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Tuning transfer function of fiber-optic Fabry–Pérot interferometer via introduction of birefringence in the cavity

Hirsch Marzena, Wierzba Paweł, Jędrzejewska-Szczerska Małgorzata

Optica Applicata

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2019

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Vol. 49, nr 2

241--248

EN

The study investigates the impact of birefringence exhibited by the cavity material of a fiber-optic Fabry–Pérot interferometer on its transfer function. The theoretical approach to analyze the effect of birefringence in the cavity of a plane Fabry–Pérot interferometer is described. The case of high- and low-finesse interferometer is investigated. It is shown that introduction of a birefringent medium of optimized parameters can be used to increase the density of interference fringes in certain wavelength range – the feature can be used either for reduction of the cavity length in an interferometric sensor or operation with sources of narrower spectral characteristics.

2

Machine learning system for automated blood smear analysis

Grochowski Michał, Wąsowicz Michał, Mikołajczyk Agnieszka, Ficek Mateusz, Kulka Marek, Wróbel Maciej S., Jędrzejewska-Szczerska Małgorzata

Metrology and Measurement Systems

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2019

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Vol. 26, nr 1

81--93

EN

In this paper the authors propose a decision support system for automatic blood smear analysis based onmicroscopic images. The images are pre-processed in order to remove irrelevant elements and to enhancethe most important ones – the healthy blood cells (erythrocytes) and the pathologic ones (echinocytes). The separated blood cells are analysed in terms of their most important features by the eigenfaces method. The features are the basis for designing the neural network classifier, learned to distinguish between erythrocytes and echinocytes. As the result, the proposed system is able to analyse the smear blood images in a fully automatic way and to deliver information on the number and statistics of the red blood cells, both healthy and pathologic. The system was examined in two case studies, involving the canine and human blood, and then consulted with the experienced medicine specialists. The accuracy of classification of red blood cells into erythrocytes and echinocytes reaches 96%.

3

Fibre-optic sensor for simultaneous measurement of thickness and refractive index of liquid layers

Marzejon Marcin, Karpienko Katarzyna, Mazikowski Adam, Jędrzejewska-Szczerska Małgorzata

Metrology and Measurement Systems

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2019

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Vol. 26, nr 3

561--568

EN

In this paper, we present a fibre-optic sensor for simultaneous measurement of refractive index and thickness of liquid layers. We designed an experimental low-coherence setup with two broadband light sources and an extrinsic fibre-optic Fabry-Pérot interferometer acting as the sensing head. We examined how the refractive index of a liquid film and its thickness affect spectrum at the output of a fibre-optic interferometer. We performed a series of experiments using two light sources and only one sensing head. The spectra were collected in ranges of 1220-1340 nm and 1500-1640 nm. The obtained results show that using two spectra recorded simultaneously for two wavelength ranges enables to determine thickness in a range of 50-500 μm, and refractive index of a liquid film in a range of 1.00-1.41 RIU using only one sensing head.