JP2007139665A - Object detection device and object detection method - Google Patents

Object detection device and object detection method Download PDF

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JP2007139665A
JP2007139665A JP2005336232A JP2005336232A JP2007139665A JP 2007139665 A JP2007139665 A JP 2007139665A JP 2005336232 A JP2005336232 A JP 2005336232A JP 2005336232 A JP2005336232 A JP 2005336232A JP 2007139665 A JP2007139665 A JP 2007139665A
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distance
detection
object
continuity determination
reference value
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Shoichi Hayasaka
Hisashi Satonaka
祥一 早坂
久志 里中
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Toyota Motor Corp
トヨタ自動車株式会社
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Abstract

PROBLEM TO BE SOLVED: To provide an object detection device capable of accurately detecting the position of an object.
An object detection apparatus includes a sonar that emits an ultrasonic wave and detects a distance from the object from a reflection state of the ultrasonic wave, and repeatedly detects the distance from the object while moving the sonar. This is a device for detecting the position and contour of an object. The object detection apparatus 10 further includes a movement distance detection unit 41 that detects the movement distance of the sonar 50, and a distance between detection results obtained from the movement distance of the sonar 50 and the change amount of the detection distance. And a continuity determination unit 42 for determining the continuity of the detection result by determining whether or not it is within the continuity determination reference value set according to the above. The continuity determination unit 42 changes the continuity determination reference value to a larger value when the movement distance of the sonar 50 after the distance to the object starts to be detected exceeds a predetermined distance.
[Selection] Figure 1

Description

  The present invention relates to an object detection device and an object detection method.

Ultrasonic sensors that measure the time from transmission of a detection wave (ultrasonic wave) to reception of the reflected wave and detecting the distance from the measurement time and the propagation speed of the ultrasonic wave to the detection target are known (For example, refer to Patent Document 1). Patent Document 1 discloses an ultrasonic sensor that can prevent a decrease in distance detection accuracy due to noise by appropriately adjusting a detection threshold and a transmission output according to a noise level.
JP-A-9-150710

  However, even if the ultrasonic sensor described in Patent Document 1 is used, it is difficult to completely suppress variations in detection results. On the other hand, in general, an ultrasonic sensor has low directivity and has a characteristic that the detection range extends in a substantially elliptical shape with respect to the ultrasonic wave emission direction, and it is difficult to specify the ultrasonic reflection position (reflection direction). . Therefore, when there is no reflection point on the ultrasonic emission line, a deviation occurs between the distance from the detected object on the ultrasonic emission line and the actual detection distance. Further, this deviation varies depending on the positional relationship between the ultrasonic sensor and the detection object.

  Therefore, when the distance from the detection object is detected repeatedly while moving the ultrasonic sensor, and the position (arrangement) of the detection object is estimated from the detection result, due to the variation and deviation of the detection result described above. It is difficult to accurately classify the detected object to which each detection result belongs and to estimate the position of the detected object with high accuracy.

  The present invention has been made to solve the above-described problems, and can detect the position of an object with high accuracy using a sensor that detects the distance to the detected object from the reflected state of the emitted detection wave. An object is to provide an object detection device and an object detection method.

  An object detection apparatus according to the present invention includes a distance detection unit that emits a detection wave and detects a distance from the object from a reflection state of the detection wave, and repeatedly detects the distance to the object while moving the distance detection unit. Thus, in the object detection device for detecting the position of the object, the distance between the detection results obtained from the movement distance detection means for detecting the movement distance of the distance detection means and the amount of change in the distance between the movement distance and the object is Continuity determination means for determining the continuity of the detection result by determining whether or not it is within the continuity determination reference value set according to the moving distance, the continuity determination means, The continuity determination reference value is changed when a predetermined reference value change-over condition is satisfied.

  Further, the object detection method according to the present invention detects the position of the object by repeatedly detecting the distance to the object while moving the distance detection means for detecting the distance from the object from the reflected state of the emitted detection wave. In the object detection method, the distance between detection results obtained from the movement distance detection step for detecting the movement distance of the distance detection means and the amount of change in the distance between the movement distance and the object is set according to the movement distance. And a continuity determination step for determining the continuity of the detection results by determining whether or not they are within the sex determination reference value. In this continuity determination step, a predetermined reference value change condition is satisfied. In this case, the continuity determination reference value is changed.

  According to the object detection device or the object detection method of the present invention, the distance between two detection results included in a plurality of detection results acquired while moving the distance detection means is set according to the moving distance of the distance detection means. The continuity of the two detection results is determined based on whether or not they are within the continuity determination reference value. At that time, the continuity judgment reference value for judging the continuity between the detection results is changed when a predetermined reference change condition is satisfied. Appropriate judgment can be made accordingly. Therefore, the detected object to which each detection result belongs can be accurately classified, and the position of the object can be detected with higher accuracy.

  The continuity determination means may change the continuity determination reference value to a larger value when the moving distance of the distance detection means after the distance to the object starts to be detected exceeds a predetermined distance. preferable.

  In the continuity determination step, the continuity determination reference value is changed to a larger value when the moving distance of the distance detecting unit after the distance to the object starts to be detected exceeds a predetermined distance. It is preferable.

  For example, in order to detect the distance to an object such as a parked vehicle while moving along the object, when the distance detection means approaches the object from the near side, the detection range of the distance detection means expands in a substantially elliptical shape. When having the characteristic, the distance to the object is detected before the distance detecting means reaches the position of the object. Thus, in a situation where the distance detection device is positioned in front of the object and the detection wave is reflected at the end of the object, the movement amount of the detection wave reflection point with respect to the movement amount of the detection means is small. On the other hand, when the side surface of the object is moved substantially parallel to the object, the amount of movement of the detecting means and the amount of movement of the reflection point are substantially equal, and the amount of movement of the detecting means is compared with the case of being reflected at the end of the object. The amount of movement of the reflection point with respect to is increased.

  Accordingly, the amount of movement of the reflection point is small relative to the amount of movement of the distance detection means at the beginning of detection, for example, while the reflection point moves from the end of the object to the side surface, and the detection result becomes redundant. For this reason, in such an area, it is preferable to strictly determine continuity, that is, to tighten conditions for removing inappropriate detection results (noise). On the other hand, when the reflection point is on the side surface of the object, as described above, the movement amount of the reflection point with respect to the movement amount of the detection means becomes larger and the redundancy is reduced. Therefore, the continuity determination reference value is set larger. Therefore, it is preferable to make the determination of continuity (noise removal conditions) gentle.

  According to the object detection apparatus or the object detection method of the present invention, when the moving distance of the distance detection unit after the distance to the object starts to be detected exceeds a predetermined distance, the predetermined distance is exceeded. Compared with the case where there is no continuity, the continuity criterion value is changed to a larger value. For this reason, strict continuity judgment is made early in the detection period when the detection result is redundant to suppress variation in the detection result, and continuity judgment is moderated in an area where the redundancy is lowered, so that the It is possible to suppress that the detected detection result is erroneously determined not to be continuous.

  Preferably, the continuity determination means changes the continuity determination reference value to a larger value when the distance between detection results after the distance to the object starts to be detected exceeds a predetermined value.

  In the continuity determination step, the continuity determination reference value may be changed to a larger value when the distance between detection results after the distance to the object starts to be detected exceeds a predetermined value. preferable.

  In this case, since it is possible to determine whether the detection is in the initial stage based on the distance between the detection results after the distance to the object is detected, it is possible to obtain substantially the same effect as in the case described above. It becomes. In other words, continuity judgment is made stricter at the initial stage of detection when the detection result is redundant to suppress variations in the detection result, and in the region where the degree of redundancy is reduced, continuity judgment is moderated so It is possible to suppress that the detected detection result is erroneously determined not to be continuous.

  It is preferable that the continuity determination means changes the continuity determination reference value to a larger value when the ratio of the change amount with respect to the movement distance becomes smaller than a predetermined value set in advance.

  In the continuity determination step, it is preferable to change the continuity determination reference value to a larger value when the ratio of the change amount to the movement distance is smaller than a predetermined value set in advance.

  As described above, in the situation where the distance detection device is positioned in front of the object and the detection wave is reflected at the end of the object, the movement of the detection means is small because the movement amount of the reflection point is small relative to the movement amount of the detection means. Along with this, the detection distance becomes shorter. This tendency increases as the distance between the distance detecting means and the object increases. That is, as the distance between the distance detection unit and the object increases, the ratio of the change amount of the detection distance to the movement amount of the distance detection unit increases. On the other hand, when the side surface of the object is moved substantially parallel to the object, the ratio of the change amount of the detection distance to the movement amount of the detection means is substantially constant.

  According to the object detection device or the object detection method of the present invention, it is possible to determine whether the detection is in the initial stage based on the ratio of the change amount with respect to the movement distance using the above-described characteristics. By changing the continuity determination reference value to a larger value when the ratio of the amount is smaller than a predetermined value set in advance, it is possible to obtain substantially the same effect as described above. In other words, continuity judgment is made stricter at the initial stage of detection when the detection result is redundant to suppress variations in the detection result, and in the region where the degree of redundancy is reduced, continuity judgment is moderated so It is possible to suppress that the detected detection result is erroneously determined not to be continuous.

  In the object detection apparatus according to the present invention, the smaller the ratio of the change amount to the movement distance, the larger the angle formed by the straight line connecting the distance detection means and the estimated reflection position of the detection wave and the movement locus of the distance detection means. The reflection position estimation means for setting the estimated reflection position as described above is provided, and the continuity determination means switches the continuity determination reference value to a larger value when the angle becomes larger than a predetermined angle set in advance. It is preferable.

  Further, in the object detection method according to the present invention, the smaller the ratio of the change amount to the movement distance, the more the angle formed between the straight line connecting the distance detection means and the estimated reflection position of the detection wave and the movement locus of the distance detection means. A reflection position estimation step for setting an estimated reflection position so as to increase, and in the continuity determination step, the continuity determination reference value is set to a larger value when the angle is larger than a predetermined angle set in advance. It is preferable to change it.

  According to the object detection apparatus or the object detection method of the present invention, the distance detection means utilizes the fact that the ratio of the change amount of the detection distance to the movement amount of the distance detection means is substantially equal to the tangent in the normal direction of the object plane. The smaller the ratio of the change in the detection distance to the amount of movement, the rotation of the reflection position of the detection wave is corrected so that the angle formed by the straight line connecting the distance detection means and the reflection position and the movement locus of the distance detection means becomes larger. Is done. Here, since it is possible to determine whether the detection is in the initial stage based on the angle, the continuity determination reference value is changed to a larger value when the angle becomes larger than a predetermined angle set in advance. As a result, it is possible to obtain substantially the same effect as described above. In other words, at the initial stage of detection, the judgment of continuity is made strict to prevent the detection result from becoming redundant to prevent the estimated reflection position after rotation correction from concentrating on the edge of the object, and the redundancy is reduced. By making the determination of continuity in a region to be moderated, it is possible to suppress that a continuous detection result is erroneously determined to have no continuity during detection.

  The continuity determination means preferably removes the detection result as noise when the detection result does not fall within the continuity determination reference value.

  In the continuity determination step, when the detection result does not fall within the continuity determination reference value, the detection result is preferably removed as noise.

  If the detection result does not fall within the continuity criterion value, that is, if the interval between the two detection results is larger than the continuity criterion, the detection result that does not fall within the continuity criterion value is judged as noise. By removing the variation in detection results, the detection accuracy of the object position can be improved.

  Preferably, the continuity determination means separates the detection results when the detection results are not continuously within the continuity determination reference value.

  In the continuity determination step, it is preferable that the detection results are separated when the detection results are not continuously within the continuity determination reference value.

  If the detection results are not continuously within the continuity criterion value, that is, if the interval between one detection result and each of the other two detection results is greater than the continuity criterion, the former and the latter Is detected as a detection result of different objects, and the detection results for different objects can be separated with high accuracy.

  According to the present invention, the continuity of the detection results is determined by determining whether the distance between the detection results is within a continuity determination reference value set according to the moving distance of the distance detection means. At the same time, when the predetermined reference value change condition is satisfied, the continuity determination reference value is changed, so the distance detection means for detecting the distance from the detection object from the reflected state of the detected detection wave is moved. In the object detection apparatus that repeatedly detects the distance to the object while detecting the position of the object, it is possible to accurately classify the detected object to which each detection result belongs and to detect the position of the object with high accuracy.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the figure, the same reference numerals are used for the same or corresponding parts. Here, the object detection device and the object detection method according to the embodiment will be described by taking as an example a case where the present invention is applied to a parking assistance device that supports movement to a target parking position set by automatic steering or steering assistance.

  First, the structure of the parking assistance apparatus 1 comprised including the object detection apparatus 10 which concerns on embodiment is demonstrated using FIG. FIG. 1 is a block diagram illustrating a configuration of a parking assistance device 1 including an object detection device 10.

  The parking assist device 1 supports the operation of garage entry and parallel parking by performing steering control in addition to the video and audio guidance behind the vehicle displayed on the monitor screen. The vehicle includes a travel control device 20 and an automatic steering device 30, and is controlled by a parking assist ECU 40 that is an electronic control device. The parking assist ECU 40 includes a CPU, a ROM, a RAM, an input signal circuit, an output signal circuit, a power supply circuit, and the like, and includes a movement distance detection unit 41 that controls the object detection device 10, a continuity determination unit 42, and a reflection position estimation unit. 43, a traveling control unit 44 that controls the traveling control device 20, and a steering control unit 45 that controls the automatic steering device 30. The movement distance detection unit 41, the continuity determination unit 42, the reflection position estimation unit 43, the travel control unit 44, and the steering control unit 45 may be separated in hardware in the parking assist ECU 40. The same CPU, ROM, RAM, or the like may be used for and may be divided by software.

  The parking assist ECU 40 calculates and predicts each guide line created based on position information such as a parked vehicle input from the object detection device 10 and a vehicle state signal input from the travel control device 20 or the automatic steering device 30. The video and the video behind the vehicle are combined and output to the monitor screen, and the control signals are output to the automatic steering device 30 and the travel control device 20 based on the above information and signals, so that each control of parking assistance can be performed. Execute.

  For example, a sonar (ultrasonic sensor) 50 that detects a distance from an object such as a parked vehicle is disposed in the vehicle on which the parking assist device 1 is mounted. Input to the parking assist ECU 40. For example, the sonar 50 periodically transmits an ultrasonic wave (detection wave) and determines whether or not an object such as a parked vehicle exists according to the time until the reflected wave is received. The distance to the object is detected. That is, the sonar 50 functions as a distance detection unit. A laser radar or the like may be used instead of the sonar 50.

  The parking support ECU 40 includes a support mode changeover switch 51 for selecting a parallel parking support mode or a garage storage support mode by a driver's operation for parking support, a rear camera 52 for acquiring an image behind the vehicle, and wheels of each wheel. A wheel speed sensor 63 for detecting the speed is connected, and an output signal of the support mode changeover switch 51, an image signal acquired by the rear camera 52, and an output signal of the wheel speed sensor 63 are input. The parking assist ECU 40 is also connected to a monitor 53 that displays information by an image to the driver and a speaker 54 that presents information by voice.

  The object detection apparatus 10 includes the above-described movement distance detection unit 41, continuity determination unit 42, reflection position estimation unit 43, sonar 50, support mode changeover switch 51, and wheel speed sensor 63.

  The movement distance detection unit 41 calculates the movement distance of the vehicle every predetermined time, that is, the movement distance of the sonar 50 attached to the vehicle, from the vehicle speed obtained based on the output of the wheel speed sensor 63. Thus, the wheel speed sensor 63 and the parking assist ECU 40 function as a movement distance detection unit and execute a movement distance detection step.

  The continuity determination unit 42 calculates the distance between two detection results included in a plurality of detection results repeatedly acquired while moving the sonar 50 along a parked vehicle or the like, and the sonar 50 obtained by the movement distance detection unit 41. And the amount of change in the distance from the object detected by the sonar 50 (hereinafter referred to as “detection distance”), and the distance between the two obtained detection results depends on the movement distance of the sonar 50 The continuity of both detection results is determined by determining whether or not the value is within the set continuity determination reference value.

  Here, when the detection result does not fall within the continuity determination reference value, that is, when the interval between the two detection results is larger than the continuity determination reference value, the detection result that does not fall within the continuity determination reference value is regarded as noise. Judge and remove. In addition, when the detection results are not continuously within the continuity determination reference value, that is, when the interval between a certain detection result and each of the other two consecutive detection results is larger than the continuity determination criterion. The former and the latter are judged as different object detection results and separated. Note that the continuity determination reference value for determining the continuity between detection results is changed when a predetermined reference change-over condition is satisfied. Details will be described later. That is, the continuity determination unit 42 functions as continuity determination means and executes a continuity determination step.

  The reflection position estimation unit 43 estimates the reflection position of the ultrasonic wave emitted from the sonar 50 from the detection distance and the movement distance of the sonar 50 with respect to the detection result after being filtered by the continuity determination unit 42. The position of the object (for example, the parking position of the parked vehicle) and the contour are estimated. At that time, the smaller the ratio of the change amount of the detection distance to the movement amount of the sonar 50, the larger the angle formed by the straight line connecting the sonar 50 and the reflection position and the movement locus of the sonar 50. By correcting the reflection position (hereinafter referred to as “rotation correction”) so that the reflection position is projected onto the movement trajectory of the sonar 50, the smaller the ratio of the change amount of the detection distance to the movement amount of the sonar 50 is, the smaller the reflection position is. The reflection position is corrected so that the projected reflection position is located closer to the sonar 50. That is, the reflection position estimation unit 43 functions as reflection position estimation means and executes a reflection position estimation step.

  In addition, as a pre-process for performing the above-described rotation correction, the reflection position estimation unit 43 may approximate the point sequence formed by the filtered detection result by a straight line or a curve in addition to the continuity determination. Good.

  The travel control device 20 includes the travel control unit 44 described above, a braking system, and a drive system. The braking system is an electronically controlled brake (ECB) system in which the braking force applied to each wheel is electronically controlled by the brake ECU 60, and the brake hydraulic pressure applied to the wheel cylinder 61 of the hydraulic brake disposed on each wheel is controlled by the actuator 62. By adjusting, it has the function to adjust independently the braking force given to each wheel.

  The brake ECU 60 includes an acceleration sensor 64 that detects the acceleration of the vehicle, an actuator 62, a hydraulic sensor group (not shown) that detects the hydraulic pressure applied to the inside and the wheel cylinder 61, and a brake pedal 65. Each output signal of a master cylinder (M / C) oil pressure sensor 67 for detecting the oil pressure of the master cylinder 66 connected between the actuator 62 is input. The brake ECU 60 also receives an output signal from the wheel speed sensor 63 described above.

  The engine 71 constituting the drive system is controlled by the engine ECU 70, and the engine ECU 70 and the brake ECU 60 communicate with each other and perform cooperative control with the travel control unit 44.

  The automatic steering device 30 includes a drive motor 82 that also serves as a power steering device disposed between the steering wheel 80 and the steering gear 81, and a displacement sensor 83 that detects a displacement amount of the steering, and the steering control unit 45 is driven. While controlling the drive of the motor 82, the output signal of the displacement sensor 83 is input.

  Next, the operation of the object detection device 10 and the object detection method during parking support control will be described with reference to FIGS. More specifically, as shown in FIG. 2, an example is garage entry support in which the host vehicle MC once passes in front of the parked vehicles PC1 and PC2 and then moves backward and parks between the parked vehicles PC1 and PC2. explain. FIG. 2 is a diagram showing a travel route of the host vehicle MC in the garage entry support.

  When the object detection device 10 passes in front of the parked vehicle PC1, the sonar 50 repeatedly detects the distance from the parked vehicle PC1 intermittently. Here, FIG. 3 schematically shows an example of a point sequence representing a detection result when the vehicle is detected while passing in front of the parked vehicle PC1. Since the parked vehicle PC2 is the same as or similar to the parked vehicle PC1, description thereof is omitted here. In FIG. 3, “□” indicates the movement trajectory of the sonar 50. More specifically, the host vehicle MC to which the sonar 50 is attached moves in front of the parked vehicle PC1 in the right direction (arrow A1 direction) in FIG. The trajectory is shown. On the other hand, “◯” in FIG. 3 is a point representing a detection result detected while the sonar 50 moves along the trajectory. In the present embodiment, points indicating detection results are plotted at positions separated by a detection distance in a direction perpendicular to the direction of ultrasonic emission, that is, the moving direction of the sonar 50 (the traveling direction of the host vehicle MC).

  In the continuity determination unit 42 constituting the object detection device 10, the distance between two detection results included in the obtained point sequence is the change in the movement distance and detection distance of the sonar 50 obtained by the movement distance detection unit 41. Both detection results by determining whether the distance between the two obtained detection results is within the continuity determination reference value set according to the movement distance of the sonar 50. Are detected, and detection results that are not within the continuity determination reference value, that is, detection results that are not continuous with other detection results (hereinafter referred to as “noise”) are removed. Here, the noise removal method will be described more specifically with reference to FIG.

First, coordinate information of three points (a ′, b ′, c ′ in FIG. 4) is acquired from the point sequence, and the point a ′ is calculated from the movement distance a of the sonar 50 by the following equation (1). A continuity determination reference value c as a reference is calculated.
c = A × a (1)
However, A is a coefficient. The coefficient A is obtained when the movement distance of the sonar 50 after the detection result starts to be acquired, that is, when the distance from the parked vehicle PC1 starts to be detected exceeds a predetermined value (for example, 50 cm). Can be changed. In addition, this predetermined value is set to the distance which can be confident that it is an object (a parked vehicle in this embodiment) which should be detected, for example.

  Here, the process of changing the coefficient A, that is, the process of changing the continuity determination reference value c will be described with reference to FIG. FIG. 6 is a flowchart showing a processing procedure of the continuity determination reference value transfer process. This process is repeatedly executed at a predetermined timing from when the parking assist ECU 40 is turned on until it is turned off.

  In step S100, a determination is made as to whether a distance from an obstacle has been detected. Here, when the distance from the obstacle is not detected, that is, when the obstacle is not detected, the process is temporarily exited. On the other hand, if the distance from the obstacle is detected, the process proceeds to step S102.

  In step S102, the movement distance of the sonar 50 is read. Then, in the subsequent step S104, it is determined whether or not the movement distance of the sonar 50 after the distance from the obstacle starts to be detected is equal to or less than a predetermined value (50 cm in the present embodiment). Here, when the movement distance of the sonar 50 after the distance to the obstacle starts to be detected is equal to or less than the predetermined value, the process proceeds to step S106. On the other hand, when the moving distance of the sonar 50 exceeds the predetermined value, the process proceeds to step S108.

In step S106, a smaller value (for example, 2 1/2 ) is set as the coefficient A as compared with the case where the movement distance of the sonar 50 exceeds a predetermined value. Therefore, the continuity determination reference value c in this case is (2 1/2 ) a.

  On the other hand, in step S108, a larger value (for example, 2) is set as the coefficient A than when the movement distance of the sonar 50 is equal to or less than a predetermined value. Therefore, the continuity determination reference value c in this case is 2a. Thus, the continuity determination reference value c is changed to a larger value when the movement distance of the sonar 50 after the distance from the obstacle starts to be detected exceeds a predetermined value.

  Returning to FIG. The continuity determination unit 42 determines whether or not the point b 'is located within the continuity determination reference value c with respect to the point a'. This determination can be made by determining whether or not the distance between the points a ′ and b ′ obtained from the movement distance a of the sonar 50 and the change amount Δd1 of the detection distance is equal to or less than the continuity determination reference value c. Here, when the point b 'is not located within the continuity determination reference value c, the point b' is determined as noise. On the other hand, when the point b 'is located within the continuity determination reference value c, the point b' is treated as valid data.

Further, a continuity determination reference value d corresponding to the movement distance (a + b) of the sonar 50 is calculated by the following equation (2).
d = A × (a + b) (2)
Here, since the coefficient A is obtained by the same method as described above, the description thereof is omitted here. Then, a determination is made as to whether or not the point c ′ is located within the continuity determination reference value d with respect to the point a ′. In this determination, as in the above case, it is determined whether the distance between the points a ′ and c ′ obtained from the movement distance a + b of the sonar 50 and the change amount Δd2 of the detection distance is equal to or less than the continuity determination reference value d. Can be done. Here, when the point c ′ is located within the continuity determination reference value d, the point c ′ is treated as valid data, and the point b ′ is removed as noise.

  The noise is removed from the detection result (point sequence) of the sonar 50 by sequentially repeating the noise removal processing described above for other points constituting the point sequence.

  Subsequently, the continuity determination unit 42 separates the detection results by determining whether the detection results are continuously within the continuity determination reference value. In other words, if the interval between one detection result and each of the other two detection results is larger than the continuity criterion, the former and the latter are judged to be different object detection results and are separated. Detection results belonging to the object are separated (hereinafter also referred to as “grouping”). Here, the point grouping method will be described more specifically with reference to FIG.

  First, the continuity determination reference value c based on the point a ′ is calculated by the above equation (1) according to the moving distance a of the sonar 50, and the continuity corresponding to the moving distance (a + b) of the sonar 50 is calculated. The judgment reference value d is calculated by the above formula (2). In this case, the coefficient A is obtained by the same method as described above.

  Then, a determination as to whether the point b ′ is located within the continuity determination reference value c with reference to the point a ′, and the point c ′ within the continuity determination reference value d with reference to the point a ′ A determination is made as to whether or not it is located. Here, when the point b ′ is not positioned within the continuity determination reference value c and the point c ′ is not positioned within the continuity determination reference value d, the point sequence is separated at the reference point a ′. Each separated point sequence is separated into another group. When only the point b ′ is not located within the continuity determination reference value, the point b ′ is removed as noise as described above.

  The grouping of point sequences is performed by sequentially repeating the grouping process described above for other detection results constituting the point sequence. Further, the linear approximation and / or the curve approximation may be performed on the point sequence after the growing by using an algorithm such as RANSAC (Random Sample Consensus). Here, RANSAC is to select a minimum necessary number of data from all data at random, calculate a constraint parameter from the selected data, and evaluate the validity of the value from the remaining data. This is a method of adopting a value obtained by performing the operation many times and obtaining the maximum evaluation and data supporting it. This makes it possible to estimate both correct parameters and correct data at the same time. More specifically, random approximation line candidate setting and evaluation of the approximation degree of the approximation line candidate according to the distance between the approximation line candidate and each point constituting the point sequence are repeatedly performed. Let the highest approximate line candidate be an approximate line.

Subsequently, the reflection position estimation unit 43 calculates the rotation correction angle for the point sequence after the straight line or curve approximation. More specifically, as shown in FIG. 7, the rate of change of the detected distance d n to the movement amount l n of the sonar 50 is utilized to become substantially equal to the normal direction of the tangent of the object surface, the following Based on the equation (3), the rotation correction angle φ n is calculated for each point P n constituting the point sequence. And each point Pn is rotationally corrected based on the calculation result.
Rotation correction angle φ n = atan {(d n + 1 -d n) / l n} ··· (3)
However, n is a natural number.

Here, "□" S n in FIG. 7 shows the change in the position of the sonar 50 when the vehicle has moved in the right direction (arrow A2 direction) from the left side of FIG. In FIG. 7, “◯” P n indicates a detection result after pre-processing (hereinafter also referred to as “estimated reflection point (estimated reflection position) before correction”).

For example, when the detection distance when the sonar 50 is positioned at S 1 is d 1 , the estimated reflection point before correction is P 1 . In addition, when the detection distance when positioned at S 2 is d 2 , the estimated reflection point before correction is P 2 . Here, the correction angle calculation method will be described using these two points as an example. First, the rotation correction angle φ 1 is calculated by substituting the detection distances d 1 and d 2 and the movement amount l 1 which is the interval between S 1 and S 2 into the above equation (3). Next, the estimated reflection point P 1 ′ after rotation correction is obtained by rotating the estimated reflection point P 1 in the traveling direction by the obtained rotation correction angle φ 1 .

Further, by performing rotation correction in the same manner for the other estimated reflection points P n , a point sequence constituted by the estimated reflection points P n ′ after rotation correction is acquired. In the case where the rate of change of the detected distance to the movement amount l n (d n + 1 -d n) is decreasing is rotated corrected ahead in the traveling direction, it is rotated corrected rearwardly when increasing. As described above, the parking position and contour of the parked vehicle PC1 are acquired.

Here, the point sequence before correction and the point sequence after rotation correction are shown in FIG. In FIG. 8, “□” indicates the estimated reflection point P n before correction, and “▲” indicates the estimated reflection point P n ′ after rotation correction. In FIG. 8, “◯” indicates a true parking position. As shown in FIG. 8, the estimated reflection point P n ′ after the rotation correction matches the true parking position better than the estimated reflection point P n before the correction.

  In order to detect the distance from an object such as a parked vehicle while moving along the object, when the sonar 50 approaches the object from the near side, the detection range of the sonar 50 has a characteristic of spreading in a substantially elliptical shape. The distance from the object is detected before the sonar 50 reaches the position of the object. In this manner, in a situation where the sonar 50 is positioned in front of the object and the ultrasonic wave is reflected at the end of the object, the moving amount of the ultrasonic reflection point is small relative to the moving amount of the sonar 50. On the other hand, when the side surface of the object moves substantially parallel to the object, the amount of movement of the sonar 50 and the amount of movement of the reflection point are substantially equal, and the amount of movement of the sonar 50 as compared to the case of being reflected at the end of the object. The amount of movement of the reflection point with respect to is increased.

  Therefore, the amount of movement of the reflection point is small relative to the amount of movement of the sonar 50 during the initial detection, for example, while the reflection point moves from the end of the object to the side surface, and the detection result becomes redundant. For this reason, in such an area, it is preferable to strictly determine continuity, that is, to tighten conditions for removing inappropriate detection results (noise). On the other hand, when the reflection point is on the side surface of the object, as described above, the movement amount of the reflection point with respect to the movement amount of the sonar 50 becomes larger and the redundancy decreases, so the continuity determination reference value is set larger. Therefore, it is preferable to make the determination of continuity (noise removal conditions) gentle.

  According to the present embodiment, when the movement distance of the sonar 50 after the distance from an object such as a parked vehicle starts to be detected exceeds a predetermined distance, the continuity determination reference value becomes a larger value. Can be changed. For this reason, strict continuity judgment is made early in the detection period when the detection result is redundant to suppress variation in the detection result, and continuity judgment is moderated in an area where the redundancy is lowered, so that the It can suppress that the detection result currently performed is judged that there is no continuity accidentally. As a result, the position and contour of the object can be detected with higher accuracy.

  According to the present embodiment, when the detection result does not fall within the continuity determination reference value, that is, when the interval between the two detection results is larger than the continuity determination reference value, the detection result does not fall within the continuity determination reference value. The detection result is removed as noise. As a result, variations in detection results are suppressed, and the object position detection accuracy can be improved.

  Further, according to the present embodiment, when the detection results do not continuously fall within the continuity determination reference value, that is, the interval between one detection result and each of the other two detection results is based on the continuity determination criterion. Is larger, the former and the latter are judged to be different object detection results and separated, so that the detection results for different objects can be accurately separated.

  Next, a second processing form of the continuity determination reference value transfer process will be described with reference to the flowchart shown in FIG. This second processing form is a modification of the above-described first processing form, and as shown in FIG. 9, the first processing is performed in that steps S102a and S104a are executed instead of the above-described steps S102 and S104. It differs from the form. Since the other processing steps are the same as those in the first processing mode, description thereof is omitted here.

  In the second processing mode, the distance between detection results is read in step S102a. Note that the distance between detection results can be obtained from the movement distance of the sonar 50 and the amount of change in the detection distance, as described above. Then, in the subsequent step S104a, a determination is made as to whether or not the distance between the detection results after the distance from the obstacle has been detected is a predetermined value (for example, 70 cm) or less. Here, when the distance between the detection results after the distance from the obstacle starts to be detected is equal to or smaller than the predetermined value, the process proceeds to step S106 described above. On the other hand, when the distance between detection results exceeds a predetermined value, the process proceeds to step S108 described above. As described above, in the second processing mode, the continuity determination reference value is changed to a larger value when the distance between detection results after the distance from the obstacle starts to be detected exceeds a predetermined value.

  According to this processing mode, since it is determined whether or not detection is in the initial stage based on the distance between detection results after the distance to an object such as a parked vehicle has started to be detected, this is substantially the same as the first processing mode described above. An equivalent effect can be obtained. In other words, continuity judgment is made stricter at the initial stage of detection when the detection result is redundant to suppress variations in the detection result, and in the region where the degree of redundancy is reduced, continuity judgment is moderated so It can suppress that the detection result currently performed is judged that there is no continuity accidentally. As a result, the position and contour of the object can be detected with higher accuracy.

  Next, a third processing mode of the continuity determination reference value transfer process will be described with reference to the flowchart shown in FIG. This third processing form is a modification of the above-described first processing form. As shown in FIG. 10, the first processing is performed in that steps S102b and S104b are executed instead of the above-described steps S102 and S104. It differs from the form. Since the other processing steps are the same as those in the first processing mode, description thereof is omitted here.

  In the third processing mode, in step S102b, the ratio of the change amount of the detection distance to the movement distance of the sonar 50 is calculated. Then, in the subsequent step S104b, a determination is made as to whether this ratio is equal to or greater than a predetermined value. If the ratio is greater than or equal to the predetermined value, the process proceeds to step S106 described above. On the other hand, when the ratio is less than the predetermined value, the process proceeds to step S108 described above. Thus, in the third processing mode, the continuity determination reference value is changed to a larger value when the ratio of the change amount of the detection distance to the movement distance of the sonar 50 becomes smaller than the predetermined value.

  As described above, in a situation where the sonar 50 is positioned in front of the object and the detection wave is reflected at the end of the object, the amount of movement of the reflection point with respect to the amount of movement of the detection means is small. Detection distance is shortened. This tendency increases as the distance between the sonar 50 and the object increases. That is, as the distance between the sonar 50 and the object increases, the ratio of the change amount of the detection distance to the movement amount of the sonar 50 increases. On the other hand, when the side surface of the object is moved substantially parallel to the object, the ratio of the change amount of the detection distance to the movement amount of the sonar 50 is substantially constant.

  According to this processing mode, since it is determined whether or not detection is in the initial stage based on the ratio of the change amount of the detection distance to the movement distance of the sonar 50 using the characteristics described above, the first process described above. An effect substantially equivalent to the shape can be obtained. In other words, continuity judgment is made stricter at the initial stage of detection when the detection result is redundant to suppress variations in the detection result, and in the region where the degree of redundancy is reduced, continuity judgment is moderated so It can suppress that the detection result currently performed is judged that there is no continuity accidentally. As a result, the position and contour of the object can be detected with higher accuracy.

  Next, a fourth processing mode of the continuity determination reference value transfer process will be described with reference to the flowchart shown in FIG. This fourth processing form is a modification of the above-described first processing form. As shown in FIG. 11, the first processing is performed in that steps S102c and S104c are executed instead of the above-described steps S102 and S104. It differs from the form. Since the other processing steps are the same as those in the first processing mode, description thereof is omitted here. However, the continuity determination reference value transfer process according to the first processing form is executed before the rotation correction is performed, but the continuity determination reference value transfer process according to the fourth process form is performed in parallel with the execution of the rotation correction. Implemented.

In the fourth process embodiment, in step S102b, the rotational correction angle phi n is read. Then, at the next step S104a, the rotational correction angle phi n it is determined whether the larger than a predetermined angle is performed. Here, if the rotation correction angle phi n is a predetermined angle greater than, the flow advances to step S106 described above. On the other hand, the process proceeds to step S108 described above when the rotational correction angle phi n is a predetermined angle or less. Thus, in the fourth processing mode, when the rotation correction angle φ n is equal to or smaller than the predetermined angle, that is, the straight line connecting the sonar 50 and the estimated reflection point P n ′ after the rotation correction, the movement of the sonar 50 When the angle between the track lines is larger than a predetermined angle, the continuity determination reference value is changed to a larger value.

According to this processing mode, since whether the detected initial is determined based on the rotational correction angle phi n, it becomes possible to obtain a first processing mode and substantially the same effect as described above. In other words, strict continuity is judged at the beginning of detection when the detection result is redundant, and concentration of the estimated reflection point after rotation correction on the object end is suppressed, and continuity is judged in an area where the redundancy is lowered. By making it gentle, it is possible to suppress the fact that a continuous detection result is erroneously determined not to be continuous during detection. As a result, the position and contour of the object can be detected with higher accuracy.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made. For example, in the above-described embodiment, the present invention is applied to a parking assistance device. However, the present invention can be applied to devices other than the parking assistance device or used alone.

  In the above-described embodiment, the change of the continuity determination reference value is performed in two stages. However, the continuity determination reference value may be changed in multiple stages or steplessly.

  Further, the moving direction of the own vehicle relative to an object such as a parked vehicle is detected or estimated, and the continuity determination reference value is changed or the continuity is determined in consideration of the moving direction of the own vehicle relative to the parked vehicle or the like. May be.

It is a block diagram which shows the structure of the parking assistance apparatus containing the object detection apparatus which concerns on embodiment. It is a figure which shows the driving | running route of the own vehicle in garage entry assistance. It is a schematic diagram which shows an example of the point sequence showing a detection result. It is a figure for demonstrating the removal method of noise. It is a figure for demonstrating the grouping method. It is a flowchart which shows the process sequence of a continuity judgment reference value transfer process. It is a figure for demonstrating the correction method of rotation correction. It is a figure which shows an example of the point sequence before correction | amendment, and the point sequence after rotation correction | amendment. It is a flowchart which shows the process sequence of the continuity determination reference value change process which concerns on a 2nd processing form. It is a flowchart which shows the process sequence of the continuity judgment reference value change process which concerns on a 3rd processing form. It is a flowchart which shows the process sequence of the continuity judgment reference value change process which concerns on a 4th process form.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Parking assistance apparatus, 10 ... Object detection apparatus, 20 ... Travel control apparatus, 30 ... Automatic steering apparatus, 40 ... Parking assistance ECU, 41 ... Movement distance detection part, 42 ... Continuity judgment part, 43 ... Reflection position estimation part , 44 ... Travel control unit, 45 ... Steering control unit, 50 ... Sonar, 51 ... Assist mode switching switch, 52 ... Rear camera, 53 ... Monitor, 54 ... Speaker, 60 ... Brake ECU, 61 ... Wheel cylinder, 62 ... Actuator , 63 ... Wheel speed sensor, 64 ... Acceleration sensor, 65 ... Brake pedal, 66 ... Master cylinder, 67 ... Hydraulic sensor, 70 ... Engine ECU, 71 ... Engine, 80 ... Steering wheel, 81 ... Steering gear, 82 ... Drive motor 83 Displacement sensors.

Claims (14)

  1. A distance detection unit that emits a detection wave and detects a distance to the object from a reflection state of the detection wave, and repeatedly detecting the distance to the object while moving the distance detection unit, thereby determining the position of the object. In the object detection device to detect,
    A moving distance detecting means for detecting a moving distance of the distance detecting means;
    By determining whether the distance between the detection results obtained from the moving distance and the amount of change in the distance from the object is within a continuity determination reference value set according to the moving distance, Continuity determination means for determining the continuity of the detection results,
    The continuity determination unit changes the continuity determination reference value when a predetermined reference value transfer condition is satisfied.
  2.   The continuity determination means sets the continuity determination reference value to a larger value when the movement distance of the distance detection means after the distance to the object starts to be detected exceeds a predetermined distance. The object detection apparatus according to claim 1, wherein the object detection apparatus is replaced.
  3.   The continuity determination means changes the continuity determination reference value to a larger value when the distance between detection results after the distance from the object starts to be detected exceeds a predetermined value. The object detection apparatus according to claim 1.
  4.   The continuity determination means changes the continuity determination reference value to a larger value when the ratio of the change amount to the movement distance becomes smaller than a predetermined value set in advance. The object detection apparatus according to claim 1.
  5. The estimation is performed such that the smaller the ratio of the change amount to the movement distance, the larger the angle formed between the straight line connecting the distance detection means and the estimated reflection position of the detection wave and the movement locus of the distance detection means. A reflection position estimating means for setting the reflection position;
    2. The object according to claim 1, wherein the continuity determination unit changes the continuity determination reference value to a larger value when the angle is larger than a predetermined angle set in advance. Detection device.
  6.   The said continuity determination means removes this detection result as noise, when a detection result does not fit in the said continuity determination reference value, The one of Claims 1-5 characterized by the above-mentioned. Object detection device.
  7.   The said continuity judgment means detaches | disconnects a detection result, when a detection result does not fit in the said continuity judgment reference value continuously, The any one of Claims 1-5 characterized by the above-mentioned. Object detection device.
  8. In the object detection method for detecting the position of the object by repeatedly detecting the distance to the object while moving the distance detection means for detecting the distance from the object from the reflected state of the detected detection wave,
    A moving distance detecting step for detecting a moving distance of the distance detecting means;
    By determining whether the distance between the detection results obtained from the moving distance and the amount of change in the distance from the object is within a continuity determination reference value set according to the moving distance, A continuity determination step for determining the continuity of the detection results,
    In the continuity determination step, the continuity determination reference value is changed when a predetermined reference value change-over condition is satisfied.
  9.   In the continuity determination step, the continuity determination reference value is set to a larger value when the moving distance of the distance detection unit after the distance to the object starts to be detected exceeds a predetermined distance. The object detection method according to claim 8, wherein the object is switched.
  10.   In the continuity determination step, the continuity determination reference value is changed to a larger value when the distance between detection results after the distance from the object starts to be detected exceeds a predetermined value. The object detection method according to claim 8.
  11.   In the continuity determination step, the continuity determination reference value is changed to a larger value when a ratio of the change amount to the movement distance becomes smaller than a predetermined value set in advance. The object detection method according to claim 8.
  12. The estimation is performed such that the smaller the ratio of the change amount to the movement distance, the larger the angle formed between the straight line connecting the distance detection means and the estimated reflection position of the detection wave and the movement locus of the distance detection means. A reflection position estimation step for setting the reflection position;
    9. The object according to claim 8, wherein, in the continuity determination step, the continuity determination reference value is changed to a larger value when the angle is larger than a predetermined angle set in advance. Detection method.
  13.   13. The continuity determination step according to claim 8, wherein if the detection result does not fall within the continuity determination reference value, the detection result is removed as noise. Object detection method.
  14.   13. The detection of the continuity determination step according to claim 8, wherein the detection result is separated when the detection result does not continuously fall within the continuity determination reference value. Object detection method.
JP2005336232A 2005-11-21 2005-11-21 Object detection device and object detection method Pending JP2007139665A (en)

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102008048490A1 (en) 2007-10-31 2009-05-14 Mitsubishi Electric Corp. Parking assistance system
JP2009118416A (en) * 2007-11-09 2009-05-28 Alpine Electronics Inc Vehicle-periphery image generating apparatus and method of correcting distortion of vehicle-periphery image
JP2013108921A (en) * 2011-11-24 2013-06-06 Panasonic Corp Ultrasonic sensor system
US8588029B2 (en) 2009-12-22 2013-11-19 Denso Corporation Obstacle detection device
JP5506803B2 (en) * 2009-08-26 2014-05-28 三菱電機株式会社 Parking assistance device
EP2653367A3 (en) * 2012-04-19 2014-07-02 Toyota Jidosha Kabushiki Kaisha Parking aid device, parking aid method, program, and storage medium storing the program
JP2014159182A (en) * 2013-02-19 2014-09-04 Nippon Soken Inc Parking space sensing device
WO2016063532A1 (en) * 2014-10-22 2016-04-28 株式会社デンソー In-vehicle object determining apparatus

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102008048490A1 (en) 2007-10-31 2009-05-14 Mitsubishi Electric Corp. Parking assistance system
DE102008048490B4 (en) * 2007-10-31 2017-04-20 Mitsubishi Electric Corp. Parking assistance system
JP2009118416A (en) * 2007-11-09 2009-05-28 Alpine Electronics Inc Vehicle-periphery image generating apparatus and method of correcting distortion of vehicle-periphery image
JP5506803B2 (en) * 2009-08-26 2014-05-28 三菱電機株式会社 Parking assistance device
US8588029B2 (en) 2009-12-22 2013-11-19 Denso Corporation Obstacle detection device
JP2013108921A (en) * 2011-11-24 2013-06-06 Panasonic Corp Ultrasonic sensor system
EP2653367A3 (en) * 2012-04-19 2014-07-02 Toyota Jidosha Kabushiki Kaisha Parking aid device, parking aid method, program, and storage medium storing the program
JP2014159182A (en) * 2013-02-19 2014-09-04 Nippon Soken Inc Parking space sensing device
WO2016063532A1 (en) * 2014-10-22 2016-04-28 株式会社デンソー In-vehicle object determining apparatus

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