A real-time, VanderLugt-type optical correlator using a single SLM is developed. A field programmable gate array is used to capture and process images obtained from a CCD camera at a rate of 60 video fields/s. During both enrollment and verification, a finger slides over a glass prism and is input to the system via the frustration of the total internal reflection process. An autoenrollment procedure captures the optimal image during each slide. An optimal composite filter is implemented. The correlation detection process comprises real-time tracking of the correlation peak while the finger is sliding and a decision process based on projective decision boundaries. Real-life tests yielded a false rejection rate of 1% and a false acceptance rate of 0.2%.