JPH06113308A - Picture processing method in on-vehicle image pickup device - Google Patents

Abstract

PURPOSE:To improve a visual field at driving in the mist with inexpensive configuration by using not an infrared ray camera but a CCD camera as a display means. CONSTITUTION:Picture data for a vehicle in existence in front picked up by a CCD camera 11 are ADD-converted by an A/D converter 12. Then a mist density discrimination means 14 detects a change in a mist density based on a change in the picture data for each frame subject to A/D conversion, and when the mist density changes densely, a matching means 15 checks a change in a position of a high luminance region whose luminance level is a prescribed level or over in both of a frame picture before density change and a frame picture after density change stored in a frame memory 13. A picture of a vehicle in existence in front before a mist density change is modified by a picture synthesis means 16 based on a change in a position of a tail lamp being an introduced high luminance area, the picture data after modification are D/A- converted by a D/A converter 17 and the picture after modification is displayed on a monitor display means 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing method in a vehicle-mounted image pickup device for picking up an image of the periphery of a vehicle by an image pickup means and displaying an image picked up by the image pickup means by a display means.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS. 9 and 10, an image processing method in an in-vehicle image pickup device of this type is as shown in FIG. 9 and FIG.
The front image obtained by the image pickup means 2 is displayed on the instrument panel 3
The information is displayed on the display means 4 for a monitor such as a liquid crystal television installed in the vehicle to give the driver information to assist the driver when traveling. Especially, it is applied to improve the visibility when traveling in fog. In order to do so, an infrared camera is used as the image pickup means 2.

[0003]

However, since the infrared camera usually requires cooling, it is very expensive, and it receives light of a long wavelength. Therefore, in the size of a vehicle-mounted camera, the display means 4 for monitoring is used. There is a problem in that the resolution of the displayed image is poor and it is not possible to provide sufficient image information for improving the visibility in fog.

Therefore, the present invention has been made to solve the above problems, and an object thereof is to improve the field of view during traveling in fog with an inexpensive structure.

[0005]

An image processing method in a vehicle-mounted image pickup device according to the present invention is a vehicle-mounted device in which an image pickup means mounted on a vehicle picks up an image of a surrounding area and an image picked up by the image pickup means is displayed by a display means. In the imaging device,
A change in fog density is detected by the fog density determination means, and when the fog density is changed to a high density, the holding means holds the data of the image before the change by the image pickup means, and the image after the change by the image pickup means and the held Derivation means derives a change in the position of a high-brightness region having a predetermined brightness level or higher in the image before change, the image before change is deformed based on the change by the image combining means, and the image after deformation Is displayed by the display means.

[0006]

According to the present invention, when the fog density changes to a high level, the holding unit holds the image data of the image capturing unit before the change, and the data of the changed image and the image before the change are equal to or higher than a predetermined brightness level. A change in the position of the high-brightness area is derived and derived, and the image combining unit deforms the image before the change based on this position change. Therefore, an inexpensive CCD camera is used as the display unit instead of the conventional infrared camera. It can be used, which improves the visibility when driving in fog without the loss of resolution as in infrared cameras.

[0007]

1 is a flow chart for explaining the operation of an embodiment of the present invention, FIG. 2 is a block diagram of an in-vehicle image pickup device to which the present invention is applied, and FIGS. 3 to 8 are operation explanatory views.

First, the structure of the on-vehicle image pickup device will be described. The data of the image of the front vehicle taken by the CCD camera 11 which is the image pickup means is A / D converted by the A / D converter 12 to be A / D converted. The created data is stored in the frame memory 13 which is a holding unit.

Then, the fog density determination means 14 detects a change in the fog density from the change in the A / D-converted image data for each frame, and when the fog density changes, the fog held by the frame memory 13 is changed. The matching means 15 as a deriving means derives a change in the position of the high-luminance region having a predetermined luminance level or higher in both the frame image before the density change and the frame image after the density change.

At this time, since the tail lamp is normally turned on in the fog, even if the fog density changes, the tail lamp of the vehicle in front becomes a high brightness area above a predetermined brightness level in the captured image, as shown in FIG. 3, for example. Whether the fog density is low (solid line in FIG. 3) or dark (dashed line in FIG. 3), the tail lamp portion has a brightness equal to or higher than a predetermined brightness level Th and before the fog density changes. By binarizing the changed image data at a predetermined brightness level Th, the position of the image of the tail lamp portion of the vehicle ahead can be detected and the amount of change can be derived.

Further, the image synthesizing means 16 transforms the image of the front vehicle before the change of the fog density on the basis of the derived change amount of the position of the tail lamp which is the high brightness region,
The transformed image data is D / A converted by the D / A converter 17, and the transformed image is displayed on the monitor display means 18.

By the way, the deformation of the image in this case will be explained. For example, the images of both tail lamps before the change of the fog density are TL and TR as shown by the circles of the one-dot chain line in FIG. When the images of the rear tail lamps are TL 'and TR' as shown by the solid circles in FIG. 4, the movement amount between the center of gravity of the left tail lamp image and the movement amount between the center of gravity of the right tail lamp are derived. , The distance D between the two tail lamp images TL and TR before the change and the distance D'between the two tail lamp images TL 'and TR' after the change are derived to derive the reduction / enlargement amount of the image, and before the change. Of the line connecting the center of gravity of the two tail lamp images TL and TR and the line connecting the center of gravity of the two tail lamp images TL 'and TR' after the change
Is derived.

Then, how much the image of the front vehicle before the change of the fog density is moved, reduced / enlarged, and rotated from the derived movement amount between center of gravity, reduction / enlargement amount, and inclination angle θ. It is understood how the image is transformed before the fog density changes.

Next, a series of control procedures will be described with reference to the flowchart of FIG.

First, an image of a front vehicle is taken by the CCD camera 11 (step S1), the image of the front vehicle is displayed on the display means 18, and the fog density determination means 14 determines the fog density on the basis of the image data. It is determined whether or not there is a change (step S2), and the determination result is N.
If it is O, the process returns to step S1. If the determination result is YES, the data of the frame image before the change in fog density is updated and stored in the frame memory 13 (step S3), and the frame image after the change in fog density is It is taken into the matching means 15 (step S4).

Next, by the matching means 15, a high brightness area equal to or higher than a predetermined brightness level Th in the image before the change in fog density and the image after the change in fog density stored in the frame memory 13, that is, An image such as a tail lamp portion of a vehicle ahead is detected (step S5), and it is determined whether or not there is an overlapping portion in the high brightness region in the image before and after the change in fog density (step S6). If NO, the overlapping portion disappears, for example, because the front vehicle has turned off the tail lamp, so that the process returns to step S1 without performing the subsequent process.

On the other hand, if the decision result in the step S6 is YES, the amount of movement between the centers of gravity of the high brightness areas in the image before and after the change of the fog density detected in the step S5 is derived, and the distance between the centers of gravity is derived. After the image of the front vehicle before the change of the fog density is transformed by the image synthesizing means 16 on the basis of the movement amount (step S7), the transformed image of the front vehicle is displayed on the display means 18 (step S8). Then step S1
Return to.

The image deformation according to the above procedure will be described with reference to a specific example. When the image shown in FIG. 5 is input to the CCD camera 11 when the fog density is low, the image is taken by the CCD camera 11. The image is the same as the input image of FIG. 5, as shown in FIG.

Here, in FIGS. 5 and 6, R is a reflector provided near the guardrail.

Next, the CC when the fog density changes strongly
When the image captured by the D camera 11 becomes as shown in FIG. 7, the images TL and TR of the tail lamp of the vehicle ahead appear bright, and the reflector R appears bright due to the reflection of the head lamp of the vehicle. Before the change in fog density,
By binarizing the subsequent image at a predetermined brightness level Th, the tail lamp images TL and TR in the high brightness region are obtained.
, The amount of change in the image of the reflector R is derived, and the image before the change in fog density shown in FIG. 6 is deformed based on this amount of change,
An image after deformation as shown in FIG. 8 is displayed by the display unit 18, and even if there is almost no view due to the thick fog, the display unit 18 displays a composite image with the same view as when the fog is thin. It will be.

Therefore, it is not necessary to use an expensive infrared camera as in the prior art, and an inexpensive CCD camera 11 can be used.
The visibility during traveling in fog can be improved by an inexpensive structure.

In the above embodiment, the case where the vehicle ahead is imaged has been described, but it goes without saying that it is possible to image not only the front but also the surroundings such as the rear and the sides.

The display means is not limited to the above CCD camera.

[0024]

As described above, according to the image processing method of the vehicle-mounted image pickup apparatus of the present invention, when the fog density is changed to a high density, a predetermined brightness level in the image after change and the image before change is equal to or higher than a predetermined brightness level. Since the change in the position of the high brightness area is derived and the image before the change is transformed by the image synthesizing means based on this change, an inexpensive CCD camera can be used as the display means instead of the conventional infrared camera. As a result, it is possible to satisfactorily improve the visibility during traveling in fog without lowering the resolution as in the case of an infrared camera, and improve the safety of traveling in fog.

[Brief description of drawings]

FIG. 1 is a flowchart for explaining the operation of an embodiment of an image processing method in an in-vehicle image pickup device of the present invention.

FIG. 2 is a block diagram of an apparatus applied to the present invention.

FIG. 3 is an operation explanatory diagram of FIG. 2;

FIG. 4 is an operation explanatory diagram of FIG. 2;

5 is an operation explanatory diagram of FIG. 2;

FIG. 6 is an operation explanatory diagram of FIG. 2;

FIG. 7 is an operation explanatory diagram of FIG. 2;

FIG. 8 is an operation explanatory diagram of FIG. 2;

FIG. 9 is an explanatory diagram of a layout of a conventional vehicle-mounted imaging device.

FIG. 10 is an explanatory diagram of a layout of a conventional vehicle-mounted image pickup device.

[Explanation of Codes] 11 CCD Camera 13 Frame Memory 14 Fog Density Determining Means 15 Matching Means 16 Image Composing Means 18 Display Means

Claims (1)

[Claims] 1. An in-vehicle image pickup device for picking up an image of a surrounding area by an image pickup means mounted on an automobile and displaying an image picked up by the image pickup means on a display means, wherein a change in fog density is detected by a fog density determination means, and fog density is detected. When the density is changed to a high density, the holding unit holds the image data of the image capturing unit before the change, and the image data of the image capturing unit after the change and the predetermined luminance level in the held image before the change are equal to or higher than a predetermined brightness level. An in-vehicle device characterized by deriving a change in the position of the high-brightness region by deriving means, deforming the image before the change based on the change by the image synthesizing means, and displaying the deformed image by the display means. An image processing method in an imaging device.