A method for correcting an artifact in a measurement caused by a pixel in a focal plane array randomly changing offset level, the method comprising: in an image processor: given a residual cube derived from a hyperspectral image data cube of measurements of different wavebands generated by a focal plane array sampled at different times, the residual cube is generated by approximating the spectra of each spatial pixel in the HSI data cube, as a linear combination of basis vectors having coefficients to best approximate the HSI data cube and storing the residual errors in this approximation in the residual data cube; determining a suspicious pixel suspected of causing an artifact in a measurement as a function of a statistical analysis of a collection of samples representing residual error values associated with a subject focal plane pixel measuring one waveband at different times; based on the determination of the suspicious pixel, identifying a pattern of residual error values for a span of time in which transitions among the collection of samples are identified, the pattern being indicative of the artifact caused by the suspicious pixel; determining a correcting time-dependent offset substantially reciprocal to the identified pattern of residual error values; and applying the correcting time-dependent offset to the measurement to correct for the artifact in the measurement. in an image processor: given a residual cube derived from a hyperspectral image data cube of measurements of different wavebands generated by a focal plane array sampled at different times, the residual cube is generated by approximating the spectra of each spatial pixel in the HSI data cube, as a linear combination of basis vectors having coefficients to best approximate the HSI data cube and storing the residual errors in this approximation in the residual data cube; determining a suspicious pixel suspected of causing an artifact in a measurement as a function of a statistical analysis of a collection of samples representing residual error values associated with a subject focal plane pixel measuring one waveband at different times; based on the determination of the suspicious pixel, identifying a pattern of residual error values for a span of time in which transitions among the collection of samples are identified, the pattern being indicative of the artifact caused by the suspicious pixel; determining a correcting time-dependent offset substantially reciprocal to the identified pattern of residual error values; and applying the correcting time-dependent offset to the measurement to correct for the artifact in the measurement. given a residual cube derived from a hyperspectral image data cube of measurements of different wavebands generated by a focal plane array sampled at different times, the residual cube is generated by approximating the spectra of each spatial pixel in the HSI data cube, as a linear combination of basis vectors having coefficients to best approximate the HSI data cube and storing the residual errors in this approximation in the residual data cube; determining a suspicious pixel suspected of causing an artifact in a measurement as a function of a statistical analysis of a collection of samples representing residual error values associated with a subject focal plane pixel measuring one waveband at different times; based on the determination of the suspicious pixel, identifying a pattern of residual error values for a span of time in which transitions among the collection of samples are identified, the pattern being indicative of the artifact caused by the suspicious pixel; determining a correcting time-dependent offset substantially reciprocal to the identified pattern of residual error values; and applying the correcting time-dependent offset to the measurement to correct for the artifact in the measurement.