Filter for a special purpose lens and method of making filter

摘要

A filter and method for making a filter for enhancing a person's ability to differentiate between different shades of a spectral color of interest involves obtaining spectral data for the different shades and plotting the data on a chromaticity diagram. The standard deviation of the data is determined and a merit function based on the standard deviation is developed. Filters having positive merit functions are deemed appropriate candidates for the special purpose lens.