| 摘要 |
Film scratches that produce errors in video signals produced by a film scanner generally run vertically over one or more moving picture frames and are particularly troublesome where they are intersected by picture contours, i.e. oblique boundaries between light and dark picture content. For concealing the disturbance produced by film scratch in such a case the course of a picture contour across the scratch is determined. First the pixel values before and after a television line crosses the scratch are compared line by line, with simple interpolation inbetween if the difference found is slight. In other cases the direction of rise of an oblique picture contour crossing the scratch is determined and the pixel coordinates of the entrance and exit of the contrast edge into and out of the scratch are generated and stored, while at the same time the pixel values at the edge opposite the entry and exit are also stored. When the pixel values at opposite sides of the scratch are again equal the other end of the crossing of the scratch by the picture contour has been reached, the position of the picture contour across the scratch is determined when the contour transition point in each line is calculated for controlling the concealment of the scratch disturbance.
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