Spectral image processing method, the spectral image processing program, and spectral imaging system

The present invention provides a spectral image processing method of performing robust unmixing on measurement noise and a spectral image processing program. The spectral image processing method of the present invention is a spectral image processing method of, based on an observed spectral image acquired from a specimen and emission spectral data of each of plural materials contained in the specimen, unmixing a contribution of each of the plural materials to the observed spectral image (S4), including an evaluating step of, based on a predicted spectral image of the observed spectral image, evaluating reliability of each component of the observed spectral image (S1, S2), and a reflecting step of reflecting a result of the evaluation in a content of the unmixing.