Fast image colourisation based on twin-codebook vector quantisation

A novel colourisation scheme for grey-level images based on twin-codebook vector quantisation (TBVQ) is presented. Different from the traditional vector quantiser with the same codebook in the encoding and decoding processes, the proposed TBVQ adopts two different but related codebooks in the encoder and decoder, respectively. During the colourisation process, the target image is first encoded by the greyscale codebook and then decoded by the related chromatic codebook. Experimental results demonstrate the effectiveness and efficiency of the proposed algorithm.