Survey of the Tsuzuraozaki Underwater Archaeological Site Using Hovering Type Autonomous Underwater Vehicle

Many pottery have been discovered in the waters around Tsuzuraozaki, which is located on the northern shore of Lake Biwa in Shiga Prefecture. However the cause of the archaeological site has not yet been determined, because of the depth and high turbidity of the water, it is difficult for divers to investigate the area. Therefore, in December 2023, we conducted an observation survey of the lake bed by mounting a camera on an Autonomous Underwater Vehicle Tuna-Sand2. We created a mosaic image by enhancing the image with Malti-Scale Retinex and pasting it along the trajectory of the AUV. The survey results showed the location of the pottery-like objects and the surrounding terrain. However, it is difficult to determine from the image whether the object is pottery or not, and in which period it was made. In future research, we aim to delve deeper into the intricacies of the objects found in this survey. In addition, it is also essential to have a technology that can remove floating matter from images of water with high turbidity.