Figure 4 (7): Example of cascading decomposition using Tree- structured wavelet transform. Texture Features Vector: The first 5 largest energy values of leaf nodes in the energy map were selected as features.
Related Figures (6)
DWT algorithm is used for two-dimensional pictures in similar way as fora signal. The DWT is computed for all image rows at the first, and then for all columns as shown in figure (2). The resultant sub-bands images for one level wavelet decomposition for two-dimensional pictures are illustrated in figure (3) Figure (2): One level wavelet decomposition for two- dimensional pictures. Figure (4): Sub-band images for three decomposition levels. Figure (5): One level of 2-D multi wavelet decomposition of a 2-D image decomposition, 16-subband intermediate image will be as shown in figure (5).The next decomposition will be in the "low- low pass" sub-matrix, the shaded part in figure (6). According to advance process, an L-level decomposition of a 2-D image will produce 4(3L+1) sub-bands [12]. The result of this procedure is called Energy Map. Figure (77) shows an example for sub-band images of cascading decomposition using Tree-Structured Wavelet Transform, and figure (8) illustrates the resultant Energy Map. Image decomposition: As in TSWT, DITCWT depends on calculating the energy in the sub-bands images to continue the cascading decomposition. But, DTCWT instead of decomposing the image to 4 sub-band images, each texture image was decomposed to 8 sub images (2 low pass, and 6 band pass). The next level of decomposition was to that sub-images which had a significant value of energy -using same equation (3) - for extra 8 sub images. Figure (9) illustrates an example for one texture image [15]. Figure (9): Decomposition example for a texture image using DITCWT.