User Guide

Canvas 12 User Guide
To use the Despeckle filter:
The Despeckle filter can remove defects such as dust and other speckling in images. The filter blends
pixels with the lightness values of neighboring pixels. It’s a good idea to select areas that need
correction before applying the filter.
1. Select an area in an image to adjust. If you don’t make a selection, the entire image is
affected.
2. Choose Image | Filter | Noise | Despeckle.
3. Drag the slider or type a number in the text box to set the Threshold value. Higher values
produce greater blending of pixels.
To reduce dust and scratch marks:
The Dust and Scratches filter can remove dust specks by replacing a pixel’s value with a median
value. The filter does not change a pixel’s value unless the absolute value of the difference of its gray
value and the median gray value of its neighborhood is greater than the Threshold. Larger numbers
of pixels are replaced by the median value when the Threshold is low.The practical effect of this is
that larger pixels regions (larger “specks”) are reduced or removed with a lower Threshold.
Therefore, you can use the Threshold to control the size of the artifacts you want to remove.
1. Select an area to adjust in an image. If you don’t make a selection, the entire object is
affected.
2. Choose Image | Filter | Noise | Dust & Scratches.
3. Enter a value from 1 to 16 in the Radius text box. Smaller radius values produce a subtler
effect than larger ones.
4. Type a value from 0 to 255 in the Threshold text box. After entering the settings you want,
click OK.
Smoothing video images
Because video images contain two interlaced pictures, you can sometimes see a slight banding effect
in images acquired from video-recording devices. You can correct this by using the De-Interlace
filter and then applying the Unsharp Mask filter. De-Interlace works with all image modes except
Black & White.
To smooth video images:
1. Select one or more paint objects to adjust. You can select an area in one image to de-
interlace the selected area only.
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