Professor Hideo Kuma from Control Engineering Department of Matsue College investigates and aims to establish a new method — 3D scans deep inside the narrow drift mine utilizing specially-developed remote control robot, and also the ground surface around the entrance — to estimate the start age and the production amount of drift mines across Japan.
Obstacles to Investigation on Silver Mine of Historical Value
There are many remains of mines all across Japan including Iwami Ginzan Silver Mine which was certified as UNESCO World Heritage in 2007 for its historical value that it produced nearly one third of the silver circulated around the world in sixteenth century and later.
Those mines are, however, now heavily wooded, and the entry is often restricted for the risk of rock-fall, so that it is difficult, or even impossible to grab the complete picture and investigate in detail. Therefore, the research was mainly to record the outside of the drift mines by sketches and photos. Some tried 2D-scanning inside the drift mine, but the obtained data was inaccurate and insufficient for the investigation.
3D Scan the Ground Surface — Auto Detect and Removal of Woods in Point Cloud Data
One day at a trade show, Professor Kuma met 3D laser scanner and point cloud handling software, InfiPoints, which provides a functionality to extract the ground surface from the obtained point cloud data. He quickly introduced a new method to his research — 3D scans the remains of mines, and then extract the points for the ground surface from the obtained point cloud data using InfiPoints.
He investigated one of the most valuable mines, Tada Silver-and-copper Mine, using this new method, and successfully identified the mark of open-pit mining, a characteristic surface mining technique.
Moreover, he optimized the 3D scanned data for 3D printing using InfiPoints, and created a model of remain of the mine for further investigation — estimated the total amount of silver production from the volume of the mark of open-pit mining.
He even succeeded to unveil the cultural landscape around the mine by minutely studying the ground surface to identify the artifact such as stone walls.
Auto Noise Reduction for 3D Scanned Data from Inside the Drift Mine
The entry to the drift mine is often physically restricted, and even when it is possible, it is still very hard to conduct minute survey for many hours inside the narrow, dusty drift mine. A special robot developed by students in Professor Kuma’s office achieved unattended 3D scanning inside the drift mine. After preprocessing obtained point cloud data using InfiPoints — register shorts, and remove noises caused by dust inside the drift, 3D scanned data is fully utilized for their virtual investigation and researches.
Possibility to Apply Point Cloud Handling Technology to Disaster Prevention
Professor Kuma has investigated about one hundred remains of drift mines all over Japan, and he is seeing a great possibility to apply this 3D scanning and point cloud handling technology to disaster prevention, for example, detecting a risk of landslides by regular observation of mountain slope for the variation.