Mapping impervious surfaces from superresolution enhanced CHRIS/Proba imagery using multiple endmember unmixing

In this paper, the potential of superresolution (SR) image reconstruction methods for sub-pixel land-cover mapping in dense urban areas is studied. A multiple endmember approach (MESMA) is used for unmixing both original hyperspectral CHRIS/Proba and SR enhanced CHRIS/Proba data. Validation based on high resolution orthophotos (25 cm) shows that land-cover fraction maps generated from SR-enhanced CHRIS/Proba data (9 m) have a lower overall fractional error compared to the land-cover fractions produced from the original CHRIS data (18 m), when validating both results at the 18 m resolution. Validation of SR results at the 9 m resolution produces an overall mean absolute error (OMAE) of 16.7% compared to an OMAE of 14.3% at the 18 m resolution, with the original data, yet the impervious surface map produced at 9 m has a much higher level of detail than the original map, better representing the built-up pattern of the urban environment. Detailed analysis of impervious surface mapping results for different reference proportion intervals points at smaller average fractional errors for impervious surface fractions produced from SR-enhanced data when validation is done at the original 18 m resolution, over the entire range of proportions. Only for pixels not containing any impervious surface cover the fractional error is marginally higher than with the original data. These results demonstrate the potential of SR-enhanced data for more accurate impervious surface mapping in dense and heterogeneous urban areas.