1. A detector device comprising an x-ray detector structure having a detection surface defining a plurality of separately addressable regions disposed in an area array for detecting incident x-ray radiation intensity thereon, wherein the separately addressable region is divided into a plurality of sub-regions provided spaced across the detection surface of the separately addressable region, each sub-region provided with a filter layer on the detection surface, the filter layers of each sub-region of a given separately addressable region comprising discrete and different materials with discrete defined and spectroscopically spaced x-ray absorption edges, whereby each separately addressable region is divided into at least three sub-regions, wherein each region includes a filter layer selected with reference to a target material with a particular characteristic edge of interest such as to comprise a filter layer having a characteristic absorption edge below the edge of interest, a filter layer having a characteristic absorption edge above the edge of interest, and a filter layer having an absorption edge with the edge of interest, and wherein the detector structure is itself adapted to resolve incident radiation spectroscopically simultaneously across at least three energy bands within the spectrum of a source.