The Smoothing Method for Finding PRIs from the PRI Transform Spectrum

This paper presents a smoothing method to find the jittered PRIs from the PRI spectrum yielded from the PRI transform algorithm. It first makes the spectrum smooth with some smoothing algorithms, and then identifies the peaks over the threshold as the PRI values. To examine the method and find what kind of smoothing algorithms is available, the paper first compares the results attained by using smoothing algorithm with those not, and concludes that using smoothing algorithm is quite necessary. Secondly, a comparison is made among three kinds of smoothing algorithms, which reveals the advantage of the smoothing algorithm using low-pass filter with adjustable cutoff frequency parameter. Eventually, the paper tries to find the optimal cutoff frequency of the low-pass filter in different environments.