Evaluation of subpixel unmixing algorithms in mapping the porphyry copper alterations using EO-1 Hyperion data, a case study from SE Iran

An EO‐1 Hyperion scene was used to assess various subpixel unmixing algorithms in a study area at the central Iranian volcano-sedimentary complex, where abundant porphyry copper deposits like Sarcheshmeh, Darrehzar, and Sereidun as well as numerous occurrences of copper exist. Different subpixel unmixing algorithms such as matched filtering (MF), constrain energy minimization (CEM) and mixture tune matched filtering (MTMF) were applied to map the sericite occurrences within alteration systems associated with porphyry deposits. The output results were evaluated by semi-quantitative XRD analysis of corresponding field samples and their accuracies were assessed using R2 coefficients and deviation errors. Generally, MF results provided a moderate consistency with the corresponding XRD abundances following a positive relation. The CEM algorithm provided weak results for Hyperion data. MTMF had the best performance and this is definitely because of segregating power in the mixture tuning, which can distinguish high infeasible samples with unreliable fractions of target mineral.