The blurring of a particular filtered frame is determined by the centre frequency of the corresponding passband. This program normally reads the filter structure in the same manner as the program qmf and performs blurring by the appropriate filter. It is also possible to specify a fixed centre frequency, as an alternative to specifying he filter structure. Normal operation in image segmentation is to preceed the application of this program by the application of the tanh program
See: ``Multi-channel filtering techniques for texture segmentation and surface quality inspection'', Farshid Farrokhnia, Ph.D. dissertation, Michigan State University, Dept. of Elect. Eng., 1990