Accession Number:

ADA236955

Title:

Estimation and Correction of Geometric Distortions in Side-Scan Sonar Images

Descriptive Note:

Doctoral thesis,

Corporate Author:

WOODS HOLE OCEANOGRAPHIC INSTITUTION MA

Personal Author(s):

Report Date:

1990-03-01

Pagination or Media Count:

144.0

Abstract:

This thesis introduces a new procedure for the enhancement of acoustic images of the bottom of the sea produced by side-scan sonars. Specifically, it addresses the problem of estimating and correcting geometric distortions frequently observed in such images as a consequence of motion instabilities of the sonar array. This procedure estimates the geometric distortions from the image itself, without requiring any navigational or attitude measurements. A mathematical model for the distortion is derived from the geometry of the problem, and is applied to estimates of the local degree of geometric distortion obtained by cross-correlating segments of adjacent lines of the image. The model parameters are then recursively estimated through deterministic least-squares estimation. An alternative approach based on adaptive Kalman filtering is also proposed, providing a natural framework in which a priori information about the array dynamics may be easily incorporated. The estimates of the parameters of the distortion model are used to rectify the image, and may also be used for estimating the attitude parameters of the array. A simulation is employed to evaluate the effectiveness of this technique and examples of its application to high-resolution side-scan sonar images are provided.

Subject Categories:

  • Cybernetics
  • Acoustic Detection and Detectors

Distribution Statement:

APPROVED FOR PUBLIC RELEASE