🚀 go-pugleaf

In article <C0ozIH.AMJ@compsci.liverpool.ac.uk> chris47@uxb.liv.ac.uk (Chris Brown ) writes:
>Well you could help me by finding a method to automatically edge detect
>the cardiac shadow on cardio angiograms

Well, I suppose I could. :-)

There are a number of edge detection algorithms.  The usually involve
a convolution of some sort.  One of the more popular is the Sobel
filter, the kernel of which looks like

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

or

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

Check your favorite image processing book for more details.  Here's a
list of mine:

Russ, John C., _The Image Processing Handbook_, ISBN 0-8493-4233-3

Pratt, William K., _Digital Image Processing, Second Edition_, 
ISBN 0-471-85766-1

Lim, Jae S., _Two-Dimensional Signal and Image Processing_, ISBN
0-13-935322-4.

Gonzalez, Rafael C. and Woods, Richard E., _Digital Image Processing_, 
ISBN 0-201-50803-6  (There's also an earlier edition by Gonzalez and
Wintz that some have criticised for minor errors in math, etc.)

Jain, Anil K., _Fundamentals of Image Processing_, ISBN 0-13-336165-9

Castleman, Kenneth R., _Digital Image Processing_, ISBN 0-13-212365-7

although it's a little old, these days, I also like

Pavlidis, Theo, _Algorithms for Graphics and Image Processing_,
ISBN 0-914894-65-X

							spl
-- 
Steve Lamont, SciViGuy -- (619) 534-7968 -- spl@szechuan.ucsd.edu
UCSD Microscopy and Imaging Resource/UCSD Med School/La Jolla, CA 92093-0608
"Personally, I don't care whether someone is cool enough to quote Doug
Gwyn--I only care whether Doug Gwyn is cool enough to quote." - Larry Wall