SELECTING TRAINING SAMPLES AUTOMATICALLY FROM VHR SATELLITE IMAGES FOR IMAGE CLASSIFICATION

Abstract

Classification is one of the most significant phases for remote sensing image interpretation. All the supervised classifiers need sufficient and efficient training samples, which are usually selected manually and labeled by visual inspection or field survey. Selecting training samples manually requires more time and human effort. A new method is proposed for automatic selection of training samples from a Very High Resolution (VHR) satellite image. The proposed method is tested for selecting training samples automatically for standard supervised pixel-based classification methods instead of manual samples selection. The proposed method uses a set of indices with specific thresholds to identify the training areas for each class. A certain part of each index histogram can be chosen for each class and consider as training samples. Automatic training samples are compared with manual samples for three standard classification methods. The average accuracy achieved by the proposed automatic sample selection is promising; 76.56% for maximum likelihood classifier, 74.06% for spectral correlation mapper classifier, and 70.00% for spectral angle mapper classifier. Although their accuracy scores are slightly nearby classification with manually selected samples by an average of 1.74% for maximum likelihood, 2.44% for spectral correlation mapper, and 3.75% for spectral angle mapper classifier.