YCbCr, YIQ and RGB Color Spaces with Haar, Cosine, Hartley and Slant Transforms for Grayscale Image Colorization using Thepade’s Transform Error Vector Rotation Algorithms

Hartley, Cosine, Slant and Haar Transforms for Grayscale Image Colorization Using Thepade‟s Transform Error Vector Rotation(TTEVR) Algorithms of Vector Quantization in YIQ, RGB and YCbCr color spaces are compared here for color pallet(codebook) size 32, 64, 128, 256 and 512. Here a color pallet is produced from reference(color) image from which color traits need to be taken using vector quantization using Thepade‟s transform error vector rotation algorithms in the first stage. Then colors are transferred to a target (grayscale) image using generated color pallet in the second stage. There exist no objective criteria for checking the performance of the colorization quality of proposed technique, here the grayscale version of original color image is recolored using proposed techniques and the mean squared error between original color image and recolored image is used as quality comparison criteria. The experimentation is done on 15 different images in RGB, YCbCr and YIQ color spaces for 5 different color pallet sizes. The proposed technique performs better in RGB color space. For RGB color space, the proposed technique using THEVR for color pallet size 512 gives better results, for YIQ color space, the proposed technique using TSlEVR for color pallet size 256 gives better results and for YCbCr color space, the proposed technique using THtEVR, TSlEVR, TCEVR for color pallet size 32 give better results.