An improved JPEG image coder using the adaptive fast approximate Karhunen-Loeve transform (AKLT)
Leu-Shing Lan, I.S. Reed · 2002
A new fast approximate Karhunen-Loeve transform (AKLT) [Lan and Reed, 1993; Reed and Lan, 1993] was discovered. This novel transform is derived by use of the perturbation theory of linear operators. The theoretical advantages of the AKLT over the DCT, the current industrial standard for image compression, are discussed thoroughly in Reed and Lan, and Lan and Reed for the first-order Markov image model. In the present paper, an improved JPEG image coder which uses the adaptive AKLT is presented. An improvement of 5% in compression ratio as compared with the DCT-JPEG system is obtained when the desired nominal data rate is above 0.4 bits/pixel for typical real-life images. The rate-distortion curves indicate a superiority of the adaptive AKLT scheme over the DCT scheme for all ranges of the data rate. It is worthwhile to note that this new adaptive AKLT-JPEG system can be really implemented using the existing JPEG chip set with only a slight modification.>