We propose phase retrieval from three or more interferograms corresponding to different tilts of an object wavefront. The algorithm uses the information contained in the interferogram differences to reduce the problem to phase shifting. Three interferograms is the minimum for restoring the phase over most of the image. Four or more interferograms are needed to restore the phase over the whole image. The method works with images including open and closed fringes in any combination.
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http://dx.doi.org/10.1364/opex.13.003743 | DOI Listing |
We propose a multi-wavelength digital holography based on Kramers-Kronig (KK) relations, introducing a unified angle-multiplexing multi-wavelength KK model to overcome the accuracy and resolution limitations of angle-multiplexing techniques. By linking the real and imaginary parts of the multi-wavelength complex function via the KK relation, the method captures object light waves with the full effective bandwidth from a single interferogram and reference wave intensity. This method greatly improves spectral utilization and measurement accuracy in multi-wavelength interference.
View Article and Find Full Text PDFPLoS One
August 2024
College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao, Shandong Province, China.
Aiming at the characteristics that the signal noise ratio (SNR) gradually decreases from the near to far range of the swath, an adaptive phase filtering algorithm based on Goldstein filtering and combined with multiple quality-guided graphs was proposed. Firstly, the components used to determine the filtering parameters were obtained through residue density, pseudo-coherence coefficient and pseudo-SNR, the three quality-guided graphs. Then, the filter parameters were calculated by weighting the three components.
View Article and Find Full Text PDFAnimals (Basel)
June 2024
Veterinary Faculty, University of Ljubljana, Gerbičeva 60, 1000 Ljubljana, Slovenia.
Hemolysis is a common cause of errors in laboratory tests as it affects blood parameters and leads to a positive or negative bias. This study aims to examine the relationship between the level of hemolysis (expressed as cell-free hemoglobin concentration, g/L) and the variability of metabolic and endocrine parameters and to determine the threshold level of hemolysis that causes an analytically and clinically significant bias for the twenty most frequently examined blood parameters in cows. Paired blood samples of 10 mL each were obtained from 30 cows.
View Article and Find Full Text PDFSurf Topogr
January 2024
Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 USA.
The vertical scale calibration of an interferometric microscope is important for establishing traceability of surface topography measurements to the International System of Units (SI) unit of length, the meter. Building on the calibration procedure for the amplification coefficient developed by de Groot and Beverage [Proc. SPIE , 952610 (2015)], this paper describes a calibration procedure that yields the response curve for the entire vertical scan motion of a coherent scanning interferometric microscope.
View Article and Find Full Text PDFAnal Chem
June 2024
Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
NMR spectroscopy is often described as a quantitative analytical technique. Strictly, only the simple pulse-acquire experiment is universally quantitative, but the poor signal resolution of the H NMR pulse-acquie experiment frequently complicates quantitative analysis. Pure shift NMR techniques provide higher resolution, by reducing signal overlap, but they are susceptible to a variety of sources of site-dependent signal loss.
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