Figure 1.

Basic multiresolution block. Top: Two-channel analysis filter bank. The filter h is a highpass filter and g is a lowpass filter. Bottom: A 2-level filter bank decomposition of actin. If the original image is of size N × N, the ones in the middle are of sizes N/2 × N/2 and the ones on the right are of sizes N/4 × N/4. Each branch has either the lowpass filter g or the highpass filter h followed by downsampling by 2 as in the top figure. Filtering and sampling are performed along the horizontal direction (rows) followed by the same operations along the vertical direction (columns).