Fractal signatures for multiscale processing of hyperspectral image data

A multiscale approach to hyperspectral image data analysis using fractal signatures was proposed and implemented in the Interactive Data Language (IDL). For 2-D hyperspectral curves, fractal signature measures the changes in curve length with changing scale. Using NASA’s Earth Observing-1 (EO-1) Hyperion image from a study area near Denton, Texas, USA, the capabilities of fractal signatures in discriminating different land cover types were presented in three different ways: (1) fractal signature curves, (2) distances between fractal signatures, and (3) fractal signature images. The asymmetry in length measurement was found to be effective in handling hyperspectral curves obtained from Hyperion radiance data. The contribution of fractal signature images was shown through comparison of image classification results. The results from the Hyperion radiance data suggest that fractal signatures at certain scales can reveal important differences in land cover types.     

Sub-pixel mineral mapping of a porphyry copper belt using EO-1 Hyperion data

The main aim of the present study was to examine the feasibility of the EO-1 Hyperion data in discriminating and mapping diagnostic alteration minerals around porphyry copper deposits (PCDs), verified by field surveys and laboratory analyses. A partial sub-pixel method, mixture tuned matched filtering (MTMF), was implemented on a pre-processed and calibrated Hyperion dataset. The tested area is situated at the Central Iranian Volcano-Sedimentary Complex, where abundant porphyry copper deposits like Sarcheshmeh, Darrehzar, and Sereidun are located. The characteristic alteration minerals identified by Hyperion data included biotite, muscovite, illite, kaolinite, goethite, hematite, jarosite, pyrophyllite, and chlorite. Discrimination of these minerals especially biotite and iron oxide (hematite and goethite) can provide valuable evidences for PCD exploration projects. Results revealed that Hyperion data prove to be powerful in discriminating and mapping various types of alteration zones while the data were subjected to adequate pre-processing.