JP2012018613A - Vehicle peripheral obstacle monitoring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle peripheral obstacle monitoring device capable of improving a detection rate while suppressing a harmful influence on the obstacle detection performance of an ultrasonic sensor.SOLUTION: An image processing section 4 measures a position of an obstacle viewed from a vehicle based on image information of the periphery of the vehicle and recognizes a type of the obstacle. An ultrasonic sensor control section 3 controls a timing of transmitting ultrasonic waves transmitted from the ultrasonic sensor 1 based on a reflected wave selection threshold parameter and an ultrasonic wave transmission interval parameter, detects the obstacle at the periphery of the vehicle from information of the intensity of the received reflected wave, and measures a distance between the vehicle and the obstacle. A parameter adjusting section 5 adjusts a control parameter of the ultrasonic sensor control section 3 based on the processing result of the image processing section 4.

Description

  The present invention relates to a vehicle surrounding obstacle monitoring apparatus that measures a distance between a vehicle and an obstacle around the vehicle.

  In order to facilitate safety checks around the vehicle during driving, conventionally, devices such as clearance sonar and corner sensors are commonly used to detect obstacles and measure distances using ultrasonic sensors. Yes. Various ideas have been made to improve the detection accuracy of obstacles by these sensors and to expand the detection range.

  For example, there has been an obstacle detection device described in Patent Document 1 as a technique for detecting a two-wheeled vehicle that passes between a vehicle side surface and a road shoulder using an ultrasonic sensor attached to the vehicle side surface. This is because when the approach of a motorcycle is predicted from inter-vehicle communication, etc., the transmission interval of ultrasonic waves is made longer than before, and the threshold of reflected wave intensity for selecting a reflected wave regarded as an obstacle is lowered. This is a technology that enables detection of a motorcycle passing through the side of the vehicle.

JP 2008-299562 A

  However, in the device as described in Patent Document 1, the method for ensuring the distance information acquisition cycle within a certain value, the transmission interval of ultrasonic waves, and the threshold of reflected wave intensity are changed. There is no disclosure of avoiding adverse effects on performance such as a decrease in the accuracy of obstacle detection positions and a decrease in the information acquisition cycle.

By increasing the transmission interval of the ultrasonic sensor and increasing the waiting time until the reception of the reflected wave, it is possible to receive the reflected wave from a distant place that was ignored without waiting for the arrival of the reflected wave, The detectable distance is extended. However, in this case, since the delay time from when the obstacle appears until the detection result is notified becomes longer, the risk of collision with the obstacle becomes higher.
Moreover, when the threshold value of the reflected wave intensity is lowered to make it easy to detect an obstacle, there is a problem that the possibility of erroneous detection is increased due to the influence of noise.

  The present invention has been made to solve the above-described problems. Obstacle monitoring around a vehicle that can improve the detection rate while minimizing adverse effects on the obstacle detection performance of the ultrasonic sensor as much as possible. The object is to obtain a device.

  The vehicle surrounding obstacle monitoring device according to the present invention detects an obstacle from image information around the vehicle, and measures at least one of the position of the obstacle viewed from the vehicle and the recognition of the type of the obstacle. Based on the image processing unit that performs processing, control of the transmission timing of the ultrasonic wave transmitted from the ultrasonic sensor, detection of obstacles around the vehicle from the received reflected wave intensity information, the vehicle and the obstacle An ultrasonic sensor control unit that measures a distance to an object and a parameter adjustment unit that adjusts a control parameter of the ultrasonic sensor control unit based on a processing result of the image processing unit.

  The vehicle periphery obstacle monitoring device according to the present invention controls the ultrasonic sensor control unit that measures the distance between the vehicle and the obstacle using an ultrasonic sensor based on the output result of the image processing unit that acquires image information around the vehicle. Since the parameters are adjusted, the detection rate can be improved while minimizing adverse effects on the obstacle detection performance of the ultrasonic sensor.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows the vehicle periphery obstruction monitoring apparatus by Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the vehicle periphery obstruction monitoring apparatus by Embodiment 1 of this invention. It is explanatory drawing which shows the installation condition of the ultrasonic sensor and camera of the vehicle periphery obstacle monitoring apparatus by Embodiment 1 of this invention. It is explanatory drawing which shows the image of the vehicle periphery by the camera of the vehicle periphery obstruction monitoring apparatus by Embodiment 1 of this invention. It is explanatory drawing which shows the mode of the time series data of the voltage value according to the transmission interval of the ultrasonic wave of the vehicle periphery obstruction monitoring apparatus by Embodiment 1 of this invention, and the reflected wave to receive. It is explanatory drawing which shows the calculation method of the distance of an obstruction from the time series data of the reflected wave output voltage of the vehicle periphery obstruction monitoring apparatus by Embodiment 1 of this invention. It is explanatory drawing which shows presence of the obstruction on the image of the vehicle periphery obstruction monitoring apparatus by Embodiment 1 of this invention. It is a flowchart which shows the process which determines the parameter adjustment content of the vehicle periphery obstruction monitoring apparatus by Embodiment 1 of this invention. It is explanatory drawing which shows the example of the time change of the reflected wave selection threshold value of the vehicle periphery obstruction monitoring apparatus by Embodiment 1 of this invention. It is a flowchart which shows the parameter adjustment process of the vehicle periphery obstruction monitoring apparatus by Embodiment 2 of this invention. It is explanatory drawing which shows the change of the ultrasonic transmission period of the vehicle periphery obstruction monitoring apparatus by Embodiment 2 of this invention. It is explanatory drawing which shows the relationship between the ultrasonic sensor of the vehicle periphery obstruction monitoring apparatus by Embodiment 3 of this invention, and an obstruction. It is explanatory drawing which shows the relationship between the distance measurement area | region of the ultrasonic sensor of the vehicle periphery obstruction monitoring apparatus by Embodiment 3 of this invention, and an obstruction. It is a flowchart which shows the parameter adjustment process of the vehicle periphery obstruction monitoring apparatus by Embodiment 3 of this invention. It is a flowchart which shows the parameter adjustment process of the vehicle periphery obstruction monitoring apparatus by Embodiment 4 of this invention. It is explanatory drawing which shows operation | movement of the vehicle periphery obstruction monitoring apparatus by Embodiment 5 of this invention. It is explanatory drawing which shows operation | movement of the vehicle periphery obstruction monitoring apparatus by Embodiment 6 of this invention.

Embodiment 1 FIG.
1 is a block diagram showing a vehicle peripheral obstacle monitoring apparatus according to Embodiment 1 of the present invention.
The vehicle surrounding obstacle monitoring apparatus shown in FIG. 1 includes an ultrasonic sensor 1, a camera 2, an ultrasonic sensor control unit 3, an image processing unit 4, a parameter adjustment unit 5, and a display processing unit 6. The ultrasonic sensor 1 is a sensor for detecting an obstacle by sending an ultrasonic wave to a predetermined range around the vehicle and receiving the reflected wave. The received signal is controlled by the ultrasonic sensor. Part 3 is input. The camera 2 is a camera provided at a position close to the ultrasonic sensor 1 and acquires an image in the ultrasonic transmission direction of the ultrasonic sensor 1, and an output signal thereof is input to the image processing unit 4. The ultrasonic sensor control unit 3 intermittently transmits ultrasonic waves by applying a voltage to the ultrasonic sensor 1 at predetermined time intervals, and the voltage value corresponding to the reflected wave received by the ultrasonic sensor 1 ( This is a control unit that obtains time series data (hereinafter referred to as a reflected wave output voltage value), specifies a time when a reflected wave that can be regarded as being from an obstacle arrives, and calculates the distance of the obstacle. The ultrasonic sensor control unit 3 includes a reflected wave selection threshold parameter storage unit 7 that stores a reflected wave selection threshold parameter, and an ultrasonic transmission interval parameter storage unit 8 that stores an ultrasonic transmission interval parameter.

  The image processing unit 4 is a processing unit that performs measurement of the position of an obstacle, recognition of the type of obstacle, or both from an image obtained from the camera 2. The display processing unit 6 is a process for presenting the user with information about the current image around the vehicle and the position of the obstacle in the image based on the processing results in the image processing unit 4 and the ultrasonic sensor control unit 3. Part. The parameter adjustment unit 5 is a parameter used for processing of the ultrasonic sensor control unit 3 based on the distance value output from the ultrasonic sensor control unit 3 and the position and type of the obstacle output from the image processing unit 4. Outputs a command to change. The parameters to be changed are the reflected wave selection threshold parameter and the ultrasonic transmission interval parameter.

  The reflected wave selection threshold parameter selects, from the time-series data of the voltage value of the reflected wave received by the ultrasonic sensor 1, which time of the peak of the waveform is considered to be the reflected wave from the obstacle. This is a parameter indicating a threshold value of a voltage value used for the operation. The threshold value itself is called a reflected wave selection threshold value. For example, it is a parameter indicating a threshold value used in a process in which a time when a voltage value having a magnitude exceeding a certain threshold is observed is a time when a reflected wave from an obstacle is received. The ultrasonic transmission interval parameter is a parameter indicating the length of the time interval of ultrasonic burst wave transmission that is performed intermittently.

  FIG. 2 is a flowchart showing the processing contents of the vehicle surrounding obstacle monitoring apparatus according to Embodiment 1 of the present invention. With respect to the operation of the first embodiment, the configuration of each part will be described with reference to a flowchart, taking as an example the case where one ultrasonic sensor and one camera shown in FIG. 3 are attached to the vehicle.

  First, the image processing unit 4 acquires an image around the vehicle with the camera 2 (step ST1). The input image here is shown in FIG. Next, the image processing unit 4 extracts an area on the image in which a certain amount of optical flow appears as an obstacle candidate area (step ST2). Although an example in which an obstacle candidate area is extracted using an optical flow will be described here, other means may be used.

  Next, the image processing unit 4 determines whether or not an obstacle has been detected in the obstacle detection process of step ST2 (step ST3). If it is determined in step ST3 that an obstacle has been detected, the process proceeds to step ST4. If no obstacle is detected, the process proceeds to an ultrasonic transmission process (step ST7). Here, a case where no obstacle is detected will be described as an example. In this case, the process proceeds to step ST7.

  The ultrasonic sensor control unit 3 outputs a command to transmit ultrasonic waves to the ultrasonic sensor 1 at a time interval determined by the ultrasonic transmission interval parameter stored in the ultrasonic transmission interval parameter storage unit 8 (step ST7). ). Thereby, an ultrasonic wave is transmitted from the ultrasonic sensor 1.

Subsequent to step ST7, the ultrasonic sensor control unit 3 receives a reflected wave signal received by the ultrasonic sensor 1 (step ST8). FIG. 5 shows the state of time-series data of voltage values corresponding to the transmission interval of ultrasonic waves and the received reflected waves.
In FIG. 5, the period indicated by the ultrasonic wave transmission period (the part indicated by hatching) is the period during which ultrasonic waves are transmitted, and the period indicated by the reflected wave observation period (the part where hatching is not performed). The period during which the reflected wave is received is shown.

  Next, the ultrasonic sensor control unit 3 calculates the distance of the obstacle (step ST9) from the time-series data of the received reflected wave output voltage value output by the ultrasonic sensor 1. FIG. 6 is a diagram for explaining a method for calculating the distance of the obstacle from the time-series data of the reflected wave output voltage.

  First, the ultrasonic sensor control unit 3 searches for a waveform that exceeds the reflected wave selection threshold value (threshold value Vth in FIG. 6) specified by the reflected wave selection threshold parameter among the reflected wave waveforms. If it exists, the peak time t1 of the waveform in the vicinity of the portion where the reflected wave output voltage value exceeding the reflected wave selection threshold is observed is obtained.

  In the vehicle surrounding obstacle monitoring device, the purpose is to detect an obstacle that may cause a collision, and it is important to obtain the distance of the nearest obstacle. Therefore, in this example, the reflected wave output voltage is When the threshold value Vth is exceeded at a plurality of times, the earliest time is set as t1. However, this is not the case when it is known that the nearest obstacle may be ignored for other reasons.

Then, from the difference between the time t0 at the intermediate point in the immediately preceding ultrasonic wave transmission period and the time t1, the value obtained by dividing the elapsed time until reception of the reflected wave by 2 is divided by the current speed of sound to reach the obstacle. The distance is calculated. The calculation formula is shown below.
(Distance to obstacle) = (t1-t0) / (current sound speed) / 2

  Although the times t0 and t1 corresponding to the output wave and the reflected wave are the times at the peak of the waveform, the time when the ultrasonic wave starts to be transmitted and the time when the reflected wave output voltage value starts to exceed the threshold value Vth May be t0 and t1, respectively. Other combinations may be used.

As described above, the ultrasonic sensor control unit 3 measures the distance by assuming that there is a reflected wave from an obstacle only in a portion of the voltage waveform corresponding to the received reflected wave that exceeds the threshold value Vth. Therefore, regarding the first ultrasonic transmission in FIG. 5, the peak 51 of the reflected waves 51 and 52 is considered to be a reflected wave from an obstacle because it exceeds the threshold value Vth. Since the peak 52 does not exceed the threshold value Vth, it is ignored because it is not reflected wave from the obstacle but noise.
The above steps ST1 to ST9 are repeated.

The above is the processing flow when no obstacle is found in the image processing unit 4. Next, the flow of processing when an obstacle is found in step ST2 in the image processing unit 4 will be described.
The processing flow is the same up to the condition judgment (step ST3) in FIG. If an obstacle is found in the image processing unit 4, the process proceeds to step ST4. Here, a case will be described as an example in which the image processing unit 4 and the parameter adjusting unit 5 output that the obstacle o1 and the obstacle o2 exist in the region on the image surrounded by the double line in FIG.

  In this case, the image processing unit 4 estimates the position of the obstacle and recognizes the obstacle (step ST4). The estimated position of the obstacle is, for example, the attachment position of the camera 2 given in advance, assuming that the midpoint of the lowermost side of the obstacle area on the detected image is in contact with the horizontal road surface. It is obtained by calculating the coordinates on the road surface of the midpoint from the information on the mounting direction.

Next, the parameter adjustment part 5 performs the process (step ST5) which determines parameter adjustment content. A detailed flow of this processing is shown in FIG.
Assume that the positions of the two obstacles in FIG. First, it is determined whether or not the output position is in a region detectable by the ultrasonic sensor 1 (dotted line region 72 in FIG. 7) (condition determination (step ST501)). The process moves to step ST7 in FIG.

  If it is determined in step ST501 that the position of one of the obstacles o1 and o2 obtained by image processing is within the region 72 detectable by the ultrasonic sensor 1, the process proceeds to step ST502. In step ST502, the process of lowering the reflected wave selection threshold is performed only for the time corresponding to the vicinity of each obstacle position obtained in the image. An example of the time change of the reflected wave selection threshold when this processing is performed is shown in FIG.

  FIG. 9 shows a situation where an obstacle has not been found in the image processing unit 4 at the timing when the ultrasonic wave is transmitted for the first time, and has been discovered thereafter. At this time, the processing of the obstacle from the own vehicle is calculated from the position of the obstacle discovered by the image processing, and a time range corresponding to the vicinity of the position of the obstacle is obtained (ranges 91 and 92 in FIG. 9). . Then, the reflected wave selection threshold is lowered only for the time range (step ST502). On the other hand, the threshold value Vth of the time corresponding to the position where it is determined that there is no obstacle in the image processing is kept high without being changed.

By lowering the reflected wave selection threshold from the position information of the obstacle obtained from the image information around the vehicle, it is easy to exceed the reflected wave selection threshold even for a portion having a small voltage value among the received reflected waves. As a result, since the voltage value of the reflected wave is small for some reason such as the direction of the object, it is easy to detect an object that has been difficult to detect as an obstacle so far, and the obstacle detection rate is increased.
Furthermore, because the reflected wave selection threshold is kept high for positions that are not considered to be obstacles in the image, there may be obstacles that were not considered to be obstacles in the image. It is possible to suppress the ratio of erroneous detection due to noise picked up at a portion that is considered to be low.

  As described above, according to the vehicle surrounding obstacle monitoring apparatus of the first embodiment, the obstacle is detected from the image information around the vehicle, the position of the obstacle viewed from the vehicle, and the kind of the obstacle are detected. An image processing unit that performs at least one of the processes of recognition, control of the transmission timing of the ultrasonic wave transmitted from the ultrasonic sensor based on the control parameter, and information on the intensity of the reflected wave received from the surroundings of the vehicle An ultrasonic sensor control unit that detects an obstacle and measures a distance between the vehicle and the obstacle, and a parameter adjustment unit that adjusts a control parameter of the ultrasonic sensor control unit based on a processing result of the image processing unit Therefore, the detection area can be expanded and the detection rate can be improved while minimizing the adverse effects on the obstacle detection performance of the ultrasonic sensor.

  Further, according to the vehicle surrounding obstacle monitoring apparatus of the first embodiment, the parameter adjusting unit detects the obstacle when the obstacle is detected by the image processing unit and the position of the obstacle is within the predetermined range. Since the sensor control unit adjusts the control parameter in a direction to increase the possibility of detecting the obstacle, the obstacle can be detected accurately.

  In addition, according to the vehicle surrounding obstacle monitoring apparatus of the first embodiment, the parameter adjustment unit is a control parameter that increases the possibility of obstacle detection only for the position of the obstacle obtained by the image processing unit and its surroundings. For other positions, the control parameter is set so that the possibility of detecting an obstacle does not change, so that the detection rate can be improved and erroneous detection can be suppressed.

Embodiment 2. FIG.
In the second embodiment, as parameter adjustment, an ultrasonic transmission interval parameter that extends the reception waiting time of the reflected wave is used. Since the configuration on the drawing is the same as that of the first embodiment, description will be made with reference to FIG.
The parameter adjustment unit 5 according to the second embodiment uses the image processing unit 4 based on the result of performing at least one of the measurement of the position of the obstacle and the recognition of the type of the obstacle by the image processing unit 4. The control parameter of the ultrasonic sensor control unit 3 is adjusted so as to wait for reception of the reflected wave at a time interval corresponding to the time required for the reflected wave to reach from the measured position of the obstacle. is there. Since the configuration other than this is the same as that of FIG. 1, a description thereof is omitted here.

Next, the operation of the vehicle surrounding obstacle monitoring apparatus according to the second embodiment will be described.
The entire processing flow is as shown in FIG. 2 as in the first embodiment. However, since the processing contents (contents of step ST5 and step ST6) in the parameter adjustment unit 5 are different, only this part will be described. The arrangement of obstacles will be described by taking a case as shown in FIG. 3 as an example as in the first embodiment.

FIG. 10 is a flowchart of processing in the parameter adjustment unit 5 in the second embodiment.
Assume that the estimated positions on the road surface of the two obstacle candidate areas in FIG. 7 are obtained. First, it is determined whether or not the farthest estimated position of the obstacles o1 and o2 obtained by this image processing is in the current distance measurement region of the ultrasonic sensor (condition determination (step ST511)). If not, the process proceeds to the next condition judgment (step ST512).

  In FIG. 7, a broken line area 71 is the current distance measurement area. In the example, the obstacle o1 is at the farthest position, and this is in a state of being out of the current distance measurement area 71. In this case, the process proceeds to the next condition determination (step ST512).

  In the condition determination (step ST512), it is determined whether or not the position of the farthest obstacle candidate region is within the distance expansion possible region by the ultrasonic sensor 1. If yes, the process proceeds to the next condition judgment (step ST513). Note that the above-described distance-expandable area is the longest distance measurement area for the ultrasonic sensor 1. Since a reflected wave from a far distance is attenuated, there is a limit that can be received by the ultrasonic sensor 1 and a voltage having a certain magnitude can be output. Therefore, the above-described distance-expandable area is a finite area. In FIG. 7, a dashed-dotted area 72 is an area where the distance of the ultrasonic sensor 1 can be increased, and a candidate area for the obstacle o1 is included in this area 72. In such a case, the process proceeds to the next condition determination (step ST513).

Further, when the elapsed time from the extension of the previous ultrasonic transmission interval is equal to or greater than the set value (condition determination: step ST513), the reflected wave from the vicinity of the farthest estimated position obtained by the image processing is determined. The ultrasonic transmission interval parameter of the corresponding ultrasonic sensor 1 is adjusted only once so as to be long enough to be received (step ST514). The parameter is adjusted only once because a long period of time for outputting the detection result of the obstacle from the ultrasonic sensor control unit 3 is continuous. This is to avoid becoming. Taking into consideration the impression given to the user, such as flickering, the interval of acquiring distance data of distant obstacles is long by adjusting the ultrasonic transmission interval parameter intermittently, such as every few times, and acquiring the distance of nearby obstacles Operate to make the period as short as possible. FIG. 11 shows this state. Simultaneously with the ultrasonic wave transmission interval, as shown in the vicinity of the center of FIG. 11, the reflected wave selection parameter dynamically changes the threshold value Vth so that a weak reflected wave from a distance can be regarded as an obstacle. Thereby, not only the reflected wave 111 from the obstacle o2 at a short distance but also the reflected wave 112 from the obstacle o1 at a long distance can be received and the distance can be measured.
Also in the second embodiment, the processing from step ST1 to step ST9 in FIG. 2 is repeated.

  As described above, the time interval for detecting the obstacle and acquiring the distance with the ultrasonic sensor 1 only when it is determined to be necessary from the image processing result, that is, by extending the ultrasonic wave transmission interval, the image is obtained. Since nothing is found in the distance in the process and there is no possibility of an obstacle being present, it is unnecessary to wait for the arrival of reflected waves from a distance. Information on the distance of distant obstacles can be obtained while avoiding the constant increase in length. Further, by intermittently changing this ultrasonic wave transmission interval, it is possible to reduce the influence that the response time for obstacle detection becomes longer for nearby obstacles.

  In the first and second embodiments, the case where one ultrasonic sensor 1 is attached to the vehicle has been described, but the same applies to the case where a plurality of ultrasonic sensors 1 are attached to the vehicle. When a plurality of ultrasonic sensors 1 are attached, it is possible to determine whether or not to extend the ultrasonic transmission interval by performing the entire process of FIG. 2 or a part thereof for each sensor. As in the case of using this sensor, it is possible to obtain information on the distance of a distant obstacle while avoiding a waste of time and avoiding that the response time of the obstacle detection of the entire apparatus is constantly long. .

  In addition, instead of transmitting and receiving ultrasonic waves from the same ultrasonic sensor 1, any one ultrasonic sensor 1 may transmit and receive by another ultrasonic sensor 1.

  As described above, according to the vehicle surrounding obstacle monitoring apparatus of the second embodiment, the parameter adjustment unit is at least one of the measurement of the position of the obstacle and the recognition of the type of the obstacle by the image processing unit. The ultrasonic sensor control unit waits for reception of the reflected wave at a time interval corresponding to the time required for the reflected wave from the position of the obstacle measured by the image processing unit to arrive from the result of performing the process Since the control parameter is adjusted, it is possible to improve the detection rate while suppressing the adverse effect on the obstacle detection performance of the ultrasonic sensor as much as possible.

  Moreover, according to the vehicle surrounding obstacle monitoring apparatus of the second embodiment, the parameter adjustment unit intermittently performs the control parameter adjustment of the ultrasonic sensor control unit at predetermined time intervals. It is possible to reduce the influence that the detection response time becomes longer for nearby obstacles.

Embodiment 3 FIG.
In the third embodiment, the distance measurement area of the reflected wave is enlarged as parameter adjustment. Since the configuration on the drawing is the same as that of the first embodiment, description will be made with reference to FIG.
In the parameter adjusting unit 5 according to the third embodiment, when the obstacle is detected by the image processing unit 4 and the position of the obstacle is within a predetermined range, the ultrasonic sensor control unit 3 detects the obstacle. The control parameters are adjusted in the direction of increasing the possibility. That is, the parameter adjustment unit 5 outputs a reflected wave selection threshold parameter that enlarges the distance measurement region of the reflected wave. Since the configuration other than this is the same as that of FIG. 1, a description thereof is omitted here.

Next, the operation of the vehicle surrounding obstacle monitoring apparatus according to the third embodiment will be described.
The entire processing flow is as shown in FIG. 2 as in the first embodiment. However, since the processing contents (contents of step ST5 and step ST6) in the parameter adjustment unit 5 are different, this portion will be mainly described.

  The reflected wave is received by the ultrasonic sensor 1 but is excluded from the distance measurement target area in the output signal processing stage in the ultrasonic sensor control unit 3 (the reflected wave falls below the threshold Vth shown in FIG. 5 and the like). If an obstacle is detected by the image processing unit 4 in an area that is within the field of view of the camera 2, the distance measurement area of the ultrasonic sensor 1 is temporarily reduced by lowering the reflected wave selection threshold. Expanding.

  For example, as shown in FIG. 12A, due to the problem of spatial resolution in the horizontal direction (vertical direction in the figure) of the ultrasonic sensors 101 to 103, the obstacles o1 and o2 are located at positions outside the detection region during normal operation. Think if there is. In the image processing in the image processing unit 4, as shown in FIG. 13, when it is obtained that an obstacle exists at these positions, the ultrasonic sensor (ultrasonic sensor 103 in the illustrated example) is temporarily stored. The distance measurement area is enlarged to obtain distance information.

FIG. 14 is a flowchart of processing in the parameter adjustment unit 5 in the third embodiment.
Assume that the estimated positions on the road surface of the two obstacle candidate areas shown in FIG. 13 are obtained. First, it is determined whether or not the estimated position of the obstacle obtained by this image processing is in the current distance measurement region of the ultrasonic sensor (condition determination (step ST521)). The process proceeds to step ST522). In FIG. 13, the inside of the broken line frame indicates the current distance measurement region, and the positions of the obstacles o1 and o2 are out of the current distance measurement region. In this case, the process proceeds to the next condition determination (step ST522).

  In the condition determination (step ST522), it is determined whether or not the position of the obstacle candidate region is within the region where the width can be expanded by the ultrasonic sensors 101 to 103. If yes, the process proceeds to the next condition judgment (step ST523). In addition, this width expandable area | region is the widest distance measurement area | region (area | region where a receiving angle is the largest) about the ultrasonic sensors 101-103. As shown in FIG. 12 (b), the estimated positions of the obstacles o 1 and o 2 are within the widest distance measurement region in the ultrasonic sensor 103. In such a case, the process proceeds to the next condition determination (step ST523).

Further, when the elapsed time from the previous reflected wave selection parameter adjustment is equal to or greater than the set value (condition determination: step ST523), the reflected wave selection parameter is reflected from the vicinity of the estimated positions of the obstacles o1 and o2 obtained by the image processing. The reflected wave selection parameter of the corresponding ultrasonic sensor is adjusted only once so as to be wide enough to receive a wave (step ST524). The reason for adjusting the parameter only once is to avoid a permanent decrease in spatial resolution due to the continuous wide distance measurement region that outputs the obstacle detection result from the ultrasonic sensor control unit 3. Also in the third embodiment, the reflected wave selection threshold parameter is adjusted intermittently, such as every few times, in consideration of the impression given to the user such as flicker. By performing such processing, it is possible to obtain distance information of a wide range of obstacles while avoiding a constant decrease in spatial resolution.
Furthermore, also in Embodiment 3, the processing from step ST1 to step ST9 in FIG. 2 is repeated.

  As described above, according to the vehicle surrounding obstacle monitoring device of the third embodiment, the parameter adjusting unit detects an obstacle in the image processing unit and the position of the obstacle is within a predetermined range. In addition, the ultrasonic sensor control unit uses a control parameter that expands the distance measurement area to increase the possibility of obstacle detection, while minimizing the adverse effects on the obstacle detection performance of the ultrasonic sensor as much as possible. , Improvement in detection rate can be realized.

  Moreover, according to the vehicle surrounding obstacle monitoring apparatus of the third embodiment, the parameter adjustment unit intermittently performs the control parameter adjustment of the ultrasonic sensor control unit at predetermined time intervals. This can reduce the influence that the distance measurement area becomes wider for the obstacle near the center.

Embodiment 4 FIG.
In the fourth embodiment, as a parameter adjustment, the control parameter of the transmission interval of ultrasonic waves is adjusted based on the recognition result of the type of obstacle in the image processing unit 4. Since the configuration on the drawing is the same as that of the first embodiment, description will be made with reference to FIG.
The parameter adjustment unit 5 according to the third embodiment corresponds to the time required for the reflected wave from the position of the obstacle measured by the image processing unit 4 to arrive from the recognition result of the type of the obstacle by the image processing unit 4. The control parameter of the ultrasonic sensor control unit is adjusted so as to wait for reception of the reflected wave at a predetermined time interval. Since the configuration other than this is the same as that of FIG. 1, a description thereof is omitted here.

Hereinafter, the operation of the fourth embodiment will be described.
The overall processing flow is the same as that of the first embodiment, and the processing contents (contents of step ST5 and step ST6) in the parameter adjustment unit 5 are different. Therefore, only this part will be described. As in the first embodiment, the arrangement of obstacles will be described by taking the case of FIG. 3 as an example.
FIG. 15 is a flow of processing in the parameter adjustment unit 5.
If it is determined from the result of identification of the type of obstacle in the image processing unit 4 that this obstacle is an obstacle for which distance information should be acquired at high speed (condition judgment: step ST521), an ultrasonic transmission interval Is performed (step ST522). An obstacle from which distance information should be acquired at high speed is, for example, a person who may move at a relatively high speed. Identification of whether or not a person is, for example, is performed by paying attention to a moving part on the image and further performing identification processing based on knowledge of color and shape. Note that other methods may be used.

  Whether or not it is an obstacle for which distance information should be acquired at high speed is determined by whether or not the identification result of the type of obstacle is registered in the parameter adjustment unit 5 as that for which distance information should be acquired at high speed. And when it is judged that what should acquire distance information at high speed exists in the area | region currently monitored, it memorize | stores in the ultrasonic transmission interval parameter memory | storage part 8 so that an ultrasonic transmission interval may become short. Rewrite the value that is being used.

  As described above, the processing for accelerating the distance information acquisition cycle by the ultrasonic sensor 1 according to the obstacle based on the recognition result of the obstacle shortens the distance information acquisition cycle of the obstacle. Obstacles can be monitored at high speed, so that safer vehicle surroundings can be monitored.

  As described above, according to the vehicle surrounding obstacle monitoring apparatus of the fourth embodiment, the parameter adjusting unit detects the position of the obstacle measured by the image processing unit from the recognition result of the type of the obstacle by the image processing unit. The control parameter of the ultrasonic sensor control unit is adjusted to wait for the reception of the reflected wave at a time interval corresponding to the time required for the reflected wave to reach from the vehicle. It can be carried out.

Embodiment 5 FIG.
Embodiment 5 of the present invention will be described below with reference to the drawings.
In the fifth embodiment, a plurality of ultrasonic sensors 101 to 104 are used side by side in a vehicle 100 as shown in FIG. The overall processing flow is the same as in the first embodiment. However, since the processing contents (contents of step ST5 and step ST6) in the parameter adjustment unit 5 are different, only this part will be described. The arrangement of the obstacles o1 to o4 will be described by taking the case of FIG. 16 as an example.

  In the fifth embodiment, a series of processing from step ST5 to step ST9 in the ultrasonic sensor control unit 3 and parameter adjustment unit 5 described in the first embodiment is performed for each sensor, so that each sensor Adjust parameters, send and receive ultrasound, and measure distance to obstacles.

  In the parameter adjustment unit 5, before performing the condition determination in FIG. 10 (step ST511), the currently focused ultrasonic sensor is sandwiched between the other ultrasonic sensors (the other ultrasonic sensors are left and right). It is determined whether or not they are in a positional relationship, and the processes after step ST511 are performed only when the left and right are sandwiched between other ultrasonic sensors.

  In the case of FIG. 16, it is assumed that obstacles o1, o2, and o3 have been found as obstacle candidate regions by the image processing unit 4. In this case, for the ultrasonic sensors 102 and 103 that have the obstacle o2 and the obstacle o3 in the distance expansion possible region, the ultrasonic sensor 101 and the ultrasonic sensor 104 are adjacent to each other, and therefore the sensing rate is reduced. Process. On the other hand, for the ultrasonic sensor 104, the vicinity of the obstacle o1 is an area where the distance can be expanded, but since there is an area where there is no adjacent ultrasonic sensor, a process for extending the interval of transmitting ultrasonic waves is not performed. Also in the fifth embodiment, the ultrasonic transmission interval parameter is adjusted intermittently, such as every few times, in consideration of the impression given to the user such as flickering.

  In this way, by shortening the ultrasonic transmission interval of the ultrasonic sensors at both ends, obstacle detection processing is fast around the detection areas at both ends where there is a high possibility that obstacles will suddenly appear in the monitored area. For example, since the acquisition period of the distance information of the ultrasonic sensor 104 is extended in order to obtain the distance of the obstacle o1 of FIG. 16, the obstacle o4 approaching the ultrasonic sensor 104 is measured by the ultrasonic sensor. It is possible to avoid the occurrence of a dangerous situation where the detection is delayed and an obstacle starts to be detected suddenly at a short distance.

  As described above, according to the vehicle surrounding obstacle monitoring apparatus of the fifth embodiment, the parameter adjustment unit includes a detection area of another ultrasonic sensor adjacent to a detection area of the ultrasonic sensor currently focused on. Only in the case where the control parameter of the ultrasonic sensor control unit is adjusted so as to change the interval at which the ultrasonic wave is transmitted from the currently focused ultrasonic sensor, so that the detection rate can be improved. At the same time, the vehicle surroundings can be monitored more safely.

Embodiment 6 FIG.
Embodiment 6 of the present invention will be described below with reference to the drawings.
In the sixth embodiment, as shown in FIG. 17, a plurality of ultrasonic sensors 101 to 104 are used side by side as in the fifth embodiment. The overall processing flow is the same as in the first embodiment. However, since the processing contents (contents of step ST5 and step ST6) in the parameter adjustment unit 5 are different, only this part will be described. The arrangement of the obstacles o1 to o5 will be described by taking the case of FIG. 17 as an example.

  Before the parameter adjustment unit 5 performs the condition determination in FIG. 10 (step ST511), an obstacle is detected nearer than a predetermined distance by the ultrasonic sensor currently focused on or by an ultrasonic sensor adjacent thereto. If there is, the process after step ST511 is not performed for the ultrasonic sensor.

  In the case of FIG. 17, it is assumed that obstacles o1, o2, and o3 have been discovered by the camera 2 as obstacle candidate regions. In this case, for the ultrasonic sensors 101 and 102 having the obstacles o1 and o2 in the distance expandable area, no obstacle is detected by the ultrasonic sensors having the adjacent detection areas, and therefore the distance information acquisition cycle. Process to extend. On the other hand, for the ultrasonic sensor 103, since the obstacle o5 is detected by the adjacent ultrasonic sensor 104, the obstacle o3 exists in the area where the distance can be expanded, but the process of extending the ultrasonic wave transmission interval is performed. Absent.

  By doing this, the obstacle detection response is extended by extending the transmission interval of ultrasonic waves in areas where obstacles already exist in the adjacent area and obstacles are likely to appear suddenly in the monitored area. Since the time can be avoided, for example, when the period of distance information acquisition of the ultrasonic sensor 103 is extended, the obstacle o4 appears behind the obstacle o5, and the detection of the obstacle o4 is delayed. Thus, it is possible to avoid a situation in which an obstacle begins to be detected suddenly at a short distance.

  As described above, according to the vehicle surrounding obstacle monitoring apparatus of the sixth embodiment, the parameter adjusting unit is an ultrasonic sensor having a detection area adjacent to the detection area of the ultrasonic sensor currently focused on. Only when it is not detected, the control parameter of the ultrasonic sensor control unit is adjusted so as to change the interval at which ultrasonic waves are transmitted from the currently focused ultrasonic sensor, so that the detection rate can be improved. And safer monitoring of the surroundings of the vehicle.

  The embodiments described above may be used in combination. A part of the flow of each process described with reference to FIGS. 2, 8, 10, 14, and 15 may be omitted.

  1, 101-104 Ultrasonic sensor, 2 cameras, 3 ultrasonic sensor control unit, 4 image processing unit, 5 parameter adjustment unit, 6 display processing unit, 7 reflected wave selection threshold parameter storage unit, 8 ultrasonic transmission interval parameter storage Part, 100 vehicles.

Claims (7)

An image processing unit that detects an obstacle from image information around the vehicle and performs at least one of measurement of the position of the obstacle viewed from the vehicle and recognition of the type of the obstacle;
Based on the control parameters, control of the transmission timing of ultrasonic waves transmitted from the ultrasonic sensor, detection of obstacles around the vehicle from received reflected wave intensity information, measurement of the distance between the vehicle and the obstacles, An ultrasonic sensor control unit for performing
A vehicle peripheral obstacle monitoring device including a parameter adjustment unit that adjusts the control parameter of the ultrasonic sensor control unit based on a processing result of the image processing unit.   When the obstacle is detected by the image processing unit and the position of the obstacle is within a predetermined range, the parameter adjustment unit increases the possibility of the obstacle detection by the ultrasonic sensor control unit. The vehicle surrounding obstacle monitoring apparatus according to claim 1, wherein a control parameter is adjusted in a direction to perform.   The parameter adjustment unit is a control parameter that increases the possibility of detecting the obstacle only for the position of the obstacle obtained by the image processing unit and its surroundings, and the obstacle can be detected for other positions. The vehicle surrounding obstacle monitoring device according to claim 1, wherein the control parameter is such that the property does not change.   The parameter adjustment unit is configured to measure the obstacle measured by the image processing unit based on a result of performing at least one of the measurement of the position of the obstacle and the recognition of the type of the obstacle by the image processing unit. The control parameter of the ultrasonic sensor control unit is adjusted so as to wait for reception of the reflected wave at a time interval corresponding to the time required for the reflected wave from the position of the object to arrive. Vehicle surrounding obstacle monitoring device.   The vehicle surrounding obstacle monitoring device according to claim 1, wherein the parameter adjustment unit performs control parameter adjustment of the ultrasonic sensor control unit intermittently at predetermined time intervals.   The parameter adjustment unit transmits an ultrasonic wave from the currently focused ultrasonic sensor only when a detection area of another ultrasonic sensor is adjacent to a detection area of the currently focused ultrasonic sensor. The vehicle surrounding obstacle monitoring apparatus according to claim 1, wherein a control parameter of the ultrasonic sensor control unit is adjusted so as to change the interval.   The parameter adjustment unit detects the ultrasonic wave from the currently focused ultrasonic sensor only when an obstacle is not detected by the ultrasonic sensor having a detection area adjacent to the detection area of the currently focused ultrasonic sensor. The vehicle surrounding obstacle monitoring apparatus according to claim 1, wherein a control parameter of the ultrasonic sensor control unit is adjusted so as to change an interval of transmitting the sound.

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