local mean and standard deviation

sir is there any difference between local mean and mean of a pixel?????????? i need to calculate the local mean and standard deviation of a pixel..... how to do it.... please do reply.....

Answer 1

[Matt J]

For example, if you want sliding means and stds in all 3x3 neighborhoods

slidingmean=conv2(A,ones(3)/9,'same');

slidingstd=stdfilt(A);

or if you don't have the Image Processing Toolbox

 slidingstd=sqrt( conv2(A.^2,ones(3)/9,'same') - slidingmean.^2 );

Answer 2

[Image Analyst]

I'm not sure you got the terminology right, but the mean of a pixel is just the value of the pixel, because a pixel has a single value unless you're talking about the pixel going across different color channels (in a true color or multispectral image) or across the z dimension in a volumetric image where each slice or plane is the image at a different depth. I don't think you're talking about such images and that you're talking about a normal gray scale 2D image. Correct me if I'm wrong.

The local mean is the mean of several pixels in a region (for example a rectangular 3 by 3 window) around the pixel. The code Matt gave you will do that.