Extended Depth-of-Field Iris Image Capture Device Based on Auto Bracketing Focus

One of the major challenges for accurate iris recognition is to capture a high-quality image of the iris since current iris recognition systems´ performance is greatly affected by poor-quality imaging. This paper discusses the methods of capturing iris images with accurate focus, and based on the above methods, an extended depth-of-field iris image capture prototype Irising3000 is developed. Irising3000 combining the infrared distance sensor with the weighted brightness algorithm, achieves the function of auto bracketing focus, which can capture a sequence of multi-focal iris images. Based on the assessment of focusing accuracy, an iris image with extended depth-of-field is reconstructed from the image sequence. The prototype Irising3000 reduces the need for users to meet the minimum requirements in image capture, and improves the success rate of capturing high-quality iris image.