define double(img(:,:,1))

can anybody explain double(img(:,:,1))??

Answer 1

[Wayne King]

That code is casting the first "page" of img (a 3D array) to type double.

So perhaps img is uint8 to begin with (or something like that)

img = uint8(ones(256,256,3));
xy = double(img(:,:,1));
class(img)
class(xy)