Singh, Rajendra (1997) Digital Photogrammetry for Automatic Close Range Measurement of Textureless and Featureless Objects. Photogrammetric Record, 15 (89). pp. 691-702. ISSN 1477-9730

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Abstract

Diffraction grating based simultaneous projection of large number of distinct and circular laser dots was adopted to solve correspondence and accuracy problems during automatic three dimensional measurement of a textureless and featureless object at close range. After rigid placement of the projector over the telescope of a geodimeter, accurate calibration and derivation of a camera model of the virtual active camera (the projector) was done without a control field and using a bundle adjustment procedure. While automatic detection and labeling of the actively placed tares points over any given object remained a problems, algorithms were developed to locate and label these target points placed over a nearly flat and textureless surface. A conventional thresholding method was combined with least squares matching (LSM) to provide automatic subpixel image co-ordinate measurement of the target ponts placed over a textureless object but, considering the real object conditions, semi-automatic image co-ordinate measurement was done by LSM. The system provided an intersection parallax of 0.3 mm during a laboratory test scan of a planar object at 4.5 m distance.

Item Type:	Article
Subjects:	Thick Seam Mining
Divisions:	UNSPECIFIED
Depositing User:	Dr. Satyendra Kumar Singh
Date Deposited:	20 Feb 2012 05:53
Last Modified:	20 Feb 2012 05:53
URI:	http://cimfr.csircentral.net/id/eprint/963

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