DeepOrientation: convolutional neural network for fringe pattern orientation map estimation

Fringe pattern based measurement techniques are the state-of-the-art in full-field optical metrology. They are crucial both in macroscale, e.g., fringe projection profilometry, and microscale, e.g., label-free quantitative phase microscopy. Accurate estimation of the local fringe orientation map can significantly facilitate the measurement process on various ways, e.g., fringe filtering (denoising), fringe pattern boundary padding, fringe skeletoning (contouring/following/tracking), local fringe spatial frequency (fringe period) estimation and fringe pattern phase demodulation. Considering all of that the accurate, robust and preferably automatic estimation of local fringe orientation map is of high importance. In this paper we propose novel numerical solution for local fringe orientation map estimation based on convolutional neural network and deep learning called DeepOrientation. Numerical simulations and experimental results corroborate the effectiveness of the proposed DeepOrientation comparing it with the representative of the classical approach to orientation estimation called combined plane fitting/gradient method. The example proving the effectiveness of DeepOrientation in fringe pattern analysis, which we present in this paper is the application of DeepOrientation for guiding the phase demodulation process in Hilbert spiral transform. In particular, living HeLa cells quantitative phase imaging outcomes verify the method as an important asset in label-free microscopy

Hilbert phase microscopy based on pseudo thermal illumination in Linnik configuration

Quantitative phase microscopy (QPM) is often based on recording an object-reference interference pattern and its further phase demodulation. We propose Pseudo Hilbert Phase Microscopy (PHPM) where we combine pseudo thermal light source illumination and Hilbert spiral transform phase demodulation to achieve hybrid hardware-software-driven noise robustness and increase in resolution of single-shot coherent QPM. Those advantageous features stem from physically altering the laser spatial coherence and numerically restoring spectrally overlapped object spatial frequencies. Capabilities of the PHPM are demonstrated analyzing calibrated phase targets and live HeLa cells in comparison with laser illumination and phase demodulation via temporal phase shifting and Fourier transform techniques. Performed studies verified unique ability of the PHPM to couple single-shot imaging, noise minimization, and preservation of phase details

Optically-sectioned two-shot structured illumination microscopy with Hilbert-Huang processing

We introduce a fast, simple, adaptive and experimentally robust method for reconstructing background-rejected optically-sectioned images using two-shot structured illumination microscopy. Our innovative data demodulation method needs two grid-illumination images mutually phase shifted by π (half a grid period) but precise phase displacement between two frames is not required. Upon frames subtraction the input pattern with increased grid modulation is obtained. The first demodulation stage comprises two-dimensional data processing based on the empirical mode decomposition for the object spatial frequency selection (noise reduction and bias term removal). The second stage consists in calculating high contrast image using the two-dimensional spiral Hilbert transform. Our algorithm effectiveness is compared with the results calculated for the same input data using structured-illumination (SIM) and HiLo microscopy methods. The input data were collected for studying highly scattering tissue samples in reflectance mode. Results of our approach compare very favorably with SIM and HiLo techniques

Cykle hydrogeologiczne w świetle badań monitoringowych w Karpatach

W ramach monitoringu w Karpatach bada się zmiany wahań zwierciadła wód podziemnych i wydajności źródeł. Uwzględnione w artykule obserwacje prowadzone były przez PIG-PIB w okresie od 1989 r. do października 2013 r. oraz przez IMGW od lat 60 ubiegłego wieku do 2000 r. W ramach Państwowej Służby Hydrogeologicznej obserwacje realizuje się w 88 punktach badawczych, z czego 49 stanowią studnie wiercone, 35 źródła i 4 studnie kopane. W wielu punktach obserwacyjnych zaznaczają się wieloletnie (trwające około 20 lat), cykliczne zmiany wydajności źródeł i wahań zwierciadła wód podziemnych. Wyniki prowadzonych w ramach monitoringu wód podziemnych obserwacji zmian położenia ich zwierciadła dały podstawę do wyznaczenia cykli hydrogeologicznych związanych ze zmianami stanu retencji

Visualization 1: Generation of phase edge singularities by coplanar three-beam interference and their detection

Movie with experimental verification of the phase edge dislocation theory Originally published in Optics Express on 06 February 2017 (oe-25-3-2432

Continuous phase estimation from noisy fringe patterns based on the implicit smoothing splines

We introduce the algorithm for the direct phase estimation from the single noisy interferometric pattern. The method, named implicit smoothing spline (ISS), can be regarded as a formal generalization of the smoothing spline interpolation for the case when the interpolated data is given implicitly. We derive the necessary equations, discuss the properties of the method and address its application for the direct estimation of the continuous phase in both classical interferometry and digital speckle pattern interferometry (DSPI). The numerical illustrations of the algorithm performance are provided to corroborate the high quality of the results.Fil: Wielgus, Maciek. Uniwersytet Warszawski; ArgentinaFil: Patorski, Krzysztof. Uniwersytet Warszawski; ArgentinaFil: Etchepareborda, Pablo Gonzalo. Instituto Nacional de Tecnología Industrial. Centro de Electrónica e Informática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Federico, Roque Alejandro. Instituto Nacional de Tecnología Industrial. Centro de Electrónica e Informática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Visualization 2: Quantitative phase imaging by single-shot Hilbert–Huang phase microscopy

Dynamic experiment: cross-sections. Originally published in Optics Letters on 15 September 2016 (ol-41-18-4344

Visualization 1: Quantitative phase imaging by single-shot Hilbert–Huang phase microscopy

Dynamic experiment with flowing micro-beads and 20× lens. (a)-(b) and (c)-(d) are the wrapped and 3D plot phase distributions retrieved using S2H2PM and FT techniques, respectively. Originally published in Optics Letters on 15 September 2016 (ol-41-18-4344