Wyniki wyszukiwania - BazTech

1

Usuwanie tła w wideo nagraniach pochodzących z monitorowania basenu pływackiego

Reiter K., Kowalczuk Z.

Pomiary Automatyka Robotyka

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2018

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R. 22, nr 3

15--22

PL

Automatyczna obróbka obrazu w czasie rzeczywistym jest kluczowa dla wielu rozwiązań monitoringu wykorzystywanych m.in. w celach bezpieczeństwa. Często jednym z ważniejszych etapów obróbki jest oddzielenie tła od obiektów na pierwszym planie, tak aby wykluczyć wszystkie nieistotne informacje z obrazu. Celem pracy jest podsumowanie doświadczenia zdobytego podczas śledzenia pływaków oraz pokazanie możliwości skutecznego automatycznego nadzoru wideo osób korzystających z basenu. Porównano skuteczność działania dwóch wybranych algorytmów (MOG i KNN) przy użyciu różnych odwzorowań kolorów oraz omówiono zalety i wady analizowanych metod.

EN

Automatic real-time image processing is crucial for many (video surveillance) monitoring solutions used, among others for security purposes. Often one of the most important stages of computer vision processing is separating the background from the objects in the foreground, so as to exclude all irrelevant information from the image. The aim of this work is to summarize the experience gained while tracking swimmers and to show the possibility of effective automatic video surveillance of people using a swimming pool. The effectiveness of two selected algorithms (MOG and KNN) is compared using different color mappings and the advantages and disadvantages of the analyzed methods are discussed.

2

Noninvasive monitoring with strongly absorbed light

McEwen M P, Reynoldsk J

Optica Applicata

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2014

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Vol. 44, nr 2

177--190

EN

The transmission of light through tissue is used in noninvasive monitoring, in particular photoplethysmography. Investigations involving the transmission of wavelengths absorbed by bilirubin (short wavelength visible light) have been limited, due to strong absorption by haemoglobin. Achieving transmission of these wavelengths through tissue may advance noninvasive monitoring of substances like bilirubin. This work investigates the use of high power light sources together with improvements in signal-to-noise ratio as a means of enabling the transmission of strongly absorbed light through tissue. A custom device using multiple high-power short-wavelength visible light sources together with low power red and infrared sources, and background light cancellation – to improve signal-to-noise ratio, was constructed. Transmission of 454–1200 nm light through tissue was achieved, with pulsations present in measured signals. The transmission through tissue of multiple wavelengths of strongly absorbed light can be achieved by using high power light sources in conjunction with cancelling the effect of background light. Use of these techniques may allow investigations into the noninvasive monitoring of substances such as bilirubin using photoplethysmography.

3

Ultra-low-voltage LNA with high gain and low noise figure

Bastos I., Oliveira L. B., Oliveira J. P., Goes J., Silva M. M.

International Journal of Microelectronics and Computer Science

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2013

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Vol. 4, nr 3

124--128

EN

We present a balun LNA with noise and distortion cancellation using double feedforward. A common-gate and a common-source stage are combined, and their resistive loads are replaced by transistors biased close to saturation to allows low supply voltage, without gain degradation. The proposed feedforward boosts the LNA gain and reduces the noise ﬁgure (NF). Simulation results with a 130 nm CMOS technology show that the gain is up to 24 dB and the NF is below 3.2 dB. The total power dissipation is 2.25 mW, leading to an FoM of 6.4 mW-1 with 0.6 V supply.

4

A Spectral Subtraction Based Algorithm for Real-time Noise Cancellation with Application to Gunshot Acoustics

Ramos A. L. L., Holm S., Gudvangen S., Otterlei R.

International Journal of Electronics and Telecommunications

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2013

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Vol. 59, No. 1

93-98

EN

This paper introduces an improved spectral subtraction based algorithm for real-time noise cancellation, applied to gunshot acoustical signals. The derivation is based on the fact that, in practice, relatively long periods without gunshot signals occur and the background noise can be modeled as being short-time stationary and uncorrelated to the impulsive gunshot signals. Moreover, gunshot signals, in general, have a spiky autocorrelation while typical vehicle noise, or related, is periodic and exhibits a wider autocorrelation. The Spectral Suppression algorithm is applied using the pre-filtering approach, as opposed to post-filtering which requires a priori knowledge of the direction of arrival of the signals of interest, namely, the Muzzle blast and the Shockwave. The results presented in this work are based on a dataset generated by combining signals from real gunshots and real vehicle noise.

5

Adaptacyjne tłumienie zakłóceń z wykorzystaniem funkcji bazy ortonormalnej

Stanisławski R., Marciak C., Latawiec K., Hunek W.

Zeszyty Naukowe. Elektryka / Politechnika Opolska

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2004

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Vol. 297, z. 54

133-147

PL

Artykuł przedstawia nowe zastosowania funkcji bazy ortonormalnej (ang. orhonormal basis functions - OBF) w zadaniu adaptacyjnego tłumienia szumów. Krótko podano zasady modelowania liniowych systemów dynamicznych z wykorzystaniem OBF. Została również przedstawiona koncepcja modelowania odwrotnego OBF (wprowadzona przez autorów). Poddano analizie porównawczej metody adaptacyjnego tłumienia szumów za pomocą filtrów Laguerre'a, Kautza, odwrotnego filtra Laguerre'a oraz FIR. Przeprowadzono szereg eksperymentów identyfikacyjnych demonstrujących właściwości adaptacyjnego tłumienia zakłóceń. Pokazano, że jakość tłumienia zakłóceń zależy od 1) rodzaju dynamiki modelowanych filtrów, 2) specyfiki użytego modelu filtra oraz 3) stosunku poziomu szumu wejściowego do wyjściowego.

EN

The paper presents a new application of Laguerre filters and inverse Laguerre filters in adaptive noise cancellation. An orthonormal basis function approach to modeling of linear dynamical systems is outlined. The inverse OBF modeling concept (introduced by the authors) is also recalled. Laguerre, Kautz, inverse Laguerre and FIR filters are comparatively applied in the problem of adaptive noise cancellation. In a series of simulation experiments it is demonstrated that the performance of the noise cancellation system for the above filter models is dependent on 1) a type of dynamics of the filter involved, 2) a specific filter model used and 3) a ratio of input-to-output noise. Laguerre and Kautz models are particularly recommended in the task of adaptive noise cancellation.