Automatic Color-to-Gray Conversion for Digital Images in Gradient Domain

摘要

Color-to-grayscale conversion for digital color images is widely used in many applications. In this paper an automatic gradient domain color-to-gray conversion method is described. By enhancing the luminance gradient with a modulated chromatic difference enhancement in CIELAB space, a gradient field is created to construct the resulting grayscale image using a Poisson equation solver. A sign function for the gradient is defined for isoluminance color images to keep correct color ordering. By introducing a structural similarity index measurement (SSIM), the main parameters of the method are automatically optimized in the sense of human vision. Therefore, this method can automatically produce artifact-free and salience-preserving grayscale images that coincide with human perception for the color difference.