1 March 1992 Grazing-incidence lighting techniques for machine vision inspection
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Illumination characteristics play an important part in machine vision inspection by making certain critical features conspicuous. Frequently, the angle of illumination can be of importance in enhancing the detection of features that have height or depth. The highlights or shadows produced by grazing-incidence illumination produce contrast differences that are easily detected by an appropriate vision system. This paper explores the role of this lighting technique in machine vision applications. Three examples are presented that describe the application of this technique on paper documents. In the first example, grazing-incidence is used to detect the presence of an erased signature on a forged personal check. In the second example, the technique is used to detect the presence of an address label on a piece of mail. In the third example, grazing-incidence is used to verify the impression signature of a financial document.
© (1992) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
John J. Lumia, John J. Lumia, } "Grazing-incidence lighting techniques for machine vision inspection", Proc. SPIE 1614, Optics, Illumination, and Image Sensing for Machine Vision VI, (1 March 1992); doi: 10.1117/12.57966; https://doi.org/10.1117/12.57966

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