Scilab 5.2 Wavelet Transformation

This image is from my monthly column in the Dutch computer magazine PC-Active. It is a depiction of a two-dimensional wavelet transformation of an image of Lena, a standard test image for image processing algorithms. One of the things you can see here is that the top right block detects vertical structures in the image, such as Lena's hair and her arm. The left bottom block detects horizontal structures, such as her mouth and shoulder. The bottom right block detects diagonal structures. The smaller blocks do the same, but on a smaller scale.