This paper describes a method of identifying authorship of Ukiyoe prints by using Rakkan images found in the prints. A weighted direction index histogram method has been used to create the feature vector for Rakkan character analysis. Also the Pseudo Mahalanobis distances were used to judge distances between dictionary templates and test data. The method includes binarization of Rakkan images which has been done by recursively applying the Otsu method, which realized good character segmentation performance, eliminating the influence of stain and smears. We used 100 Ukiyoe prints which were drawn by 10 artists as both templates and test samples. The identification experiment was done using the leave-one-out method. The results of the experiment indicate there is a possibility of successfully using this method for identifying authorship of Ukiyoe.

We propose a method for estimating inherent surface color robustly against image noises from two registered images taken under different outdoor illuminations. We formulate the estimation based on maximum likelihood manner while considering both inter-pixel and intra-pixel relationships. We define inter-pixel relationship based on stochastic behavior of image noises and properties of outdoor illumination chromaticity. We rely on the spatial continuity of both surface color and illumination to define intra-pixel relationship. We also propose to maximize the estimation function in two step manner. Experimental results demonstrate the significant improvement of the proposed method in estimation accuracy compared to previous methods.