Coastal Bathymetric Plotting.
Abstract
The research is concerned with the development of improved passive techniques for automatic bathymetric plotting in turbid, relatively shallow coastal waters. Initially the technique uses narrower slicing (200 A) bandpass interference filters than have heretofore been utilized in multispectral photography of coastal waters. This is done to reject all of the non-image forming light for bottom photography. Coupled with this is an attempt to adequately characterize (for calibration of the plotting) the water column by a modulation transfer function (MTF) derived either from laser or photographic techniques. Finally, widely-spaced repetitive imagery of identical sites under randomly varying conditions of water column transmission properties were employed to linearly combine, by computer, film isodensity contours. These isodensity contours may be due to combinations of suspended sediment and bottom relief. The former are considered random variations and the latter relatively stable features. This statistical approach has yielded a superior estimate of actual depth contours, since the random sediment effects average out and the bottom features reinforce. Finally, additive multicolor additive processing techniques were examined and found to require normalization for use in the image merging from multiple missions outlined above. This latter work led to an additional spectral reflectivity difference ratioing concept for depth determination and characterizing coastal waters. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 1971
- Accession Number
- AD0730830
Entities
People
- David T. Hodder
- Gary A. Mccue
- Phillip B. Chandler