JIP_V1_N2_RP3 G. Hemanth Kumar V. Meenakshi T. Milindapurna Journal on Image Processing 2349-6827 1 2 15 21 Change Detection, Difference Image, Active Contours, Environmental Monitoring, Level Sets, Multi-temporal Images, Optical Images, Un-decimated Discrete Wavelet Transform (UDWT) In this paper, an unsupervised change detection method is proposed for satellite images and optical images. The multitemporal data and two discriminate areas of the land covers are changed between different time instances due to its robustness in opposition to noise. The UDWT is exploited to obtain a multi-resolution representation of the difference image which are taken from two satellite images acquired from the same geographical area but at different time instances. For multi-resolution representation of the difference image, a region-based active contour model is applied, then it is segmented into unchanged and changed regions. The proposed change detection method has been conducted based on the optical images. The extensive model results show that, the proposed change detection method constantly gives a better performance. April - June 2014 Copyright © 2014 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=2826