Adaptive mechanism control and scanner positioning for improved three-dimensional laser scanning

• US 9,322,646 B2
• Filed: 04/08/2011
• Issued: 04/26/2016
• Est. Priority Date: 04/09/2010
• Status: Expired due to Fees

• Current Assignee: The Trustees of The Stevens Institute of Technology (Stevens Institute Of Technology)
• Original Assignee: The Trustees of The Stevens Institute of Technology (Stevens Institute Of Technology)
• Inventors: Pochiraju, Kishore V., Men, Hao, Gebre, Biruk Assefa
• Primary Examiner(s): Breene, John
• Assistant Examiner(s): Ngo, Peter
• Application Number:
  US13/581,742
• Publication Number:
  US 20130054187A1
• Time in Patent Office: 1,845 Days
• Field of Search: 702/150
• US Class Current: 1/1
• CPC Class Codes: G01C 15/002 Active optical surveying means optical plumbing G01C15/105
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4808 Evaluating distance, position or velocity data
• CPC Class Codes: G01S 7/4811 common to transmitter and receiver
• CPC Class Codes: G01S 7/4817 relating to scanning

Abstract

A method of adaptively positioning a scanner [10] within a three-dimensional scene identifies an optimal next position for the scanner [40] based on analysis of a data point cloud that mimics the scanned portion of the scene. Occluded areas [38] are delineated from scan data and scans made at different locations in the scene are registered to a reference four-coordinate system. The fourth coordinate corresponds to the hue observed by the scanner at each data point.

Claims

1. A method of adaptively positioning a range-measuring scanner within a three-dimensional scene, comprising the steps of:

(a) positioning the scanner at a first vantage position, the first vantage position having positional values associated therewith;

(b) scanning a first portion of the scene with the scanner, said first portion of the scene having a spatial arrangement of hues, thereby generating a first set of data points, each data point of the first set of data points having three positional values and a hue value associated therewith, the positional values defining the position of the data point on a first spatial three-coordinate system and the hue value being invariant with camera angle and lighting conditions and defining a fourth coordinate such that said first set of data points mimics the spatial arrangement of hues of the scanned first portion of the scene, the first spatial three-coordinate system and the fourth coordinate constituting a first four-coordinate system;

(c) identifying occlusion boundaries of partially-occluded objects within the scanned first portion of the scene, said identifying step including a step of analyzing the distances from the scanner to adjacent data points of said first set of data points so as to identify pairs of adjacent data points in which the distance from the scanner of one member of each pair of points is greater than the distance from the scanner of the other member of the pair of points by at least a reference value;

(d) projecting positional data from at least some of the first plurality of data points and the positional data for first vantage position, onto a bounded grid defining a plurality of cells, so as to locate traversable cells corresponding to areas within the scene through which the scanner may move and to locate occluded cells corresponding to the occlusion boundaries through which the scanner cannot move;

(e) identifying cells on the grid corresponding to possible next vantage positions near the boundary of the grid, the possible next vantage positions not including occluded cells;

(f) identifying the nearest possible next vantage position that requires the scanner to traverse the least number of traversable cells;

(g) moving the scanner to a position within the scene corresponding to the next vantage position on the grid identified in step (f);

(h) scanning a second portion of the scene, said second portion of the scene having a spatial arrangement of hues, thereby generating a second set of data points, each data point of the second set of data points having three positional values and a hue value associated with it, the positional values defining the position of the data point of the second set of data points on a second spatial three-coordinate system and the hue value being invariant with camera angle and lighting conditions and defining a fourth coordinate such that the second set of data points mimics the spatial arrangement of hues of the scanned a second portion of the scene, the second spatial three-coordinate system and the fourth coordinate constituting a second four-coordinate system;

(i) registering the second set of data points against the first set of data points, said registering step including use of a hue-assisted iterative closest point (“

HICP”

) algorithm and the step of transforming the second four-coordinate system to a transformed four-coordinate system which approximates the first four-coordinate system, said transforming step including the performance of mathematical operations performed on the positional values and hue values associated with data points in the second set of data points.