Hierarchical preprocessing for improving the blotch detection performances

In this work, we are interested in detecting a special type of degradation called blotch in old films. More precisely, our goal is to improve the detection performances by simultaneously increasing the correct detection rate and reducing the false alarmrate achieved by some conventional detectors. The detection procedure consists of mainly two steps. The regions that are likely to be corrupted are firstly located. Then, a conventional detector is applied only on these candidate regions to locate the blotched pixels. The novelty of our contribution is to detect the candidate regions at different resolution levels. This allows to handle both the different blotch sizes and the varying motion magnitudes of the objects. Experimental simulations carried out on real degraded sequences indicate the efficiency of the proposed approach.