...

LIS Thinning - point cloud thinning and homogenization

This package contains tools for point cloud thinning, including 2D and 3D blockthinning, TIN-based thinning as well as tools for adaptive thinning based on local surface roughness.

Tool: Block Thinning 2D

Features
• thinning of a point cloud by 2D block filtering (from all points contained within a 2D grid cell only one is kept)
• filter methods: lowest, highest, nearest (cell center), mean, median, min(attribute), max(attribute)
Applications
• point cloud thinning / data reduction
• point cloud thinning based on attribute value, e.g., point with highest intensity value is kept
• homogenization of point density

Tool: Block Thinning 3D

Features
• thinning of a point cloud by 3D block filtering (from all points contained within a 3D voxel only one is kept)
• filter methods: lowest, highest, nearest (voxel center), mean, median, z-slice mean, min(attribute), max(attribute), center
Applications
• point cloud thinning / data reduction
• point cloud thinning based on attribute value, e.g., point with highest intensity value is kept
• homogenization of point density

Tool: Delaunay Thinning 2D

Features
• thinning is controlled by a deviation tolerance describing the elevation difference allowed between the 2D triangulation of the thinned point cloud and that of the original point cloud
• points with a high curvature, e.g., along breaklines, can be kept, optional
• output of the final (thinned) TIN as 3D shapes layer, optional
Applications
• point cloud thinning / data reduction
• TIN generation (3D shapes layer)
• detection of (terrain) keypoints

Tool: Segment Centroids

Features
• condense segments to their centroids
• optional: output of mean attribute value per segment
Applications
• point cloud segmentation
• object based analysis/classification

Tool: Segment Thinning

Features
• thinning of points on point cloud segments by 3D block filtering
• filter methods: lowest, highest, nearest, mean, median, z-slice mean, min(attribute), max(attribute), center
Applications
• point cloud thinning

Tool: Thinning by Surface Roughness

Features
• thinning of a point cloud (e.g., a bare earth model) in consideration of surface roughness
• areas with a low surface roughness will be thinned out more rigorous than areas with a high roughness
• additional output: final (thinned) TIN as 3D shapes layer
• TIN can be constrained to data, optional
• detection of (terrain) breaks by normal vector difference, optional
Applications
• point cloud thinning / data reduction
• TIN generation (3D polygon shapes layer)
• detection of (terrain) keypoints