Directionally classified image vector quantisation using Walsh Hadamard subspace distortion
Lai-Man Po, C.-K. Chan · Electronics Letters · 1991
A novel directionally classified subspace image vector quantisation coding scheme using a new gradient based edge classifier and Walsh Hadamard transform subspace distortion measures is proposed. The new coding scheme can reduce both the computational complexity and memory requirement of the conventional classified vector quantisation technique3 while the reproduced image quality is maintained.