Methods, systems and computer readable media for quantifying and removing offset bias signals in a chemical array data set having one or more channels. In one embodiment, for each channel of data in the data set, a first set of features is selected from the data set. Surface intensities are calculated for features in the first selected set of features and surface intensifies of features not in the first selected set are calculated from the calculated surface intensities. A second set of features is selected, the intensity values of which are within a range of correspondingly located surface intensity values defined by upper and lower threshold intensities. Secondary surface intensifies are calculated for features in the second selected set of features and secondary surface intensities for all other locations on the array that were not locations corresponding to the features having secondary surface intensities calculated therefore, are calculated. Feature intensities of the channel features are then corrected as a function of the secondary surface intensities.