GNU Image Manipulation Program - A quick rundown
Table of contents
Other
Filtering
With the chosen layer selected over in the Layers window. You can apply various Filters to it by accessing the menu from the Menu Bar.
Blur
Gaussian blur
Performs an averaging of neighboring pixels with the normal distribution as weighting
This is the most basic blur filter available and really quick. Has the option to change blur size in X and Y independently.
Selective Gaussian blur
Blur neighboring pixels, but only in low contrast areas
This filter is more advanced and lets you set a threshold so that only similar pixels are blurred together. Should help retain sharp edges while reducing grain. This filter is much slower than Gaussian blur but this probably won’t amount to much addtional processing time unless working with a high resolution image. Unfortunately you cannot control blur in X&Y independently instead it is controlled by a Blur radius.
