An Extended Performance Comparison of Colour to Grey and Back using the Haar, Walsh, and Kekre Wavelet Transforms

The storage of colour information in a greyscale image is not a new idea. Various techniques have been proposed using different colour spaces including the standard RGB colour space, the YUV colour space, and the YCbCr colour space. This paper extends the results described in [1] and [2]. While [1] describes the storage of colour information in a greyscale image using Haar wavelets, and [2] adds a comparison with Kekre’s wavelets, this paper adds a third transform – the Walsh transform and presents a detailed comparison of the performance of all three transforms across the LUV, YCbCr, YCgCb, YIQ, and YUV colour spaces. The main aim remains the same as that in [1] and [2], which is the storage of colour information in a greyscale image known as the “matted” greyscale image.