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Matlab Version : 7.8.0(R2009a)

I am getting edges from an image by using Canny edge detector using standard 'edge' function. But for my project I need to get intermediate Gradient Magnitude matrix. I.e. gradient magnitude values for each pixel.

I know we could do it using imgradientxy(), But I need exact result what canny would have given and I don't know the implementation used by Matlab for Canny. Is there any way to do it or do I have to implement canny from scratch?

Background: I am basically changing intensity values for some pixels on the edges as detected by canny. I need to know that after the change, when the gradient is calculated using new values, will they still come under Threshold values?

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To find the implementation of the Canny edge detector in Matlab, you can simply open the file (edit edge), since the function isn't built-in. This way, you can check the filtering and gradient scheme that is used in your release of Matlab.

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@Andrey: thanks. I forgot that I had my own function canny on the path. :)
That was great. It solved my problem. I thought edge function is coded in C as library for matlab. Thanks a lot
@MangatRai: This may happen in the future, but certainly older versions of Matlab have a lot of functions still written in Matlab.
What does it mean that canny isn't built-in? Without doing any manipulations to the matlab path or files, edge(image, 'canny') seems to be valid (using matlab R2012b).
@solvingPuzzles: "built-in" in Matlab-speak means that the function has been compiled, which means that you can no longer see the source code. You can call built-in functions as builtin('fcnName'), which can be useful in overloading.

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