IMAGE MEASUREMENT OF WAVE HEIGHT DISTRIBUTION AROUND A SHIP MODEL

A measurement system for wave height distribution using visualised image has been developed and applied in a towing tank. When a laser sheet illumination is given from the bottom of the tank, the free surface is visualised as the boundary of bright and dark are on the image. The high contrast image is obtained by large light scattering in water. Combining the visualization and an image proceeding technique, the image measurement system has been developed, and is modified so as to apply to measurement in a towing tank. A high power laser is required to obtain enough contrast on the visualised image in a large size towing tank, and the simple coordinate transformation should be considered to make up a practical system. A two camera system is used to obtain a wide range distribution in the same spatial resolution. The measured result shows that the system can be applied on the wave measurement around not only a high speed craft but also an ordinary displacement type ship model.