CE TOP - Contrast Enhancement - Top Hat

(2/14/05)

PURPOSE

Applies "top-hat" filter to an image/volume. Useful for segmenting circular/spherical objects from image/volume when objects have intensity above background.   Example.

SEE ALSO

CE VAR [Contrast Enhancement - Variance]

USAGE

.OPERATION: CE TOP

.INPUT FILE: VOL001
[Enter the name of the input file.]

.OUTPUT FILE: VOL002
[Enter name for output file.]

.INNER & OUTER DIAMETERS: 3,7
[Diameter of the object and reference area around the object.]

NOTES

  1. Image/volume is "circularly closed" so that pixels on boundaries have a neighbor on opposite boundary.

  2. Output image is the difference between the maximum pixel value within the inner radial region and the maximum pixel value in the outer radial region.

  3. To produce a "standard top-hat filter" this output image can be thresholded at any desired level. This two step process allows easy interactive determination of the threshold that is suitable inside the filter.

  4. Reference: John C. Russ, "The Image Processing Handbook", CRC Press, Inc. (2000)

SUBROUTINES

FILTER

CALLER

UTIL2

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