Wavelet filter and changing rate based tire runout test algorithm

As tire performance specifications become more stringent, tire manufacturers are facing the challenge to develop accurate measuring device for their products. Runout is a standard test performed to determine whether a tire ldquoqualifiesrdquo. Unfortunately, tires have letters, trademarks and pin vents on their sidewalls, which can bring a lot of trouble to the runout data analysis. In this paper a data smoothing algorithm for tire runout test is presented. The algorithm consists of discrete wavelet filtering and a ldquochanging raterdquo based de-noising method. Experimental results have shown that, the presented algorithm can successfully remove all the signal ldquonoisesrdquo caused by grooves on tire surface, as well as marks and letters on sidewall while preserving the original profile of the tire, so that the runout can be tested easily.