hii all,
I am working in matlab for a sorting system.
i would like to know how to detect edges of a square object from the background,
i am planning to use sobel filter. How is threshold value calculated???
is the idea of using sobel filter good.where will i find more infomation about the coding part.thank u so much.
wait for reply.

"prachi " <prachi.ykulkarni@yahoo.in> wrote in message <hi9h79$9vd$1@fred.mathworks.com>...
> hii all,
> I am working in matlab for a sorting system.
> i would like to know how to detect edges of a square object from the background,
> i am planning to use sobel filter. How is threshold value calculated???

The threshold is probably supposed to be slightly less than the expected amplitude of your edge

prachi:
Just try some thresholds and see - it will be easy.
Here's a tutorial on thresholding/labeling/measuring that may help
you:
http://www.mathworks.com/matlabcentral/fileexchange/25157