Matlab, How to get the result generated by imagesc?

Question

I read some similar article, but they are not what I want.
Get the matrix after imagesc?
imagesc plot to matrix in matlab

My Problem
I have a matrix A with all elements are double.
I do imagesc(A) and then I have an image.
Now, I want to get the matrix that make the image. How can I do that?

From those articles, if I do

I = imagesc(A)
B = get(I, 'CData')

Then B == A that is not what I want.

Answer 1

To scale the image in the same way as imagesc do the following

Amin = min(A(:));
Amax = max(A(:));
A_scaled = (A - Amin)/(Amax - Amin);

To prove that the scaled image is what imagesc does internally then try this

imagesc(A,[Amin Amax]);
pause
imagesc(A_scaled);

Answer 2

It can be done in a simpler way. I tried my code in Octave.

colormap gray;
h=imshow(F,[]);
B=get(h, 'CData');