Assessment of the Wiener-Retinex process

We assess the performance of the Retinex transformation, the Wiener restoration, and the combined Wiener-Retinex process in the context of the end-to-end model of color visual-communication channels for near-surface acquisition. We extend the formulations of panchromatic imaging for the nonlinear Retinex transformation and the linear Wiener and Wiener-Retinex restoration filters to color imaging. We further assess the accuracy by which colors are restored in the cases of uniform and spatially varying irradiance levels, and the shadow depth for which color consistency is still possible with reasonable accuracy. Finally, we assess the sensitivity of these processes to perturbations in the visual channel, including the image-gathering design and the spatial support of the Retinex transformation.