Singh, Rajendra (1996) Laser Dot Matrix based digital system for for monitoring Textureless Roof Strata of Mines. International Archives of Photogrammetry and Remote Sensing, 35 (5). pp. 540-545. ISSN 0256-1840

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Projection of a large number of target points through a tiny diffraction grating based diode laser is used to solve two close range digital photogrammetric problems conjugate point identification and targeting the object. Laboratory investigations showed high spatial stability and repeatability of dot matrix projection through a diffraction grating. A measurement repeatability of around 1/30th of a pixel was achieved during their image co-ordinate measurement by least squares based template matching. Accurate calibration of the projector was done with the help of an autoreflecting spherical target and placing the projector rigidly over the telescope of a geodimeter. Using standard bundle adjustment procedures of photogrammetry, a camera model of the projector was developed. The interior orientation and lens distortion parameters of the projector were found comparable with those of a real CCD camera which were derived using a standard three dimensional testfiled. A CCD camera placed over a motor driven turning and tilting system is combined with this arrangement of the projector to scan a large surface area and automatic derivation of three dimensional information of textureless and featureless object can be achieved.

Item Type: Article
Uncontrolled Keywords: CCD, Close Range, Triangulation, Orientation Parameters, Template Matching, Textureless object
Subjects: Thick Seam Mining
Depositing User: Dr. Satyendra Kumar Singh
Date Deposited: 17 Jan 2012 06:56
Last Modified: 17 Jan 2012 06:56

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