Reverce Engeneering of Wood-block Printing

Ukiyo-e is a multi-woodblock color print and an important historical and cultural heritage from the Edo period in Japan. An Ukiyo-e print is produced with three processes: drawing by an E-shi, a painter or a designer; woodblocks engraving by a Hori-shi, an engraving technician; and printing by a Suri-shi, a printing technician. The produced prints from the same woodblocks are not exactly the same between each other, and they have own characteristics. Although 200 to 300 sheets were printed from the same woodblocks, few prints exist today in Japan because of overseas outflows and war fires. Furthermore, it is very difficult to re-utilize the existing woodblocks because of their cracking, wearing and warping. Therefore, preserving Ukiyo-e is a very important mission. The authors have worked an Ukiyo-e preserving project [1] based on a woodblock printing technique. The main objective of the project is to preserve not only a virtual printing image but also the process of printing with virtual woodblocks. Virtual woodblocks, made from information of a real Ukiyo-e print, are used for creating virtual Ukiyo-e prints with a virtual woodblock printing system [2]. Therefore, it is important to estimate information of real woodblocks from a real Ukiyo-e print. In this paper we propose a method for estimating the information by using multiple regression analysis. This paper is organized as follows. In Sec. 2 the outline of the Ukiyo-e preserving project and its elemental technologies are introduced. In Sec. 3 the process for estimating the information of real woodblocks is illustrated. Finally, the experimental results show the effectiveness of the proposed method to generate virtual woodblocks automatically from a real Ukiyo-e which has overlap-printed