JP7101896B2 - Obstacle detection device - Google Patents

Description

The present invention relates to an obstacle detection device.

There is a technique for detecting obstacles by transmitting and receiving signal waves such as ultrasonic waves.
For example, in Patent Document 1, a pulsed ultrasonic wave is radiated into space as an exploration wave, a reflected wave which is an exploration wave reflected by an object is received, and a predetermined time window is set for the received reflected wave. Further, a method of determining whether or not an object reflecting an exploration wave is a person is disclosed based on whether or not a forest-like echo which is a plurality of reflected waves exists in a set time window.

US8432770B2 Gazette

In order to detect an obstacle existing in a distant place by transmitting and receiving a signal wave such as an ultrasonic wave, it is necessary to increase the power of the transmitted wave to be transmitted (hereinafter referred to as "transmission power").
Transmission power is defined by the product of the amplitude of the transmitted wave and the pulse width of the transmitted wave. Therefore, the transmission power can be increased by widening the pulse width of the transmission wave without increasing the amplitude of the transmission wave.
However, in the conventional method such as the method disclosed in Patent Document 1, when the pulse width of the transmitted wave is widened in order to detect an obstacle existing in a distant place, it is reflected at a plurality of positions on the obstacle. Since the reflected waves, which are the transmitted waves, overlap with each other, the received reflected waves may not form a forest echo.

The present invention is for solving the above-mentioned problems, and is an obstacle detection device capable of determining whether or not a detected obstacle is a person by increasing the transmission power by widening the pulse width of the transmitted wave. Is intended to provide.

The obstacle detection device according to the present invention is a window setting unit that sets a range in which a distance measuring sensor that transmits / receives a signal wave having a frequency equal to or lower than a predetermined frequency exists and a received wave received by the distance measuring sensor as a window. The correlation calculation unit that acquires the correlation waveform and the correlation calculation unit acquire the received wave that exists in the window set by the window setting unit by performing the correlation calculation using the transmitted wave transmitted by the ranging sensor. When a plurality of peaks are present in the correlated waveform, a determination unit for determining that a person exists as an obstacle and an output unit for outputting determination information indicating the determination result of the determination unit are provided.

According to the present invention, it is possible to increase the transmission power by widening the pulse width of the transmission wave and determine whether or not the detected obstacle is a person.

FIG. 1A is a diagram showing an example of the positional relationship between the sensor that transmitted and received the exploration wave in the conventional method and the reflection surface in the obstacle. FIG. 1B is a diagram showing an example of time-dependent changes in the transmitted wave and the received wave in the conventional method. FIG. 2A is a diagram showing an example of the positional relationship between the sensor that transmitted and received the exploration wave in the conventional method and the reflection surface in the obstacle. FIG. 2B is a diagram showing an example of time-dependent changes in the transmitted wave and the received wave in the conventional method. FIG. 3 is a block diagram showing an example of the configuration of a main part of the obstacle detection device according to the first embodiment. FIG. 4A is a diagram showing an example of the positional relationship between the distance measuring sensor that transmits and receives the exploration wave in the obstacle detection device according to the first embodiment and the reflective surface of the obstacle. FIG. 4B is a diagram showing an example of a transmission signal generated by the transmission signal generation unit, a reception signal acquired by the reception signal acquisition unit, time series information generated by the obstacle detection unit, and a correlation waveform acquired by the correlation calculation unit. Is. 5A and 5B are diagrams showing an example of the hardware configuration of the main part of the hardware constituting the obstacle detection device according to the first embodiment, excluding the distance measuring sensor. FIG. 6 is a flowchart illustrating an example of processing of the obstacle detection device according to the first embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1.
The obstacle detection device 100 according to the first embodiment will be described with reference to FIGS. 1 to 6.
Before explaining the configuration of the obstacle detection device 100 according to the first embodiment, first, a conventional general obstacle detection method (hereinafter referred to as “conventional method”) will be described.
In the conventional method, a signal wave having a predetermined frequency is transmitted as a search wave from a sensor of a method such as a sonar or a millimeter wave radar, and the reflected wave, which is a search wave reflected by an obstacle, is received by the sensor as a received wave. ..
In the conventional method, the presence or absence of an obstacle is detected using the received received wave, and the distance from the sensor to the obstacle is calculated.
Specifically, for example, in the conventional method, when the magnitude of the amplitude of the received wave is larger than the predetermined amplitude threshold value, it is determined that there is an obstacle within the reach of the transmitted wave transmitted by the sensor. Detects the presence or absence of obstacles.
Further, in the conventional method, the distance from the sensor to the obstacle is calculated by using the period from the transmission of the transmitted wave to the reception of the received wave (hereinafter referred to as “propagation delay time”).

Specifically, for example, in the conventional method, the distance from the sensor to the obstacle is calculated by using the following equation (1).
L = (V × T1) / 2 ・ ・ ・ Equation (1)
Here, L is the distance from the sensor to the reflective surface of the obstacle. Further, V is the propagation velocity of the exploration wave. Further, T1 is a propagation delay time.

When there are multiple obstacles, or when there are multiple reflective surfaces in one obstacle, the conventional method is to calculate the distance between the sensor and each of the multiple reflective surfaces. Must have a distance between a plurality of reflective surfaces greater than the distance resolution. In other words, the minimum distance difference between the plurality of reflecting surfaces that can be calculated by separating the received signal indicating the exploration wave reflected by each of the plurality of reflecting surfaces for each reflecting surface is determined by the distance resolution.
Specifically, for example, the distance resolution can be expressed by the following equation (2).
LR = ( _V × T2) / 2 ・ ・ ・ Equation (2)
Here, _LR is the distance resolution. Further, T2 is the pulse width of the exploration wave which is the transmission wave. The pulse width of the exploration wave, which is the transmitted wave, means a period during which the sensor continuously radiates the exploration wave, which is the transmitted wave.

For example, in an obstacle where the distance between the two reflecting surfaces (hereinafter referred to as "distance between the reflecting surfaces") is D, the user sets the distance between the sensor and each of the two reflecting surfaces. When it is desired to acquire the indicated information, the distance resolution and the distance between the reflecting surfaces must satisfy the following equation (3).
_D > LR ... Equation (3)
Therefore, in this case, the pulse width of the exploration wave, which is the transmitted wave, must satisfy the following equation (4).
T2 <(D / V) x 2 ... Equation (4)

The relationship between the transmitted wave, the received wave, and the distance between the reflecting surfaces will be described with reference to FIGS. 1 and 2.
FIG. 1 is a diagram showing an example of the relationship between the transmitted wave, the received wave, and the distance between the reflecting surfaces.
In particular, FIG. 1 is a diagram showing an example of the relationship between the transmitted wave, the received wave, and the distance between the reflecting surfaces when the pulse width of the exploration wave, which is the transmitted wave, satisfies the equation (4).

FIG. 1A is a diagram showing an example of the positional relationship between the sensor that transmitted and received the exploration wave in the conventional method and the reflection surface in the obstacle.
As shown in FIG. 1A, the obstacle is described as having two reflective surfaces having a distance between the reflecting surfaces of D.
As shown in FIG. 1A, a part of the exploration wave which is a transmission wave radiated from the sensor is reflected by the reflection surface of the obstacle, and a part of the reflected wave which is the reflected exploration wave is a sensor as a reception wave. Received by.

FIG. 1B is a diagram showing an example of time-dependent changes in the transmitted wave and the received wave in the conventional method. In FIG. 1B, the vertical axis indicates the magnitude of the amplitude of the transmitted wave or the received wave, and the horizontal axis indicates the passage of time with the time point at which the transmitted wave is output as the origin. The horizontal axis of FIG. 1B is the time normalized by doubling the inverse number of the propagation velocity of the exploration wave in order to make the position of the reflecting surface in the obstacle shown in FIG. 1A correspond to the position of the sensor. It is shown by the axis.
As shown in FIG. 1B, when the relationship between the pulse width of the transmitted wave and the distance between the reflecting surfaces satisfies the equation (4), the received wave is divided into two periods, so that even the conventional method is an obstacle. It is possible to detect that there are two reflecting surfaces in the above.

FIG. 2 is a diagram showing an example of the relationship between the transmitted wave, the received wave, and the distance between the reflecting surfaces in the conventional method.
In particular, FIG. 2 shows the distance between the transmitted wave, the received wave, and the reflecting surface when the pulse width of the exploration wave, which is the transmitted wave, does not satisfy the equation (4) and the left side and the right side of the equation (4) are equal to each other. It is a figure which shows an example of a relationship.

FIG. 2A is a diagram showing an example of the positional relationship between the sensor that transmitted and received the exploration wave in the conventional method and the reflection surface in the obstacle.
Since FIG. 2A is the same as FIG. 1A, the description thereof will be omitted.
FIG. 2B is a diagram showing an example of time-dependent changes in the transmitted wave and the received wave in the conventional method. Since the vertical axis and the horizontal axis in FIG. 2B are the same as the vertical axis and the horizontal axis in FIG. 1B, the description thereof will be omitted.
The exploration wave shown in FIG. 2B has a wider pulse width than the exploration wave shown in FIG. 1B. As shown in FIG. 2B, by widening the pulse width of the exploration wave, the transmission power of the exploration wave is increased, and in the case of FIG. 2 as compared with the case of FIG. 1, obstacles existing farther can be detected. It will be possible.
However, when the pulse width of the exploration wave is widened, as shown in FIG. 2B, the relationship between the pulse width of the transmitted wave and the distance between the reflecting surfaces does not satisfy the equation (4), and the left side of the equation (4). When the right side is equal, the received wave is not divided into two periods but becomes one continuous period. Therefore, it may not be possible to detect the existence of two reflecting surfaces in an obstacle by the conventional method. be.

As a method of increasing the transmission power, there is a method of not only widening the pulse width of the exploration wave but also increasing the amplitude of the exploration wave, but in order to increase the amplitude of the exploration wave, a high output sensor is used. It is necessary and the cost increases. Further, by increasing the amplitude of the exploration wave, the transient power consumption when transmitting the exploration wave increases, so that it is necessary to increase the electric capacity of the equipment for supplying power. Therefore, it is preferable to widen the pulse width of the exploration wave rather than increasing the amplitude of the exploration wave.

With reference to FIG. 3, the configuration of the main part of the obstacle detection device 100 according to the first embodiment will be described.
FIG. 3 is a block diagram showing an example of the configuration of a main part of the obstacle detection device 100 according to the first embodiment.
The obstacle detection device 100 includes a distance measuring sensor 110, a transmission signal generation unit 120, a reception signal acquisition unit 130, an obstacle detection unit 140, a window setting unit 150, a correlation calculation unit 160, a determination unit 170, and an output unit 190. ..

The range-finding sensor 110 is composed of a sensor of a type such as a sonar or a millimeter-wave radar, and transmits / receives a signal wave having a frequency equal to or lower than a predetermined frequency.
The transmission signal generation unit 120 generates a transmission signal for radiating a transmission wave, which is a signal wave, as a search wave from the ranging sensor 110, and converts the generated transmission signal into an electric signal by D / A conversion. , The converted transmission signal is output to the ranging sensor 110 as an electric signal. Further, the transmission signal generation unit 120 outputs, for example, the generated transmission signal to the correlation calculation unit 160.
Specifically, for example, the transmission signal generation unit 120 generates a modulated signal modulated by a signal having an autocorrelation equal to or higher than a predetermined autocorrelation as a transmission signal.
More specifically, for example, the transmission signal generation unit 120 generates a transmission signal having an autocorrelation characteristic such as a PN (Pseudo Noise) code.
For example, the transmission signal generation unit 120 may generate a modulated signal modulated by phase modulation as a transmission signal. Further, for example, the transmission signal generation unit 120 may generate a modulation signal modulated by frequency modulation as a transmission signal instead of phase modulation.

The ranging sensor 110 receives the transmission signal generated by the transmission signal generation unit 120 from the transmission signal generation unit 120, and radiates the transmission wave, which is the signal wave corresponding to the transmission signal, as a search wave. When the distance measuring sensor 110 is composed of a sonar type sensor, the exploration wave is, for example, a sparse and dense wave such as an ultrasonic wave.
A part of the exploration wave emitted by the distance measuring sensor 110 is reflected by an obstacle, and a part of the reflected wave which is the reflected exploration wave is received as a received wave by the distance measuring sensor 110.
The ranging sensor 110 converts the received received wave into an electric signal and outputs it to the received signal acquisition unit 130.
The reception signal acquisition unit 130 receives the electric signal indicating the received wave output by the ranging sensor 110 as a reception signal, converts it into a digital signal by A / D conversion, and converts the reception signal into a digital signal. To get. The reception signal acquisition unit 130 outputs the received signal converted into a digital signal to the obstacle detection unit 140 and the correlation calculation unit 160.

The obstacle detection unit 140 receives the reception signal output by the reception signal acquisition unit 130, and detects the presence or absence of an obstacle by using the reception signal.
Specifically, for example, when the magnitude of the amplitude of the received signal acquired by the received signal acquisition unit 130 is larger than the predetermined amplitude threshold value, the obstacle detection unit 140 transmits the transmission wave transmitted by the distance measuring sensor 110. By determining that there is an obstacle within the reach of, the presence or absence of the obstacle is detected.
Further, the obstacle detection unit 140 calculates the distance from the distance measuring sensor 110 to the detected obstacle by using the equation (1).
The method of detecting an obstacle by the obstacle detection unit 140 and the method of calculating the distance from the distance measuring sensor 110 to the obstacle detected by the obstacle detection unit 140 are the same as the conventional methods, and thus the description thereof will be omitted. ..

When the obstacle detection unit 140 determines that there is an obstacle within the reach of the transmitted wave, for example, the period in which the magnitude of the amplitude of the received signal is larger than the predetermined amplitude threshold value is set to 1, and the received signal Binary time series information in which the period in which the magnitude of the amplitude is smaller than the predetermined amplitude threshold value is 0 is generated, and the generated time series information is output to the window setting unit 150.

The window setting unit 150 receives the time-series information output by the obstacle detection unit 140, sets a period in which the value indicated by the time-series information is 1, as a time window, and correlates the window information indicating the set time window. Output to the calculation unit 160. Although the window setting unit 150 describes the time window as a window, the propagation delay time and the distance from the distance measuring sensor 110 to the reflection point of the obstacle linearly correspond to each other on a one-to-one basis. Therefore, the window setting unit 150 may set a distance window as a window.

The correlation calculation unit 160 receives the window information output by the window setting unit 150, the reception signal output by the reception signal acquisition unit 130, and the transmission signal output by the transmission signal generation unit 120, and enters the window indicated by the window information. A correlation waveform is acquired by performing a correlation calculation on an existing received signal using the transmitted signal. The correlation calculation unit 160 outputs the correlation waveform information indicating the acquired correlation waveform to the determination unit 170.

Specifically, for example, the correlation calculation unit 160 uses the window information output by the window setting unit 150, and among the received signals output by the reception signal acquisition unit 130, the period corresponding to the time window indicated by the window information. A received signal (hereinafter referred to as "cut-out reception signal") is cut out and acquired. The correlation calculation unit 160 calculates a correlation waveform by performing a cross-correlation calculation between the cut-out reception signal and the transmission signal. Since the transmitted signal has self-correlation characteristics such as a PN code, the received signal corresponds to the reflected wave, which is a search wave reflected by two or more reflecting surfaces, even when they overlap each other. By comparing the autocorrelation characteristics included in the transmission signal with the autocorrelation characteristics included in the transmission signal, the received signal corresponding to the reflected wave, which is a search wave reflected by different reflection surfaces, can be separated as a correlation waveform. ..

The determination unit 170 receives the correlation waveform information output by the correlation calculation unit 160, and determines that a person exists as an obstacle when a plurality of peaks are present in the correlation waveform indicated by the correlation waveform information.
More specifically, for example, the determination unit 170 extracts a section in which the value indicated by the correlation waveform is continuously larger than a predetermined threshold value, and acquires the number of the extracted sections. When the number of the sections is two or more, the determination unit 170 determines that the obstacle detected by the obstacle detection unit 140 is a person, and when the number of the sections is one, the obstacle detection unit 170. It is determined that the obstacle detected by 140 is not a person but an object such as a stationary object.

In the obstacle detection device 100, the window setting unit 150 sets the range in which the received signal indicated by the received wave received by the ranging sensor 110 exists as a window, so that the window setting unit 150 determines the determination unit 170 according to the state of the received signal. However, since the range for determining whether or not a plurality of peaks are present in the correlation waveform can be limited, noise immunity can be improved. More specifically, for example, when the obstacle is a person, the relative distance from the sensor of the reflecting surface of the person who reflects the search wave transmitted by the sensor changes depending on the direction or posture of the person. That is, when the obstacle is a person, the distance between the reflecting surfaces changes depending on the direction or posture of the person. In the obstacle detection device 100, the window setting unit 150 sets the range in which the received signal indicated by the received wave received by the ranging sensor 110 exists as a window according to the distance between the reflecting surfaces, so that the direction of the person or the direction of the person or the obstacle detection device 100 is set. Since the determination unit 170 can appropriately set the range for determining whether or not there are a plurality of peaks in the correlation waveform according to the posture and the like, the noise immunity is improved and whether or not the obstacle is a person. Can be accurately determined.

The output unit 190 outputs determination information indicating the result of the determination by the determination unit 170.
Specifically, for example, the output unit 190 outputs the determination information to a display device (not shown). By outputting the determination information to the display device, the obstacle detection device 100 can notify the user whether or not the detected obstacle is a person.
Further, for example, the output unit 190 may output the determination information to a driving support device (not shown). When the obstacle detection device 100 outputs the determination information to the operation support device, the operation support device receives the determination information output by the output unit 190, and based on the result of the determination by the determination unit 170 indicated by the determination information, the operation support device receives the determination information. It controls the braking or traveling direction of the vehicle.
The output destination from which the output unit 190 outputs the determination information is not limited to a display device, a driving support device, or the like, and is, for example, a vehicle control device, a parking support device, a collision avoidance device, a vehicle side object detection device, or a vehicle side object detection device. It may be a corner sensor control device or the like.

With reference to FIG. 4, the search wave emitted by the obstacle detection device 100 according to the first embodiment, the reflected wave which is the search wave reflected by the reflection surface, the transmission signal generated by the transmission signal generation unit 120, and the reception signal acquisition. The received signal acquired by the unit 130, the time series information generated by the obstacle detection unit 140, and the correlation waveform acquired by the correlation calculation unit 160 will be described.

FIG. 4A is a diagram showing an example of the positional relationship between the distance measuring sensor 110 that transmits and receives the exploration wave in the obstacle detection device 100 according to the first embodiment and the reflective surface of the obstacle.
Hereinafter, as shown in FIG. 4A, the obstacle will be described as having three reflecting surfaces.
As shown in FIG. 4A, a part of the exploration wave, which is the transmitted wave emitted from the ranging sensor 110, is reflected by each of the three reflecting surfaces of the obstacle, and is one of the reflected exploration waves. Each unit is received by a sensor as a received wave.

FIG. 4B shows a transmission signal generated by the transmission signal generation unit 120, a reception signal acquired by the reception signal acquisition unit 130, time-series information generated by the obstacle detection unit 140, and a correlation waveform acquired by the correlation calculation unit 160. It is a figure which shows an example.
In FIG. 4B, the vertical axis in the figure showing the transmission signal generated by the transmission signal generation unit 120, the reception signal acquired by the reception signal acquisition unit 130, and the correlation waveform acquired by the correlation calculation unit 160 is the transmission signal and the reception signal. , And the magnitude of the amplitude of the correlation waveform. Further, in FIG. 4B, the vertical axis in the figure showing the time-series information generated by the obstacle detection unit 140 indicates the binary value indicated by the time-series information. Further, in FIG. 4B, the transmission signal generated by the transmission signal generation unit 120, the reception signal acquired by the reception signal acquisition unit 130, the time series information generated by the obstacle detection unit 140, and the correlation acquired by the correlation calculation unit 160. The horizontal axis in the figure showing an example of the waveform shows the passage of time with the time point when the transmission signal is output to the ranging sensor 110 as the origin. In addition, the horizontal axis of FIG. 4B is a value obtained by doubling the inverse of the propagation velocity of the exploration wave in order to make the position of the reflecting surface in the obstacle shown in FIG. 4A correspond to the position of the distance measuring sensor 110. It is shown by the changed time axis.

As shown in FIG. 4B, the transmission signal generation unit 120 generates a transmission signal having an autocorrelation characteristic in which a part of the phase is inverted in the middle of the pulse width of the transmission signal.
The transmission signal generation unit 120 will be described as generating a modulated wave transmission signal as shown in FIG. 4B by modulating with a signal having an autocorrelation equal to or higher than a predetermined autocorrelation. May generate a modulated wave transmission signal modulated by phase modulation, or may generate a modulated wave transmission signal modulated by frequency modulation.

When the transmitted signal has a steep auto-correlation characteristic due to a PN code or the like, the correlation calculation unit 160 has a first received signal corresponding to the reflected wave which is a search wave reflected by the first reflecting surface and a second reflection. If the second received signal corresponding to the reflected wave, which is the probe wave reflected by the surface, is deviated by 1 bit or more in the time axis direction, the first received signal and the second received signal can be separated. can.
Here, the width of one bit in the time axis direction (hereinafter referred to as “bit width”) is, as shown in FIG. 4B, between, for example, the time when the phase is inverted and the time when the phase is inverted next. It is a period. The bit width is, for example, a period during which a reflected wave, which is a search wave reflected by a person's body, and a reflected wave, which is a search wave reflected by a person's hand or foot, can be separated, that is, several tens of cm (centimeters). It is desirable that the period is shorter than the period during which the exploration wave such as ultrasonic waves propagates back and forth.
The reception signal acquisition unit 130 receives a reception signal on which a plurality of signals having the autocorrelation characteristic are superimposed from the ranging sensor 110, and acquires the reception signal as shown in FIG. 4B. Specifically, for example, as shown in FIG. 4A, when an obstacle has three reflecting surfaces, the signal received from the ranging sensor 110 by the received signal acquisition unit 130 has three autocorrelation characteristics. The signal is superimposed.

The obstacle detection unit 140 detects the presence or absence of an obstacle, and if there is an obstacle, in addition to calculating the distance from the distance measuring sensor 110 to the obstacle, when the value is binary as shown in FIG. 4B. Generate series information.
The window setting unit 150 receives the time-series information output by the obstacle detection unit 140, and sets a period in which the value indicated by the time-series information is 1 as a time window.
The window set by the window setting unit 150 is not limited to the time window, and may be, for example, a distance window based on the distance axis calculated by the equation (1).
The correlation calculation unit 160 acquires a cut-out reception signal using a time window and performs cross-correlation calculation between the cut-out reception signal and the transmission signal to calculate a correlation waveform as shown in FIG. 4B.
The determination unit 170 acquires the number of peaks in the correlation waveform calculated by the correlation calculation unit 160. For example, in the correlation waveform as shown in FIG. 4B, the determination unit 170 acquires 3 as the number of peaks of the correlation waveform, and since there are a plurality of peaks, the obstacle detected by the obstacle detection unit 140 is a person. Judge that there is.

With reference to FIGS. 5A and 5B, the hardware configuration of the main part of the hardware constituting the obstacle detection device 100 according to the first embodiment, excluding the distance measuring sensor 110, will be described.
5A and 5B are diagrams showing an example of the hardware configuration of the main part of the hardware constituting the obstacle detection device 100 according to the first embodiment, excluding the distance measuring sensor 110.

As shown in FIG. 5A, the hardware of the main part of the obstacle detection device 100 except for the distance measuring sensor 110 is composed of a computer, and the computer has a processor 201 and a memory 202. The memory 202 is a program for making the computer function as a transmission signal generation unit 120, a reception signal acquisition unit 130, an obstacle detection unit 140, a window setting unit 150, a correlation calculation unit 160, a determination unit 170, and an output unit 190. Is remembered. When the processor 201 reads out and executes the program stored in the memory 202, the transmission signal generation unit 120, the reception signal acquisition unit 130, the obstacle detection unit 140, the window setting unit 150, the correlation calculation unit 160, and the determination unit 170 are executed. , And the output unit 190 is realized.

Further, as shown in FIG. 5B, the hardware of the main part of the obstacle detection device 100 other than the distance measuring sensor 110 may be configured by the processing circuit 203. In this case, even if the functions of the transmission signal generation unit 120, the reception signal acquisition unit 130, the obstacle detection unit 140, the window setting unit 150, the correlation calculation unit 160, the determination unit 170, and the output unit 190 are realized by the processing circuit 203. good.

Further, the hardware of the main part of the obstacle detection device 100 other than the distance measuring sensor 110 may be configured by the processor 201, the memory 202, and the processing circuit 203 (not shown). In this case, some of the functions of the transmission signal generation unit 120, the reception signal acquisition unit 130, the obstacle detection unit 140, the window setting unit 150, the correlation calculation unit 160, the determination unit 170, and the output unit 190 are processors. It may be realized by 201 and the memory 202, and the remaining functions may be realized by the processing circuit 203.

Further, the hardware of the main part of the obstacle detection device 100 other than the distance measuring sensor 110 is a D / A conversion circuit (not shown) for D / A conversion of the transmission signal generated by the transmission signal generation unit 120, or reception. The signal acquisition unit 130 may include an A / D conversion circuit (not shown) that A / D-converts the received signal received from the ranging sensor 110.

The processor 201 uses, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a microprocessor, a microcontroller, or a DSP (Digital Signal Processor).

The memory 202 uses, for example, a semiconductor memory or a magnetic disk. More specifically, the memory 202 includes a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), and an EPROM (Electrically Memory). It uses an HDD or the like.

The processing circuit 203 may be, for example, an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), an FPGA (Field-Programmable Gate Array), or a System-System (System) System Is used.

The operation of the obstacle detection device 100 according to the first embodiment will be described with reference to FIG.
FIG. 6 is a flowchart illustrating an example of processing of the obstacle detection device 100 according to the first embodiment.
The obstacle detection device 100, for example, repeatedly executes the processing of the flowchart.

First, in step ST601, the transmission signal generation unit 120 generates a transmission signal.
Next, in step ST602, the ranging sensor 110 radiates an exploration wave which is a transmission wave.
Next, in step ST603, the ranging sensor 110 acquires the reflected wave as a received wave.
Next, in step ST604, the reception signal acquisition unit 130 acquires the reception signal.
Next, in step ST605, the obstacle detection unit 140 determines whether or not an obstacle has been detected.
If it is determined in step ST605 that the obstacle detection unit 140 has not detected an obstacle, the obstacle detection device 100 ends the processing of the flowchart, returns to the processing of step ST601, and processes the flowchart. Is repeated.

When it is determined in step ST605 that the obstacle detection unit 140 has detected an obstacle, the obstacle detection unit 140 calculates the distance from the distance measuring sensor 110 to the obstacle in step ST606.
After step ST606, in step ST607, the obstacle detection unit 140 generates binary time series information.
After step ST607, in step ST608, the window setting unit 150 sets the time window.
After step ST608, in step ST609, the correlation calculation unit 160 acquires the correlation waveform.
After step ST609, in step ST610, the determination unit 170 determines that a person exists as an obstacle when a plurality of peaks are present in the correlation waveform.
After step ST610, in step ST611, the output unit 190 outputs determination information indicating the determination result determined by the determination unit 170.
After step ST611, the obstacle detection device 100 ends the processing of the flowchart, returns to the processing of step ST601, and repeatedly executes the processing of the flowchart.

As described above, the obstacle detection device 100 covers the range in which the distance measuring sensor 110 that transmits / receives a signal wave having a frequency equal to or lower than a predetermined frequency and the received signal indicated by the received wave received by the distance measuring sensor 110 exist. , The window setting unit 150 set as a window and the received signal existing in the window set by the window setting unit 150 are subjected to a correlation calculation using the transmission signal indicated by the transmission wave transmitted by the distance measuring sensor 110. The result of the determination by the correlation calculation unit 160 that acquires the correlation waveform, the determination unit 170 that determines that a person exists as an obstacle when the correlation waveform acquired by the correlation calculation unit 160 has a plurality of peaks, and the determination unit 170. It is provided with an output unit 190 for outputting determination information indicating the above.

With this configuration, the obstacle detection device 100 can increase the transmission power by widening the pulse width of the transmission wave and determine whether or not the detected obstacle is a person. Therefore, the obstacle detection device 100 can increase the transmission power by widening the pulse width of the transmitted wave, and can determine whether or not the obstacle existing in the distance is a person.
Further, the obstacle detection device 100 transmits and receives a signal wave having a frequency lower than a predetermined frequency, so that the distance measuring sensor 110 transmits and receives a high frequency exploration wave, and the atmospheric attenuation of the exploration wave is compared with the case where the exploration wave is transmitted and received. Since it is possible to reduce the number of obstacles, it is possible to determine whether or not an obstacle existing at a greater distance is a person.
Further, the obstacle detection device 100 transmits and receives a signal wave having a frequency lower than a predetermined frequency, so that the distance measuring sensor 110 transmits and receives a high frequency exploration wave. Since the sound absorption of waves can be reduced, it is possible to determine whether or not an obstacle existing farther away is a person.

Further, the obstacle detection device 100 determines according to the state of the received signal by setting the range in which the received signal indicated by the received wave received by the ranging sensor 110 exists as a window by the window setting unit 150. Since the range in which the unit 170 determines whether or not a plurality of peaks are present in the correlation waveform can be limited, the noise immunity can be improved. Therefore, in the obstacle detection device 100, the window setting unit 150 sets the range in which the received signal indicated by the received wave received by the ranging sensor 110 exists as a window, so that whether or not the obstacle is a person. Can be accurately determined.
Further, the obstacle detection device 100 can notify the user whether or not the obstacle is a person by outputting the result of determining whether or not the obstacle is a person to, for example, a display device. can.
Further, the obstacle detection device 100 can make the driving support device perform highly accurate driving support by outputting the result of determining whether or not the obstacle is a person to, for example, the driving support device. ..

Further, in the above configuration, the obstacle detection device 100 is configured such that the transmitted wave transmitted by the ranging sensor 110 is a modulated wave modulated by a signal having an autocorrelation equal to or higher than a predetermined autocorrelation.
With this configuration, the obstacle detection device 100 can determine that the received signal corresponds to the search wave reflected by the plurality of reflecting surfaces even when the distance between the reflecting surfaces is short. It is possible to accurately determine whether or not an obstacle is a person.

Further, in the obstacle detection device 100, in the above configuration, the transmission wave transmitted by the ranging sensor 110 is configured as a modulated wave modulated by phase modulation.
With this configuration, the obstacle detection device 100 can determine that the received signal corresponds to the search wave reflected by the plurality of reflecting surfaces even when the distance between the reflecting surfaces is short. It is possible to accurately determine whether or not an obstacle is a person.

Further, in the above-mentioned configuration, the obstacle detection device 100 configures the transmission wave transmitted by the ranging sensor 110 as a modulated wave modulated by frequency modulation.
With this configuration, the obstacle detection device 100 can determine that the received signal corresponds to the search wave reflected by the plurality of reflecting surfaces even when the distance between the reflecting surfaces is short. It is possible to accurately determine whether or not an obstacle is a person.

In the present invention, within the scope of the invention, it is possible to modify any component of the embodiment or omit any component in the embodiment.

The obstacle detection device according to the present invention can be applied to a vehicle or the like.

100 Obstacle detection device, 110 ranging sensor, 120 transmission signal generation unit, 130 reception signal acquisition unit, 140 obstacle detection unit, 150 window setting unit, 160 correlation calculation unit, 170 judgment unit, 190 output unit, 201 processor, 202 memory, 203 processing circuit.

Claims (4)

A ranging sensor that sends and receives signal waves with frequencies below a predetermined frequency,
A window setting unit that sets the range in which the received signal indicated by the received wave received by the ranging sensor exists as a window, and a window setting unit.
A correlation calculation unit that acquires a correlation waveform by performing a correlation calculation on the received signal existing in the window set by the window setting unit using the transmission signal indicated by the transmission wave transmitted by the ranging sensor. ,
When there are a plurality of peaks in the correlation waveform acquired by the correlation calculation unit, a determination unit that determines that a person exists as an obstacle, and a determination unit.
An output unit that outputs determination information indicating the result of the determination by the determination unit, and an output unit.
Obstacle detection device characterized by being equipped with. The obstacle detection device according to claim 1, wherein the transmitted wave transmitted by the distance measuring sensor is a modulated wave modulated by a signal having an autocorrelation equal to or higher than a predetermined autocorrelation. The obstacle detection device according to claim 2, wherein the transmitted wave transmitted by the distance measuring sensor is the modulated wave modulated by phase modulation. The obstacle detection device according to claim 2, wherein the transmitted wave transmitted by the distance measuring sensor is the modulated wave modulated by frequency modulation.

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