Image synthesis display method and apparatus for vehicle camera
When multiple cameras (CAM 1 ) to (CAM 8 ) for shooting the periphery of a local vehicle are mounted on the vehicle, and when obtained camera images are to be synthesized to display a synthesized image on the screen of a display device ( 16 ), the pixel data for the camera images constituting the synthesized image are compensated for, so that differences in the pixel data for adjacent camera images is reduced. For example, the pixel data are corrected so their values equal the average values of the pixel data for the adjacent camera images. Therefore, an easily viewed image, produced by synthesizing the images obtained by the multiple vehicle cameras, can be displayed on the monitor device ( 16 ).
1. An image synthesis display method for a vehicle camera comprising the steps of:
obtaining images from a plurality of vehicle cameras shooting the periphery of a local vehicle;
compensating the images obtained from the plurality of vehicle cameras to reduce differences between pixel data of the images of the plurality of vehicle cameras based on a flag table;
superimposing the images to form a synthesized image;
displaying the synthesized image on a screen of a display device,
wherein the flag table defines pixel areas in the images obtained from adjacent vehicle cameras as pixel areas for the compensation process, the pixel areas corresponding to a common portion between the images obtained from the adjacent vehicle cameras; and
wherein the images obtained from the plurality of vehicle cameras are compensated on the basis of pixel data of the images which correspond to the pixel areas defined by the flag table.
2. The image synthesis display method according to claim 1 , wherein the compensation to reduce differences is performed to equalize average values of pixel data of adjacent camera images of the plurality of vehicle cameras.
3. The image synthesis display method according to claim 2 , wherein the average values are obtained by using the entire pixel data of at least one of said adjacent camera images.
4. An image synthesis display method according to claim 2 , wherein the average values are obtained by using pixel data of a vicinity of the local vehicle in the entire pixel data of at least one of the adjacent camera images.
5. The image synthesis display method according to claim 2 , wherein the average values are obtained by using the pixel data of the overlapping shooting regions of the adjacent camera images.
6. The image synthesis display method according to claim 2 , wherein the average values are obtained by using pixel data of the vicinity of said local vehicle in pixel data of the overlapping shooting regions of the adjacent camera images.
7. The image synthesis display method according to claim 2 , wherein the flag table is prepared in correlation with pixel positions for the plurality of vehicle cameras, and the average values are obtained by using pixel data displayed at pixel positions that correspond to pixel areas written in advance in the flag table.
8. The image synthesis display method according to claim 1 , wherein the values of the image data for which said differences are to be reduced represent brightness or colors.
9. The image synthesis display method according to claim 1 , wherein the compensation is performed to gradually reduce differences along the time axis near a target compensation value.
10. An image synthesis display method for a vehicle camera comprising the steps of:
synthesizing images obtained by a plurality of vehicle cameras shooting the periphery of a local vehicle;
displaying a synthesized image on the screen of a display device,
wherein the synthesized image of the plurality of vehicle cameras is displayed on the screen by performing a compensation to reduce differences between pixel data of the adjacent camera images of the plurality of vehicle cameras,
wherein, when three or more vehicle cameras are prepared, a camera image whose average value is nearest the average value for pixel data for all the camera images is regarded as a reference image,
wherein the compensation of the image data of the adjacent camera images are performed to adjust to the average value for the reference image.
11. The image synthesis display method according to claim 1 ,
wherein the synthesized image is a synthesized image by synthesizing images of which a view point is changed; wherein the viewpoint is a virtual viewpoint viewed from above the local vehicle.
12. An image synthesis display apparatus for a vehicle camera, wherein images obtained by a plurality of vehicle cameras shooting a periphery of a local vehicle are superimposed to form a synthesized image and the synthesized image is displayed on the screen of a display device, comprising:
compensation means for carrying out an image synthesis display method according to claim 1 .
13. The image synthesis display method according to claim 11 , wherein the entire periphery of the local vehicle is identified on the screen.
14. The image synthesis display method according to claim 1 , wherein the common portion is an overlapped area between the images obtained from adjacent vehicle cameras.