Study On The Evaluation Of The Red Color Appearance Quality Of Coral

This paper combines colorimetry,using the CIECAM02 color appearance model and the CAM16 model to calculate the color appearance parameters of the red coral,and the feasibility of its application in predicting the color appearance parameters of the coral was discussed.In addition,the influence and degree of the conditions on the color appearance parameters of the samples were observed when the conditions of environment,illumination and light source changed.The similarity and difference of the predicted results of the two color appearance models were compared and analyzed,in order to select a suitable model to master the color changes of coral under different conditions without testing the real objects.A total of 57 corals were selected in this paper,the Fourier Transform Infrared spectrometer test showed that the inorganic components are mainly carbonate minerals,calcite and aragonite,and they also contained organic components.The characteristic ultraviolet spectrum of the corals are measured by the GEM-3000 UV-Vis,and combined with the color data of the coral obtained by the X-Rite SP62 spectrophotometer,it is found that the characteristic peak at the position of312 nm gradually moved to the lower wavelength direction with the increase of the hue angle.The CIECAM02 color appearance model can predict the color appearance parameters of the corals when the environment,illuminance,and light source change.During the gradual darkening of the environment,the lightness J and brightness Q of corals increased gradually,the chroma C and colorfulness M increased first and then decreased,and the value of saturation s decreased gradually;In the process of increasing illumination,Q and M of corals show a significant increasing trend,which effectively verifies the Stevens effect and Hunt effect;The change of light source has the most significant effect on the saturation value of corals,and the effect of light source A is the most significant,which is more conducive to corals to show the color appearance with high saturation.Through single-factor variance and multiple comparison analysis,the influence degree of environmental conditions on each color appearance parameters is Q> s> J> C> M> h.The influence degree of illumination changes is Q> M> s.The CAM16 color appearance model can also predict the effects of environment,illumination and light source changes on the color appearance parameters of red corals.As the environment gradually darkens,the J and Q of the corals increase,the C and M show a trend of first increasing and then decreasing,while the s decreased.And in this process,the C and M of the pink corals showed a monotonous decreasing trend.The influence degree of environmental conditions on each color appearance parameters is Q> s> C= M> J> h.Comparing the prediction results of the two models,it is showed that the predicted value of CAM16 model for the color appearance parameters of corals is overall higher than that of CIECAM02 color appearance model.Through similarity analysis,it is found that the CAM16 model is more suitable for the prediction of the lightness of corals,and the CIECAM02 model is more suitable for the prediction of the chroma value of corals.