JPEG
History
The JPEG committee investigated the patent claims in 2002 and were of the opinion that they were invalidated by prior art, a view shared by various experts. The patent describes an image compression algorithm based on the discrete cosine transform (DCT), a lossy image compression technique that originated from a 1974 paper by Nasir Ahmed, T. Natarajan and K. R. Rao. Wen-Hsiung Chen further developed their DCT technique, describing a fast DCT algorithm in a 1977 paper with C.H. Smith and S.C. Fralick. The 1992 JPEG specification cites both the 1974 Ahmed paper and the 1977 Chen paper for its DCT algorithm, as well as a 1984 paper by Chen and W.K. Pratt for its quantization algorithm. Compression Labs was founded by Chen, and was the first company to commercialize DCT technology. By the time Chen had filed his patent for a DCT-based image compression algorithm with Klenke in 1986, most of what would later become the JPEG standard had already been formulated in prior literature. JPEG representative Richard Clark also claimed that Chen himself sat in one of the JPEG committees, but Forgent denied this claim.
JPEG-15