THE APPLICATION OF VIDEO IMAGE PROCESSING TO THE STUDY OF NEARSHORE PROCESSES

h o u r s . . . PERHAPS THE MOST POPULAR oceanographic setting for the public is the beach and nearshore environment. Poetic accounts since early history describe the comings and goings of tides, waves and sand. More recently economic, recreational and defense pressures have lead to greatly increased efforts to achieve a more quantitative understanding. Critical to progress in understanding nearshore dynamics has been the abi l i ty to make physical measurements under natural conditions. This has t rad i t iona l ly been accompl i shed with arrays of f ixed-point measurements of fluid mot ions and surveys of beach response. Although costly and logistically difficult, the resulting insight has been invaluable . Yet. in some ways, these data sets have provided only a glimpse of the variability of a natural beach system. This paper will explore an alternative approach to sampling in the nearshore, taking advantage of the visible nature of the fluid motions and, indirect ly , of the beach response . Over the past decade, the avai labi l i ty of low-cos t video hardware and of image processing systems capable of extract ing valuable data from video images has provided a valuable tool for s tudying the nearshore, In the fol lowing section, we descr ibe the general physics of the nearshore and the resulting sampling constraints. We then discuss the basic elements of video image processing. Finally, we illustrate several examples of fluid and bathymetry measurements that can be made at low cost and over long periods of t ime using these video techniques.