Understanding and Reconstruction of Folding Process

Origami is popular art of folding paper with long-time traditions. In its long history, a great number of traditional works have been accumulated, and moreover, more and more original works are designed and published into origami drill books etc. every year. For the majority of origami lovers, the origami drill books are probably the most convenient means for learning and enjoying origami making. However, as complicated origami works increase, origami illustrations, a common way to explain the folding process in origami drill books, become difficult to understand, especially for children. This is because some folding operations are difficult to be expressed by a 2-D drawing when the intermediate state of an origami model has gotten complex. From the viewpoint of supporting people's enjoying origami art, this paper proposes a framework (Fig.1) for understanding and reconstruction of folding process explained by a sequence of illustrations of origami drill books. Concretely speaking, we aim at automatically converting a sequence of images of origami illustrations into a 3-D animation that can be seen from any viewpoint as users want. To achieve this goal, the following three issues have to be discussed and overcome: 1. How to recognize successive folding operations from images, 2. How to generate recognized operations against a sheet of virtual paper, 3. How to simulate (reconstruct) the folding process interpreted by the system. This paper addresses the first two issues. As shown in Fig.1, our framework with the goal consists of three units: graphic element extraction, folding operation recognition, folding operation generation, and one internal model that keeps 3-D information of recognition results and also the information for folding processing reconstruction. We first describe how the framework works, then give the technical details of each unit and finally show the validity of the framework by using various experimental results. Figure 1 Framework for understanding and reconstruction of folding process.