2-D Perfect Reconstruction Filter Bank

In our implementation of a DWT based Image Compression system, we used a 2-D 4 level separable filter bank obtained from the 1-D 9/7 Prototype Filter Bank. We thought that the increase in coding gain for more than four levels is not appreciable enough to be implemented. However, our code is very easily extendible to incorporate a higher number of decomposition levels and/or other separable/non-separable Wavelets.. All the results given were obtained with four levels of decomposition.

The Decomposition and Reconstruction Filter Banks are given below in Figure 1 & Figure 2. The subbands into which the input image is partitioned are numbered therein, and are shown pictorially in Figure 3.

Figure 1: 2-D 4 Level Analysis Tree

Figure 2: 2-D 4 Level Synthesis Tree corresponding to the Analysis Tree in Figure 1.

Figure 3: Subbands into which input image is resolved