Removal of Vertical Scratches in Digitised Historical Film Sequences Using Wavelet Decomposition

Movie films are often damaged through ageing, chemical changes and contact with mechanical parts of the film projector. In this paper methods for the detection and removal of vertical scratches in digitised film sequences are discussed. This specific type of scratch arises by the contact of the film material running against a mechanical part of the camera or film projector. The proposed technique is based on the discrete wavelet decomposition. This transformation splits an image into approximation and detail coefficients, where the latter separate into horizontal, vertical, and diagonal representations. The algorithm reconstructs the missing data in the region of the scratch and finally the synthesis of the wavelet coefficients generates a restored version of the scratched image frame. The results show that the combination of scratch detection and removal in the wavelet domain is superior to other techniques based in the image domain which use single frames.