DSP techniques for protein coding region identification based on background noise and nonlinear phase delay reduction from period-3 spectrum using zero phased anti-notch filter and Savitzky-Golay (S-G) filter

Abstract

Short time discrete Fourier transform (STDFT) and anti-notch filters (ANF) are perhaps the most common DSP tools that uses the period-3 feature of protein coding sequences to discriminate between protein-coding regions and noncoding regions. However, the performance of these techniques is still limited due to the background noise present in their period-3 spectrum. The drawback with existing de-noising techniques is that it also distorts the period-3 feature besides noise suppression. In this article, the Savitzky-Golay (SG) filter is used to suppress the background noise from period-3 spectrum. A zero phased anti-notch filter (ZANF) is also used to overcome the effect of nonlinear phase delay from the period-3 spectrum of ANF. It is obtained that the combined use of ZANF and SG filters increases the prediction accuracy of conventional ANF by around 19% -26%.