Embedded Linked Significant Tree Wavelet Image Coder

This paper presents a new linked significant tree (LST) wavelet coding method for efficient compression of images. The proposed method links all the significant coefficients together within a wavelet tree to facilitate encoding algorithm. Insignificant parents with at least one significant child found in the wavelet data are changed to significant to link them together. Their location is saved for identification, and they are then treated just like other significant coefficients during encoding. LST encoding process is performed next on the processed output for compression. It exploits the fact that since all the significant coefficients within a wavelet tree are linked together, no descendent of an isolated coefficient can be significant any more. This eliminates the need to check descendents of those coefficients that are found as insignificant. Locations of converted coordinates are sent to the decoder after each encoding pass, in order to change these values back to original during reconstruction. Better compression is achieved when the proposed method is applied to smooth images