Kyu YOSHIMORI,¹ Kazuyoshi ITOH² and Yoshiki ICHIOKA³

¹Furuno Electric Co., Ltd., 9-52, Ashihara-cho, Nishinomiya, 662 Japan, ²Department of Applied Physics, Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita, 565 Japan, ³Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita, 565 Japan

(Received April 26, 1996; Accepted June 11, 1996)

When a random rough surface is viewed obliquely by an imaging system, the position of a viewed point fluctuates with surface displacements. This fluctuation introduces an additional blur to the images that are mapped on the average surface. A new class of spread function, which represents the resolution associated with the randomness of an imaging object, is introduced to treat this problem and an analytical expression of the function is obtained for a Gaussian random surface under the presence of shadowing effects. This spread function is useful in understanding the loss in resolution of images of a random surface such as the thermal imagery of an ocean surface in the near horizon.

Key words : image resolution, ocean, rough surface, shadowing, thermal imagery