Improvement of inkjet printer spur gear teeth number estimation by fixing the order in maximum entropy spectral analysis

In this paper, we estimated the number of inkjet printer spur gear teeth from shorter pitch data strings than previous study by fixing the order in maximum entropy method (MEM). The purpose of this study is to improve the efficiency of inkjet printer model identification based on spur mark comparison method (SCM) in the field of forensic document analysis. Experiments were performed using two spur gears in different color inkjet printer models. The eight kinds of pitch data length whose length ranges from three to 10 rotations of spur gear was provided for analysis. The experimental results showed that proper teeth number was estimated from shorter pitch data string compared with the strategies based on minimum AIC estimate in our previous study. The estimation was successful from the short data length nearly equal to the condition of nyquist frequency. The proposed method was considered to improve the accuracy of printer model identification based on SCM.