This paper introduces a new angular-based VQ scheme based on converting the 3D-Layered (angular) vectors into 2D-
Layered (greyscale wise) vectors using the Mahalanobis Colour Distance (MCD). The proposed VQ scheme (VQ-MCD)
exhibits a comparable output performance with the conventional 3D VQ schemes at very low bit rates while at higher bit
rates VQ-MCD exhibits a better visual reconstruction quality than 3D VQ. The main advantage of using the proposed VQ
scheme is the high reduction in the coding time that reaches 58?67% depending on the implemented codebook size.