JP2011149856A - Object discrimination method and object discrimination device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an object discrimination method and an object discrimination device capable of suppressing erroneous recognition of an object, even on a place where a reflecting object exists. <P>SOLUTION: This object discrimination device 1 includes: a laser device 3 for irradiating an object in front of a vehicle with laser light, and measuring a distance to the object by the reflection state of the laser light from the object; and a camera 5 including a filter part 5a, for receiving at least light in a wavelength band of the laser light. The device 1 measures the distance to the object by the laser device 3, images by the camera in the state where an imaging direction is allowed to approximately agree with the irradiation direction of the laser light of the laser device 3, and invalidates a distance value to the object measured by the laser device 3, when the camera 5 recognizes an irradiation locus of the laser light. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an object identification method and an object identification device for recognizing a distance from an object.

  Conventionally, a driving support device for a vehicle described in Patent Document 1 below is known. In this driving support device, a blind spot object reflected on a curve mirror and a curve mirror in front of the host vehicle is detected, and the blind spot object and the host vehicle may collide based on information on the image of the blind spot object reflected on the curve mirror. Predict.

JP 2006-199055 A

  However, the driving support device may not be able to detect the curve mirror itself. If there is a reflective object that reflects light at the mirror surface, such as a curved mirror, if the reflected object cannot be detected, the object reflected in the reflective object is misrecognized as an object located behind the reflective object. It can be considered. In driving support, it is desired to detect an object more accurately even in a place where a reflective object exists.

  Accordingly, an object of the present invention is to provide an object identification method and an object identification device that can suppress erroneous recognition of an object even in a place where a reflective object exists.

  The object identification method of the present invention includes a distance measuring unit that irradiates an object with laser light and measures a distance from the object according to a reflection state of the laser light from the object, and a filter unit that receives at least light in the wavelength band of the laser light The distance measuring unit measures the distance from the object using the imaging unit provided, and the imaging unit performs imaging with the imaging direction substantially coincident with the irradiation direction of the laser light of the distance measuring unit. When the irradiation locus of the laser beam is recognized, the distance value with the object measured by the distance measuring unit is invalidated.

  In addition, the object identification device of the present invention includes a distance measuring unit that irradiates a laser beam on the object and measures a distance from the object according to a reflection state of the laser light from the object, and a filter that receives at least a wavelength band of the laser light A distance measuring unit that measures the distance to the object, and that the imaging unit substantially matches the imaging direction with the laser light irradiation direction of the distance measuring unit, and performs imaging. When the unit recognizes the irradiation locus of the laser beam, the distance value measured by the distance measuring unit is invalidated.

  In this object identification method and object identification device, the distance measuring unit measures the distance from the object based on the reflection state of the laser light. Here, a case is considered where there is a reflective object having a mirror surface at the target location of the distance measurement process, and another object appears to be reflected on the reflective object. At this time, if the laser beam is irradiated to the reflecting object, the laser beam is irradiated to the other object via the reflecting object, and the reflected laser beam returns to the distance measuring unit again via the reflecting object. Therefore, in this case, the distance measuring unit may erroneously recognize the other object reflected in the reflective object as an object existing behind the reflective object. In such a case, an irradiation locus of the laser beam is formed so as to extend from the reflecting object to the other object. Therefore, if the imaging unit performs imaging with the imaging direction substantially matched with the laser beam irradiation direction, the irradiation locus can be recognized as a light beam image. That is, by recognizing the irradiation locus on the imaging screen, it is possible to detect that a reflective object is involved in the distance measurement processing of the distance measuring unit. Accordingly, when the irradiation locus of the laser beam is recognized, the measured distance value to the other object is invalidated assuming that the reflecting object is involved in the distance measuring process. As a result, in this object identification method and object identification device, it is possible to suppress erroneous recognition when a reflective object is involved in the distance measurement processing.

  Further, the irradiation locus may be recognized as an image of light rays extending linearly on the imaging screen obtained by the imaging unit.

  According to the object identification method and the object identification device of the present invention, erroneous recognition of an object can be suppressed even when a reflective object is present.

It is a block diagram which shows one Embodiment of the object identification apparatus of this invention. It is a top view which shows an example of the condition around the own vehicle where the object identification apparatus of FIG. 1 is used. (A), (b) is the imaging screen ahead of the own vehicle in FIG. 2, (c) is a figure which shows the irradiation locus | trajectory extracted from the imaging screen. It is a flowchart which shows the process by the object identification apparatus of FIG.

  Hereinafter, preferred embodiments of an object identification process and an object identification device according to the present invention will be described in detail with reference to the drawings.

  An object identification device 1 shown in FIG. 1 is used by being mounted on an automobile, and has a distance measuring function for measuring the distance to each object ahead of the host vehicle. As shown in FIG. 1, the object identification device 1 includes a laser device (ranging unit) 3, a camera (imaging unit) 5, and a control ECU 10. The control ECU 10 includes a scanning unit 11, a distance calculation unit (ranging unit) 13, an irradiation imaging synchronization unit 15, a locus detection unit 17, a specular reflection object detection unit 19, and an environment map creation unit 21. ing.

  The control ECU 10 is an electronic control unit that performs overall control of the object identification device 1, and is configured mainly by a computer including a CPU, a ROM, and a RAM, for example. The scanning unit 11, the distance calculation unit 13, the irradiation imaging synchronization unit 15, the locus detection unit 17, the specular reflection object detection unit 19, and the environment map creation unit 21 are a CPU, a RAM, a ROM, and the like of the control ECU 10. The hardware is a component realized by software by cooperating according to a predetermined program.

  The laser device 3 irradiates laser light toward each point in front of the host vehicle while two-dimensionally scanning left and right and up and down. The laser beam scanning operation is performed under the control of the scanning unit 11 and the irradiation imaging synchronization unit 15. The scanning unit 11 changes the irradiation direction of the laser beam from the laser device 3 left and right and up and down. Further, the laser device 3 receives reflected laser light reflected from an object in front of the host vehicle. The distance calculation unit 13 receives a data signal from the laser device 3 and calculates the distance from the host vehicle to the object based on the time from when the laser beam is irradiated until the reflected laser beam returns. As described above, the laser device 3 and the distance calculating unit 13 constitute a distance measuring unit that measures the distance to the object according to the reflection state of the laser light. Hereinafter, the laser light used for the distance measurement processing may be referred to as “range measurement laser light”.

  For example, as shown in FIGS. 2 and 3A, when a pedestrian W is present near the intersection 100 in front of the host vehicle M1, the laser light is irradiated to the pedestrian W and reflected by the pedestrian W. The laser device 3 receives the reflected laser beam. And the distance calculation part 13 calculates the distance from the own vehicle M1 to the pedestrian W based on the time from when a laser beam is irradiated until a reflected laser beam returns. Similarly, the distance from the host vehicle M1 is also calculated for each object (such as the other vehicle M3, the bicycle B, and the wall existing in front of the host vehicle M1) within the range where the ranging laser beam is scanned. Then, the environment map creation unit 21 creates an environment map in which the distances to the respective objects ahead of the host vehicle M1 are mapped. The environment map is further transferred to a subsequent system and used for creating a risk map ahead of the host vehicle M1.

  Here, consider a case where a specular reflection object exists within a range in which the ranging laser beam is scanned. The specular reflection object is an object having a reflection surface that specularly reflects the distance measuring laser beam. For example, a curved mirror or the like installed on a road corresponds to a specular reflection object. Hereinafter, as shown in FIG. 2 and FIG. 3, a situation where the curve mirror 101 exists at the intersection 100 will be described as an example. Further, it is assumed that another vehicle M2 exists on the road in the direction of intersection of the intersection 100, and that the other vehicle M2 appears on the curve mirror 101 when viewed from the position of the host vehicle M1.

  When the distance measuring laser light from the laser device 3 is applied to the curve mirror 101, the distance measuring laser light is reflected by the curve mirror 101 and applied to the other vehicle M2. Then, the reflected laser light from the other vehicle M2 returns to the laser device via the curve mirror 101 again along the same optical path. At this time, since the distance calculation unit 13 calculates the distance to the object existing in the direction of the curve mirror 101 based on the time until the reflected laser light returns, the other vehicle M2 reflected on the curve mirror 101 is The distance value is calculated by misrecognizing that the object is behind the curve mirror 101. That is, if the distance from the curve mirror 101 itself should be acquired, the distance value from the virtual image M2 'of the other vehicle M2 that is erroneously formed on the back side of the curve mirror 101 is calculated. In this way, if a specular reflection object is involved in the distance measuring process by the laser device 3, erroneous recognition occurs.

  Therefore, in order to suppress the erroneous recognition caused by the specular reflection object as described above, the object identification device 1, as shown in FIG. 1, the camera 5, the locus detection unit 17, the specular reflection object detection unit 19, It has. The camera 5 captures an image in front of the host vehicle as illustrated in FIG. The trajectory detection unit 17 receives a video signal from the camera 5 and performs image processing of the captured image. The specular reflection object detection unit 19 detects a specular reflection object in front of the host vehicle M <b> 1 by a method described later based on the image processing of the trajectory detection unit 17.

  The camera 5 is installed in the immediate vicinity of the laser device 3 and is installed so that the optical axis direction (imaging direction) of imaging of the camera 5 and the irradiation optical axis direction of the distance measuring laser beam are substantially the same direction. Has been. The camera 5 includes a filter unit (filter means) 5a that can receive at least light in the wavelength band of the distance measuring laser beam. As such a filter unit 5a, for example, an optical filter that is installed in front of the lens of the camera 5 and selectively transmits the wavelength band of the distance measuring laser beam may be used. Further, the imaging operation of the camera 5 is synchronized with the irradiation operation of the distance measuring laser beam by the laser device 3 by the control of the irradiation imaging synchronization unit 15. That is, during scanning of the distance measuring laser light, when the laser device 3 irradiates a laser beam to one point in front, one frame of the front image is captured by the camera 5 in synchronization with the irradiation timing. .

  As described above, when the specular reflection object is involved in the distance measurement processing of the laser apparatus 3, the irradiation locus of the distance measurement laser light is formed so as to extend from the specular reflection object to another object. For example, in the case of FIGS. 2 and 3, the laser beam irradiation locus L1 is formed as a straight line connecting the curve mirror 101 and the other vehicle M2. Therefore, if the imaging direction is substantially matched with the laser beam irradiation direction and imaging is performed by the camera 5, the irradiation locus L1 crosses the screen on the imaging screen 200 as shown in FIG. It can be recognized as an image of light rays extending linearly. This is because part of the distance measuring laser light traveling from the curve mirror 101 toward the other vehicle M2 is reflected by fine particles such as dust in the air and enters the camera 5. As described above, when the camera 5 includes the filter unit 5a that selectively transmits the wavelength band of the distance measuring laser beam, as shown in FIG. 3C, the camera 5 transmits the light beam on the irradiation locus L1. It can be selectively recognized, and the irradiation locus L1 can be more easily recognized.

  In addition, when the distance measuring laser light is irradiated to other than the specular reflection object (for example, the pedestrian W or the bicycle B), the reflected laser light that is biased and reflected in one specific direction is not generated. A linearly extending irradiation locus is not generated. Further, since the irradiation optical axis direction of the laser device 3 and the optical axis direction of the imaging of the camera 5 are substantially the same, the laser light path L2 (FIG. 2) from the laser device 3 to the pedestrian W or the laser device 3 The laser light path L3 (FIG. 2) toward the curve mirror 101 looks almost one point when viewed from the camera 5. Therefore, the laser light paths L2 and L3 can be easily distinguished from the irradiation locus L1 extending linearly on the imaging screen. In addition, when the sky or infinity point is reflected on the curve mirror 101 when viewed from the own vehicle M1, the reflected laser light does not return to the laser device 3, and therefore the distance value cannot be calculated in the first place. The problem of misrecognition does not occur.

  The trajectory detection unit 17 recognizes an irradiation trajectory L1 extending linearly on the imaging screen 200 by image processing of the imaging screen 200 by the camera 5. The specular reflection object detection unit 19 detects a specular reflection object (curve mirror 101) involved in the distance measurement processing of the laser device 3 based on the detection of the irradiation locus L1. If the specular reflection object detection unit 19 detects a specular reflection object, the specular reflection object detection unit 19 determines that the distance value obtained by the distance measurement processing of the laser apparatus 3 is erroneous recognition, and discards the distance value as invalid.

  Next, specific processing by the object identification device 1 will be described with reference to the flowchart of FIG. First, the laser device 3 irradiates a laser beam toward one irradiation point in front of the host vehicle and receives a reflected laser beam (S101). The laser device 3 calculates the distance from the host vehicle to the irradiation point based on the time from when the laser beam is irradiated until the reflected laser beam returns (S103). At this time, the scanning unit 11 transmits irradiation direction information indicating the irradiation direction of the laser light to the specular reflection object detection unit 19.

  In synchronization with the laser beam irradiation by the laser device 3, the camera 5 captures one frame of the image in front of the host vehicle in a state where the optical axis direction of the lens is substantially coincident with the irradiation optical axis direction of the distance measuring laser beam. (S105). Next, the trajectory detection unit 17 performs image processing based on the video signal from the camera 5 and performs processing for detecting the irradiation trajectory of the distance measuring laser light from within the imaging screen of one frame (S107). That is, the trajectory detection unit 17 attempts to detect an image of light rays extending linearly on the imaging screen.

  Here, when the trajectory detection unit 17 detects the irradiation trajectory (Yes in S109), the specular reflection object detection unit 19 detects the specular reflection object existing at the irradiation point, and is obtained in the processing S103. The distance value is invalidated (S111). Then, the specular reflection object detection unit 19 transmits an information signal indicating the irradiation direction information from the scanning unit 11 and that the distance value is invalid to the environment map creation unit 21. On the other hand, when the trajectory detection unit 17 cannot detect the irradiation trajectory (No in S109), the specular reflection object detection unit 19 is obtained in step S103, assuming that no specular reflection object is detected at the irradiation point. The distance value is validated (S113). The specular reflection object detection unit 19 associates the irradiation direction information from the scanning unit 11 with the distance value, and transmits the information to the environment map creation unit 21 as an information signal. Thereafter, the environment map creation unit 21 recognizes the irradiation direction of the laser light and the distance of the object in the irradiation direction based on the information signal of the specular reflection object detection unit 19. The processes S101 to S113 as described above are repeatedly performed while moving the irradiation point left and right and up and down one by one, thereby creating an environment map in front of the host vehicle.

  As a result of this processing, in the object identification device 1 and the object identification method, it is possible to eliminate erroneous distance values when the specular reflection object is involved in the distance measurement processing, and to suppress erroneous recognition due to the presence of the specular reflection object. it can.

  As another method for detecting the curve mirror on the road, for example, it is conceivable to recognize the presence of the curve mirror by including the position information of the curve mirror in the map information of the car navigation system. However, there is a problem that the capacity of the map information becomes too large. In this case, even if the curved mirror can be detected, a specular reflecting object other than the curved mirror such as a moving specular reflecting object cannot be detected. Further, although it is conceivable to detect the curve mirror by detecting the support of the curve mirror on the imaging screen, there is a problem that a curve mirror having no support cannot be detected. On the other hand, the object identification method by the object identification device 1 can also solve the above problems.

  DESCRIPTION OF SYMBOLS 1 ... Object identification apparatus 3 ... Laser apparatus (distance measuring part) 5 ... Camera (imaging part) 5a ... Filter part 13 ... Distance calculation part (distance measuring part) 15 ... Irradiation imaging synchronization part 17 ... Trajectory detection part 200 ... Imaging screen L1 ... Irradiation locus

Claims (3)

A distance measuring unit that irradiates an object with laser light and measures the distance to the object according to a reflection state of the laser light from the object;
With an imaging unit including a filter unit that receives at least light in the wavelength band of the laser beam,
The distance measurement unit measures the distance to the object, and the imaging unit substantially matches the imaging direction with the laser beam irradiation direction of the distance measurement unit, and the imaging unit performs imaging.
When the imaging unit recognizes an irradiation locus of the laser light, the distance value measured by the distance measuring unit is invalidated. The irradiation locus is
The object identification method according to claim 1, wherein the object recognition method is recognized as an image of light rays extending linearly on an imaging screen obtained by the imaging unit. A distance measuring unit that irradiates an object with laser light and measures the distance to the object according to a reflection state of the laser light from the object;
An image pickup unit including at least a filter unit that receives light in the wavelength band of the laser light,
The distance measurement unit measures the distance to the object, and the imaging unit substantially matches the imaging direction with the laser beam irradiation direction of the distance measurement unit, and the imaging unit performs imaging.
When the imaging unit recognizes an irradiation locus of the laser beam, the object identification device invalidates a distance value from the target measured by the distance measuring unit.

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