JP7162427B2 - Vehicle rear image display device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle rear image display device that is mounted on a vehicle and captures and displays the rear image.

Conventionally, when a camera attached to a vehicle captures an image of the area in front of the vehicle, and the pixel value of each pixel included in the obtained image has reached the saturation level and there are pixels in a saturated state adjacent to each other for a predetermined number of pixels or more. Furthermore, there is known an in-vehicle camera control device that changes the pixel value/brightness characteristics when the camera next captures an image so as to suppress high-brightness portions (see, for example, Patent Document 1). By performing such processing, when the image captured by the camera contains high-brightness areas such as the headlights of oncoming vehicles and the taillights and brake lights of preceding vehicles, the pixel values and brightness characteristics of the camera are In addition to lowering the sensitivity of pixel value changes to brightness, the higher the brightness level, the smaller the pixel value/brightness characteristics change. contrast can be detected.

JP 2006-339994 A

By the way, recently, a method of converting the rearview mirror into an electronic mirror by installing a camera at the rear of the vehicle and drawing an image of the rear of the vehicle captured by the camera on an LCD panel arranged in the rearview mirror has been put to practical use. be. When such a method is used to display an image behind the vehicle, the illuminance of surrounding roads is low during nighttime driving, and the rearward visibility is extremely poor due to halation caused by the headlights of following vehicles. On the other hand, according to the CMS (Camera Monitoring System) standard, in order to support PLS (Point Light Source), it is necessary to draw the two headlights of the following vehicle located 250 m behind the vehicle as two separate light sources.

In order to meet such a demand, it is conceivable to use the technique of Patent Document 1 described above. However, when trying to change the pixel values and brightness characteristics by controlling various optical elements of the camera each time in accordance with the brightness of the headlights of the following vehicle, there was a problem that the processing load would increase. On the other hand, even if the left and right headlights of the following vehicle can be drawn separately, the left and right headlights of the following vehicle may suddenly appear in the darkness if the distance from the own vehicle to the following vehicle is dark. As a result, there is a problem that it is difficult to grasp the distance from the own vehicle to the following vehicle.

The present invention was created in view of such a point, and its purpose is to separately draw the left and right headlights of the following vehicle included in the vehicle rear image, and to calculate the distance from the own vehicle to the following vehicle. To provide a rear image display device for a vehicle, which enables easy grasping of a space.

In order to solve the above-described problems, the vehicle rear image display device of the present invention is set to a gain that enables separate drawing of the left and right headlights of the following vehicle when the left and right headlights of the following vehicle are turned on. A first imaging means for imaging the rear of the vehicle, a second imaging means for imaging the front of the vehicle illuminated by the left and right headlights of the own vehicle, and a forward image obtained by imaging by the second imaging means a partial image extraction means for extracting a partial image by cutting out a part thereof; and a composite image is generated by superimposing the partial image extracted by the partial image extraction means on the rearward image obtained by imaging by the first imaging means. and display means for displaying a synthesized image synthesized by the image synthesizing means.

By adjusting the gain of the first imaging means, the left and right headlights of the following vehicle included in the rear image can be drawn separately, and a partial image obtained by cutting out a part of the front image can be used as the rear image. Since only superimposing is performed, the processing load can be reduced.

Further, the above-described image synthesizing means converts a plurality of partial images extracted by the partial image extracting means from each of the plurality of front images obtained by imaging by the second imaging means as the vehicle moves into a rear image. should be superimposed on As a result, in the rear image, the area between the own vehicle and the following vehicle can be drawn using a partial image corresponding to the road surface illuminated by the headlights of the own vehicle, and the separated left and right headlights of the following vehicle can be drawn. In addition, by displaying such a road surface, it becomes easier to grasp the distance from the own vehicle to the following vehicle.

Moreover, it is desirable that the partial image extracted from the forward image by the partial image extracting means described above includes a range wider than the width of the lane in which the vehicle is traveling. As a result, it is possible to display a rearward image that reproduces the actual width of the lane (road), and to display a natural image.

Further, the above-described image synthesizing means performs image synthesizing by setting a running locus corresponding to the running state of the own vehicle on the rearward image, and arranging a plurality of partial images along the running locus in the order of imaging times. is desirable. In particular, it is desirable that the above-described running state includes the direction, speed, and angle of the own vehicle. As a result, the shape of the road in the rearward image can be changed according to the running state of the own vehicle, and the sense of incongruity caused by using the synthesized image can be further reduced.

Moreover, it is desirable that the display means described above displays the composite image on a part of the rearview mirror. As a result, the actually visible rear image and the synthesized image can be displayed side by side, and by comparing these images, it becomes easier to grasp the distance from the own vehicle to the following vehicle.

It is a figure showing composition of a back image display for vehicles of one embodiment. Fig. 10 is a flow chart showing an operation procedure of image synthesis performed when separating the left and right headlights of the following vehicle in the rear image during night driving. FIG. 10 is a diagram showing a specific example of extracting a partial image from a forward image; It is a figure which shows the set running locus. FIG. 5 is an explanatory diagram of arranging partial images along the running locus shown in FIG. 4 ; FIG. 10 is a diagram showing a display example of a synthesized image;

A vehicle rear image display device according to an embodiment to which the present invention is applied will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of a vehicle rear image display device according to one embodiment. As shown in FIG. 1, the vehicle rear image display device 1 of the present embodiment includes a front camera 10F, a rear camera 10R, a front image storage section 20F, a rear image storage section 20R, a partial image extraction section 30, and a superimposed image storage section. 40 , a running state detection unit 50 , an image synthesizing unit 60 , and a display unit 70 .

The front camera 10F images the front of the vehicle. The imaging range is a range that includes the road surface that is illuminated when the headlights of the host vehicle are turned on, and includes at least a range that is wider than the width of the lane on which the vehicle is traveling.

Assuming that a rearview mirror is provided, the rear camera 10R captures an image of the rear of the vehicle so that the area reflected in the rearview mirror as seen from the driver of the vehicle is included in the imaging range. Further, in the present embodiment, the gain of the rear camera 10R is set so that when the left and right headlights of the following vehicle running behind the host vehicle are turned on, the left and right headlights can be drawn separately. ing.

An image (front image) captured by the front camera 10F is stored in the front image storage unit 20F. An image (rear image) obtained by imaging with the rear camera 10R is stored in the rear image storage unit 20R.

The partial image extraction unit 30 extracts a partial image by cutting out a part of the front image captured by the front camera 10F and stored in the front image storage unit 20F. When the front camera 10</b>F captures front images at predetermined time intervals, partial images are sequentially extracted from each front image and stored in the superimposed image storage unit 40 .

The running state detection unit 50 detects at least the direction, speed, and angle of the own vehicle as the running state. For example, the orientation of the own vehicle can be detected using a GPS device or an acceleration sensor. Also, the speed of the own vehicle can be detected by measuring the output interval of the vehicle speed pulse. Furthermore, the snake angle can be detected by measuring the operating angle of the steering wheel with a sensor. It should be noted that a specific detection method other than these methods may be used.

The image synthesizing unit 60 sets the traveling locus of the own vehicle corresponding to the traveling state of the own vehicle detected by the traveling state detecting unit 50 on the rearward image read out from the rear image storing unit 20R. By arranging a plurality of partial images with different image capturing times stored in , along this running locus, the plurality of partial images are superimposed on the rearward image to generate a composite image. The travel locus set here corresponds to the shape of the road that can be seen behind the vehicle. , a road locus curving to the right with a radius of curvature corresponding to the running speed is set. On the rearward image, the shape of the running locus is obtained after performing viewpoint conversion focusing on the position of the viewpoint of the driver with respect to such a curved shape.

The display unit 70 displays the synthesized image generated by the image synthesizing unit 60 . For example, the display unit 70 is configured by a liquid crystal display device and embedded in a part of the rearview mirror.

The rear camera 10R described above serves as first imaging means, the front camera 10F serves as second imaging means, the partial image extracting section 30 and superimposed image storage section 40 serve as partial image extracting means, and the image synthesizing section 60 serves as image synthesizing means. 2, the display section 70 respectively corresponds to the display means.

The vehicle rear image display device 1 of the present embodiment has such a configuration, and the operation thereof will be described next.

In this embodiment, when driving at night, halation occurs due to the illumination light of the left and right headlights of the following vehicle captured by the rear camera 10R, and the left and right headlights may not be separated. In order to separate the headlights, the gain (sensitivity) of the rear camera 10R is lowered so as not to saturate the pixel values. Further, a process of synthesizing a partial image cut out from the front image captured by the front camera 10F with the rear image captured by the rear camera 10R is performed.

Therefore, the timing for executing such processing is (1) when high-brightness areas corresponding to the left and right headlights of the following vehicle are extracted and it is detected that the high-brightness areas cannot be separated into left and right parts. , (2) when a sensor (not shown) detects that the surroundings of the own vehicle have become dark, and (3) when the headlights of the own vehicle are turned on.

FIG. 2 is a flow chart showing the operation procedure of image composition performed when separating the left and right headlights of the following vehicle in the rear image when driving at night. This operating procedure is repeated at predetermined time intervals.

First, the respective imaging ranges are captured by the front camera 10F and the rear camera 10R (step 100). Since the vehicle is assumed to be traveling at night, the headlights of the vehicle are turned on, and a predetermined range including the road surface in front of the vehicle is bright, and the bright road surface is captured by the front camera 10F. Also, since the gain of the rear camera 10R for imaging the rear of the vehicle is set to be low, even if the following vehicle with its headlights turned on enters the field of view (imaging range), the rear image corresponds to the left and right headlights. You can separate the areas that A front image obtained by imaging with the front camera 10F is stored in the front image storage unit 20F. A rear image obtained by imaging with the rear camera 10R is stored in the rear image storage unit 20R.

Next, the partial image extraction unit 30 reads out the front image stored in the front image storage unit 20F, cuts out a part thereof, and extracts a partial image (step 102). The partial images extracted in this way are sequentially stored in the superimposed image storage unit 40 .

FIG. 3 is a diagram showing a specific example of extracting a partial image from a forward image. In FIG. 3, P indicates an area from which a partial image is cut. This area P is a horizontally long area located a predetermined distance (for example, 3 m) ahead of the own vehicle, and has a width wider than the width of the lane in which the own vehicle is traveling.

Next, the running state detection unit 50 detects the running state of the own vehicle, specifically the orientation, speed, and angle of the own vehicle (step 104).

Next, the image synthesizing unit 60 reads out the rear image from the rear image storage unit 20R, and sets the running locus of the own vehicle corresponding to the detected running state on the rear image (step 106). Further, the image synthesizing unit 60 reads a plurality of partial images captured at different times stored in the superimposed image storage unit 40, and arranges them along the travel locus to superimpose the plurality of partial images on the rearward image. to generate a composite image (step 108). The composite image generated in this manner is displayed on the display unit 70 (step 110).

FIG. 4 is a diagram showing a set running locus. In FIG. 4, T1 and T2 are running trajectories set corresponding to the running state of the own vehicle. These two running trajectories T1 and T2 correspond to, for example, left and right tire tracks of the own vehicle. You may make it use one driving|running|working control.

FIG. 5 is an explanatory diagram of arranging partial images along the running trajectories T1 and T2 shown in FIG. 5, S1, S2, S3, S4, . . . indicate a plurality of partial images extracted from forward images captured at different times. S1 is the partial image extracted from the front image with the latest imaging time, and the imaging time becomes older in the order of S2, S3, and S4. The width of each of the partial images S1, S2, .

FIG. 6 is a diagram showing a display example of a synthesized image. In FIG. 6, HL indicates the left headlight of the following vehicle, and HR indicates the right headlight of the following vehicle. In addition, hatching represents darkness (background portion with unclear contrast) included in the rear image. As shown in FIG. 6, in the composite image, the left and right headlights HL and HR of the following vehicle are drawn separately, and the road surface facing the following vehicle is brightly illuminated. ing. Actually, since the partial image extracted from the front image is superimposed on the rear image, there is a gap of several meters between the actual position where the partial image is extracted and the drawing position. Since the image synthesis is performed using the actually captured image of the road surface, a realistic synthetic image can be generated.

As described above, in the vehicle rear image display device 1 of the present embodiment, by adjusting the gain of the rear camera 10R, the left and right headlights of the following vehicle included in the rear image can be drawn separately. , a synthesized image is generated only by superimposing a partial image obtained by cutting out a part of the front image on the rear image, and the processing load can be reduced.

In addition, in the rear image, the area between the own vehicle and the following vehicle can be drawn using a partial image corresponding to the road surface illuminated by the headlights of the own vehicle. By displaying such a road surface, it becomes easier to grasp the distance from the own vehicle to the following vehicle.

In addition, by using a partial image including a range wider than the width of the driving lane of the own vehicle, it is possible to display a rearward image that reproduces the actual width of the lane (road), and perform display without discomfort. It becomes possible.

In addition, a running locus corresponding to the running state of the own vehicle (for example, the direction, speed, and angle of the own vehicle) is set on the rearward image, and a plurality of partial images are arranged in the order of imaging time along the running locus. Thus, image synthesis is performed, and the shape of the road in the rearward image can be changed in accordance with the running state of the own vehicle, and the sense of discomfort caused by using the synthesized image can be further reduced.

In addition, by displaying a composite image on part of the rearview mirror, it is possible to display the actual rear view image and the composite image side by side. becomes easier to comprehend.

It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the gist of the present invention. For example, in the embodiment described above, the display unit 70 is provided in a part of the rearview mirror, but the display unit 70 may be provided in a position other than the rearview mirror.

As described above, according to the present invention, by adjusting the gain of the first imaging means, the left and right headlights of the following vehicle included in the rearward image can be drawn separately. The processing load can be reduced because the partial image cut out is simply superimposed on the rear image.

1 Rear image display device for vehicle 10F Front camera 10R Rear camera 20F Front image storage unit 20R Rear image storage unit 30 Partial image extraction unit 40 Superimposed image storage unit 50 Running state detection unit 60 Image synthesizing unit 70 Display unit

Claims (6)

a first imaging means for capturing an image of the rear of the vehicle, the gain being set to a gain capable of separately drawing the left and right headlights of the following vehicle when the left and right headlights of the following vehicle are turned on;
a second imaging means for imaging the front of the vehicle illuminated by the left and right headlights of the own vehicle;
partial image extracting means for extracting a partial image by cutting out a part of the forward image obtained by imaging by the second imaging means;
an image combining means for generating a combined image by superimposing the partial image extracted by the partial image extracting means on the rearward image obtained by imaging by the first imaging means;
display means for displaying the synthesized image synthesized by the image synthesizing means;
A vehicle rear image display device comprising: The image synthesizing means synthesizes the plurality of partial images extracted by the partial image extracting means from each of the plurality of front images captured by the second imaging means as the host vehicle moves. 2. The vehicle rear image display device according to claim 1, wherein the rear image is superimposed on the rear image. 3. The vehicle rear image display device according to claim 1, wherein the partial image extracted by the partial image extracting means includes a range wider than the width of the lane in which the vehicle is traveling. The image synthesizing means performs image synthesizing by setting a running locus corresponding to a running state of the own vehicle on the rearward image, and arranging the plurality of partial images along the running locus in order of imaging time. The vehicle rear image display device according to any one of claims 1 to 3, characterized by: 5. The vehicle rear image display device according to claim 4, wherein the running state includes the orientation, speed, and angle of the own vehicle. 6. The vehicle rear image display device according to claim 1, wherein the display means displays the composite image on a part of a rearview mirror.

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