JP3464368B2 - Rear side monitoring device for vehicles - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video camera mounted on a vehicle such as an automobile, and uses a video image of the rear and side of the video camera. The present invention also relates to a vehicle rear side monitoring device for detecting a vehicle approaching from the side and giving a warning to a driver. 2. Description of the Related Art When a vehicle changes lanes while traveling on a road having two or more lanes on one side, if a vehicle running at a speed higher than that of the own vehicle is overlooked in an adjacent lane to be changed, a large problem occurs. The risk of accidents is great. In addition, if there is a following vehicle traveling in the same lane as the own vehicle, there is a danger of a rear-end collision if a sudden brake is applied when approaching suddenly. Therefore, it is necessary to recognize a nearby vehicle. [0003] As a conventional example for recognizing a vehicle traveling in an adjacent lane and a following vehicle, Japanese Patent Application Laid-Open No. 1-189289 (vehicle information display device) has been proposed. Japanese Patent Application Laid-Open No. 1-189289 discloses a technique in which a rear and a side of a vehicle are photographed by a camera, and the photographed image is displayed on a monitor so that a vehicle traveling in an adjacent lane and a following vehicle can be recognized. ing. [0004] However, in a method of recognizing a vehicle traveling in an adjacent lane and a following vehicle by displaying a captured image on a monitor,
The driver is often required to look at the monitor during driving, which is not desirable for safe driving. SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has been made in consideration of the above-mentioned problems, and is intended to facilitate and accurately recognize that a vehicle traveling in an adjacent lane and a following vehicle have suddenly approached the own vehicle. It is intended to propose a side monitoring device. [0006] In order to solve the above-mentioned problems, a vehicle rear-side monitoring apparatus according to the present invention is shown in FIG.
As shown in FIG. 2 and FIG. 2, an image pickup means (2) for picking up an image of a rear view from a running vehicle is provided, and the image pickup means (2) is provided.
In the vehicle rear side monitoring device that detects a vehicle approaching the host vehicle from the rear lane or an adjacent lane based on the image captured by the vehicle and allows the driver (9) to recognize this, the imaging means (1) Using the obtained image signal (S1), a vehicle approaching the own vehicle from the rear or adjacent lane is detected, and the risk and the direction of the greater risk are determined according to the degree of the approach. And the same visibility as the door mirror on the right side
A first indicator which is provided near the right side door mirror (6) and gives a warning display when the risk determination means (3, 4) obtains a determination result indicating that the risk of the adjacent lane on the right side is large. (5A) and the same as the left side door mirror
Near the left door mirror (8) so that you can see
Setting vignetting, and a second indicator displaying a warning when a determination result indicating that the risk of left adjacent lane is large is obtained by the risk determination means (3,4) (5C), back
Rearview mirror (7) so that it is in the same view as the mirror
And a third indicator (5B) for displaying a warning when the risk determination means (3, 4) obtains a determination result indicating that the rear risk is high. . [0007] In the above configuration, for example, when the driver tries to change lanes to the right adjacent lane, the first indicator (5A) enters the field of view when looking at the right door mirror (6). The confirmation of the lane on the right side and the confirmation of the first indicator (5A) can be performed simultaneously. As a result, the operation of checking the indicator during driving can be omitted, so that safe driving can be performed. When the first, second, or third indicator (5A, 5C, or 5B) displays a warning, the driver's line of sight turns toward the indicator.
At this time, since the door mirrors (6, 8) or the rearview mirror (7) are within the field of view, the driver's attention can be naturally directed to the direction of the mirror on which the vehicle approaching suddenly is reflected. An embodiment of the present invention will be described below with reference to the drawings. (1) Configuration In FIG. 1, reference numeral 1 denotes a vehicle rear side monitoring device according to the embodiment as a whole. The vehicle rear side monitoring device 1 sends an image signal S1 obtained by a video camera 2 arranged near a rear window so as to face the rear of the vehicle, for example, to the image processing unit 3. Here, the image processing unit 3 and the risk determination unit 4
Detects a vehicle approaching from the rear or an adjacent lane to the own vehicle using the image signal S1 obtained by the video camera 2, and detects the degree of danger and the degree of danger according to the degree of the approach. It is provided as danger determining means for determining the direction. That is, the image processing unit 3 obtains the movement of the same point in the rear view taken as an optical flow based on two frames before and after a predetermined time. The danger determining unit 4 determines the direction of the vehicle that is approaching the own vehicle rapidly and the danger thereof based on the optical flow velocity vector obtained by the image processing unit 3. The details of the processing of the image processing unit 3 and the risk determination unit 4 will be described later. The danger determining unit 4 sends display control signals S2A, S2B and S2C to the indicators 5A, 5B and 5C corresponding to the directions in which the danger is determined to be high, so that the indicators corresponding to the directions with the high danger are determined. 5
A, 5B and 5C are turned on. More specifically, when a determination result indicating that the degree of danger of the adjacent lane on the right side is large is obtained, a display control signal S2A is transmitted to the right warning display indicator 5A so that the right warning display indicator 5A is displayed. Turn on. When a determination result indicating that the degree of danger of the adjacent lane on the left side is large is obtained, the display control signal S2C is transmitted to the left warning display indicator 5C to light the left warning display indicator 5C. When a determination result indicating that the degree of danger behind is greater is obtained, a display control signal S2B is sent to the brake warning display indicator 5B to light the brake warning display indicator 5B. As shown in FIG. 2, the right warning display indicator 5A, the left warning display indicator 5C, and the braking warning display indicator 5B are located near the right door mirror 6, near the left door mirror 8, and the rearview mirror, respectively. 7 is provided in the vicinity. As a result, the driver can see the right door mirror 6 and the right warning display indicator 5A, the left door mirror 8 and the left warning display indicator 5C, and the rearview mirror 7 and the brake warning display indicator 5B in the same field of view. As a result, the operation of checking the indicator during driving can be omitted, so that safe driving is possible. (2) Calculation of Danger Next, the risk determination processing by the image processing unit 3 and the risk determination unit 4 as the risk determination means will be described in detail. FIG.
(A) is a figure for explaining change of the back side view picture obtained by video camera 2, and (b) is video camera 2 imaged at time t in a situation including own vehicle shown in (a). (C) shows an image captured at time t + Δt. Now, assuming that the vehicle is traveling straight on a flat road, for example, focusing on a road sign and a building shown in FIG. At time t + Δt, (b),
An image as shown in (c) is obtained. By searching for corresponding points in these two images and connecting them, a velocity vector as shown in (d) is obtained. This is the optical flow. When the following vehicle approaches, the direction of the velocity vector of the optical flow shown in FIG. 3D is reversed. Here, these optical flows appear radially from one point called an FOE (Focus of Expansion) in the image. The FOE is called an infinity point or a vanishing point, and corresponds to one point indicating a direction directly opposite to a traveling direction of the own vehicle on an image when the vehicle is traveling straight. Thus, the optical flow required when the host vehicle is traveling is in a radial direction from the FOE. Here, the optical flow emitted from the vehicle traveling in the following or adjacent lane includes information including the position and the relative speed of the following or adjacent vehicle with respect to the own vehicle, the optical flow is longer, and the direction is larger than that of the FOE. If diverging, the risk is considered to be high. Next, the details will be described with reference to FIG. And have you optically placement in FIG, 2A is a video camera 2
Lens, 2B is the image plane of the video camera, f
Is the distance from the lens 2A to the image plane 2B, P
(X, Y, Z) is an arbitrary point on the following vehicle, p (x,
Assuming that y) is a point corresponding to the point P on the image plane 2B, x = f × X / Z (2) from the similarity ratio of the triangle. By transforming this equation and differentiating it over time, X '= (Δx / Δt · Z + x · Z ′) / f (3) Further, since the x-direction component u of the optical flow is u = Δx / Δt (4), using this, Z = (f × X′−xZ ′) / u (5) Become. Here, Z '= the relative speed between the following vehicle or the vehicle traveling in the adjacent lane and the own vehicle = -α (6) Therefore, the above equation (5) gives Z = (f × X ′ + xα). ) / U (7) Therefore, the x-direction component u of the optical flow is as follows: u = (f × X ′ + xα) / Z (8) The same applies to Y. Therefore, from the above equation (8), as Z becomes smaller, that is, as the distance to the following vehicle or a vehicle traveling in the adjacent lane becomes smaller, or as α becomes larger, that is, as the relative speed becomes larger,
The x component of the optical flow increases. This is the same in the Y direction. Therefore, the optical flow becomes longer as the distance to the following vehicle or the like becomes smaller, and further, as the relative speed becomes larger, whereby the direction of the optical flow becomes FO.
It is considered that the divergence with respect to E and the risk when the length is longer than when the length is shorter are relatively greater for the following vehicle or the adjacent vehicle. In this embodiment, the fact that the optical flow is obtained in a radial direction from the FOE is used to obtain the optical flow at a high speed. The method will be described below with reference to FIG. FIG. 5 is a diagram showing an example of a method for obtaining an optical flow at high speed. First, time t
A window is set in a radial direction from the FOE with respect to one point of interest in the image of FIG. Next, at time t +
In the image at Δt, the window is moved one point at a time in the radial direction from the FOE, and the sum of the absolute values of the luminance differences from the window at time t is obtained. Then, the moving amount of the window when the sum is minimized is obtained as a speed vector of one point of interest (FIG. 5B). The luminance difference is, for example, between the pixels at the corresponding positions indicated by ● in (a) and (b) for each pixel constituting the window. By repeating the above processing at all points of the image at the time t, the optical flow of the entire image can be obtained. Alternatively, a pixel in the window may be scanned to extract a point of interest, and the extracted points may be connected to obtain an optical flow. Next, a method for obtaining the degree of risk will be described. If the direction of the optical flow is the direction toward the FOE, it indicates that the speed of the following vehicle is lower than the speed of the own vehicle and is away from the own vehicle. On the contrary, the direction of the optical flow is divergent with respect to the FOE. In some cases, it indicates that the vehicle is approaching. The direction of the optical flow generated by the scenery photographed in the set area, the mark on the road surface, or the like is all toward the FOE, and can be easily distinguished from the approaching following vehicle. Therefore, for example, for those whose optical flow direction diverges from the FOE, the length is weighted, and if the weighted value exceeds a certain threshold value, it is determined to be dangerous. In addition, several levels of thresholds can be set to determine the level of risk. Incidentally, in the vehicle rear side monitoring device 1 of this embodiment, since the degree of danger is determined based on the rear lane, the right adjacent lane and the left adjacent lane of the own vehicle, the image processing unit 3 determines the danger degree.
An optical flow is created for each of the three regions, and the risk determining unit 4 determines the risk of each of the three regions by using these optical flows. Here, the procedure of the risk determination process by the image processing section 3 and the risk determination section 4 is summarized as shown in FIG. First, in step SP1, the image processing unit 3
Captures the image at time t from the video camera 2, and then captures the image at time t + Δt in step SP2. After that, the FOE is set in step SP3. Then, the process proceeds to step SP4, where F is set in the set area.
Only the optical flow in the direction diverging from the OE is obtained, and in the next step SP5, the risk is calculated by the risk determining unit 4 using the weighted value. (3) Operation In the configuration described above, the rear side monitoring device 1 for a vehicle is configured as shown in FIG.
The indicators 5A to 5C are turned on in accordance with the degree of danger by executing the rear side monitoring processing procedure shown in FIG. That is, when the process is started in step SP10, first, the image processing unit 3 and the risk determination unit 4
An optical flow is created in step SP11, a risk is determined based on the vector of the optical flow, and a threshold determination is performed in step SP12 to determine whether or not the vehicle is in a dangerous state (i.e., a vehicle that approaches rapidly). Is determined). If it is determined in step SP12 that the state is not dangerous, the process returns to step SP11. If it is determined that the state is dangerous, step S11 is performed.
Move to P13. At step SP13, step SP12
Is determined to be a dangerous state, and if the direction is the direction of the adjacent lane on the right, the process proceeds to step S
Moves to P14, and if it is backward, step SP15
If it is the direction of the left adjacent lane, the process proceeds to step SP16. In step SP14, the danger determining unit 4 sends the display control signal S2A to the right warning display indicator 5A to turn on the right warning display indicator 5A, so that the vehicle approaching the driver from the right adjacent lane rapidly. Recognize that there is. In step SP15, the danger determining unit 4 sends the display control signal S2B to the braking warning display indicator 5B to turn on the braking warning display indicator 5B, thereby confirming that there is a vehicle approaching the driver from behind. Recognize. In step SP16, the danger determining unit 4 sends the display control signal S2C to the left warning display indicator 5C to turn on the left warning display indicator 5C, and there is a vehicle that is suddenly approaching the driver from the left adjacent lane. Recognize that. Then, after the processing in step SP14, SP15 or SP16, the process returns to step SP11. (4) Effect According to the above configuration, the driver displays the right warning display indicator 5A, the left warning display indicator 5C, and the braking warning display indicator 5B respectively on the right side mirror 6, the left side mirror 8, and the rear view mirror 7. A vehicle that can easily and accurately recognize that a vehicle traveling in an adjacent lane and a following vehicle have suddenly approached the host vehicle by being provided at a position where the vehicle can be seen within the same field of view. The rear side monitoring method device 1 can be realized. (5) Other Embodiments In the above embodiment, as shown in FIG. 2, the right warning display indicator 5A and the left warning display indicator 5C are provided on the front pillar, and the brake warning display indicator 5B is mounted on the ceiling. However, the present invention is not limited to this, and the right warning display indicator 5A, the left warning display indicator 5C, and the braking warning display indicator 5B may be provided in the respective mirrors 5A, 5C, 5B.
B may be provided in the frame portion. In short, it may be provided at a position near each mirror so as to enter the same field of view as the mirror. In the above-described embodiment, the image processing unit 3 and the risk determining unit 4 are provided as risk determining means.
The movement of the same point in the two frames of images before and after the predetermined time is detected as an optical flow, and from the point at infinity (FOE) in the image that appears for a point on the vehicle traveling on the following vehicle or an adjacent lane. Although the case where the degree of danger is determined based on the magnitude of the optical flow vector in the diverging direction has been described, the present invention is not limited to this, and the point is that the relative position of the vehicle running in the rear lane or the adjacent lane with respect to the own vehicle is important. Any risk determination process may be performed as long as the risk can be determined based on the positional relationship. As described above, according to the present invention, there is provided an image pickup means for picking up an image of a rear side view from a running host vehicle, and the image pickup means is provided for the host vehicle based on the image picked up by the image pickup means. On the other hand, in a vehicle rear side monitoring device that detects a vehicle approaching from the rear or an adjacent lane and allows the driver to recognize this,
Using the image signal obtained by the imaging means, to detect a vehicle approaching from the rear or adjacent lane to the own vehicle,
Danger determining means for determining the degree of danger and the direction in which the degree of danger is large according to the degree of approach ;
Near the right side mirror so that it is in the same field of view as
A first indicator for displaying a warning when the risk determination means obtains a determination result indicating that the risk of the adjacent lane on the right side is high, and a door mirror on the left side.
A second indicator that is provided near the left side door mirror so as to enter one view, and that displays a warning when the risk degree determination unit obtains a determination result indicating that the degree of risk of the left adjacent lane is large; Enter the same field of view as the rearview mirror
A third indicator is provided in the vicinity of the rear-view mirror, and provides a warning display when the risk determination means obtains a determination result indicating that the rear risk is large, A vehicle rear side monitoring device that can easily and accurately recognize that a vehicle traveling in an adjacent lane and a following vehicle has suddenly approached the own vehicle can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a configuration of a vehicle rear side monitoring device according to an embodiment. FIG. 2 is a diagram showing locations where respective indicators are installed. FIG. 3 is a schematic diagram illustrating a foreground, an image, and an obtained optical flow captured by the video camera in FIG. 1; FIG. 4 is a schematic diagram for explaining a method of detecting an obstacle or the like; FIG. 5 is a schematic diagram for explaining a method of obtaining an optical flow. FIG. 6 is a flowchart showing a processing procedure for obtaining a degree of risk. FIG. 7 is a flowchart for explaining the operation of the vehicle rear side monitoring device according to the embodiment; [Description of Signs] 2 Video camera (imaging means) 3 Image processing section (risk determining means) 4 Danger determining section (risk determining means) 5A Right warning display indicator (first indicator) 5B Braking warning display indicator ( (3rd indicator) 5C Left warning display indicator (2nd indicator)

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60R 21/00 B60R 21/34

Claims (1)

(57) [Claim 1] An image pickup means for picking up an image of a rear side view from a running own vehicle, and based on an image picked up by the image pickup means, the rearward or rearward of the own vehicle. In a vehicle rear side monitoring device that detects a vehicle approaching from an adjacent lane and allows a driver to recognize this, using an image signal obtained by the imaging unit, the rear or adjacent lane to the own vehicle Danger determining means for detecting the approaching vehicle from the vehicle and determining the danger and the direction of the greater danger according to the degree of the approach, and the right door so as to enter the same field of view as the right door mirror.
Set in the vicinity of the mirror vignetting, the same view as the first indicator of warning display, and the left door mirror when the determination result indicating that the greater the risk of the right adjacent lane is obtained by the risk determination means As you enter the left door
Provided in the vicinity of the mirror, and a second indicator displaying a warning when a determination result indicating that a large risk of left adjacent lane is obtained by the risk determination means, into the same field of view and rearview mirror Like a rearview mirror
A third indicator provided in the vicinity and for displaying a warning when a judgment result indicating that the rear risk is large is obtained by the risk judgment means. Monitoring device.