1. A system for acquiring spectral characteristics of a scene under a first scene illumination, wherein light received from the scene has a spectral power distribution (SPD) response characteristic of the scene, the system comprising: an imaging device configured to detect a finite number (N) of spectral components of light received from the scene, the imaging device having characteristic spectral response functions R n (λ), n=1,. .. N, for detecting such spectral components and wherein: the image device comprises one or more imaging pixels, each configured to detect at least one of a finite number M of spectral components corresponding to M primary components of a color gamut of the imaging device; and an imaging pixel is configured to detect one of three spectral components corresponding to subtractive cyan, magenta, and yellow primary color components of a color gamut of the imaging device; a supplemental illumination device operable to provide a second scene illumination with light having a known spectral distribution; and processing circuitry coupled to the imaging device and responsive at least to: the detected spectral components of light received from the scene under the first and second scene illuminations; the characteristic spectral response functions of the imaging device; and the known spectral distribution of the light provided by the supplemental illumination device, to produce a signal indicative of the SPD response characteristic of the scene.