Bio-Rad Quantity One 1-D Analysis Software - Manual (Page 88)

Chapter 3. Viewing and Editing Images
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Step 3: Begin Filtering
After you have completed the selections, the filter name and size will be displayed at
the bottom of the Filter Wizard dialog.
To being filtering, click on the OK button. Because filtering is an irreversible process,
you will be prompted to filter the original image, filter a copy of the image, or cancel
the operation.
If you choose Copy and Filter, enter a name and/or version number for the new copy
in the pop-up box and click on OK.
3.11.b Selecting a Filter Directly
If you know the type and size of filter you want, you can select it directly from the
Image > Filter List submenu. The submenu includes all the available filters.
The types of filters are:
• Weighted Mean. This filter is useful for reducing Gaussian noise. It calculates
the weighted mean of the pixels within the filtering window and uses it to replace
the value of the pixel being processed.
• Out of Range Pixel. This filter is useful for suppressing salt-and-pepper noise;
its effect on Gaussian noise is minimal. This filter calculates the mean of the
pixel values in the filtering window, including the pixel being processed. If the
difference between the mean and the individual pixel value is above a certain
threshold, then the individual value is replaced by the mean.
• Median. Also useful for suppressing salt-and-pepper noise, this filter calculates
the median value of the pixels within the filtering window and uses it to replace
the value of the pixel being processed. The median filter produces very little
blurring if a small-sized window is selected.
• Maximum. This filter is useful for eliminating pepper noise in an image (it
worsens the effect of salt noise). It replaces the value of the pixel being processed
with the maximum value of the pixels within the filtering window.
• Minimum. This filter replaces the value of the pixel being processed with the
minimum pixel value within the filtering window. This filter is useful for
eliminating salt noise in an image (it worsens the effect of pepper).
• 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