Essilor International (compagnie Generale D'optique)

Centre National De La Recherche Scientifique

Margalith Harrar

Bernard Bourdoncle

Gilles Baillet

Françoise Vienot

A method of improving an initial color filter comprises a numerical generation of sinusoidal spectra. Two steps of selecting said spectra are then executed. The first selection is carried out according to a criterion of colorimetric similitude with respect to the initial filter. The second selection is carried out according to the capacity of dummy filters corresponding to each spectrum to restore hues in a natural manner. To do this, observations of samples of hues through each dummy filter are simulated numerically, using a color appearance model to take account of a visual perception of a human observer. In this way, an improved filter is determined, which has a color close to that of the initial filter and which affords a natural rendition of hues.

Method of improving a color filter

A quantitative evaluation of a color filter () in accordance with the capacity of said filter to restore hues comprises the use of a numerical color appearance model. Values of a perceptive attribute are calculated for hue samples (), by simulating the observation of each of the samples through the filter () and without a filter. The values of the perceptive attribute correspond to the visual perception of the samples by an observer (), and a deviation between the values with and without filter constitutes the result of the evaluation of the filter. Such a method makes it possible to quantitatively rank several color filters, and the ranking obtained corresponds to that which would be established by real observers evaluating the filters.

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Charenton le Pont, France

Margalith Harrar