Papers by Andrzej Walczak
Opto-Electronics Review, 2009
Image analysis using polarizing methods allows removing the polarized light component from record... more Image analysis using polarizing methods allows removing the polarized light component from recorded images. This is known as polarization difference imaging (PDI). The use of liquid crystals (LC) in PDI was proposed in 2002. Modified LC unit with a properly oriented LC layer was proposed by the authors. The main parameters which characterize an imaging system, employing a circular LC filter, were determined and presented in previous papers.In this work, the basics of the circular LC filter construction and theory are presented. Two application configurations of PDI imaging systems are shown. Experimental results of image processing based on object’s polarization properties are discussed.
Biuletyn Wojskowej Akademii Technicznej, 2002
MATEC Web of Conferences, 2017
The aim of the article is to present the possibilities offered by network models. This article di... more The aim of the article is to present the possibilities offered by network models. This article discusses the network model of risk analysis in technical structures. We are discussed some network centrality measures and their use in risk analysis. We have proposed a mixed, expert-formal model for analyzing the risk of asset risk in technical structures based on own methodology of network building. We shown that mathematically model of structure of the network and its corresponding physical are linked by bijection. This creates a unequivocal model for quantitative risk analysis.
Photonics Letters of Poland, 2015
2013 IEEE 15th International Conference on e-Health Networking, Applications and Services (Healthcom 2013), 2013
ABSTRACT Bayesian networks have become a very popular model used to represent probabilistic medic... more ABSTRACT Bayesian networks have become a very popular model used to represent probabilistic medical knowledge bases. On the other hand the medical knowledge mostly contains fuzzy relationships among patients, diseases, symptoms and examination and assessment results. In this paper, we present a framework, which will enable us to assess the efficacy of treatment in the presence of imprecise and incomplete information. At its core is the intuitionistic fuzzy generalization of the McNemar test where Bayesian inference reasoning is employed to determine the membership and non-membership functions. Our approach integrates machine-learning techniques to support the hypothesis testing problem where the efficacy of treatment needs to be addressed with regard to imprecise and incomplete patient data stored in medical datasets.
Photonics Letters of Poland, 2010
Molecular Crystals and Liquid Crystals, 2012
Theoretical discussion and numerical results for experimentally obtained new kind of the optical ... more Theoretical discussion and numerical results for experimentally obtained new kind of the optical waveguide has been presented. Discussed waveguide is optically self-induced during light beam propagation along boundary between liquid crystal and semiconducting polymer. Light is propagated in electrically driven liquid crystal (LC) cell. Experimental results obtained earlier are reported in here shortly, and theoretical model of the observed phenomena
Opto-Electronics Review, 2008
The novel two-dimensional (2D) wavelet with anisotropic property and application of it has been p... more The novel two-dimensional (2D) wavelet with anisotropic property and application of it has been presented. Wavelet is constructed in the polar coordinate system to obtain anisotropic properties. A novel edge detection method has been developed with the aid of this wavelet. This method detects gradient jump and than follows along this jump. In this way the number of calculation for edge localization is reduced. Moreover, the presented method is able to detect all edges in an image in multi-scale together with its spatial orientation. Proposed wavelet as well as edge extraction method seems to be new way to edge detection for an image.
JMIR mHealth and uHealth, 2021
Heart failure (HF) is a major clinical, social, and economic problem. In view of the important ro... more Heart failure (HF) is a major clinical, social, and economic problem. In view of the important role of fluid overload in the pathogenesis of HF exacerbation, early detection of fluid retention is of key importance in preventing emergency admissions for this reason. However, tools for monitoring volume status that could be widely used in the home setting are still missing. The physical properties of human tissues allow for the use of impedance-based noninvasive methods, whose different modifications are studied in patients with HF for the assessment of body hydration. The aim of this paper is to present the current state of knowledge on the possible applications of these methods for remote (home-based) monitoring of patients with HF.
Proceedings of the 2017 Federated Conference on Computer Science and Information Systems, Sep 24, 2017
This article proposes a laser beam encoding method that is used to control an augmented reality s... more This article proposes a laser beam encoding method that is used to control an augmented reality system. Experiments were performed using a red laser emitting a wavelength of λ = 650 nm and a power of P = 3 mW. The purpose of the study was to investigate the methods of modulation and demodulation of the encoded laser signal, and to examine the influence of parameters such as laser pulse duration, camera image resolution, the number of recorded frames per second on the demodulation result of the optical signal. The results show that the proposed coding method provides the transmission of the necessary information in a single laser beam (no less than 36 codes with a decoding efficiency of 99.9%). The developed coding method enables, based on the sequence analysis of video images, the influence on the course of the simulation performed in augmented reality, including distinguishing players and actions taken by them. This is an important advancement in relation to interaction systems used to influence augmented reality.
MATEC Web of Conferences, 2018
Stochastic resonance model for medical patient condition is proposed. Approach has been generaliz... more Stochastic resonance model for medical patient condition is proposed. Approach has been generalized by means of fractional Fokker-Planck equation and subdiffusion processes. Nonadditive entropy method has been used to achieve nonlinear fractional Fokker-Planck equation. We proved that duration of an unchanged patient situation can be estimated and fulfills rules for "fat tail" probability distribution. We also proved that probability of patient staying in an unchanged condition behaves the same. Formal rules were built on concept of similarity between real patient condition and potential well model. Such approach is new and allows new results as alternative for discrete models of prediction. Obtained results get probability for patient health parameter behavior in really detailed way.
12th Conference on Integrated Optics: Sensors, Sensing Structures, and Methods, 2017
The article presents the method of encoding a laser beam for control systems. The experiments wer... more The article presents the method of encoding a laser beam for control systems. The experiments were performed using a red laser emitting source with a wavelength of λ = 650 nm and a power of P ≈ 3 mW. The aim of the study was to develop methods of modulation and demodulation of the laser beam. Results of research, in which we determined the effect of selected camera parameters, such as image resolution, number of frames per second on the result of demodulation of optical signal, is also shown in the paper. The experiments showed that the adopted coding method provides sufficient information encoded in a single laser beam (36 codes with the effectiveness of decoding at 99.9%).
MATEC Web of Conferences, 2016
The article presents the concept of building a network security model and its application in the ... more The article presents the concept of building a network security model and its application in the process of risk analysis. It indicates the possibility of a new definition of the role of the network models in the safety analysis. Special attention was paid to the development of the use of an algorithm describing the process of identifying the assets, vulnerability and threats in a given context. The aim of the article is to present how this algorithm reduced the complexity of the problem by eliminating from the base model these components that have no links with others component and as a result and it was possible to build a real network model corresponding to reality.
Acta Physica Polonica A, 1998
Measurements of the refractive index profile have been made to provide data for obtaining local o... more Measurements of the refractive index profile have been made to provide data for obtaining local optical axis arrangement in the waveguide cross-section. Liquid crystalline planar waveguide tuned with the electric field has been. used. A new approach is proposed to accomplish refractive index profile measurements n1 a direct way. The modal line method is presented as a tool that allows one to do it and to improve the attenuated total reflection disadvantages as well. The obtained results maintain applicability of the modal line method for a direct refractive index profile measurement. To verify the method, nematic 6CHBT (4-trans-4-υ-hexyl-cyclohexyl-isothiocyanatobenzene) described earlier in the literature has been examined. A nematic mixture W602 contained 6CΗBΤ as a main component has been examined too.
Advances in intelligent and soft computing, 2012
We present an interpolation algorithm for digital images based on the extended Edge-Directed Inte... more We present an interpolation algorithm for digital images based on the extended Edge-Directed Interpolation. The proposed algorithm utilises localisation and orientation of edges extracted with wavelet edge extractors. The algorithm chooses an interpolation method of a given point of an image, depending on localisation with respect to extracted edges. We apply our method to grey scale digital images. In this paper we propose also some modifications to the method. We present the results obtained with our algorithm, in comparison to a few popular interpolation algorithms and we propose a plan of further algorithm extensions.
SPIE Proceedings, 1993
ABSTRACT
SPIE Proceedings, 2000
Orientation of director field can be obtained by liquid crystalline (lc) waveguide application. T... more Orientation of director field can be obtained by liquid crystalline (lc) waveguide application. The method has been described earlier. As it is new approach verification of the results in an independent experiment is presented here. The retardation measured in tunable lc retarder has been used to do such verification. Calculations of the retardation made with director field profile measured in the lc waveguide has been compared with measurement results obtained in the lc retarder.
XIV Conference on Liquid Crystals: Chemistry, Physics, and Applications, 2002
The direct measurement of the refraction index profile in the nematic layer (NL) creates possibil... more The direct measurement of the refraction index profile in the nematic layer (NL) creates possibility to verify and exploit the non-linear solution of the Ericksen-Leslie equation (E-L). It has been done for NL of 6 CHBT tuned in wide range of external voltage. The symmetrical case of the director field distribution has been analyzed. The way for local values of the electric field estimation inside the lc layer is discussed.
Liquid Crystals: Optics and Applications, 2005
Remote controlled spatial light modulator (SLM) has been applied to design tuned &amp... more Remote controlled spatial light modulator (SLM) has been applied to design tuned "pin-hole" filter. The name "hole" means transparent area in the spatial light modulator (SLM) window. Transparent area in the SLM is remote controlled in the presented filter in accordance with the imposed "holes" distribution. As a result desired optical field diffraction has been obtained in the SLM window.
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Papers by Andrzej Walczak