Prof. Kalju Meigas Profile

Prof. Kalju Meigas

at Tallinn Univ of Technology

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Publications (7)

Proceedings Article | 1 July 2004 Paper

Method of optical self-mixing for pulse wave transit time in comparison with other methods and correlation with blood pressure

Kalju Meigas, Jaanus Lass, Rain Kattai, Deniss Karai, Juri Kaik

Proceedings Volume 5316, (2004) https://doi.org/10.1117/12.524273

KEYWORDS: Blood pressure, Electrocardiography, Heart, Semiconductor lasers, Signal detection, Transducers, Pulsed laser operation, Sensors, Arteries, Bismuth

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This paper is a part of research to develop convenient method for continuous monitoring of arterial blood pressure by non-invasive and non-oscillometric way. A simple optical method, using self-mixing in a diode laser, is used for detection of skin surface vibrations near the artery. These vibrations, which can reveal the pulsate propagation of blood pressure waves along the vasculature, are used for pulse wave registration. The registration of the Pulse Wave Transit Time (PWTT) is based on computing the time delay in different regions of the human body using an ECG as a reference signal. In this study, the comparison of method of optical self-mixing with other methods as photoplethysmographic (PPG) and bioimpedance (BI) for PWTT is done. Also correlation of PWTT, obtained with different methods, with arterial blood pressure is calculated. In our study, we used a group of volunteers (34 persons) who made the bicycle exercise test. The test consisted of cycling sessions of increasing workloads during which the HR changed from 60 to 180 beats per minute. In addition, a blood pressure (NIBP) was registered with standard sphygmomanometer once per minute during the test and all NIBP measurement values were synchronized to other signals to find exact time moments where the systolic blood pressure was detected (Korotkoff sounds starting point). Computer later interpolated the blood pressure signal in order to get individual value for every heart cycle. The other signals were measured continuously during all tests. At the end of every session, a recovery period was included until person's NIBP and heart rate (HR) normalized. As a result of our study it turned out that time intervals that were calculated from plethysmographic (PPG) waveforms were in the best correlation with systolic blood pressure. The diastolic pressure does not correlate with any of the parameters representing PWTT. The pulse wave signals measured by laser and piezoelectric transducer are very similar and do not have any qualitative differences. Since the detection of pulse wave by piezoelectric transducer is less complicated than laser detection, the piezo transducer should be preferred in such cases, but advantage of optical method of measurement is absent of any mechanical influence to artery.

SPIE Journal Paper | 1 January 2003 Open Access

Self-mixing in a diode laser as a method for cardiovascular diagnostics

Kalju Meigas, Hiie Hinrikus, Rain Kattai, Jaanus Lass

JBO, Vol. 8, Issue 01, (January 2003) https://doi.org/10.1117/12.10.1117/1.1528949

KEYWORDS: Semiconductor lasers, Laser resonators, Doppler effect, Optical fibers, Laser damage threshold, Signal processing, Laser optics, Blood circulation, Arteries, Electrocardiography

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Proceedings Article | 28 April 2000 Paper

Simple coherence method for blood flow detection

Kalju Meigas, Hiie Hindrikus, Rain Kattai, Jaanus Lass

Proceedings Volume 3915, (2000) https://doi.org/10.1117/12.384147

KEYWORDS: Semiconductor lasers, Doppler effect, Blood circulation, Laser resonators, Optical fibers, Mirrors, Laser damage threshold, Velocity measurements, Modulation, Laser optics

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Proceedings Article | 30 April 1999 Paper

Coherent photodetection for pulse profile registration

Kalju Meigas, Hiie Hindrikus, Rain Kattai, Jaanus Lass

Proceedings Volume 3598, (1999) https://doi.org/10.1117/12.347490

KEYWORDS: Semiconductor lasers, Doppler effect, Arteries, Optical fibers, Skin, Laser resonators, Reflectivity, Photodiodes, Electrocardiography, Laser damage threshold

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SPIE Journal Paper | 1 September 1998

Method for small particle detection by laser

Kalju Meigas

OE, Vol. 37, Issue 09, (September 1998) https://doi.org/10.1117/12.10.1117/1.602012

KEYWORDS: Particles, Mirrors, Semiconductor lasers, Laser resonators, Gas lasers, Signal detection, Modulation, Laser damage threshold, Scattering, Laser scattering

Proceedings Article | 23 November 1994 Paper

Laser doppler device for air pollution detection

Hiie Hindrikus, Kalju Meigas

Proceedings Volume 2249, (1994) https://doi.org/10.1117/12.196101

KEYWORDS: Particles, Mirrors, Semiconductor lasers, 3D vision, Laser resonators, Laser scattering, Gas lasers, Air contamination, Mie scattering, Modulation

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Proceedings Article | 23 September 1994 Paper

Laser doppler device for air pollution detection

Hiie Hindrikus, Kalju Meigas

Proceedings Volume 2271, (1994) https://doi.org/10.1117/12.188151

KEYWORDS: Particles, Mirrors, Semiconductor lasers, Laser scattering, Laser resonators, Gas lasers, Scattering, Air contamination, Mie scattering, Modulation

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