User Guide

GNU Image Manipulation Program
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15.6.3 Despeckle
15.6.3.1 Overview
You can find this filter through Filters → Enhance → Despeckle.
It is used to remove small defects due to dust, or scratches, on a scanned image, and also moiré effect on image scanned from a
magazine. You ought to select isolated defects before applying this filter, in order to avoid unwanted changes in other areas of
your image.
15.6.3.2 Options
Figure 15.92: ‘Despeckle’ filter options
Preview Parameter setting results are interactively displayed in preview.
Type
• Adaptive: Adapts radius to image or selection content (using Histogram). If this option is checked, radius slider is not
efficient. It renders a result smoother than with radius alone.
• Recursive: Repeats filter action which gets stronger.
Parameters settings
• Radius: Sets size of action window from 1 (3x3 pixels) to 20 (41x41). This window moves over the image, and the color
in it is smoothed, so imperfections are removed.
• Black level: Removes pixels darker than set value (0-255).
• White level: Removes pixels whiter than set value (0-255).