Use the Top Hat Bright filter to have differences between the source image and the resulting image after the Open morphological filter operation displayed has been performed.
You can find the filter in the Process > Morphological Filter menu.
See also
Overview - Morphological Filter
Working with morphological filters
Settings for the filter
Here you'll find information on how you can set the shape and size of the morphological filter. The dialog box that is opened when you use an image processing operation is made up in the same way for every operation. Click here to switch to a description of this dialog box.
Application
The Top Hat Bright filter makes it possible to check the quality of an image that is on display. The resulting image mainly contains image defects such as noise effects or fuzzy edges on the objects. Thus it's possible to judge and check whether the filtered image meets the acceptance conditions.
The illustration demonstrates the way the filter works on a simple structure: The source image (1) shows the original structure. After the filtering with the Top Hat Bright filter has taken place, the image shows (3) only those pixels that differentiate the source image from the one that has been cleaned up by applying the Open morphological filter (2). In the image (4) the pixels that were removed by the Open filter are shown in black.
Exactly what happens?
This filter is a combination of the Open morphological filter and an arithmetic subtraction. First, the Open filter is applied to the source image. The results of this filter operation are subtracted from the source image. The resulting image is dark and the pixels that were changed by the Open morphological filter operation remain bright.
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