A method for improving the analysis of spectral data wherein light is directed through a linearly variable bandpass filter to impinge on a linear array of photodetectors. The ratio of the passband captured by a target detector to the passband captured by adjacent detectors is determined and used to calculate the amount of light to add back to the amount reported by the target detector. The value of the stored information from each target detector is then adjusted by subtracting from that detector what was added to adjacent detectors.