Analysis of Gradient Change Thresholds in the Detection of Edges of Objects from Range Data

摘要

Edges of objects setting on or within a flat terrain can be defined by the slope or gradient change occurring at the edge. A simple estimate of slope change is to calculate the Laplacian using incremental range measurements taken at different elevation angles. The Laplacian is defined as the second difference of the range data. Since the range data contains noise in the form of measurement error, consideration must be given to the statistical aspects of detecting edges in order to differentiate between actual edges and noise effects. In this report, results are presented which describe the effects on minimum detectable slope change of (1) noise levels, (2) probability of miss, (3) probability of false alarm, (4) spacing of the measurements, and (5) random distribution of edges near range measurement points.