Progressive visualization of incomplete sonar-data sets: From sea-bottom interpolation and segmentation to geometry extraction

Progressive visualization of incomplete sonar-data sets: From sea-bottom interpolation and segmentation to geometry extraction

Loke, R.E.

Jansen, F.W. (promotor)
du Buf, J.M.H. (promotor)

Electrical Engineering, Mathematics and Computer Science

2006-11-07

This thesis describes a visualization pipeline for sonar profiling data that show reflections of multiple sediments in the sea bottom and that cover huge survey areas with many gaps. Visualizing such data is not trivial, because they may be noisy and because data sets may be very large. The developed techniques are: (1) Quadtree interpolation for estimating new sediment reflections, at all gaps in the longitude-latitude plane. The quadtree is used for guiding the 3D interpolation process: gaps become small at low spatial resolutions, where they can be filled by interpolating between available reflections. In the interpolation, the reflection data are cross correlated in order to construct continuity of multiple, sloping reflections. (2) Segmentation and boundary refinement in an octree in order to detect sediments in the sonar data. In the refinement, coarse boundaries are reclassified by filtering the data with a planar kernel that is positioned on the boundary between the sediments. This improves existing algorithms and implies that gaps can also be interpolated during the down projection in the octree. (3) Triangulation conform a new version of the Discretized Marching Cubes algorithm that improves the sharpness of the extracted surfaces that lay between the sediments. By combining different surface modeling variants on the high-resolution subgrid of a cuberille, sharp manifold surfaces can be generated, in order to preserve concave and convex sediment shapes. (4) Integration of the techniques in a single-octree framework in order to make it scalable and applicable for the visualization of large data sets. The visualization pipeline has been applied for interactive visualization at low and high spatial resolutions.

computer graphics
pattern recognition
image processing
oceanic engineering

http://resolver.tudelft.nl/uuid:e80d55d3-bece-4665-b932-374960ce960c

Institutional Repository

doctoral thesis

(c) 2006 R.E. Loke