VEHICLE REAR VIEW MONITORING DEVICE

• US 20120327239A1
• Filed: 05/19/2010
• Published: 12/27/2012
• Est. Priority Date: 05/19/2010
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Inoue, Satoru, Suzuki, Ryotaro, Mitsugi, Tatsuya, Shimizu, Hirokazu
• Granted Patent: US 9,047,779 B2
• Time in Patent Office: Days
• US Class Current: 348/148
• CPC Class Codes: B60R 1/26 to the rear of the vehicle
• CPC Class Codes: B60R 1/28 with an adjustable field of view
• CPC Class Codes: B60R 2300/301 combining image information with other obstacle sensor information, e.g. using RADAR/LIDAR/SONAR sensors for estimating risk of collision
• CPC Class Codes: B60R 2300/307 virtually distinguishing relevant parts of a scene from the background of the scene
• CPC Class Codes: B60R 2300/607 from a bird's eye viewpoint
• CPC Class Codes: B60R 2300/70 characterised by an event-triggered choice to display a specific image among a selection of captured images
• CPC Class Codes: G01S 15/876 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S15/872 takes precedence
• CPC Class Codes: G01S 15/931 of land vehicles
• CPC Class Codes: G01S 2015/932 for parking operations
• CPC Class Codes: G01S 2015/933 for measuring the dimensions of the parking space when driving past
• CPC Class Codes: G01S 7/6245 Stereoscopic displays; Three-dimensional displays; Pseudo-three dimensional displays
• CPC Class Codes: G08G 1/16 Anti-collision systems road vehicle drive control systems for predicting or avoiding probable or impending collision otherwise than by control of a particular sub-unit B60W30/08
• CPC Class Codes: G08G 1/165 for passive traffic, e.g. including static obstacles, trees
• CPC Class Codes: G08G 1/166 for active traffic, e.g. moving vehicles, pedestrians, bikes

Abstract

Because a vehicle rear view monitoring device changes the detection threshold level of each of distance sensors 4-1 to 4-4 to change horizontal and vertical detection areas and a bearing resolution, determines the display position of an obstacle mark 16 from the distances to an obstacle 15 detected by the plurality of distance sensors 4-1 to 4-4, and amplitude information about the amplitude of a reflected wave from the obstacle, and overlays the obstacle mark 16 on the obstacle 15 by using an overlay unit 17, the vehicle rear view monitoring device improves the degree of positional precision of the overlay of the obstacle mark on the obstacle displayed on a captured image.

Claims

1. A vehicle rear view monitoring device including a plurality of distance sensors each for detecting a distance to an obstacle, a threshold level changing unit for changing a detection threshold level of each of said distance sensors to change a horizontal detection area. a vertical detection area, and a bearing resolution, an obstacle determination unit for determining whether or not an obstacle is existing according to a threshold level outputted from said threshold level changing unit and received signals of said distance sensors, and a display screen switching unit for changing a display image between a directly-captured image and a bird'"'"'s-eye view image according to the distance to the obstacle determined by said obstacle determination unit, wherein said vehicle rear view monitoring device comprises:

an overlay unit for measuring a bearing of the obstacle and a distance to the obstacle from a position where each of said distance sensors is mounted and the distance to the obstacle, and amplitude information about an amplitude of a reflected wave from the obstacle, the position and the distance to the obstacle being determined by said obstacle determination unit, for determining a display position and a shape of an obstacle mark according to a corresponding distance and a corresponding bearing on a screen for changing a display image as an expression of the obstacle mark between a directly-captured image and a bird'"'"'s-eye view image when the distance to the obstacle determined by said obstacle determination unit has a predetermined value, and for overlaying the obstacle mark having said determined shape on an image captured by a camera and furnished from said display screen switching unit in such a way that the obstacle mark is positioned at said determined display position.

2. The vehicle rear view monitoring device according to claim 1, wherein the threshold level changing unit has a function of changing the detection threshold level according to propagating distance-sensitivity characteristics of the distance sensors and on a basis of a propagation distance or a propagation time to form each of the distance sensors into a rectangular or radial shape, and arrange the detection areas of any two distance sensors located horizontally adjacent to each other in such a way that they partially overlap each other or they do not overlap each other, and a function of, when arranging the detection areas of any two distance sensors located horizontally adjacent to each other in such a way that they partially overlap each other, implementing a logical AND operation on results of detection of the object at a same distance by adjacent distance sensors to determine a bearing of the obstacle.

3. The vehicle rear view monitoring device according to claim 1, wherein said vehicle rear view monitoring device includes a steering angle sensor, and the threshold level changing unit has a function of setting the detection threshold level of a distance sensor disposed on a side of an inner wheel to a lower level according to angle information of the steering angle sensor in such a way that the distance sensor has a wider horizontal detection area than that at a time when a vehicle is travelling straight ahead, and also setting the detection threshold level of a distance sensor disposed on a side of an outer wheel to a higher level according to the angle information in such a way that the distance sensor has a narrower horizontal detection area than that at the time when the vehicle is travelling straight ahead.

4. The vehicle rear view monitoring device according to claim 1, wherein the threshold level changing unit has a function of sequentially changing the detection threshold level to change the vertical detection area to determine a height of the obstacle in a detection area having a detectable maximum height.

5. The vehicle rear view monitoring device according to claim 3, wherein the threshold level changing unit has a function of acquiring a steering angle from the steering angle sensor while sequentially changing the detection threshold level to change the horizontal detection area, and making a distinction between an inside area whose width is same as that of the vehicle travelling, and an area outside the inside area having the same width as the vehicle to determine a detectable area.

6. The vehicle rear view monitoring device according to claim 5, wherein the vehicle rear view monitoring device has wheel speed sensors, and makes it possible to detect entrance of a moving obstacle into the inside area having the same width as the vehicle by grasping a time-varying state of detection of the obstacle according to movement locus information of the vehicle which said vehicle rear view monitoring device calculates by using information from said wheel sensors.

7. The vehicle rear view monitoring device according to claim 3, wherein when an obstacle whose distance between a leading edge portion thereof including a direction of a height of the obstacle specified by the distance sensors and the vehicle is shortest is existing and can collide with the vehicle, the overlay unit overlays the obstacle mark on the camera image.

8. The vehicle rear view monitoring device according to claim 5, wherein when a corner sensor mounted to a corner portion of the vehicle detects an obstacle existing in the area outside the inside area having the same width as the vehicle or when it is detected that an obstacle is existing in the area outside the inside area through a recognition process performed on the camera image, the overlay unit overlays the obstacle mark on a camera image of an area outside the detection areas of the distance sensors.

9. The vehicle rear view monitoring device according to claim 7, wherein when distances detected by a plurality of adjacent distance sensors fall within an allowable range Tth, the overlay unit overlays the obstacle mark over the detection areas of said distance sensors, whereas the distances exceed the allowable range Tth, the overlay unit overlays the obstacle mark at an obstacle position positioned at a shorter distance.

10. The vehicle rear view monitoring device according to claim 7, wherein when distances detected by a plurality of adjacent distance sensors fall within an allowable range Tth, and a level difference between reflected waves originated from ultrasonic waves from adjacent ultrasonic sensors and reflected from the obstacle is equal to or smaller than a predetermined allowable value Vth, the overlay unit overlays the obstacle mark over the detection areas of said ultrasonic sensors, whereas when said level difference between the reflected waves exceeds the allowable value Vth, the overlay unit overlays the obstacle mark on the detection area of the distance sensor providing a higher level of reflected wave.