Optimal illumination for local contrast enhancement based on the human visual system.

The observed color of an object is influenced by the spectral distribution of an illuminant impinging upon it. Here we explored a method to obtain optimal illumination spectra for local contrast enhancement based on human vision. First, multispectral imaging was used to measure the spectral reflectance of the sample and color segmentation was used to extract its color features. Then we obtained the target-specific optimal illumination by maximizing the color differences of mutual colors in our sample tissue. To verify the effectiveness of this method, simulated images under the optimized illumination were compared to illumination with the standard illuminant D65 and a cool white light-emitting diode (5500 K). Results showed that the sample under the optimized illumination had a better perceptual color contrast.