Quality of color filters is estimated by the differnce between the two fundamentals projected onto human visual subspace directly from input color space and indirectly via scanning filter subspace using projection operator P. The colorimetric error is graphically visualized in 3D color space assuming the input colors with sinusoidal spectral power distribution.
Hiroaki Kotera, "Quality Measure of Color Scanning Filters" in Proc. IS&T 2nd Color and Imaging Conf., 1994, pp 58 - 61, https://doi.org/10.2352/CIC.1994.2.1.art00017