Alternatively, a threshold value previously stored in the memory 4 may be acquired.

When the fluctuation amount exceeds the threshold value, it is determined that a corner exists at the distance position, that is, the distance position R4 in FIG. 12 (step S307 ). In the example of FIG. 12 , at time t=tN, the amount of variation in the angle ∠R4 is 43°, which exceeds the threshold value. More precisely, the distance and bearing from position R4 at time t=tN−1 represent the corner position of target vehicle 101 .

In addition, at the time t1<t<tN, the object present at the azimuth of 2° calculated as the azimuth of the distance position R4 changes from the corner of the target vehicle 101 to the wall 105 or the curb, so the distance of the azimuth of 2° Position R4 changes to other distance positions.

In the case of FIG. 12 , the distance position in the 2° azimuth changes from the distance position R4 to the distance position R14 at time t=tN. Therefore, the threshold value of the amount of variation may be the amount of variation in the orientation of a certain distance position of interest, or may be set as the amount of variation in the distance on a certain orientation of interest. Alternatively, it can be set to both sides.

The detection device 1 is provided with a surface detection unit 36 that judges whether the time trajectories of the distance positions R0 and R4 form the surface of the same object at time t=t2 through the above operations, thereby enabling more accurate detection of the target vehicle 101. The corner part of the rear.

Thereby, the precision of automatic parking can be improved.

In addition, as a more preferable example, it is determined that the target vehicle 101 is determined to be the object vehicle 101 when the processing of step S306 performed by the above-mentioned corner detection unit 35 is repeated multiple times, that is, when the threshold value determination by the corner detection unit 35 exceeds the threshold value consecutively two or more times. Therefore, it is possible to more accurately detect the corners of the vehicle 101 even under the influence of noise such as external disturbance.

<Other configuration examples and operation examples of the detection device 1>

In addition, the detection device 1 may have a configuration in which the switches SW1 and SW2 and the transmitting antenna TXANT2 shown in FIG. 5 of Embodiment 1 above are newly provided to the configuration of the detection device 1 in FIG. 11 .

In this case, the connection structure of the newly installed switches SW1 and SW2 and the transmission antenna TXANT2 is the same as that in FIG. 5 , so description thereof will be omitted. In addition, the transmitting antenna TXANT2 is also an antenna having a downward depression angle and an inclination characteristic, and is an antenna dedicated to detecting the curb 106 and the like in FIG. 7 .

FIG. 14 is a flowchart of an example of a detection process in a detection device in which new switches SW1 and SW2 and a transmission antenna TXANT2 are provided in the detection device 1 of FIG. 11 .

Here, the processing of steps S401 to S407 in the flowchart of FIG. 14 is the same as the processing of steps S301 to S307 in the flowchart of FIG. 13 .

In the detecting device 1, until the corner of the target vehicle 101 is detected (steps S401-S407), that is, until the time t<tN, the transmitting antenna TXANT1 is connected to the frequency generator VCO by the switch SW1.

Then, at time t=tN, when a corner detection signal is output when a corner of the target vehicle 101 is detected, the switch SW1 is turned off and the switch SW2 is turned on (step S408). As a result, the transmit antenna TXANT2 is connected to the frequency generator VCO.

As mentioned above, the transmitting antenna TXANT2 has, for example, a downward depression angle characteristic, and is an antenna dedicated to detecting the curb 106 . At time t=tN+1, the transmit antenna TXANT2 is used to detect the changed distance in the azimuth of interest, for example, the wall 105 arranged at the distance position R14 in FIG. 2 (step S409 ).

In this way, also after detecting the corner of the target vehicle 101 , the curb 106 is detected, whereby the position of the corner of the target vehicle 101 can be judged with higher accuracy.

(Embodiment 3)

In Embodiment 3, an example will be described in which the own vehicle and the target vehicle 101 are not paralleled horizontally but, for example, the target vehicle 101 has a certain inclination angle, and the corners of the vehicle 101 are suitable for detection.

<Configuration example of detection device 1>

FIG. 15 is an explanatory diagram showing an example of the configuration of the detection device 1 according to the third embodiment.

The detection device 1 shown in FIG. 15 differs from the detection device 1 of FIG. 11 in the above-mentioned second embodiment in that a threshold adjustment unit 37 is newly provided in the digital signal processing unit 3 .

In addition, the surface detection unit 36 judges whether the object constitutes a surface of the same object, calculates the inclination of the surface, and outputs the calculation result to the threshold adjustment unit 37 as inclination information. This inclination information is correction information.

A preset threshold value is input to the face detection unit 36 . This threshold value is acquired from an external input such as an ECU in charge of automatic driving control in vehicle 100 . Alternatively, a threshold value previously stored in the memory 4 may be obtained. Regarding other configurations, since they are the same as those in FIG. 4 , description thereof will be omitted.

The threshold adjustment unit 37 calculates a corrected threshold value corrected according to the inclination information output from the surface detection unit 36 , and outputs it to the corner detection unit 35 .

<Operation example of detection device 1>

FIG. 16 is an explanatory diagram of operations in the detection device 1 of FIG. 15 . FIG. 18 is a flowchart showing an example of detection processing performed by the detection device 1 of FIG. 15 . Here, in the flowchart shown in FIG. 18 , processing is mainly performed by the digital signal processing unit 3 .

First, at time t=t1 in FIG. 16 , the automatic parking process starts. At time t=t1 , the detection device 1 transmits electromagnetic waves to the target vehicle 101 , and receives reflected waves from the target vehicle 101 with the receiving antennas RXANT1 - RXANTN of the detection device 1 . In the example of FIG. 16 , it is assumed that the target vehicle 101 is parked at an inclination angle of, for example, about 5°, and the host vehicle is moving at a speed of about 10 km/h.

The reception signals received by the reception antennas RXANT1 to RXANTN are frequency-converted and converted into digital signals by the transmission/reception antenna/analog section 2 included in the detection device 1 , and output to the digital signal processing section 3 .

The digital signal is subjected to FFT processing by the distance peak detection sections 31-3N of the digital signal processing section 3, and the frequency proportional to the distance from the object to the detection device 1 is extracted and the power intensity and phase information at the frequency are extracted. The power intensity and phase information at the frequency are output to the azimuth detection unit 34 .

Based on the power intensity and phase information at the frequency generated by the distance peak detection units 31 to 3N, the orientation detection unit 34 uses DBF processing to obtain the distance and orientation information of the distance position R0 with strong reflection intensity, and the distance position R0 and the distance position R0 with strong reflection intensity. Information on the distance and orientation of the distance R4 between the distance positions where the corner of the target vehicle 101 exists (step S501 ). In the example of FIG. 16, the angle ∠R0=50°, and the angle ∠R4=6.5°.

Here, if there is no difference between the azimuth of the distance position R0 and the azimuth of the distance position R4 with the above-mentioned strong reflection intensity (step S502), it is considered that two or more reflection points cannot be detected from the target vehicle 101 as the object. , return to the processing of step S501. Alternatively, the automatic parking process may be stopped or the detection device 1 may be restarted.

If there is a difference between the orientation of the distance position R0 and the distance position R4 with strong reflection intensity (step S502), it is considered that two or more reflection points have been successfully detected from the target vehicle 101, and the distances and orientations of the distance positions R0 and R4 The information of is output to the memory 4 and the corner detection unit 35.

The memory 4 stores the distance and bearing information of the target vehicle 101 from the position R0 at the time t=t1 and the distance and bearing information at the time t=t1 from the position R4 of the target vehicle 101 input from the bearing detector 34 .

The same signal processing is performed for the next time t=t2, and information on the distance and direction of the target vehicle 101 from the positions R0 and R4 at the time t=t2 is output to the memory 4 and the surface detection unit 36 . Here, in the example of FIG. 16, the angle ∠R0=50°, and the angle ∠R4=6.7°.

The surface detection unit 36 judges the distance position based on the acquired threshold value for the information on the distance and direction from the positions R0 and R4 at time t=t1 and the information on the distance and direction from the positions R0 and R4 at time t=t2. Whether or not R0 and the distance position R4 constitute an element of the surface of the same object (step S504).

If the distance position R0 and the distance position R4 are elements constituting the surface of the same object, then as shown in FIG. 16 , the time trajectories of the distance position R0 and the distance position R4 are arranged on a certain straight line.

FIG. 17 is an explanatory diagram showing the relationship between the distance and the azimuth angle at each time between the own vehicle 100 and the target vehicle 101 from the positions R0 and R4 .

The graph in FIG. 17( a ) shows distances from positions R0 and R4 at respective times in a state where the host vehicle 100 and the target vehicle 101 are aligned at an inclination angle of about 5°.

The graph in FIG. 17( b ) similarly shows the orientations at each time from the positions R0 and R4 in a state where the own vehicle 100 and the target vehicle 101 are juxtaposed with an inclination angle of about 5°.

As shown in FIG. 17 , when the host vehicle 100 and the target vehicle 101 are not paralleled horizontally, it can be confirmed that the distance and direction from the positions R0 and R4 gradually change with the passage of time.

That is, the surface detection unit 36 and the corner detection unit 35 need to consider the amount of change in the distance and orientation of the object, that is, the target vehicle 101 , due to the inclination angle, and therefore input a threshold corresponding to the corresponding inclination angle to the surface detection unit 36 .

For example, if an inclination angle of 5° or less is to be dealt with, the azimuth variation threshold value is a value obtained by adding a variation margin due to noise to 0.2°. Information on the inclination angle between the host vehicle 100 and the target vehicle 101 detected by the surface detection unit 36 is output to the threshold adjustment unit 37 . The threshold adjusting unit 37 calculates a corrected threshold which is a threshold corrected according to the inclination information, and outputs the corrected threshold to the corner detecting unit 35 .

The corner detection unit 35 compares the information on the distance and orientation from the positions R0 and R4 at the time t=tN with the information on the distance and orientation from the position R4 at the time t=t1, t2, ... tN-1 , it is judged whether the variation of both exceeds the correction threshold (step S506).

If the fluctuation amount is smaller than the correction threshold, the process returns to step S505 again. In the example of FIG. 16 , since the fluctuation amount of the angle ∠R4 is equal to or less than the correction threshold, the process returns to step S505 .

When the variation exceeds the correction threshold, it is determined that a corner exists at the distance position, that is, the distance position R4 in FIG. 16 (step S507 ). More precisely, the distance and bearing from position R4 at time t=tN−1 represent the corner position of target vehicle 101 .

In addition, since the object existing at the azimuth of 10.7° calculated as the azimuth of the distance position R4 at time t1<t<tN changes from the corner of the target vehicle 101 to the wall 105 or the curb, the distance of the azimuth of 2° Position R4 changes to other distance positions.

In the case of FIG. 16 , the distance position in the 2° azimuth changes from the distance position R4 to the distance position R14 at time t=tN. Therefore, the threshold value of the amount of variation may be the amount of variation in the orientation of a certain distance position of interest, the amount of variation in the distance on a certain orientation of interest, or both.

Through the above operations, even when the host vehicle 100 and the target vehicle 101 are not horizontal but are paralleled at a certain inclination angle, it is possible to quickly detect the rear corner of the target vehicle 101 .

Accordingly, even if the target vehicle 101 or the like is parked on an incline, automatic parking processing can be performed with high precision.

Also in this case, it is determined that the corner of the target vehicle 101 is determined to be a corner of the target vehicle 101 when the corner detection unit 35 exceeds the correction threshold two or more times in the processing of step S506 by the corner detection unit 35. , thereby enabling more accurate detection of the corners of the vehicle 101 even under the influence of noise such as external disturbance.

<Other configuration examples and operation examples of the detection device 1>

In addition, as described in FIG. 14 of Embodiment 2 above, the detection device 1 of FIG. 15 may be newly provided with switches SW1 and SW2 and transmitting antenna TXANT2 shown in FIG. 5 of Embodiment 1 of the above invention.

Here, the newly installed transmitting antenna TXANT2 is also an antenna with a downward depression angle characteristic, and is an antenna dedicated to detecting the curb 106 and the like in FIG. 7 .

FIG. 19 is a flowchart showing an example of detection processing in a detection device provided with new switches SW1 and SW2 and a transmission antenna TXANT2.

Here, the processing of steps S601 to S607 in the flowchart of FIG. 19 is the same as the processing of steps S501 to S507 in the flowchart of FIG. 18 .

In the detection device 1, until the corner of the target vehicle 101 is detected (steps S601-S607), that is, until the time t<tN, the transmitting antenna TXANT1 is connected to the frequency generator VCO by the switch SW1.

Then, at time t=tN, when a corner detection signal is output when a corner of the target vehicle 101 is detected, the switch SW1 is turned off and the switch SW2 is turned on (step S608). As a result, the transmit antenna TXANT2 is connected to the frequency generator VCO.

As mentioned above, the transmitting antenna TXANT2 has, for example, a downward depression angle characteristic, and is an antenna dedicated to detecting the curb 106 . At time t=tN+1, the transmission antenna TXANT2 is used to detect the changed distance in the azimuth of interest, for example, the curb 106 shown in FIG. 7 (step S609 ).

In this way, also after detecting the corner of the target vehicle 101 , the curb 106 is detected, whereby the position of the corner of the target vehicle 101 can be judged with higher accuracy.

(Embodiment 4)

In Embodiment 4, on the premise that the rear corner of the target vehicle 101 is recognized, the technique of performing the automatic parking process using the information of the vacant parking space 160 detected before entering the automatic parking process is carried out. illustrate. The vacant parking space 160 is information on an area where the own vehicle 100 can be parked, for example, in the example of FIG.

If the rear corner of the target vehicle 101 is recognized by the vacant space detection before entering the automatic parking process, the target vehicle 101 may move back and forth when the self-vehicle 100 enters the automatic parking process. Therefore, it is necessary to recognize the corners of the target vehicle 101 from the side.

Details of this technique will be described below.

<Configuration example of detection device 1>

FIG. 20 is an explanatory diagram showing an example of the configuration of the detection device 1 according to the fourth embodiment.

In the detection device 1 shown in FIG. 20 , a memory 4 a is newly provided in the detection device 1 shown in FIG. 11 of the second embodiment described above. The memory 4a stores the distance and direction of the corner of the target vehicle 101 detected by the vacant parking space detection.

Information on the distance and orientation of the corners of the target vehicle 101 obtained by the vacant parking space detection is, for example, information obtained from sensors connected to the outside. Alternatively, it may be information detected by the detection device 1 .

The corner detection unit 35 is based on the information on the distance and orientation of the object output from the orientation detection unit 34, the information on the distance/orientation of the object at each time stored in the memory 4, and the vacant parking spaces stored in the memory 4a. The detected distance/direction information of the object is used to determine whether the corner of the object exists, and when the corner of the object is detected, a corner detection signal is output.

<Operation example of detection device 1>

Hereinafter, detection processing performed by the detection device 1 will be described.

FIG. 21 is a flowchart showing an example of detection processing performed by the detection device 1 of FIG. 20 .

In the automatic parking performed by the detecting device 1 of FIG. 20 , the process of detecting an empty parking space is performed before entering the process of automatic parking as described above, and it is assumed that the initial position of the target vehicle 101 is known.

In FIG. 21 , the operation at the time t0<t<tN-1 is the same as the processing in steps S301 to 306 in FIG. 13 of the second embodiment described above, and thus description thereof will be omitted.

When time t=tN, detect the distance and the orientation of the distance position R4 of the target vehicle 101, compare with the corner position information of the target vehicle 101 preserved in the memory 4a and confirm whether the target vehicle 101 moves back and forth after the vacant parking space detection (step S707).

If the corner detection of the target vehicle 101 obtained by the detection of the vacant parking space by the above sensor is consistent with the result of the corner detection by the corner detection unit 35, it is determined that the target vehicle 101 has not moved after the detection of the vacant parking space (step S708) , to perform automatic parking processing.

If the corner detection of the target vehicle 101 by the free parking space detection does not match the result of the corner detection by the corner detection unit 35 , the automatic parking process is stopped. Alternatively, if safety can be confirmed based on the positional relationship between the target vehicle 101 and the vehicle 102 behind the vehicle 101 shown in FIG. 7 , automatic parking may be maintained.

In addition, when the automatic parking processing is performed, by reconfirming the position of the corner of the target vehicle 101 with the detection device 1 , it is possible to perform the automatic parking correction processing.

As described above, even if the target vehicle 101 moves forward or backward after detection of a vacant parking space, automatic parking can be safely performed or stopped.

Thereby, the safety at the time of automatic parking can be improved.

As mentioned above, although the invention which this inventor arrived at was concretely demonstrated based on embodiment, this invention is not limited to the said embodiment, Various changes are possible in the range which does not deviate from the summary.

Explanation of reference signs

1 detection device

2 Transmitting and receiving antenna/analog section

3 Digital Signal Processing Section

4 memory

4a memory

31 Distance peak detection part

34 Orientation detection department

35 Corner detection unit

36-face detection unit

37 Threshold adjustment unit

100 vehicles

101 vehicles

105 wall

106 curb stone

VCO frequency generator

TXANT transmit antenna

RXANT receiving antenna

Mixer

ADC Analog/Digital Converter

SW1 switch

SW2 switch.

Claims (14)

1. A detection apparatus, characterized by comprising:

a 1 st transmitting antenna for transmitting a modulated signal to a space;

A plurality of receiving antennas for receiving reflected waves of the modulated signal transmitted from the 1 st transmitting antenna;

a calculation unit that obtains a distance and an azimuth of an object from received signals of the reflected waves received by a plurality of the receiving antennas at regular intervals, and calculates a time-varying amount of the distance from the obtained distance and azimuth of the object; and

a corner detection unit that detects a corner of the object based on the time variation calculated by the calculation unit,

the corner detection unit compares the time variation calculated by the calculation unit with a predetermined threshold value, and outputs a corner detection signal indicating that the corner of the object is detected when the time variation exceeds the threshold value.

2. The detection apparatus according to claim 1, wherein:

the corner detection unit detects, as a corner of the object, a point of the object corresponding to the distance and the azimuth calculated by the calculation unit before the time when the time variation exceeds the threshold.

3. The detection apparatus according to claim 1, wherein:

the corner detection unit outputs the corner detection signal when the time variation calculated by the calculation unit exceeds the threshold value at least 2 times in succession.

4. The detection apparatus according to claim 1, wherein:

a memory for storing the distance and direction of the object calculated by the calculating unit,

the corner detection unit reads the distance and the azimuth of the object from the memory, and calculates the time variation of the distance.

5. The detection apparatus according to claim 1, characterized by comprising:

a 2 nd transmitting antenna having a dip characteristic of a depression angle, spatially transmitting the modulated signal; and

a switch section that switches a connection target of the 1 st transmitting antenna and the 2 nd transmitting antenna based on the corner detection signal,

the switch section switches so that the 1 st transmitting antenna is connected to a frequency generator that generates the modulation signal before the corner detection signal is output from the corner detection section, and so that the 2 nd transmitting antenna is connected to the frequency generator when the corner detection signal is output from the corner detection section.

6. The detection apparatus according to claim 1, wherein:

the corner detection unit compares a distance and an orientation of a corner of the object, which are input from the outside in advance, with the distance and the orientation of the corner detected by the detection unit, determines that the object is not moving when the distance and the orientation match, and detects the corner of the object based on the time variation calculated by the calculation unit.

7. A detection apparatus, characterized by comprising:

a 1 st transmitting antenna for transmitting a modulated signal to a space;

a plurality of receiving antennas for receiving reflected waves of the modulated signal transmitted from the 1 st transmitting antenna;

a calculation unit that obtains a distance and an azimuth of an object at regular intervals from received signals of the reflected waves received by the plurality of receiving antennas, and calculates a time-varying amount of the distance from the obtained distance and azimuth of the object;

a corner detection unit that detects a corner of the object based on the time variation calculated by the calculation unit; and

a plane detection unit that determines whether or not the objects constitute a plane of the same object based on the time variation of the distance calculated by the calculation unit, and outputs a determination result signal to the corner detection unit when it is determined that the objects constitute the same plane,

the corner detection unit compares the time variation calculated by the calculation unit with a predetermined threshold value when the determination result signal is received, detects a corner of the object when the time variation exceeds the threshold value, and outputs a corner detection signal indicating that the corner of the object is detected.

8. The detection apparatus according to claim 7, wherein:

the surface detection unit judges the surface of the object based on the distance and the direction of the object obtained by the calculation unit at regular intervals in a dot-like manner,

the corner detection unit detects, as a corner of the object, a point of the object corresponding to the distance and the azimuth calculated by the calculation unit before the time when the time variation exceeds the threshold.

9. The detection apparatus according to claim 8, wherein:

the corner detection unit outputs the corner detection signal when the time variation calculated by the calculation unit exceeds the threshold value at least 2 times in succession.

10. The detection apparatus according to claim 9, wherein:

a memory for storing the distance and direction of the object calculated by the calculating unit,

the corner detection unit reads the distance and the azimuth of the object from the memory, and calculates the time variation of the distance.

11. A detection apparatus, characterized by comprising:

a 1 st transmitting antenna for transmitting a modulated signal to a space;

a plurality of receiving antennas for receiving reflected waves of the modulated signal transmitted from the 1 st transmitting antenna;

A calculation unit that obtains a distance and an azimuth of an object at regular intervals from received signals of the reflected waves received by the plurality of receiving antennas, and calculates a time-varying amount of the distance from the obtained distance and azimuth of the object;

a surface detection unit that determines whether or not an object forms a surface of the same object based on the time variation of the distance calculated by the calculation unit, and outputs a determination result signal to the corner detection unit when it is determined that the object forms the same surface;

an adjustment unit for generating correction information in accordance with the inclination information; and

a corner detection unit that detects a corner of the object based on the time variation calculated by the calculation unit,

the surface detecting unit detects an amount of inclination of the object based on the time-varying amount of the distance calculated by the calculating unit, outputs the detected amount of inclination as the correction information,

the corner detection unit corrects a preset threshold value based on the correction information, compares the corrected threshold value with the time variation calculated by the calculation unit when the determination result signal is received, detects a corner of the object when the time variation exceeds the corrected threshold value, and outputs a corner detection signal indicating that the corner of the object is detected.

12. The detection apparatus according to claim 11, wherein:

the corner detection unit detects, as a corner of the object, a point of the object corresponding to the distance and the azimuth calculated by the calculation unit before the time when the time variation exceeds the threshold.

13. The detection apparatus according to claim 12, wherein:

the corner detection unit outputs the corner detection signal when the time variation calculated by the calculation unit exceeds the threshold value at least 2 times in succession.

14. The detection apparatus according to claim 11, wherein:

a memory for storing the distance and direction of the object calculated by the calculating unit,

the corner detection unit reads the distance and the azimuth of the object from the memory, and calculates the time variation of the distance.