| 摘要 |
PROBLEM TO BE SOLVED: To detect a vehicle from image data even when these image data are deteriorated by dirt stuck on the lens surface of an image input device or filter surface protecting a lens. SOLUTION: A fixed reference value t0 is provided for capturing the difference of a luminance value at initial time. At the initial time without dirt, a luminance value a1 at a certain pixel position in the state of picking up the image of the vehicle is stored for each pixel of an entire picture. A value obtained by subtracting the difference between the luminance value a1 at said each pixel position and a luminance value a2 at a relevant pixel position at the time of operation from the fixed reference value t0 is provided for the entire picture, this mean value is calculated and provided as a new reference value t1 and when the difference of a luminance value greater than the new reference value t1 is detected at a certain pixel position, the presence of a change in the relevant pixel is discriminated. |
