TY - JOUR N2 - Digital holography (DH) which is the technology of acquiring and processing measurement data via a CCD camera is spreading to industrial applications, finds wide employment in engineering problems of testing and investigation. In this paper, a simple digital holographic system, comprising a He-Ne laser source, CCD camera and analyzing software, is used for testing surface flatness and detecting the presence of a propagating crack on the surface plane and the effect of the crack on the neighborhood. Phase variations across the surfaces planes are extracted to represent the surface deviation from a reference plane. The analysis methods differ according to the interference fringes in the recorded holograms. Both fringe tracking and Fourier transform with phase unwrapping methods are used in the interpretation of interferometric fringe patterns. L1 - http://www.journals.pan.pl/Content/107076/PDF/Journal10178-VolumeXVII%20Issue4_06%20paper.pdf L2 - http://www.journals.pan.pl/Content/107076 PY - 2010 IS - No 4 EP - 587 DO - 10.2478/v10178-010-0047-z KW - digital holography KW - fringe analysis KW - flatness testing KW - crack investigation A1 - Maaboud, Niveen A1 - El-Bahrawi, Mohamed A1 - Abdel-Aziz, Fedia PB - Polish Academy of Sciences Committee on Metrology and Scientific Instrumentation DA - 2010 T1 - Digital Holography in Flatness and Crack Investigation SP - 583 UR - http://www.journals.pan.pl/dlibra/publication/edition/107076 T2 - Metrology and Measurement Systems ER -