A study on defocused iris image restoration

作者：Ma Jie; Zhang Zhong Bo^*; Yang Hang; Zhou Chun Guang

来源：Acta Automatica Sinica, 2012, 38(6): 959-968.

DOI：10.3724/SP.J.1004.2012.00959

• Defocus
• Fast algorithms
• Frequency domains
• Imagerestoration
• Indicator functions
• Inverse Filtering
• Iris images
• Iris recognition
• Iris recognition systems
• Point-spread functions
• Real-world application
• Regular hexagon
• Shallow depths
• Theoretical research
• Zero distribution
• Zero point
• Zero theorem

Generally, acquisition equipments in iris recognition systems have a shallow depth of field (DOF), which are very sensitive to defocus. Methods to recover defocused images are needed both in theoretical researches and in real-world applications. In this paper, an indicator function of regular hexagon was used as the point spread PSF) to solve the recovery problem of defocused iris images. By analyzing the zero distribution of PSF in frequency domain, we theoretically, proved the zero theorem for the round of zero points nearest to the center of frequency domain. We also provided the computational method to find zero points and the fast algorithm to recovery this kind of defocused images. The experimental results showed the efficiency of the algorithm.

• 出版日期2012