Wavelet-based Image Fusion of Landsat Etm Images: a Case Study for Different Landscape Categories of Istanbul

The concept of image fusion refers to a process that integrates image data recorded at different resolutions or by different sensors to obtain more information from a single and more complete image. In this study, wavelet image fusion method was applied to merge Landsat ETM Panchromatic (P) and Multispectral (MS) imagery to produce a new image which is spectrally and spatially enhanced. Three different regions which contain the diversity of the land cover and use categories in European side of Istanbul were selected as test areas to investigate the spatial and spectral performance of wavelets. The general objective of this study is to examine the added value of multi-sensor wavelet based image fusion in terms of spatial and spectral enhancement. To evaluate spatial enhancement, different objects having different geometries were selected and a visual comparison conducted between original and fused image. To analyze the spectral improvement, some transects including different land cover types were selected. Spectral profiles of these transects were plotted for fused and MS image and a comparison was performed between them. Moreover, the correlation between MS and fused data was calculated for these transects for each band to find out the degree of spectral enhancement. All results obtained for three test sites were presented as graphics and statistics.