how to find pixel having a specific value and copy those regions to a new matrix

find pixel having a specific value and copy those regions to a new matrix...

[rows, columns] = find(L == 0);

how to copy to a new matrix

Answer 1

[Bjorn Gustavsson]

Something like this should get what you ask for:

Img = peaks;
clf
subplot(2,1,1)
imagesc(Img),colorbar
I2 = 0*Img;
Irange = [2 4];
I2(Irange(1)<=Img(:)&Img(:)<=Irange(2)) = Img(Irange(1)<=Img(:)&Img(:)<=Irange(2));
subplot(2,1,2)
imagesc(I2)

HTH

[Walter Roberson]

I usually put the condition into a variable to avoid recomputing it.

I2 = zeros(size(IMG), class(IMG));   %but 0*Img works too
mask = Irange(1) <= Img & Img <= Irange(2);
I2(mask) = Img(mask);