PRACTICAL USE OF VIDEO IMAGERY IN NEARSHORE OCEANOGRAPHIC FIELD STUDIES

An approach was developed for using video imagery to quantify, in term s of both spatial and temporal dimensions, a number of naturally occur ring (nearshore) physical processes, The complete method is presented, including the derivation of the geometrical relationships relating im age and ground coordinates, principles to be considered when working w ith video imagery and the two-step strategy for calibration of the cam era model, The techniques are founded on the principles of photogramme try, account for difficulties inherent in the use of video signals, an d have been adapted to allow for flexibility of use in field studies, Examples from field experiments indicate that this approach is both ac curate and applicable under the conditions typically experienced when sampling in coastal regions, Several applications of the camera model are discussed, including the measurement of nearshore fluid processes, sand bar length scales, foreshore topography, and drifter motions, Al though we have applied this method to the measurement of nearshore pro cesses and morphologic features, these same techniques are transferabl e to studies in other geophysical settings.