A signal processing device for the correction of signal amplitude distortion occurring in a plurality of signalling channels such as obtained from a detector array in which each detector has a different non-uniform response. Compensatory amplitude adjustment is made to each sampled signal in accordance with the statistical deviation of the signal from a preselected statistical model. A signal sampling device employs each sampled signal as a write-address for generating a statistical amplitude distribution function. Inverse distribution function means, responsive to addressing by the distribution function, provides an output signal of compensatorily modified amplitude for each signal sample.