CE FREI - Contrast Enhancement - Frei & Chen

PURPOSE

Segmentation of image using a Frei-Chen convolution. Useful for edge detection.   Example.

SEE ALSO

CE HURST	[Contrast Enhancement - Hurst]
CE HAR	[Contrast Enhancement - Haralick]
CE VAR	[Contrast Enhancement - Variance]
CE LAP	[Contrast Enhancement - Laplacian]

USAGE

.OPERATION: CE FREI

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

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

NOTES

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

2. Uses a set of 8 convolution kernals to get a ratio of "edgeness" versus "non-edgeness" for each pixel.

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

4. Not implemented for volumes. Volumes are processed slice-by-slice.

SUBROUTINES

FILTER

CALLER

UTIL2