A contrario False Alarms Removal for Improving Blotch Detection in Digitized Films Restoration

This paper introduces a novel method for improving blotch detection in digital film archive restoration, by using a high-level interpretation of false alarms, and an adaptive decision criterion, based on the a contrario decision theory. Blotch detection is performed using a bidirectional motion compensated SROD detector, and false alarms interpretation is achieved in two steps, using the a contrario criterion. In the first step, meaningful spatio-temporal alignments of detected pixels arc found, while in the second step, corresponding meaningful regions in the current detection map are selected, and removed from the detection map. The introduction of the a contrario model allows adaptive and perceptually meaningful false alarms removal, improving the restoration workflow. Performance evaluation using real blotches ground truth of defects shows a decrease in the number of false alarms for sequences with fast or with complex motions.