ISHIGAKI Retrieval through Combinatorial Optimization
Sakino Ando, Gou Koutaki, Keiichiro Shirai · 2019
Two strong earthquakes that hit Kumamoto in April 2016 damaged the infrastructure and many buildings in the area, significantly impacting the people and traditional cultural assets of Kumamoto. In this project, using information technology, we aim to reconstruct the stone walls of Kumamoto castle, which is an important nationally designated special historical site in Japan. A stone wall is called "Ishigaki'' in Japanese. During the earthquake, many of the stones of the Kumamoto castle wall fell to the ground. Therefore, to reconstruct the stone wall, we must identify the original locations of the collapsed stones, similar to a jigsaw puzzle. In this paper, we formulate the problem by defining the cost function of the similarity between before and after collapse of the stones and propose the application of a combinatorial optimization algorithm. We tested the proposed solver by identifying 269 actual collapsed stones of the castle wall, and the results demonstrated that the proposed method can identify 253 stones correctly (94% accuracy).