NITPICK workflow overview. Raw spectrum preprocessing, relevant region detection, region-wise peak picking, merging of detected peaks and peak list postprocessing. At the heart of the method lies an iterative feature selection procedurecontrolled by a statistical termination criterion, as illustrated by the large box in the center. As a tightlyinterconnected prerequisite to the main workflow, the column on the left depicts the steps required for thecalculation of the regression model matrix. Numbers in parentheses give the manuscript sections in whichthe specific steps are detailed.