JPEG on STEROIDS: Common optimization techniques for JPEG image compression

Despite its age, JPEG (formally, Rec. ITU-T T.81 - ISO/IEC 10918-1) is still the omnipresent image file format for lossy compression of photographic images. While its rate-distortion performance is not competitive with state-of-the-art schemes like JPEG 2000 or HEVC, manifold techniques have been developed over the years to improve its compression performance. This article provides a short review of the known technologies and evaluates them on the basis of the JPEG XT demo implementation available on the home page of the JPEG committee. It also puts the compression gains into perspective of more modern compression formats such as JPEG 2000.