🚀 go-pugleaf

In article <C0ytox.F7r@watserv1.uwaterloo.ca> bgilhuly@hertz.uwaterloo.ca (Barry Gilhuly) writes:
>
>
>	|  0 +1  0 |
>	| +1 -4 +1 |
>	|  0 +1  0 |
>
>When this matrix is applied to the image, it creates a 'zero-crossing'
>in the resulting output, giving both positive and negative values at 
>that point.  The problem, of course, is the negative values.  In a gray-scale
>image (or even colour I guess), the range isn't supposed to be negative.
>How is it represented?  Or, are the negative values discarded as extraneous
>since the positive value indicates where the edge is in the image?
Apply an offset so that a middle gray level (eg 128 in an 8 bit image)
represents zero.  Everything below 128 will be negative and above will be
positive.

>Thanks for all of your assistance,
>Barry.
You're welcome.
Greg