GEOMETRIC PHASE SHEAROGRAPHY SYSTEM AND METHOD THEREOF

    公开(公告)号:US20210293526A1

    公开(公告)日:2021-09-23

    申请号:US16823918

    申请日:2020-03-19

    Inventor: Jacob D. Garan

    Abstract: A shearography system uses a Geometric phase or Pancharatnam-Berry (PB) phase element to shear an image. A PB phase element provides a non-dynamical phase change used for wavefront control and results in uniform half-wave of retardation. Geometric phase may also be utilized to capture snapshot phase-resolved wavefront measurements and shearograms via a focal plane array with micro-patterned linear polarizers of different orientations. Wavefront shape control arises when the local orientation of the retarding media is spatially varied. One or more PB phase elements can be flipped or rotated to perform multiple tasks depending on its orientation. Two PB elements can be used in succession in order to provide a variable purely spatial shift between interfering wavefronts. The spatial offset of the light exiting the second element can be adjusted simply by changing the spacing between the two geometric phase surfaces. In shearography, this corresponds to an adjustable shear length.

    FIELD FLATTENING VIA INTERFERENCE FILTERS

    公开(公告)号:US20210278579A1

    公开(公告)日:2021-09-09

    申请号:US16716921

    申请日:2019-12-17

    Inventor: Jacob D. Garan

    Abstract: The present disclosure relates generally to a method of use for a field flattening interference filter. More particularly, the present disclosure relates a field flattening bandpass interference filter with the cut-on edge of the pass band at the system wavelength at a normal angle of incidence. Further discussed is a method to extend the field flattening design to work at multiple system wavelengths through the optimized design of a multi-band interference filter.

    COMPUTATIONAL SHEAR BY PHASE STEPPED SPECKLE HOLOGRAPHY

    公开(公告)号:US20220011091A1

    公开(公告)日:2022-01-13

    申请号:US16925420

    申请日:2020-07-10

    Abstract: A method and apparatus for performing shearography where the shear length and direction can be set in image processing, thus allowing all shear sizes to be computed and tested from a single data set, which can be collected in a single pass over a test surface or test object. The present process assures that a single data set can be processed with optimal shear length for multiple target types, thus reducing or eliminating the chance of missing a target detection while additionally enhancing target shape analysis by allowing the calculation of target response versus shear length and shear direction.

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