Finding energy of a window with specified dimensions

I'm planning to do the following:

1- Slide a window with dimensions 4X4 on an image 2- For each window calculate the `energy` 3- Find the histogram

For sliding the window over an image, I know that we can use `nlfilter`, but this requires a `fun`. Will this function be the energy? How can I use this with `nlfiler`?

So, how do you think I can go with 1,2, and 3 in `matlab`?

Thanks.

[Matt J]

Yes, fun will be the energy.

Answer 1

[Matt J]

Convolution might be enough if the energy is something like the sum of squares

 e=ones(1,4);
 Energy = conv2(e,e, Image.^2,'valid');

Then use HISTC or IMHIST to get the histogram...