Transonic Experimental Facility (TEF) Free-Flight Spark Range: Automation of Film Reading and Processing

Report No. ARL-TR-7387
Authors: Sophia M Haire
Date/Pages: August 2015; 26 pages
Abstract: Timely digitization of data points from projectile shadowgraphs collected from the free-flight spark ranges at the Aerodynamic and Transonic Experimental Facilities (AEF and TEF) at the US Army Research Laboratory (ARL) at Aberdeen Proving Ground, Maryland, have historically posed a challenge for ARL engineers and computer scientists. Manual processes involving the use of light tables to digitally log data points by directly reading the developed film negatives have been the standard approach. For AEF film reading, the process has only recently begun to be automated via in-house beta-version software. This software (the "film package") consists of 3 Visual Basic.NET programs (FilmScanner, FilmSorter, and FilmReader), which are used sequentially to scan, order, and extract measurements from the shadowgraphs. Each component of the film package was modified and expanded to accommodate the film format and calculations required by TEF shadowgraphs. These modifications primarily consist of methods to process TEF film's unique size and reference points, enhancements to image processing and quality, and introduction of modern hardware. Although there are several items to complete before ARL's advent of fully automatic spark-range film analysis, the package is ready for use in digital analysis of TEF tests, and the efficiency gained by the film package warrants its use in present and future range operations.
Distribution: Approved for public release
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Last Update / Reviewed: August 1, 2015