How to write code for 3x3 sliding window to process over a Image with Pixel size of 256x256

I am designing a filter removing high density noises from an Gray Scale Image(256x256).

For identifying the noise pixels in the image I need a 3x3 window to slide over the image starting from the first Pixel to the Last.

If the corrupted Pixel is found i have to do some calculation to correct it.

To find this Corrupted Pixel I need a 3x3 Window to slide over my Image.

Can Anybody give me an outline on how to write Matlab code for the above.

#I have attached flow chart for my Algorithm http://i46.tinypic.com/246nm69.jpg

Answer 1

[Image Analyst]

How about

% Blur the image with a 3x3 averaging filter.
blurredImage = conv2(grayImage, ones(3)/9, 'same');
% Get map of where "corrupted" pixels are:
binaryImage = FindCorruptedPixels(grayImage); % You write this.
% Replace corrupted pixels with averaged ones.
grayImage(binaryImage) = blurredImage(binaryImage);

Of course you need to write FindCorruptedPixels() to define what constitutes a corrupted pixels - I don't know how you define that. For example, maybe it's just pure white pixels, like

binaryImage = grayImage == 255;

[Sudharsan]

Thanks for your reply.

I Think i didn't make my point clear. To be more precise

1. Choose the first pixel. Having it as the center pixel i have to form a 3x3 window. [Being the first pixel i've padded the Matrix with Zeros]

2. If that center Pixel is Noise Pixel it's location should be returned with all its neighborhood pixels. I will convert this 3x3 Matrix into a 1-D array and do my calculations to correct the corrupted pixels.

Here i'm struggling in designing the sliding 3x3 window to move over the image.