Accession Number : ADA331379

Title :   Enhanced Imaging Techniques for the Study of the Time-Evolution of Microscale Bed Geometry

Descriptive Note : Final technical rept. 1 Jan 93-31 Dec 95

Corporate Author : WOODS HOLE OCEANOGRAPHIC INSTITUTION MA DEPT OF APPLIED OCEAN PHYSICS AND ENGINEERING

Personal Author(s) : Wheatcroft, Robert A.

PDF Url : ADA331379

Report Date : 04 NOV 1997

Pagination or Media Count : 4

Abstract : The objective of this proposal was to develop and apply computer-based, digital image processing techniques to the measurement of high-resolution (millimeter to decimeter) seafloor topography. Stereophotographs were collected as part of the 1990-1991 STRESS (Sediment TRansport Events of Shelves and Slopes) field program. A free-vehicle stereocamera tripod was deployed in mid-November 1990 at the 90-m STRESS site and successfully recovered in mid-March 1991. Results of the automatic image fusion research were disappointing, hence STRESS stereophotographs were analyzed manually using an analytical stereocomparator. During the deployment, five qualitatively different bed configurations were observed. In order of decreasing frequency these were: (1) biogenically reworked bed, (2) smoothed to scoured bed, (3) current-rippled bed, (4) scour-pitted bed, and (5) wave-rippled beds. Total vertical bed relief within the field of view was found to be typically less than 6 cm and the r-m-s vertical relief was of order 1 cm. Maximal relief occurred when the bed was current rippled (heights average 2 cm and lengths are about 15 cm) and was minimal following scour events. This study demonstrated that seafloor relief can change rapidly over short time scales.

Descriptors :   *SEDIMENT TRANSPORT, *OCEAN BOTTOM TOPOGRAPHY, IMAGE PROCESSING, TIME SERIES ANALYSIS, STEREOPHOTOGRAPHY.

Subject Categories : Physical and Dynamic Oceanography

Distribution Statement : APPROVED FOR PUBLIC RELEASE