Wyniki wyszukiwania - BazTech

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Monitoring of Water Bodies and Non-vegetated Areas in Selenica ‑ Albania with Sar and Optical Images

Belba Pietro, Kucaj Spartak, Thanas Jorgaq

Geomatics and Environmental Engineering

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2022

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Vol. 16, no. 3

5--25

EN

The availability of Sentinel satellites for providing open data with optical and SAR imagery leads to better opportunities related to Earth surface mapping and monitoring. Recently, optical fusion with radar data has shown improvement in classification quality and the accuracy of information acquired. In this setting, the main objective of this research is to monitor the environmental impact of an open-pit mine on water, vegetation, and non-vegetation areas by exploring the single and combined use of Sentinel-1 and Sentinel-2 data. The data utilized in this paper were collected from the European Space Agency Copernicus program. After selecting the Selenica region, we explored the products in the Sentinel Application Platform. According to our data, Sentinel-2 misses the small water ponds but successfully identifies the river and open-pit areas. It mistakenly identifies urban structures and cloud areas as non-vegetated and does not identify non-vegetated areas which correspond to mining operation areas. Sentinel-1 identifies very small water ponds and delivers additional information in the cloudy areas, but misses a part of the river. Alongside the strong contribution in identifying the vegetation, it also roughly identifies the non-vegetation areas of mining operations.

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A new approach to the histogram-based segmentation of synthetic aperture radar images

Siemiatkowska Barbara, Gromada Krzysztof

Journal of Automation Mobile Robotics and Intelligent Systems

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2021

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Vol. 15, No. 1

39--42

EN

Radar machine vision is an emerging research field in the mobile robotics. Because Synthetic Aperture Radars (SAR) are robust against weather and light condition, they pro‐ vide more useful and reliable information than optical images. On the other hand, the data processing is more complicated and less researched than visible light images processing. The main goal of our research is to build sim‐ ple and efficient method of SAR image analysis. In this ar‐ ticle we describe our research related to SAR image seg‐ mentation and attempts to detect elements such as the buildings, roads and forest areas. Tests were carried out for the images made available by Leonardo Airborne & Space System Company.

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Zastosowanie metod CLEAN do poprawy jakości obrazów SAR

Kulpa K., Smolarczyk M.

Prace Przemysłowego Instytutu Telekomunikacji

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2008

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Vol.58, z.141/142

54-69

PL

Obrazy SAR otrzymywane są w wyniku dwuwymiarowego przetwarzania obrazu SAR (kompresji odległościowej i azymutalnej). Efektem ubocznym dwuwymiarowej kompresji sygnału jest powstanie azymutalnych i odległościowych listków bocznych, co powoduje, że każdemu silnemu obiektowi w obrazie SAR towarzyszą charakterystyczne listki boczne widoczne na obrazie w postaci krzyża. Występujące listki boczne powodują, że słabo odbijające obiekty, znajdujące się w otoczeniu silnie odbijających punktów, maskowane są przez ich listki boczne. W artykule przedstawione zostaną metody usuwania silnych ech z sygnału radarowego z wykorzystaniem metod modelowania sygnałów pochodzących od obiektów silnie odbijających oraz ich adaptacyjnego odejmowania, znanych w literaturze pod nazwą CLEAN, pozwalające na poprawę jakości otrzymanego zobrazowania ziemi.

EN

SAR imaging process is a method of ground mapping alternative to different optical systems and allows to obtain SAR maps of Earth independently to time (day and night) and weather conditions. Additionally maximum range of radar sensors is much longer than any optical. Final SAR image is a result of two-dimensional, in-range and in-azimuth, compression process. A strong scatterer produces sidelobes in range and cross-range dimension forming characteristic cross-shaped pattern centred on dominant scatterer. The presence of these sidelobes decrease the overall image quality and can mask weak scatterers close to the strong one. The paper presents method of adaptive removal of modeled strong scatterer echoes from raw radar data denoted as CLEAN algorithm. Applied CLEAN algorithms results in higher image dynamic range (10 ÷ 30 dB), visibility of weakly scatterers and finally SAR image enhancement.

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Metoda przetwarzania mikrofalowych zdjęć satelitarnych terenów o urozmaiconej rzeźbie z wykorzystaniem numerycznego modelu terenu

Stankiewicz K.

Prace Instytutu Geodezji i Kartografii

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1998

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T. 45, z. 97

7--80

PL

W pracy przedstawiono metodę usuwania zniekształceń geometrycznych i radiometrycznych występujących w obrazach mikrofalowych SAR odnoszących się do obszarów o urozmaiconej rzeźbie. Podstawowym źródłem informacji wykorzystywanym w tym procesie jest numeryczny model terenu. Zastosowanie korekcji geometrycznej i radiometrycznej do obrazów mikrofalowych Gór Izerskich umożliwiło przeprowadzenie ich klasyfikacji tematycznej.

EN

The method of removing geometrie and radiometrie distortions, which appear in SAR microwave images covering terrain with varied relief, was presented in the article. Those basie rules of capturing and creating microwave images were discussed, which have direct impact on interpretation of images covering terrain with varied relief. In order to analyse SAR images correctly, data about shape and location of surface, which scatters radar signal, are needed. These data can be derived from the digital terrain model. Problem of transformation of digital terrain model to the global reference system, in which all calculations needed for image georeferencing are performed, was described in the article. In order to determine geometrical relations between satellite and scanned fragments of EaruYs surface, data on location and speed of satellite during scanning are also needed. The method of approximation of satellite movement on the orbit and algorithm for determining proper spatial relations were presented. Radiometrie correction has been widely discussed, as new method of determining correction coefficient had to be proposed. The method , which enables to generate additional information layers, useful for interpretation of radar images, was also described. Use of the method results in generating data conceming angle of incidence of radar beam onto Earth's surface and in pointing those parts of images, which cannot be properly corrected and hence they are not suitable for thematic interpretation. The prepared method was tested using images of Izerskie Mountains. i Thematic classification of these images was done after making the necessary corrections; it confirms possibility of.