TUTCRIS - Tampereen teknillinen yliopisto


Additional lossless compression of JPEG images based on BPG



OtsikkoImage Processing: Algorithms and Systems XVII
DOI - pysyväislinkit
TilaJulkaistu - 13 tammikuuta 2019
OKM-julkaisutyyppiA4 Artikkeli konferenssijulkaisussa
Tapahtuma17th Image Processing: Algorithms and Systems Conference, IPAS 2019 - Burlingame, Yhdysvallat
Kesto: 13 tammikuuta 201917 tammikuuta 2019


NimiIS and T International Symposium on Electronic Imaging Science and Technology


Conference17th Image Processing: Algorithms and Systems Conference, IPAS 2019


The task of additional lossless compression of JPEG images is considered. We propose to decode JPEG image and recompress it using lossy BPG (Better Portable Graphics) codec based on a subset of the HEVC open video compression standard. Then the decompressed and smoothed BPG image is used for calculation and quantization of DCT coefficients in 8x8 image blocks using quantization tables of the source JPEG image. A difference between obtained quantized DCT coefficients and quantized DCT coefficients of the source JPEG image (prediction error) is calculated. The difference is lossless compressed by a proposed context modeling and arithmetical coding. In this way the source JPEG image is replaced by two files: compressed BPG image and the compressed difference which needed for lossless restoration of the source JPEG image. It is shown that the proposed approach provides compression ratios comparable with state of the art PAQ8, WinZip and STUFFIT file archivers. At the same time BPG images may be used for fast preview of compressed JPEG images.