Accession Number : AD0699601

Title :   SEPARATION OF ADDITIVE AND SUBTRACTIVE MOIRE PATTERNS,

Corporate Author : CATHOLIC UNIV OF AMERICA WASHINGTON D C SCHOOL OF ENGINEERING AND ARCHITECTURE

Personal Author(s) : Clark,J. A. ; Durelli,A. J.

Report Date : DEC 1969

Pagination or Media Count : 25

Abstract : A spatial filtering technique for observing several different moire patterns in the same image of superposed gratings and for separating them at will, is described. In addition to the commonly observed moire pattern, and the equivalent patterns obtained by fringe sharpening or multiplication, patterns can be observed that correspond to different forms of the indicial equation describing the parametric properties of moire phenomena. In particular both the additive and subtractive moires are obtained individually, over the field. This method, combined with a previously developed method for obtaining spatial partial derivatives from deformed gratings (as a direct moire rather than moire of moire), permits the experimental determination of the whole field of Cartesian shears and rigid rotations. The method is applied to a circular ring subjected to diametral compression. (Author)

Descriptors :   (*STRESSES, DIFFRACTION ANALYSIS), (*DIFFRACTION GRATINGS, OPTICAL PHENOMENA), (*OPTICAL IMAGES, SEPARATION), PHOTOELASTICITY, OPTICAL FILTERS, STRAIN(MECHANICS), OPTICAL INSTRUMENTS, DEFORMATION, COLLIMATORS, LASERS, SCREENS(DISPLAYS), CAMERAS, RINGS, MATHEMATICAL MODELS, INTERFERENCE

Subject Categories : Test Facilities, Equipment and Methods
      Optics
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE