The Image Processing Corner

The gaussian filter is a smoothing of the image by convolving with a gaussian kernel.

It may be approximated with a finite size kernel (FIR). Il may also be implemented efficiently by a recursive filter (IIR). A 2-order Deriche IIR filter (variant of the gaussian filter) has been used below.

The result of the gaussian filter with a Deriche smoothing parameter of 1.5 is illustrated below. The first row gives the input noisy images, the second row gives the results and the third and fourth rows show a detail with colors which enhance contrast.

Execution time on a AMD 1800+ for the 384x288 image: 0.03 seconds.

First remark: the smoothing is very obvious and all contours are strongly damaged.

Second remark: this filter is not adapted at all to noises which strongly differ from the gaussian noise, especially the "salt and peper" noise.