Color transfer based on wavelet transform

In this paper, a color transfer technique based on Adaptive Directional Wavelet Transform with Quincunx Sampling (ADWQS) is proposed to transfer color from a color reference image to a grayscale target image. Due to ADWQS’s directional selectivity and symmetrical characteristic, the proposed scheme yields the best color transfer performance. We search the best matching only in LL subband of luminance coefficients of the two images and then transfer the chromaticity coefficients to corresponding positions. This operation greatly accelerates the colorization process and meanwhile maintains the good performance. In addition, the proposed method has no constraint on the image size, i.e., the color reference image and the grayscale target image can be of different sizes.