Single View Distance Measurement System for a floating body on the free surface

• Published in: Journal of the Japan Society of Naval Architects and Ocean Engineers Vol. 9; pp. 1 - 13
• Main Authors: Takimoto, Rogerio Yugo, Hirayama, Tsugukiyo, Hirakawa, Yoshiaki, Takayama, Takehiko
• Format: Journal Article
• Language: English
• Published: Tokyo The Japan Society of Naval Architects and Ocean Engineers 2009; Japan Science and Technology Agency
• Subjects: Marine
• ISSN: 1880-3717; 1881-1760
• DOI: 10.2534/jjasnaoe.9.1

Nowadays there are many kinds of distance measurement methods. For example, in the ocean engineering field, the distance can be measured by sensors using optical, electromagnetic waves or acoustic waves. GPS is becoming the popular method now. Of course those methods have their own merits and demerits. Here the distance is not horizontal or vertical distance between the target or obstacles but the longitudinal distance of a target from a observer or camera, and this will be said as "depth distance". Here, for the time varying depth measurement in tank experiments, we propose an alternative cheap and stand-alone optical method using continuous single calibrated optical images, combining the automatic tracking algorithm and depth distance estimation algorithm. The wave effect on measured mean depth distance time history of freely floating bodies can be eliminated by filters but the fluctuation by ship motions is an important information, so we try to carry out some simulation about this fluctuation. The main object of this paper is to describe the proposed algorithm used in the software development and the results obtained in the model experiments carried out in a towing tank to estimate the depth distance.