Abstract: A method of monitoring the thickness of a longitudinally moving strip to permit quick detection of continuous defects includes the steps of scanning the strip a predetermined number of times measuring the thickness at a plurality of sites across the strip width for thereby generating a plurality of data sets, or scans, with each data set indicative of the thickness profile of the strip. The scans are smoothed by combining the data sets and thereby generating a single representative profile. Additional profiles are generated and displayed in three dimensional format so that a plurality of profiles in sequential relation are continuously displayed to permit a continuous defect, when occurring, to be detected and displayed from at least one profile to an immediately subsequent profile.