Static laser surface authentication with low-cost microscope: Tolerances on spatial and angular disturbance

This paper provides a detailed analysis of spatial and angular robustness of static laser surface authentication system. We shot a beam of laser onto a surface of a paper, captured the reflected speckle pattern, introduced spatial and angular disturbance to the paper separately and perform the authentication process. By analyzing the cross correlation values between speckle patterns before and after the disturbance, we show how receiver operating characteristic (ROC) analysis can be utilized to calculate the robustness of the system. Defining the accuracy ≥ 95 % as robustness, the estimated spatial and angular tolerances of our system are 0.154 ±0.008 mm and 3.59 ±0.18 degrees respectively.