Passive autofocus (AF) is a key component of many digital and high megapixel smart-phone camera systems. In order to make informed choices in the selection of a passive AF search algorithm, it is essential to utilize sound performance metrics. The performance metrics currently employed do not take into account all facets involved in passive AF systems. In this article, five performance metrics are proposed to be simultaneously evaluated in order to accurately reflect all aspects of a passive AF system including focusing speed, accuracy, power consumption, and user experience. Experimental results on a prototype digital camera platform for four representative AF search algorithms are presented to show how to carry out the evaluation of any passive AF search algorithm.
Mark Gamadia, Mohammad Rahman, Nasser Kehtarnavaz, "Performance Metrics for Passive Auto-Focus Search Algorithms in Digital and Smart-Phone Cameras" in Journal of Imaging Science and Technology, 2011, pp 10507-1 - 10507-12, https://doi.org/10.2352/J.ImagingSci.Technol.2011.55.1.010507