Jan Jargus

Pre-processing and extraction techniques for vital signs analysis from phonocardiographic-based interferometric fiber-optic sensor

This paper deals with methods for processing signals from an optical interferometer to monitor vital signs (Respiration Rate and Heart Rate). Optical interferometer signals are contaminated by variety of technical and biological artifacts (motion artifacts, hospital/patient-generated noise, etc.). Tested optical sensors are very sensitive, it therefore crucial to reduce such unwanted signals. In this article, a complex application for processing the signals from optical interferometer based on virtual instrumentation was developed. The experiments were conducted on data sensed by optical interferometer using a National Instruments card NI USB-6216 BNC and application in the LabVIEW environment. Frequency selective filters were tested in the experiments. The results obtained by using optical interferometer were statistically compared with the ECG and PCG reference. According to the results, optical interferometers are able to measure both the Respiration and Heart Rate under the given conditions. Unfortunately, the measurement is very difficult to replicate in the hospital environment, which is the primary reason why these methods are not used in clinical practice.

Advanced methods for fiber-optic sensor signal processing

This article is focused on the advanced signal processing methods for third-generation sensors requirements. These sensors are based on the influence of a non-electric quantities on a light beam. This generation of sensors, also known as fiber optic sensors, is based on the principles of optoelectronics and integrated optics. These sensors are used in a variety of real-world applications such as biomedical engineering, industry 4.0, transportation, etc. In real-world applications, the signals sensed by these sensors are distorted by a variety of interference due to its sensitivity. We often encounter the problem that the useful information and the interference overlap in the spectral domain, therefore we cannot use conventional frequency selective filters. This article focuses on the implementation of adaptive filtering, Principle Component Analysis and Independent Component Analysis to reduce the interference in various application areas. The methods were tested on real data. This paper offers the comparison of the tested methods in different application areas.

Analysis of the attenuation characteristics of cylindrical waveguides made from the polydimethylsiloxane (PDMS) polymer

This article focuses on determining the attenuation properties and homogeneity of cylindrical waveguides made of specific polymer materials. Cylindrical waveguides were made from clear silicone rubbers based on polydimethylsiloxane (PDMS) - Sylgard 184 and RTV615. The mixture of PDMS and the curing agent was homogenized by means of an ultrasonic bath for two different frequencies (20 and 40 kHz) and for different time points (5, 10, and 20 minutes). Curing of the waveguides took place in a heat box at a constant temperature of 70 ° C ± 3 ° C. This procedure was applied to a total of 180 cylindrical waveguides with the same dimensions and diameter of the core. Attenuation dependencies were tested for two different light emitting diodes (LEDs) with central wavelengths of 470 and 625 nm. The analysis was conducted with respect to the use of PDMS in fiber-optic applications for its good mechanical and optical properties.

Fiber-optic Bragg grating sensors signal processing for vital signs monitoring

This article deals with the implementation of fiber-optic Bragg Grating Sensors signal processing methods for the detection of respiration rate, pulse rate, and body temperature. The sensed signals are influenced by a variety of interferences (motion artifact, environmental noise, etc.). Clinically relevant information is only available at certain frequencies, while the utilized optical sensor is able to cover relatively broad spectrum range. For real-world medical applications, the desired signal needs to be separated from the noise, which can often be other clinical information. This article introduces a virtual instrument for the extraction of clinically relevant information, such as respiration and heart rate, and body temperature. Frequency-selective filters were implemented in the proposed application. The functionality of the application was tested on real data using the FBGUARD and LabVIEW evaluation unit. The results were verified with commercially available devices and also statistically processed. Experimental results have shown that Fiber-Optic Bragg Grating Sensor signal processing is a key aspect of a successful incorporation of these sensors into clinical practice.

Analysis of encapsulation the fiber Bragg sensors for biomedical applications

The publication describes the use of fiber-optic Bragg sensors in biomedical applications. Fiber-optic sensors are characterized by the immunity to electromagnetic interference (EMI) and by the electrical passivity. Currently, these types of sensors are increasingly being used in biomedical applications, for example, for measuring the temperature or the heart and respiratory rate of the human body. It is very important to encapsulate these types of sensors because encapsulation itself has a major effect on the sensor functionality. This publication describes a comparison of two materials - polymer polydimethylsiloxane (PDMS) and fiberglass (fiberglass is a composite material made up of glass fiber (fabric) and cured synthetic resin). The comparison was conducted by a series of laboratory experiments with ten volunteers with their written consent. Acquired data were compared by the Bland-Altman method.

Analysis of transmission properties of optical couplers made from the polydimethylsiloxane (PDMS)

The authors focused on the problem of production and measurement parameters of optical couplers created from polymer polydimethylsiloxane (PDMS) for fiber-optic sensors. For the production of optical couplers, clear two-component elastomers Sylgard 184 and RTV 615 (manufacturer Dow Corning) was used. These elastomers offer a suitable combination of mechanical and optical properties. For the experiments, a total of 50 optical couplers were created. The effect of thermal aging on their transfer properties was analyzed. The thermal load was performed in a temperature box at 100 and 200 ° C under constant conditions for 48 hours. Measurements were made for a wavelength of 1550 nm and 1310 nm.

Sensor system based on the Mach-Zehnder interferometer for the rail transport

The article describes the use of fiber-optic interferometer in the rail transport. We proposed a measuring sensor system based on the Mach-Zehnder interferometer. The basic tracked parameter of vehicles are detection (count of vehicles). The proposed system was tested in the real tram traffic. Altogether, 435 vehicles were detected with 100 % success. The basic advantages of the solution include immunity to electromagnetic interference (EMI) and the ability to remotely evaluate information about the traffic.

Alternative fiber detector of vibrations

Optical fibers have many uses and in addition to communications applications for example in fiber-optic sensor applications. The area of pressure and vibration measurement is one of the many fields of applicability of optical fibers too. Very often, the fiber Bragg gratings (FBGs) is also used for medical applications. This paper describes our alternative approach to addressing this issue, based on standard optical fibers, special optical connections, PDMS-based products, and other materials. It is known that the vibrations of some machines can negatively affect the human body. The vibration detector created by us can find a use for indicative measurement of these negative vibrations of machines, especially in the frequency range up to about 100 Hz.

Temperature sensor with using of optical fibers

Optical fibers can be used in many ways. In addition to telecommunication applications, they are increasingly used in sensory applications as well. The temperature measurement is one of many areas of using of optical fibers. The most commonly used are DTS (Distributed Temperature Sensor) also known as Raman optical time-domain reflectometry (OTDR). The using of fiber Bragg gratings (FBGs) is one of the other options. This paper describes our approach to temperature measurement using optical fibers, heat-sensitive materials and specialty products based on polydimethylsiloxane (PDMS) and other materials. The temperature sensor created by us can also be used in an unfavorable environment (chemical influences, etc.) in the temperature range up to approx. 400 K.

Detection of magnetic field with use of optical sensors

Nowadays optical fibers are used in many industries. In addition to the data transmission, many sensor applications with using some special optical fibers are expanding. Faradays phenomenon is often used for detection of the magnetic field. The size of the deviation of the polarization plane of optical radiation passing through the optical fiber is evaluated in Faradays phenomenon that occurs due to the influence of the external magnetic field. This paper describes our new approach to addressing this issue using standard telecommunication fibers, PDMS-based optical connections, specialty products and some magnetic field sensitive materials. Our detector of the magnetic field can find a use for simplified measurement of weak magnetic fields up to 0.3 T.