Automatic Change Detection in Multitemporal SAR Orthoimages
ISBN 978-85-88783-11-9
Authors
1Rosa, R.; 2Fernandes, D.; 3Nogueira Júnior, J.
1BRADAR Email: rafael.rosa@bradar.com.br
2INSTITUTO TECNOLÓGICO DE AERONÁUTICA - ITA Email: david@ita.br
3SANTO ANTÔNIO ENERGIA Email: joaobosco@santoantonioenergia.com.br
Abstract
Forest monitoring is a major concern today due to climate changes, conservation of fauna and flora and to the lack of water. Therefore, several environmental monitoring techniques have been developed and used to detect changes in the scenes. However, the main techniques have limitations related to weather conditions and does not have the expected effect. The use of SAR (Synthetic Aperture Radar) seems appropriate to detect changes due to its independence of atmospheric and lighting conditions. The SAR change detection is a process that uses SAR images acquired in the same geometric conditions but in different moment (multitemporal) to identify changes in the surface that occurred between two acquisitions. This paper presents a new method of change detection in multitemporal SAR orthoimages using the difference between them. The novelty of this method is the detection threshold definition: it is usually an orthoimages difference function, but in this method it is calculated using only one of the orthoimages. In addition, another novelty is the combined use of already known techniques: the speckle filtering, the normalization and the morph close operation. Experimental tests were conducted using real SAR data obtained by the airborne sensor OrbiSAR-2 from Bradar in the Amazon Forest and the results showed a higher accuracy than those found in the literature.
Keywords
change detection; multitemporal images; synthetic aperture radar (SAR)