1. A method of hyperspectral image dimension reduction, comprising: receiving a hyperspectral image having a plurality of pixels; iteratively establishing a basis vector (BV) set comprising an initial basis vector and individual spectral vectors from the plurality of pixels that have a residual magnitude over a threshold value when a spectral vector of a current iteration is unmixed by unconstrained unmixing with a prior iteration of the BV set, wherein the initial basis vector is a spectral vector of a pixel selected from the plurality of pixels, and wherein the basis vector set comprises at least one non-endmember; for each of the plurality of pixels: reading a spectral vector from the pixel; and decomposing, by unconstrained unmixing, the spectral vector with the established BV set including the at least one non-endmember to provide a reduced dimension vector for the pixel; and providing a dimension reduced image comprising the reduced dimension vectors for each pixel.