Spatial resolution enhancement of ALOS data for geological mapping
Konstantinos Nikolakopoulos(1) and Panagiotis Tsombos(1)
(1) Institute of Geology & Mineral Exploration (IGME), 20, Chrysoupoleos str., 15127 Melissia, Athens, Greece
The Institute of Geological and Mineral Exploration of Greece (I.G.M.E), in the framework of CSF 2000 – 2006 (Community Support Framework 2000-2006, Operational Program Competitiveness, Priority axis 7: Energy and Sustainable Development, Measure 7.3: Exploitation of natural recourses and support in meeting environmental commitments, Action 7.3.1) has been implementing the project called “Collection, Codification and documentation of geothematic information for urban and suburban areas in Greece - pilot applications”. The sixth sub-project has to do with the updating of fifty geological map sheets using GIS and Remote Sensing techniques. The 1/50.000 geological map sheet of Antiparos Island is included in the updating project. Thus, the service is investigating the potentiality of using ALOS satellite data for geological mapping, as the satellite collects both panchromatic data with 2.5m spatial resolution and multispectral data with 10m spatial resolution. In order to take advantage of the spatial resolution of the panchromatic data and the spectral resolution of the multispectral data we tried different fusion methods.
Ideally, the methods used to fuse image data sets should preserve the spectral characteristics of the original multispectral input image. This paper is an attempt to fuse high-resolution panchromatic and low-resolution multispectral bands of the ALOS sensor. ALOS collects four multispectral bands with 10m resolution and a panchromatic band with 4 times better resolution (2.5m).
In this study we compare the efficiency of seven fusion techniques and more especially the efficiency of Ehlers, Modified IHS, PCA, Pansharp, Wavelet and LMM (Local Mean Matching) LMVM (Local Mean and Variance Matching) fusion techniques for the fusion of ALOS data.
In order to quantitatively measure the quality of the fused images we have made the following controls: Firstly, we have examined the optical qualitative result. Then, we examined the correlation between the original multispectral and the fused images and all the statistical parameters of the histograms of the various frequency bands. Band ratio of the fused and the original multispectral data are compared. The results are presented in this study.