Abstract:
An instrument for determining the individual proportions of specific colors within the visual spectrum which includes sensing means for each color to provide an electrical analog of the color energy/bandwidth. The sensing means comprises for each spectrum, one or more photocells each coupled with an appropriate transmission filter. These photocell-filter combinations are selected to cover uniform portions of the spectrum to provide weighted equal responses for selected color bands across the entire visual spectrum. The outputs of these combinations are summed to give the total spectrum output as well as being individually applied to separate divider circuits that also receive the summed total and provide a ratio voltage output signal. This latter signal from each divider is fed into a separate input of a chart recorder where the continuous percentage value of each color is simultaneously recorded.
Abstract:
A phototransducer has a silicon photovoltaic cell corrected with two glass filters to the standard ICI spectral response equivalent to the spectral response of the human eye. Also, a method for correcting variations in the manufacture of the glass filters to adjust the filter to the thickness required for ICI correction of the silicon photocell.