Wyniki wyszukiwania - Biblioteka Nauki

1

Nonlinear background estimation methods for video vehicle tracking systems

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Okarma P. , Mazurek P.

Archives of Transport System Telematics

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2011

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tom Vol. 4, iss. 4

42-48

EN

One of the major advantages of the video cameras' usage for tracking of vehicles is to reduce the costs of Intelligent Transport Systems. However, this requires the development of software techniques allowing an automatic extraction of the vehicle or group of vehicles from the current video frame, which is possible by using the background estimation methods, assuming a fixed camera installed over or at the side of the road. Background estimation based on the linear image filtering algorithms can be performed by averaging a certain number of video frames. However, this technique is relatively slow, which complicates its use, especially in variable lighting conditions. The paper presents an alternative background estimation technique, utilised for its further replacement, based on the nonlinear image filtering algorithms.

2

Automatic estimation of the brightness changes for background suppression methods used for video tracking of vehicles

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Okarma K. , Mazurek P.

Archives of Transport System Telematics

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2012

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tom Vol. 5, iss. 4

17-20

EN

One of the typical distortions in the background estimation methods is a change of lighting conditions, since each such change influences on the luminance of pixels in the captured images, which may be classified as the background. The global changes are relatively easy to compensate, but in practical applications the character of most of such changes is rather local. These changes may be caused e.g. by clouds, moving large objects, street lamps etc. Nevertheless, their influence on the results of the background estimation should be reduced therefore a local adaptive correction algorithm, applied as the pre-processing step, is proposed in the paper, assuming known geometrical configuration of the observed road

3

Superrozdzielczość ze znanego ruchu kamery do śledzenia ruchu pojazdu z wykorzystaniem algorytmu Spatio-Temporal Track-Before-Detect

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Mazurek P. , Okarma K.

Logistyka

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2012

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tom nr 3

PL

W artykule przedstawiono metodę wykorzystania algorytmu superrozdzielczości dla pojedynczej kamery rejestrującej obraz drogi. Pojazdy o rozmiarze mniejszym od jednego piksela pobudzają cały piksel, przez co estymacja ich położenia i prędkości jest utrudniona. Wykorzystanie algorytmu Spatio-Temporal Track-Before-Detect (ST-TBD) pozwala na śledzenie obiektów subpikselowych, jednak istnieją takie trajektorie, dla których estymacja subpikselowa nie jest możliwa. Zaproponowane rozwiązanie bazuje na kamerze, która jest nieznacznie przesuwana w pionie i poziomie w celu rejestracji obrazu sceny pozwalającego na osiągnięcie efektu superrozdzielczości w celu dokonania fuzji danych w przestrzeni stanu. W artykule przeanalizowano konfigurację śledzenia 1D odpowiadającego najgorszej możliwej trajektorii. Dla 40 różnych prędkości obiektu wyznaczono średni błąd położenia bezwzględnego dla systemu z algorytmem ST-TBD oraz z tym samym algorytmem wspomaganym dodatkowym filtrem. Rozwiązanie drugie bazujące na hierarchicznym śledzeniu pozwoliło na ponad dwukrotne zmniejszenie średniego błędu maksymalnego oraz uzyskanie trzykrotnie mniejszego błędu średniego.

EN

In the paper a method for application of the super-resolution algorithm for a single camera recording the road traffic is presented. Vehicles corresponding to the objects with size smaller than a single pixel stimulate the whole pixel, so the estimation of their location and velocity is troublesome. Using the Spatio-Temporal Track-Before-Detect (ST-TBD) algorithm it is possible to track the sub-pixel objects but there are some trajectories for which the sub-pixel estimation is not possible. Proposed solution is based on the slightly moving camera (horizontally and vertically) in order to record the images allowing to obtain the super-resolution effect and data fusion in the state space. In the paper the 1D tracking configuration has been analysed corresponding to the worst possible trajectory. The mean absolute error of location has been calculated for 40 different object’s velocities both for ST-TBD algorithm with and without additional filtering. The second solution based on the hierarchical tracking allows for more than double reduction of the average maximum error and three times less average error.

4

Kinovea analysis of high-speed video recording to determine kinematics of double pendulum in the long time scale

84%

Wojewoda J.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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tom Vol. 71, nr 6

art. no. e147918

EN

Measurement of position and velocity of rotating objects relies on installation of additional devices, which can significantly change their dynamic properties. Non-contact methods appear not to have the above-mentioned drawback. To determine the angular kinematics, a video measurement technique stands as a non-contact alternative. The rotational motion can be recorded with a high-speed camera and then analyzed with free and open-source tracking software which allows one to detect and digitize positions of chosen markers and then to calculate angular positions of selected elements. Differentiation process determines rotary speed values. Analysis of long-term dynamical behavior by recording data visualized as position maps which possess half of the information usually stored in the well-known Poincaré maps is proposed.