Bio-Rad EXQuest Spot Cutter - Manual (Page 116)

Viewing and Editing Images
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• MidValue. This filter is useful for suppressing uniform noise within an image;
however, it worsens the effect of pepper and salt. This filter replaces the value of
the pixel being processed with the mean of the maximum and minimum pixel
values within the filtering window.
• Power Mean. This filter is useful for suppressing salt and Gaussian noise within
an image (it worsens the effect of pepper noise). It replaces the value of the pixel
being processed with the power mean of the pixel values within the filtering
window.
• ContraMean. This filter is useful for suppressing pepper and Gaussian noise
within an image (it worsens the effect of salt). It replaces the value of the pixel
being processed with the contra-harmonic mean of the pixel values within the
filtering window.
• Adaptive. This filter is useful for suppressing Gaussian noise and salt and/or
pepper within an image. If your image contains a mix of salt and pepper, select
this filter.
To begin filtering, select a filter type from the pull-down list. A pop-up box will ask
you to select a filter size.
Fig. 3-23. Selecting a filter size.
The available filter dimensions range from 3 x 3 pixels to 9 x 9 pixels. (See the
previous section for guidance on selecting a size.)
Because filtering is an irreversible process, a pop-up box will give you the option of
filtering the original image, creating a copy of the image to filter, or cancelling out of
this operation.