Image Filter Tester 1.1 - Morphological Filter

• This filter implements the following morphological operators:
  • dilate
  • erode
  • close
  • open
  • hit-and-miss
  • thinning
  • thickening
  • white tophat
  • black tophat
  • h-dome
  • gradient
  • Laplacian
  • smoothing
  • noise removal
• The structure element (SE) is completely customizable.
• The h-dome operator does not require a SE.  For hit-and-miss, thinning and thickening, the pixels in SE may have 3 states: applying to foreground, applying to background, and don't care.  For all other operators, the pixels in SE can only have 2 states: applying to foreground, and don't care.
• For thinning and thickening, a set of 8 structuring elements (with each is a 45°-rotated version of its previous one) are used.  In this program, the user needs to define only the first SE, and other 7 rotated structuring elements will be generated automatically.
• For flat structure elements, van Herk/Gil-Werman's algorithm was used. This algorithm is very fast. The processing time is independent of the length of the SE. It depends on the image size linearly.
• For morphological grayscale reconstruction (required by some operators), Luc Vincent's algorithm was used. Here is a link to Luc Vincent's homepage where you can find a long list of publications of his excellent work in the field of image and document analysis.
• To learn more about morphology, Leptonica.com is a very good website where you can find information (including selected papers) about basic image processing techniques and even download well-tested C code.
• This filter works for grayscale images or 24-bit color images.

This page was last modified on 08/27/2006.