1. A method of producing a multi-layered codebook structure for image coding, comprising the steps of: transforming a plurality of training images into respective vector components in the vector transform domain; calculating a first centroid value for each vector component; calculating a second centroid value for each vector component by subtracting a mean value of said vector component therefrom; deriving a first codebook layer having a plurality of codebook elements by executing a training algorithm using said vector components and the first centroid values; deriving a second codebook layer having a plurality of codebook elements by executing a training algorithm using said vector components and the second centroid values; and deriving a third codebook layer having a plurality of codebook elements by scaler quantization of said vector components.