Nonlinear decomposition-and-demosaicing approach for a digital color camera

Abstract

This paper presents a demosaicing approach via nonlinear image decomposition for a digital color camera. This approach is composed of four stages. At the first stage, with the multiplicative BV-G image-decomposition method, each primary color channel of observed raw color data mosaicked with the Bayer color filter array is represented as a product of two components so that its structural component may correspond to a cartoon signal-approximation and its texture component may collect almost all oscillatory variations representing textures. At the second stage, each separated component is demosaicked with an interpolation method suitable to it. For demosaicing of the structural component, this paper employs a TV-regularization super-resolution deblurring-demosaicing method that can remove image blurs without producing ringing artifacts near edges. For interpolation of the texture component, this paper employs a basic averaging-type demosaicing method that is robust against noise, because the texture component gathers observation noise. At the third stage, white balancing, color enhancement and inverse gamma correction are applied to only the demosaicked structural component. At the final stage, the two interpolated components are combined. Our decomposition-and-demosaicing approach successfully performs denoising and deblurring as well as color interpolation.