Naturalness assessment can be utilized as a criterion to evaluate performance of preferred color corrections and to compare naturalness of images reproduced by displays. This paper presents a new model to assess naturalness based on three dimensional color space. Experimental results indicate that the proposed model outperforms three previous models proposed for the naturalness assessment.

The results which are from naturalness assessment and visual assessment was examined to accomplish a classification, a conclusion, a comparison and an analysis. Also statistical test was examined to identify applicability of the survey to other rivers according to the result of visual assessment. As a result of naturalness assessment and visual assessment, evaluation rate of Geumho river is the highest rank of the grade as 2.5. Also t-test was examined to apply items of visual assessment at other rivers through differences in means of river naturalness rates from which visual assessment results. Most of differences in means of river naturalness rates are significant. Thus assessment criteria can be applied to other rivers to find out unique characteristics because each item has independent characteristics.