Convolution Operator

SB
Posted By
Steve_Blenkin
Dec 13, 2006
Views
517
Replies
6
Status
Closed
I’m running Photoshop 6.0 and I am trying to find out what convolution operator the FILTERS->STYLIZE->FIND EDGES uses

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L
LenHewitt
Dec 13, 2006
The convolution engine enables you to create your own filters
S
Stroker
Dec 13, 2006
Sobel
Actually, Sobel plus an extra step (or two).
But Sobel should give you a good running start.
SB
Steve_Blenkin
Dec 14, 2006
Stroker – thank you for that. Have tried sobel but any idea what the extra step or two consists of (bluring smoothing ??)
S
Stroker
Dec 15, 2006
The last step is to find the magnitude.

gX = Sobel in the x direction
gY = Sobel in the y direction

Then use Pythagoras to get the magnitude, or distance, of (gX,gY).

magnitude = sqr ( gX*gX + gY*gY )

I think sqr() is the right function for square roots…? So, square root function for whatever language you are using.

Then it’s just a matter of cleaning it up. You know, controls for threshhold or whatever. Maybe even invert.
CC
Chris_Cox
Dec 15, 2006
Find the magnitude, and invert.
SB
Steve_Blenkin
Dec 19, 2006
thank you gents

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