Designing a physically-feasible colour filter to make a camera more colorimetric
This work addresses practical fabrication issues in camera color filter design, making it more applicable for real-world use, though it is incremental as it builds on an existing method.
The paper tackled the problem of designing physically-feasible color filters for cameras to improve colorimetric accuracy, extending a prior optimization method to incorporate smoothness and transmittance constraints, resulting in filters that are smooth, reasonably transmissive, and significantly enhance colorimetric performance.
Previously, a method has been developed to find the best colour filter for a given camera which results in the new effective camera sensitivities that best meet the Luther condition. That is, the new sensitivities are approximately linearly related to the XYZ colour matching functions. However, with no constraint, the filter derived from this Luther-condition based optimisation can be rather non-smooth and transmit very little light which are impractical for fabrication. In this paper, we extend the Luther-condition filter optimisation method to allow us to incorporate both the smoothness and transmittance bounds of the recovered filter which are key practical concerns. Experiments demonstrate that we can find physically realisable filters which are smooth and reasonably transmissive with which the effective "camera+filter" becomes significantly more colorimetric.