Bio-Rad EXQuest Spot Cutter - Manual (Page 129)

PDQuest User Guide
4-8
Note: You should first attempt to find spot centers using these default settings before
attempting to adjust them.
If you know the type of noise in your images, you can select a different filter type and
kernel size. Section 3.15, Filtering Images, provides additional guidance on filter
selection.
• Median. This filter is useful for suppressing salt and pepper noise. It has little
effect on Gaussian noise. This filter produces very little blurring if a small-sized
window is selected.
• Weighted Mean. This filter is useful for reducing Gaussian noise. It has little
effect on salt and pepper noise.
• Power Mean. This filter is useful for suppressing salt and Gaussian noise within
an image (it worsens the effect of pepper noise).
• ContraMean. This filter is useful for suppressing pepper and Gaussian noise
within an image (it worsens the effect of salt).
To adjust the Kernel Size, magnify a background region of your image using the
Zoom Box tool so that you can see the individual pixels. The filter size you select
should be larger than the average noise feature but smaller than the smallest spots.
Speckles
If you received a message upon opening the Spot Detection Wizard indicating the
detection of Ruby Speckles in your image, select the Speckles tab under optional
controls to access the ruby speckle filter settings.
Check the box labeled Apply Sypro Ruby Speckle filter to apply the filter. Use the up
and down arrows to adjust the sensitivity of the filter, or enter a specific sensitivity in
the field. Click the Find Speckles button to locate the speckles in the image.
The speckle count field indicates the number of speckles found in the image based on
the filter sensitivity. To view the speckles in the image, click show Speckles.
4.1.d Saving/Loading Parameters
After you have selected the best detection parameters for the image, save them by
clicking the Save button (next to Parameter Set below the image window). Enter an
appropriate name for the set (e.g., the type of stain used in the gel) in the pop-up box.