Cross-correlation method for identification and removal of machine contribution from tire uniformity measurements

Method to identify and remove machine contributions from tire uniformity measurements made on a tire uniformity machine by synchronizing and averaging together multiple measurements of tire uniformity made on a single test tire that is re-mounted between measurements in a randomly determined orientation relative to a rim reference mark on the rim of the tire uniformity machine. A cross-correlation function is calculated for each measurement relative to the first measurement, and an angular shift is determined from each cross-correlation function. The angular shifts are used to synchronize the measurements so that they can be averaged together. The resulting average test tire uniformity data has both machine contribution and random measurement noise minimized. An average machine contribution data set is determined by synchronizing and subtracting the average test tire uniformity data from each test tire uniformity measurement data set, then averaging together the resulting data sets. Corrected production tire uniformity data is obtained from a single measurement of production tire uniformity by subtracting the average machine contribution data from the production tire uniformity measurement data.