Accurate Color Demosaicing inspired by the Human Visual System
There is an analogy between one-chip CCD cameras and the human visual system in that these two systems acquire only one wavelength sensitivity band per spatial location. We have exploited this analogy, defining a model that characterizes a one-color per spatial position image as a coding into luminance and chrominance of the corresponding three-colors per spatial position image. Luminance is defined with full spatial resolution while chrominance contains sub-sampled opponent colors. Moreover, luminance and chrominance follow a particular arrangement in the Fourier domain, allowing for demosaicing by spatial frequency filtering. This model shows that visual artifacts after demosaicing are due to aliasing between luminance and chrominance and can be solved using a pre-processing filter. This approach gives new insights for the representation of one-color per spatial location images and enables formal and controllable procedures to design cameras with aliasing-free properties. The demosaicing algorithm we propose based on this model also performs well compared to concurrent approaches, as demonstrated by experiments.