PROCEDE D'EXTRACTION AUTOMATIQUE D'UN OBJET CONTRASTE DANS UNE IMAGE NUMERIQUE

摘要

Method for extracting a contrasting object in a digital image. The method estimates a threshold S1 for each picture element, corresponding to a background estimation threshold representing an image contrast. A local contrast function GR(i,j) is determined as a recursive gradient proportional to the difference between the average of a video signal on the line of each picture element, and a function of the averages of the estimated background contrasts and picture elements located on an identical line or a previous line. Using the local contrast function, an estimated background value for each element is determined by comparing the contrast function to the threshold. The difference is taken between the video signal and the estimated background. The result of this difference is compared to a second decision threshold to determine whether or not the picture element belongs to the contrasting object.