| 摘要 |
The device comprises: means of analysis (10, 20; 10', 20) approximating, for each pixel, the gradient of the function of grey level of the image at the site of this pixel, this gradient being defined by an argument, representing an item of direction information, and by a norm, representing an item of amplitude information from the transition of the grey level in this direction; discriminator means (30) extracting, from all these pixels, a sub-set of contour pixels, in which each contour pixel corresponds to a local maximum of the function of grey level in the direction of the gradient, this maximum being determined on the basis of the said item of transition amplitude information; means of infilling (40) completing this sub-set of contour pixels by interspaced infill pixels in the case of a discontinuity of the contour in a given vicinity; and comparator means (50) effecting, for each contour or infill pixel, a comparison of the vicinity of this pixel with a series of characteristic configurations and designating the corresponding pixel as being a straight-line contour pixel if and only if this comparison determine a correspondence of the vicinity of this pixel with one of these characteristic configurations. …<??>The localisation of straight-line contours can thus be operated in real time at video rate. …<IMAGE>… |
