METHOD FOR MEASURING GLOSSINESS OF PLANE SURFACES BASED ON PSYCHOLOGICAL SENSORY SCALE

Although the perception of gloss is based on human visual perception, some methods for measuring glossiness, in contrast to human ability, have been proposed involving plane surfaces. Glossiness defined in these methods, however, does not correspond with psychological glossiness perceived by the human eye over the wide range from relatively low gloss to high gloss. In addition, the change in the incident angle causes a deviation in the measurement of glossiness. A new method for measuring glossiness is proposed in this study. For the new definition of glossiness G(d), the brightness function is utilized. We also extract the value of smoothness of the object's surfaces for use as a factor of glossiness. The measuring equipment consists of a light source, an optical system and a personal computer. Glossiness G(d) of paper and plastics is measured with the use of this equipment. In all samples, a strong correlation, with a correlation coefficient of more than 0.97, has been observed between G(d) and psychological glossiness G(ph). The variance of measured glossiness due to the change in the incident angle of light is small in comparison with that of conventional methods. Based on these findings, it has been found that this method is useful for measuring glossiness of plane objects in the range from relatively low gloss to high gloss.