Abstract
As fundamental knowledge of color expressions and color measurement necessary when handling the information of color images,the color perception mechanism of humans and the basics of the corresponding CIE color spaces will be introduced,and the structure of color-measuring instruments and how they put color theory into practice will be examined. Further,we will also describe how,in contrast to the various ways in which colors change depending on the viewing conditions, color measuring instruments are able to accurately obtain color information by regulating viewing conditions, and also touch upon the causes of color-measurement error which are closely related to viewing conditions. Finally, we will introduce a two-dimensional color-measuring instrument, which is expected to be used in the image information field.
