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Computer-aided analysis for the Mechanics of Granular Materials (MGM) experimentThe Mechanics of Granular Materials (MGM) program is planned to provide experimental determinations of the mechanics of granular materials under very low gravity conditions. The initial experiments will use small glass beads as the granular material, and a precise tracking of individual beads during the test is desired. Real-time video images of the experimental specimen were taken with a television camera, and subsequently digitized by a frame grabber installed in a microcomputer. Easily identified red tracer beads were randomly scattered throughout the test specimen. A set of Pascal programs was written for processing and analyzing the digitized images. Filtering the image with Laplacian, dilation, and blurring filters when using a threshold function produced a binary (black on white) image which clearly identified the red beads. The centroids and areas for each bead were then determined. Analyzing a series of the images determined individual red bead displacements throughout the experiment. The system can provide displacement accuracies on the order of 0.5 to 1 pixel is the image is taken directly from the video camera. Digitizing an image from a video cassette recorder introduces an additional repeatability error of 0.5 to 1 pixel. Other programs were written to provide hardcopy prints of the digitized images on a dot-matrix printer.
Document ID
19870007342
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Parker, Joey K.
(Alabama Univ. Huntsville, AL, United States)
Date Acquired
September 5, 2013
Publication Date
November 1, 1986
Publication Information
Publication: NASA. Marshall Space Flight Center Research Reports: 1986 NASA(ASEE Summer Faculty Fellowship Program
Subject Category
Materials Processing
Accession Number
87N16775
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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