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A Real-Time S-Parameter Imaging System

100%
Naik P., Cheung C., Beling C., Fung S.
Acta Physica Polonica A
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2005
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vol. 107
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issue 5
761-768
EN
Obtaining a lateral S-parameter image scan from positrons implanted into semiconductor devices can be a helpful research tool both for localizing device structures and in diagnozing defect patterns that could help interpret function. S-parameter images can be obtained by electromagnetically rastering a variable energy positron beam of small spot size across the sample. Here we describe a general hardware and software architecture of relatively low cost that has recently been developed in our laboratory which allows the whole sub-surface S-parameter image of a sample or device to be obtained in real time. This system has the advantage over more conventional sequential scanning techniques of allowing the operator to terminate data collection once the quality of the image is deemed sufficient. As an example of the usefulness of this type of imaging architecture, S-parameter images of a representative sample are presented at two different positron implantation energies.
2
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Multifunctional, Optical Sensor for Analysis of Dynamic Pupillary Light Reflex

80%
Różanowski K., Lewandowski J., Murawski K.
Acta Physica Polonica A
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2015
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vol. 127
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issue 3
723-729
EN
The aim of the publication is to describe the multifunctional optical sensor for analysis of dynamic pupillary light reflex developed by the authors which could be used as an objective indicator of human fatigue. The authors utilized knowledge gained from past experimental studies to develop a sensor, which along with custom software for detection of parameters of dynamic pupillary reflex provides a quick analysis of the human psychophysiological condition. Furthermore, the obtained parameters may also be utilized for medical purposes. The authors present the results of pilot studies prior to the development process of the sensory solution. The obtained result show that the type of light stimulation of the retina has a significant impact on the dynamic parameters of the pupillary reflex. The results played also an important role in shaping the structural assumptions of the sensor, so that it can serve as an indicator of the human fatigue level. The article includes results of experimental research conducted during the testing process of the sensor using various parameters of frequency light excitations, luminance and chrominance.
3
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Adaptive Modulation Amplitude in 2D Spectral-Spatial EPR Imaging

80%
Czechowski T., Samolej A., Baranowski M., Boś-Liedke A., Chlewicki W., Jurga J., Tadyszak K.
Acta Physica Polonica A
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2018
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vol. 133
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issue 3
710-712
EN
A study concerning the image quality in Electron Paramagnetic Resonance Imaging (EPRI) in 2D spectral-spatial (2D SSI) experiments is presented. The aim of the measurements is to improve the signal to noise ratio (SNR) of the projections by applying a more consciously selected modulation amplitude parameter. Data is gathered by applying three constant and one adaptive modulation amplitude. The three fixed modulation amplitudes values are leading to undermodulated (0.01 G), partially overmodulated (0.15 G) and fully overmodulated (0.65 G) projections. The study demonstrates the advantages of the adaptive method, which involves selecting different and dependent on cosine function modulation amplitudes for each projection. The study is performed on a phantom containing four tubes of LiPc and TCNQ, characterized by a different peak to peak linewidth and spin concentration.
4
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Optical Sensor to Monitor Pupillary Light Reflex

80%
Różanowski K., Murawski K.
Acta Physica Polonica A
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2013
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vol. 124
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issue 3
558-562
EN
The aim of the paper is to describe design of an optical sensor intended to analyze pupillary light reflex. It also presents the results of physiological adaptation mechanisms in human eye, i.e. response of the iris to changes in the intensity of light that falls on the retina of the eye under conditions of sensory deprivation. Pupillary light reflex is a closed loop nerve reflex. It controls the amount of light that reaches the retina. Based on the test results, an optical sensor was designed, fabricated and correctly calibrated. In comparative tests with the use of F^2D Fit-For-Duty, a commercial system by AMTech, selected pupillographic parameters were primarily evaluated (baseline pupil diameter, oscillations, reflex latency, maximum reaction time, pupil constriction time, pupil dilation time, and constriction amplitude) under conditions of diminished alertness, reduced ability to concentrate, increasing fatigue, and drowsiness. The solution comes as part of a mobile pupillography device intended to be assembled in cars and airplanes to identify conditions of lower alertness, reduced ability to concentrate, increasing fatigue and drowsiness in drivers, pilots and traffic controllers, and to trigger alarm and preventive measures, if necessary.
5
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A Comparative Analysis of Associative Properties of Fourier versus Walsh Digital Holograms

80%
Derzhypolskyy A., Melenevskyy D., Gnatovskyy A.
Acta Physica Polonica A
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2007
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vol. 112
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issue 5
1101-1106
EN
A digital implementation of the Fourier holography scheme with identical reference and signal beams is considered. Investigations of the properties of this scheme were reported on in a number of papers. At the same time a concept of virtual optics is widely used in data encryption and data processing, whereas digital implementation of the Fourier holography scheme may be provided using not only discrete Fourier transform. Another discrete digital transform may be used as soon as it has several properties similar to the Fourier transform. The Walsh transform is the subject to consider in this work. A comparison of digital Fourier and Walsh versions of the named holographic scheme is conducted by means of their associative properties. Considered is the retrieving of information stored in the hologram using parts of different amounts of the original data. Comparison is provided with the two types of data stored: a raster image representing visual information and an image representing a set of data bits. Comparable parameters are the mean image contrast for visual data image and the bit detection accuracy for a set of data bits.
6
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Recent Advances in Acousto-Optic Instrumentation for Astronomy

80%
Yushkov K., Anikin S., Chizhikov S., Esipov V., Kolesnikov A., Makarov O., Molchanov V., Potanin S., Tatarnikov A.
Acta Physica Polonica A
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2015
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vol. 127
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issue 1
81-83
EN
We report recent progress and new developments of acousto-optic imaging spectrometers and spectropolarimeters for astronomical observations. Prototype performance of hyperspectral visible-to-near-UV and visible-to-near-IR imaging systems is demonstrated. Wide-angle acousto-optic paratellurite monochromators were designed and fabricated. The problem of artifacts in spectral images of celestial objects is studied.
7
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Biomedical Optical Applications of Liquid Crystal Devices

80%
Abdulhalim I., Moses R., Sharon R.
Acta Physica Polonica A
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2007
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vol. 112
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issue 5
715-722
EN
Liquid crystals exhibit large electro-optic effects which make them useful for a variety of applications as fast, compact, and tunable spectral filters, phase modulators, polarization controllers, and optical shutters. They were largely developed for liquid crystal displays and in the last decade for optical telecommunications, however their application in the field of optical imaging just started to emerge. These devices can be miniaturized thus have a great potential useful in miniature optical imaging systems for biomedical applications. Using a collection of tunable phase retarders one can perform: 1. Stokes parameters imaging for skin and eye polarimetric imaging; 2. Tunable filtering to be used for hyperspectral imaging, fluorescence microscopy, and frequency domain optical coherence tomography; 3. Adaptive optical imaging and eye aberrations correction; 4. Phase shift interferometric imaging; 5. Variable frequency structured illumination microscopy. Basic optics of liquid crystals devices is reviewed and some novel designs are presented in more detail when combined to imaging systems for a number of applications in biomedical imaging and sensing.
8
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An Infrared Sensor for Eye Tracking in a Harsh Car Environment

80%
Różanowski K., Murawski K.
Acta Physica Polonica A
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2012
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vol. 122
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issue 5
874-879
EN
The paper presents the optical sensor which is built for EyeTracker operating in car harsh environment. The sensor is based on USB high speed video infrared camera. Additional hardware was designed for control and emission of infrared light as well. The designed hardware and software of the sensor are described in the paper. Some results of work, including video processing, are also presented.
9
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Pattern Recognition Algorithm for Eye Tracker Sensor Video Data Analysis

80%
Murawski K., Różanowski K.
Acta Physica Polonica A
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2013
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vol. 124
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issue 3
509-512
EN
The aim of the paper is to discuss research conducted at the Military University of Technology as well as the Military Institute of Aviation Medicine. The essence of the research is to develop a pattern recognition algorithm for the analysis of data received from an eye tracker sensor. Data analysis can be done using computer vision algorithms. In the article the state of the art pattern recognition algorithms were presented. Particular attention was paid to the possibilities and limitations of their use. The main part of the paper is the presentation of the author's pattern recognition algorithm. In the paper we have also shown the results obtained by other techniques of image processing, which are frequently used to determine the position of the pupil of the eye on the image.
10
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An Infrared Sensor for Monitoring Meibomian Gland Dysfunction

80%
Murawski K., Różycki R., Murawski P., Matyja A., Rękas M.
Acta Physica Polonica A
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2013
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vol. 124
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issue 3
517-520
EN
Meibomian gland dysfunction is one of the most common eye disorders observed in clinical practice. It applies to almost 50% of the population, especially people using contact lenses. It is believed that meibomian gland dysfunction is the most common cause of abnormal stability and integrity of the tear film. Despite this, there is no commercially available equipment for the diagnosis. The article proposes the construction of an optical sensor and a computer system for the rapid, non-invasive diagnosis of meibomian gland dysfunction. The designed hardware and software as well as preliminary results of clinical research are also described.
11
Content available remote

Nanometer-Scale Incoherent Imaging Using Laser-Plasma EUV Source

70%
Wachulak P., Bartnik A., Fiedorowicz H., Kostecki J.
Acta Physica Polonica A
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2012
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vol. 121
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issue 2
450-453
EN
Various imaging methods and techniques capable of reaching a nanometer spatial resolution are currently under development. One of them is an extreme ultraviolet microscopy, based on the Fresnel zone plates. In this paper a compact, high-repetition, laser-plasma EUV source, with a gas puff target, capable of emitting quasi-monochromatic radiation at 13.8 nm wavelength was used in the first demonstration of a desk-top EUV transmission microscopy with a spatial (half-pitch) resolution of 50 nm. EUV microscopy images of objects with various thicknesses and the spatial resolution measurements using the knife-edge test are presented.
12
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Influence of Refractive Indices Dispersion on Parameters of Imaging AOTFs Operating with Non-Polarized Light

61%
Yukhnevich T., Voloshinov V., Pritulenko I.
Acta Physica Polonica A
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2015
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vol. 127
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issue 1
78-80
EN
The paper presents results on investigation of paratellurite based imaging tunable acousto-optic filters operating with arbitrary polarized light. We analyzed influence of dispersion of refractive indices in the crystal on a simultaneous satisfaction of the Bragg matching condition for ordinary and extraordinary polarized optical beams. The analysis was carried out at different optical wavelengths over the wide tuning range of the filters 400-1150 nm. Theoretical and experimental analysis of the problem proves that in a paratellurite tunable acousto-optic filter, the Bragg matching angle common for the two optical polarizations is varying in the limits up to 0.3°. This variation of the incidence angle may be as wide as a quarter of the filter angular aperture thus proving that the examined phenomenon should be considered in design of the imaging tunable acousto-optic filters.
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