SPIDER: CE SOBEL (Contrast Enhancement

CE SOBEL - Contrast Enhancement - Sobel

(5/03/01)

PURPOSE: Sobel edge detection on image/volume. Useful for edge detection. Example.

SEE ALSO

CE P	[Contrast Enhancement - Prewitt]
CE LAP	[Contrast Enhancement - Laplacian]

USAGE

.OPERATION: CE SOBEL

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

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

NOTES

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

Sobel 3x3 kernals in 2D are

 
           -1  0  1           1  2  1       
           -2  0  2           0  0  0 
           -1  0  1          -1 -2 -1

Kernal in 3D is a 3D extension of the 2D kernal.
The two kernals are both applied to the original data and the current pixel is replaced by the maximum returned by either of the two applications.