Overcompressing JPEG Images with Evolution Algorithms

Abstract. Overcompression is the process of post-processing compressed images to gain either further size reduction or improved quality. This is made possible by the fact that the set of all “reasonable” images has a sparse structure. In this work, we apply this idea to the overcompression of JPEG images: We reduce the blocking artifacts commonly seen in JPEG images by allowing the low frequency coefficients of the DCT to vary slightly. Evolutionary strategies are used in order to guide the modification of the coefficients towards a smoother image. 1 Statement of the problem Various compression methods have been devised in view of reducing the size of image files for purposes of storing and transmission. In order to reach substantial compression rates, lossy techniques have to be used, i.e. the compressed/decompressed image is a degraded version of the original one. Most such compression methods allow to tune the size of the compressed file, so as to reach a trade-off between r...

• Type: Conference
• Year: 2007
• Where: EVOW
• Authors: Jacques Lévy Véhel, Franklin Mendivil, Evelyne Lutton
• Keywords: Artificial Intelligence, Compression Method, EVOW 2007, Image, Various Compression Methods