Single-shot, two-frame, π-shifted spatially multiplexed interference microscopy (π-SMIM) is presented as an improvement to previous SMIM implementations, introducing a versatile, robust, fast, and accurate method for cumbersome, noisy, and low-contrast phase object analysis. The proposed π-SMIM equips a commercially available nonholographic microscope with a high-speed (video frame rate) enhanced quantitative phase imaging (QPI) capability by properly placing a beam-splitter in the microscope embodiment to simultaneously (in a single shot) record two holograms mutually phase shifted by π radians at the expense of reducing the field of view. Upon subsequent subtractive superimposition of holograms, a π-hologram is generated with reduced background and improved modulation of interference fringes. These features determine superior phase retrieval quality, obtained by employing the Hilbert spiral transform on the
In this contribution, we present the preliminary results of a 3D inspection system [1] for drill holes analysis in aeronautical surfaces. The system, based in optical triangulation, was developed by the Group of Optoelectronic Image Processing from the University of Valencia in the framework of the Airbus Defence and Space (AD&S), MINERVA project (Manufacturing industrial - means emerging from validated automation). The capabilities of the system permits to generate a point cloud with 3D information and GD&T (geometrical dimensions and tolerances) characteristics of the drill hole. For the inner surface defects detection, the system can generate an inner image of the drill hole with a scaled axis to obtain the defect position. In addition, we present the analysis performed for the drills in the wing station of the A-400 M. In this analysis the system was tested for diameters in the range of [10 – 15.96] mm, and for Carbon Fibre.
In our case, we are going to register the shifting between two images, doing the first approach by FFT based correlation, and later doing the subpixel approach using the technique described before. We consider it as ‘brute force’ method. So we will present a benchmark of the algorithm consisting on a first approach (pixel resolution) and then do subpixel resolution approaching, decreasing the shifting step in every loop achieving a high resolution in few steps. This program will be executed in three different computers. At the end, we will present the results of the computation, with different kind of CPUs and GPUs, checking the accuracy of the method, and the time consumed in each computer, discussing the advantages, disadvantages of the use of GPUs.
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