Reconstruction of degraded image sequences. Application to film restoration

A suitable detection-reconstruction approach is proposed for removing impul sive distortion and other types of deterioration from degraded image sequen ces. The main application that has motivated this work is the problem of di gital film restoration for the movie industry, which has only very recently been explored. Line artifacts, which are prominent degradations in motion picture films, are also considered here. The detection procedure consists o f two steps. First, a morphological filter provides impulsive distortions a nd line scratch candidates. Unlike impulsive distortions, which appear rand omly in an image, line artifacts persist in nearby or the same location acr oss several frames. Furthermore, the detection process is complicated by th e fact that lines occur as natural part in interesting scenes. Therefore, w e add a validation step for separating possible line defects from false det ections. It consists: in tracking the potential line artifacts over the fra mes using a Kalman filter. An interpolation technique, dealing with both lo w and high frequencies around the detected deteriorations, is investigated to achieve a nearly invisible reconstruction of damaged areas. (C) 2001 Els evier Science B.V. All rights reserved.