Research On Score Based Synthesis Of Yunnan Out-of-Print Woodcut

The technology of non-photorealistic rending (NPR) has progressed a lot. Lot of research has been down on the rendering of different art forms. However, woodcut, as an important art form, has received little attention, only little research can be found. Yunnan out-of-print woodcut is an extension of traditional woodcut. It is much more complicated and expressive than common woodcut, but we haven’t found any related studies on it except previous work of our research group. In this thesis, we present a score based stylization rendering method, which automatically synthesize Yunnan out-of-print woodcut from the input image. This thesis is a meaningful supplement to the stylized simulation of woodcut and the non-photorealistic rending technology.The key ideal of our method is to use scores collected from real woodcuts. The simulation of score, the virtual sculpture and the virtual multiple printings are the mainly three parts of the rendering of Yunnan out-of-print woodcut.The simulated score determines the quality of rendering result. To preserve the special texture of score, score collected from real woodcut is obtained. We use the closed form matting to extract score from real woodcut. Then, the parameterization of extracted score and a deformation method is introduced.Virtual sculpture imitates the sculpture by artist. A gray image, as a virtual engraved block, is obtained in this step. Yunnan out-of-print woodcut prints a limited number of colors, so color clustering is applied on the input image to simplify it. Regions with common colors are isolated as areas for sculpture, meanwhile color values are preserved for printing. In isolated regions, a stochastic algorithm is introduced to place stroke texture automatically. To guide the placement of score, a global smooth orientation field is computed by interpolation. Finally, stylized edges are extracted from images to simulate the edge scores.The virtual printing synthesizes multicolor woodcut from the gray virtual engraved block with its’related color. A virtual printing model, which is consistent with the real printing process, is proposed. In this model, the engraved block is used to determine the ratio of two mixed colors. To imitate the oil painting mixture, we use an optics model to perform color blending. Due to the uneven pressure and special texture of woodcut, previous printing color is randomly left in the present printing. So, a random texture is computed from LIC to interfere with the color blending.