Color image processing using complex wavelet transform [articol]

Abstract

Discrete wavelet transform became a powerful method for signal processing in the last decades. One of the most important applications of this tool is compression, for the bi-dimensional signals, JPEG 2000 being an example. Complex wavelet transform offers improved directionality compared with classical discrete wavelet transform but it is redundant. The paper presents an experimental study that refers to R, G, B images compressed with complex or classical wavelet transform. This study wants to emphasize the tradeoffs between redundancy and improved directionality of complex wavelet transform in compression field. For this study we used for compression Embedded Zero-Tree Wavelet (EZW) algorithm proposed by Shapiro. The experimental results discussed at the end of the paper have been realized for lower and higher bit rates for both transforms. The whole work is intended to find reliable methods for applying Dual-Tree Complex Wavelet Transform (DTCWT) in JPEG 2000 standard.