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Satellite image classification. SSIP 08, Vienna. Tamas Blaskovics University of Szeged Michael Glatz Vienna University of Technology Korfiatis Panagiotis University of Patras, José Ramos Porto University. Task.
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Satellite image classification SSIP 08, Vienna Tamas Blaskovics University of Szeged Michael Glatz Vienna University of Technology Korfiatis Panagiotis University of Patras, José Ramos Porto University
Task Satellite Image Classification: • Input: Landsat images of terrain, plus sample images of fields/ sea, forest etc • Aim: segmentation of scene based on texture (and color) • Additional goal: intenfication of key features such as cave openings etc • Output: labeled scene
Satellite image classification Input Image MRF Semi- Supervised Segmentation MRF Unsupervised Segmentation k-means Unsupervised Segmentation or or Output Image or Area classification ( User Interaction) Area classification ( Automated)
Dataset 20 images aquired with the IKONOS Satellite. (http://www.satimagingcorp.com/satellite-sensors/ikonos.html)
Method 1/2 Step 1: Image Segmentation • The RGB image was converted to L*u*v color space • Two unsupervised methods were used: • MRF segmentation ( Kato et al. ) • EM step • ICM • K-means • Parameters: • User defined: # of regions, β, temperature.
Method 2/2 Step 2: Class Characterization • User defined • User chooses the desired region for classification • The first order statistics (mean, variance, skewness, kurtosis, range) are calculated for a ROI around the selected image • Automated • Skeletonization technique was applied for each segmented region • A sliding ROI (21 x 21) was used to extract first order statistics • K-nearest neighbor classifier was used (NN) • Segmented area is also calculated
Features evaluated Segmentation Stage: • Intensity value channel U • Intensity value channel V Classification Stage: • Mean value • Standard deviation • Kurtosis • Skewness • Range
Comments • Visual evaluation seems to present good results • No serious evaluation was conducted • Segmentation process is slow • Dataset is too small to construct robust learning process
Future developments • Segmentation process Evaluation of more complex techniques • Classification process Bigger training database Other texture features Different classifiers • Evaluation Use of ground truth and shape differentiation metrics