Patrick Morvan

A handy calibrator for color vision of a human observer

The variability among human observers is a challenge to the calibration of modern displays based on Light Emitting Diodes (LED) and lasers. The spectra of the displayed colors are so peaky that slight differences in the cone sensitivities in human color vision are sufficient to make two observers perceiving different colors on the same screen. Recently published results give evidence to the existence of a small number of classes of human observers. In this paper, we present first results on the development of a prototype for a lightweight, inexpensive, temporally stable and easy to calibrate and easy to use instrument that allows classification of an observer with normal color vision in a small number of categories. The instrument employs a set of LEDs having specific wavelengths and is controlled by a computer interface. The use of such an instrument will allow adapting displays and viewing conditions to individual observers in color-critical applications.

Modern displays: Why we see different colors, and what it means?

One of the basic tenets of conventional applied colorimetry is that the whole population of color normal observers can be represented by a single “standard” observer with reasonable accuracy. The 1964 CIE standard colorimetric observer has indeed served us well in all industrial color imaging applications, until recently. With the proliferation of modern wide-gamut displays with narrow-band primaries, color scientists and engineers face a new challenge. Various recent studies, including those by the current authors, have shown that the color perception on such displays varies significantly among color normal observers. Conventional colorimetry has no means to predict this variation. In this paper, we explore this problem by summarizing the results from an ongoing study, and explain the practical significance of this issue in the context of display applications.

Multiple Color Matches to Estimate Human Color Vision Sensitivities

A color matching experiment was designed and carried out to estimate human observers’ color matching functions (CMFs). 61 color-normal observers participated in the experiment. Their results were traced back to physiological factors using a mathematical vision model. The experiment time was 15 minutes, which is much faster than previous research aimed at determining color matching functions.