What is the name of this color transformation? This is a question regarding color transformation in images. I have this color transformation matrix I am using to convert an RGB image to a color space whose name I do not know:

T = [(1/3) (1/3) (1/3); (1/2) 0 (-1/2); (-1/2) 1 (-1/2)]


What is the name of this color transform? I think I once saw somewhere that it is called KL transform because it was close to a KLT computed over a large collection of images, but I am not sure...
I do not know the name of your transformation $T$, but it can't be the Karhunen-Loeve transform: The Karhunen-Loeve transform is image specific and its transformation matrix is a rotation matrix (see for example the KLT in Mathematica).

Given the values in your matrix, it seems to attempt to separate between intensity (first row) and color (the other two rows, spanning the remaining hyperplane) while being  optimized for speed.