CREATING A SEABED MOSAIC FROM GEOCODED SIDESCAN SONAR IMAGES

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Authors
  1. Poeckert, R.H.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN)
Abstract
The use of high frequency sidescan sonar mounted on a towfish to accurately map the seabed with sufficient resolution to detect mine-sized objects (-2m) is well established. Typically such sonars have swath widths between 150 to 300 m and there is usually a region directly beneath the towfish which is poorly imaged. Multiple overlapping swaths are used to map an area wider than an individual swath and to provide useful data directly along a towfish path. The data collected on such a survey can be geocoded and mosaiced into a large seabed map. The mosaicing process involves registering overlapping images and combining them. The navigational accuracy achievable at present is -10 m RMS. Thus images will not register exactly, and, if left uncorrected the resultant mosaic will have unacceptable discontinuities across out-lines where images are joined. Several solutions exist to minimize these discontinuities and this paper describes a process in which images are warped and mosaiced in such a way as to almost eliminate cut-line discontinuities and at the same time preserve overall positional accuracy.
Keywords
Geocoding;Seabed images;Mosaics
Report Number
DREA-TM-97-215 — Technical Memorandum
Date of publication
01 Mar 1997
Number of Pages
19
DSTKIM No
97-03958
CANDIS No
504202
Format(s):
Hardcopy;Document Image stored on Optical Disk

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