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dc.contributor.authorDawson, Donald W.
dc.contributor.authorHart, Chris L.
dc.contributor.authorGilbert, Bernard R.
dc.contributor.authorAndrade, Rafael A.
dc.contributor.authorBlatt, Joel H.
dc.date.accessioned2017-10-05T17:25:27Z
dc.date.available2017-10-05T17:25:27Z
dc.date.issued1997-02-10
dc.identifier.citationDawson, D. W., Hart, C. L., Gilbert III, B. R., Andrade, R. A., & Blatt, J. H. (1997). Prediction of firing pin shape and 3-D matching of shells and firing pins based on firing pin impressions in primers. Paper presented at the Proceedings of SPIE - the International Society for Optical Engineering, , 2941 2-12.en_US
dc.identifier.urihttp://hdl.handle.net/11141/1766
dc.descriptionFiring pin matching, Real time, 3-D alignment, Shell matchingen_US
dc.description.abstractA variable resolution video machine vision system has been built which will determine the 3-D shape of a firing pin from the dent it has made in the primer of a shell. The system can also compare primer dents in different shells and determine if a 3-D match exists. A real time optical 3-D shape recognition feature allows the operator to align the shells, determine if there is a match, and quantify the quality of the 3-D match. The system uses a laser interferometer to project variable spatial frequency structural illumination on the shells which are viewed by video cameras. A computer determines the 3-D shape of the primer dent and predicts the shape of the firing pin. Optical shape recognition and alignment is achieved by mixing the video data with a computer generated mask and using this signal in a spatial light modulator to diffract a laser beam onto a detector. The magnitude and shape of the detector output indicates in real time the quality of the match or can be used to align the shells. A demonstration of the validity of the 3-D shape prediction has been carried out with large scale firing pin and shell-primer models, and the shape of a real firing pin has been determined from an actual fired shell. The result is a mixed video-optical processing system that could be used for real-time shell and firing pin matching in the forensic laboratory. Limitations and improvements in the current system are discussed. ©2004 Copyright SPIE - The International Society for Optical Engineering.en_US
dc.language.isoen_USen_US
dc.rightsThis published article is made available in accordance with publishers policy. It may be subject to U.S. copyright law.en_US
dc.rights.urihttp://spie.org/publications/journals/guidelines-for-authors#Terms_of_Useen_US
dc.titlePrediction of firing pin shape and 3-D matching of shells and firing pins based on firing pin impressions in primersen_US
dc.typeConference Proceedingen_US
dc.identifier.doi10.1117/12.266297


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