Image analysis as a method for determining grain-size distributions in sandstones

Michael B. Sawyer

doi:10.3133/ofr77280

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Image analysis as a method for determining grain-size distributions in sandstones

Michael B. Sawyer

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Abstract

A Quantimet 720 image analyzing computer is useful for A Quantimet 720 image analyzing computer is useful for determination of grain-size distributions of sand-size material. Results including histograms and statistical measures of size can be produced in approximately 5 to 10 minutes per sample. Comparison with sieve results shows only small differences in the mean grain-sizes obtained. Research into operating methods for the image analyzing computer and into mathematical methods for combining data is continuing so that material coarser and finer than sand can be measured. The instrument, which is attached to a microscope via a black and white television scanner, uses the gray shades of features in the field of view as the means of detecting those features. The image analyzing computer can then measure the features including area, perimeter, and several types of diameters. These data are then analyzed by a computer and the results are plotted. Sample preparation for this technique is conventional. Samples can be run as loose disaggregated grains, grain mounts, or thin sections.

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Michael B. Sawyer. 1977. Image analysis as a method for determining grain-size distributions in sandstones. https://doi.org/10.3133/ofr77280

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