A Generalized Model for Scratch Detection

Abstract

This paper presents a generalization of Kokaram's model for scratch lines detection on digital film materials. It is based on the assumption that scratch is not purely additive on a given image but shows also a destroying effect. This result allows us to design a more efficacious scratch detector which performs on a hierarchical representation of a degraded image, i.e., on its cross section local extrema. Thanks to Weber's law, the proposed detector even works well on slight scratches resulting completely automatic, except for the scratch color (black or white). The experimental results show that the proposed detector works better in terms of good detection and false alarms rejection with a lower computing time.

Fast removal of line scratches in old movies

“…The model used for representing the degraded image Á is the one already used for the detection step [5,4] and can be simply represented as follows…”

“…It is trivial to say that the more precise the detection the more effective the restoration. In this paper we will not deal with detection using results presented in [5,4].…”

“…They can occur in the same location of subsequent frames. Moreover they can vertically occupy all the image (principal scratches) or only a part of it (secondary scratches) [5]. Having delineated a region of the image for treatment, it is then necessary to reconstruct the image data corrupted by the line artefact.…”

“…This is a crucial point in any restoration algorithm because it implies a more precise knowledge of the investigated defect. Visibility has already been the keystone of the detection algorithms proposed in [5,4].…”

Scratches Removal in Digitised Aerial Photos Concerning Sicilian Territory

“…Bretschneider et al [1] proposed a technique based on wavelet decomposition. Bruni et al [2] generalized the Kokaram's model for scratch detection on the hypothesis that scratch is not purely additive on a given image. The same authors [3] also presented a method based on the Weber's law to detect and restore damages.…”