local variation of image

I want to calculate the local standard variation in a sliding window for an image. How it should be done using matlab ??

Answer 1

[nayomi ranamuka]

Thank you. Regarding to your comments I've a solution also. J = colfilt(I,[5 5],'sliding',@std); I hope your suggestions for my solution.

[Wolfgang Schwanghart]

Hi, your solution is good, too! The function stdfilt is probably much faster, but if this is not a problem right now, colfilt is a good alternative.

[nayomi ranamuka]

Thank you

Answer 2

[Wolfgang Schwanghart]

Hi,

http://www.mathworks.com/help/toolbox/images/ref/stdfilt.html

or

doc stdfilt

Hope this helps, Wolfgang

[nayomi ranamuka]

Thank you. But I want to calculate the local standard variation for each pixel x within a window W(x).

[nayomi ranamuka]

W(x) is a sub Window of image.

[Walter Roberson]

Yes?

J = stdfilt(I, NHOOD) calculates the local standard deviation of the input image I, where you specify the neighborhood in NHOOD. NHOOD is a multidimensional array of zeros and ones where the nonzero elements specify the neighbors. NHOOD's size must be odd in each dimension.

[nayomi ranamuka]

Ok. Thank you. I'm new for matlab & image processing .I would like to know how can I apply J = stdfilt(I, NHOOD) for sliding window in an image.

[Wolfgang Schwanghart]

What exactly is the problem? Did you try to run the example in the documentation?

[Walter Roberson]

J = stdfilt(I, ones(5,5));