Fast Transforms in Image Processing: Compression, Restoration, and Resampling
Figure 1
Illustration of the energy compaction capability of Discrete Fourier, Discrete Cosine, Walsh, and Haar transforms for a test image shown in the upper left corner. The rest of images show band-limited approximations of the test image in the domain of corresponding transforms for the approximation error variance equal to 5% of image variance. Graphs on the plot in the bottom right corner present energy contained in fractions of transform coefficients for different transforms.
