Wyniki wyszukiwania - BazTech

1

Automatic calibration of stereoscopic cameras in an electronic travel aid for the blind

Pełczyński P., Ostrowski B.

Metrology and Measurement Systems

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2013

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Vol. 20, nr 2

229--238

EN

The article describes a technique developed for identification of extrinsic parameters of a stereovision camera system for the purpose of image rectification without the use of reference calibration objects. The goal of the presented algorithm is the determination of the mutual position of cameras, under the assumption that they can be modeled by pinhole cameras, are separated by a fixed distance and are moving through a stationary scene. The developed method was verified experimentally on image sequences of a scene with a known structure.

2

Opracowanie miejskiej ortofotomapy satelitarnej na podstawie wysokorozdzielczego zobrazowania quickbird-2

Plichta A., Wyczałek I., Wyczałek E., Zdunek Z.

Acta Scientiarum Polonorum. Geodesia et Descriptio Terrarum

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2007

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Vol. 6, nr 1

25-37

PL

Dynamika rozwoju miast wymaga ciągłej bieżącej aktualizacji lokalnego systemu informacji przestrzennej. To z kolei skłania do poszukiwania efektywnych, niezbyt drogich źródeł danych o zachodzących zmianach. Niezawodnym źródłem informacji topograficznej są obrazy teledetekcyjne, pozyskiwane zarówno z pułapu lotniczego, jak i satelitarnego. W Poznaniu rokrocznie gromadzone są zdjęcia lotnicze, na podstawie których aktualizowane są zapisy w bazie mapy miejskiej, a co kilka lat odnawiana jest ortofotomapa. Jest to jednak przedsięwzięcie drogie i pracochłonne, na co nie stać mniejszych społeczności. W ramach prac badawczych realizowanych na Politechnice Poznańskiej, prowadzone są próby oceny możliwości wykorzystania do tego celu wysokorozdzielczych obrazów satelitarnych. Głównym zaś celem jest wykorzystanie przetworzonego do postaci ortogonalnej obrazu do detekcji zmian obiektów topograficznych zapisanych w bazie danych systemu. O jakości tych prac decyduje przede wszystkim jakość ortofotomapy, zarówno pod względem geometrycznym, jak radiometrycznym. Przedmiotem niniejszej pracy jest przedstawienie wniosków z zastosowanej procedury ortorektyfikacji obrazu QuickBird OrthoReady, obejmującej również jego wyostrzenie, generowanie DTM i kontrolę bezwzględnej dokładności wykonania ortofotomapy. Obszarem testowym jest fragment miasta o wymiarach 5×5 km.

EN

The dynamic of urban development requires continuous and instant updating of domestic spatial information system, e.g. Urban GIS. It inclines to search for effective, not too expensive data sources that show changes of various objects. Reliable sources of topographic information are remote sensing images gained from aerial as well as satellite altitude. Every year aerial photos are gathered in Poznan, which are then used to actualize dates in the city map base. Every couple of years the orthophotomap is also renewed. However, that is an expensive and labor-consuming task, stand on those smallest communities can't afford. Research works conducted in Poznan University of Technology attempt to estimate the capabilities of using very high resolution (VHR) satellite images for this purpose. The main target is usage an ortho-rectified images to detect the changes of topographic objects recorded in Urban GIS database. First of all, quality of the orthophotomap determines quality of these works, as well in geometric as radiometric respect. The aim of this work is to give the answer about usefulness of an employed procedure for the QuickBird image rectification, including pansharpening, DTM generation and assessment of an absolute accuracy of the created orthophotomap. Test area encircles 5x5 km part of a city recorded in QuickBird-2 OrthoReady Standard Imagery.

3

Practical camera calibration and image rectification in monocular road traffic applications

Rodríguez T.

Machine Graphics and Vision

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2006

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Vol. 15, No. 1

51-71

EN

In this paper we follow apractical approach to the problem of camera calibration and image formation in a typical computer vision based traffic monitoring system. Our study starts by analysing in detail the capturing scenario and the undesirable effects resulting from the application of the pin-hole camera model to traffic images. Based on the acquired experience, we present an integral method to obtain the transformation matrices required to calibrate the camera and to construct in real time a rectified and sub-sampled image where perspective effects on the road plane have been removed. The motivation for this perspective-free image is to reduce the amount of data which must be computed (while avoiding loss of relevant information), remove influences from objects external to the capturing area and simplify the operation of the subsequent detection and tracking stages. The latter statement is justified since vehicle shapes can now be approximated by rectangles, the distance between any two neighbouring points on the road plane remains constant all over the image, and parallel trajectories are restored in the rectified image.

4

Adaptive real-time segmentation in traffic scenes

Rodrigues T.

Machine Graphics and Vision

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2004

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Vol. 13, No. 1/2

39-52

EN

Segmantation is a critical elemeny in any computer vision traffic monitoring system. In this paper a segmentation approach is presented with the aim obtain accurate, compact movement masks suitable for a subsequent tracking stage. Two different segmentation methods using bachground subtraction techniques for day and night operation are presented. The methods are designed for all weather, hard real-time operation in outdoor highway multilane scenes observed by a fixed camera. The kay elements presented are: a convenient non-linear image sub-sampling and rectification technique, an adaptive background model estimation and a dynamic adaptation of segmentation parameters.