Image fusion for improving spatial resolution of multispectral satellite images

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Jeoloji Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2013

Öğrenci: DENİZ ÜNLÜSOY

Danışman: MEHMET LÜTFİ SÜZEN

Özet:

In this study, four different image fusion techniques have been applied to high spectral and low spatial resolution satellite images with high spatial and low spectral resolution images to obtain fused images with increased spatial resolution, while preserving spectral information as much as possible. These techniques are intensity-hue-saturation (IHS) transform, principle component analysis (PCA), Brovey transform (BT), and Wavelet transform (WT) image fusion. Images used in the study belong to Çankırı region, and are obtained from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite. MATLAB is used to build a GUI to apply and to present the results of the image fusion algorithms. Subjective (visual) and objective evaluation of the fused images have been performed to evaluate the success of the approaches. The objective evaluation methods include correlation coefficient (CC), root mean squared error (RMSE), relative global dimensional synthesis error (ERGAS), and high-pass correlation coefficient (HPCC). For visual evaluation, sulphate index (SI) and mafic index (MI) specific to thermal infrared (TIR) and hydroxyl index “a” (OHIa) specific to shortwave infrared (SWIR) bands are used. The results indicate that the IHS transformation provides the highest performance in increasing lower spatial resolutions of TIR and SWIR bands of the ASTER images to higher spatial resolution of visible near infrared (VNIR) bands, at the expense of some loss of spectral information. PCA and BT methods, on the other hand, perform better with respect to preservation of spectral information, while being less successful in increasing spatial resolution. WT performs next to IHS transformation for improving spatial resolution and comes after PCA and BT methods with respect to the preservation of spectral information.