SPIE Journal Paper | 28 July 2018
KEYWORDS: Light sources, Light emitting diodes, Tissues, Heart, Light sources and illumination, Color difference, Visualization, Optical engineering, Multispectral imaging, Reflectivity
Color perception of an object is tremendously influenced by the spectral power distribution (SPD) of a light source. Therefore, it is of great significance to seek for an optimal SPD to enhance the color contrast of a biological specimen in medical lighting. Meanwhile, considering that color rendering property and illuminance are of importance to lighting, with a multichannel LED light source and a differential evolution algorithm dealing with the constraints of color rendering and illuminance, a contrast enhancement method based on maximizing CIEDE2000 color difference (ΔE00*) was proposed in this study. An illuminance level of 500 lx was first verified as the desired illuminance. Afterward, the color contrasts of six groups of color patches were optimized under four different constraints of the Commission Internationale de l’Eclairage (CIE) general color rendering index (Ra), i.e., Ra ≥ 0, Ra ≥ 60, Ra ≥ 80, and Ra ≥ 90, manifesting their significant color contrast enhancement under the optimized light sources compared with those under the simulated CIE A, D50, D65, and D75 light sources. Further, two biological samples, pork tissues and porcine heart, were optimized under the four constraints of Ra. The results show that even in the case of Ra ≥ 90, the optimized ΔE00* values for the two specimens are, respectively, 4.13 and 3.20 higher than those under the D75 light source. More importantly, the developed method also provides a flexible lighting solution to color contrast enhancement.
