New way to search for the best base in wavelet packets
Haiwen Chen, Teresa L. P. Olson · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2002
The binary-tree best base searching method developed by Coifman and his colleagues is well known and widely used in wavelet packet applications. However, the requirement that the base vectors be chosen from either a parent or its directly related children in the binary-tree structure is a limitation because it doesn't search all possible orthogonal bases and therefore may not provide a optimal result. We have recently found that the set of all possible orthogonal bases in a wavelet packet is much larger than the set searched by the binary-tree method. Based on this observation, we have developed a new way to search the best base among the larger set of orthogonal bases. Preliminary results on 1D signals show that we can achieve considerable improvement in signal compression and feature extraction using the new method. This method can also be readily extended to 2D images for improved image compression, feature extraction, and object classification.