Unsupervised Change Detection in Multitemporal SAR Images Over Large Urban Areas
2014 (English)In: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, ISSN 1939-1404, E-ISSN 2151-1535, Vol. 7, no 8, 3248-3261 p.Article in journal (Refereed) Published
Unsupervised change detection in multitemporal single-polarization synthetic aperture radar (SAR) images often involves thresholding of the image change indicator. If one class, which is usually the unchanged class, comprises a disproportionately large part of the scene, the image change indicator may have a unimodal histogram. Image thresholding of such a change indicator is a challenging task. In this paper, we present an automatic and effective approach to the thresholding of the log-ratio change indicator whose histogram may have one mode or more than one mode. A bimodality test is performed to determine whether the histogram of the log-ratio image is unimodal or not. If it has more than one mode, the generalized Kittler and Illingworth thresholding (GKIT) algorithm based on the generalized Gaussian model (GG-GKIT) is used to detect the optimal threshold values. If it is unimodal, the log-ratio image is divided into small regions and a multiscale region selection process is carried out to select regions which are a balanced mixture of unchanged and changed classes. The selected regions are combined to generate a new histogram. The optimal threshold value obtained from the new histogram is then used to separate unchanged pixels from changed pixels in the log-ratio image. Experimental results obtained on multitemporal SAR images of Toronto and Beijing demonstrate the effectiveness of the proposed approach.
Place, publisher, year, edition, pages
2014. Vol. 7, no 8, 3248-3261 p.
Change detection, synthetic aperture radar (SAR), thresholding, unimodal, urban
Remote Sensing Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-155808DOI: 10.1109/JSTARS.2014.2344017ISI: 000343055200007ScopusID: 2-s2.0-84907989988OAI: oai:DiVA.org:kth-155808DiVA: diva2:763042
FunderSwedish National Space Board
QC 201411132014-11-132014-11-132014-11-13Bibliographically approved