I have been collaborating with Mikhail Kats, an applied physicist at UW-Madison. In recent work, we studied metamers, which are colors that appear the same to the human eye but have different electromagnetic spectra. The fact that metamers are indistinguishable is a result of the limitations of human vision. Mathematically, the human eye performs a projection of electromagnetic spectra onto three real numbers (responses from three different types of cone cells). Some animals, for example, have four or more different types of cone cells, which affords them a projection that is less lossy and the the ability to distinguish colors that might be metamers to us.
Specialized filters can be used (e.g. as glasses or contact lenses) to alter the spectra before they hit our eyes. This has the effect of modifying the projection, which can break certain metameric pairs by making them look different or take colors that were once distinct and make them into metamers. In our recent manuscript, we detail a design for glasses that use different filters for each eye. The result is that the net metamer count can be reduced dramatically without causing undue stress to the eyes. My role in this project was to help with mathematical modeling and to find a way to quantify metamers mathematically.
The work is still a preprint at the moment, and if you’re interested it is available on Arxiv. The manuscript was also picked up by the New Scientist and they published a short and accessible article summarizing the work.