基于散斑照明的成像分辨率研究

Research on Imaging Resolution via Speckle Illumination

照明方式对光学成像系统的分辨率有重大影响。从光场的相干性理论出发,研究了影响多帧散斑照明下一阶自相关成像和强度涨落二阶自相关成像分辨率的主要因素。理论和数值模拟结果表明,辐照于物面上的散斑横向相干长度大小与一阶自相关成像和强度涨落二阶自相关成像的分辨率呈非单调关系。此外,与传统非相干成像相比,一阶自相关成像和强度涨落二阶自相关成像仅能轻微地提高成像分辨率,而强度涨落二阶自相关成像只是对一阶自相关成像的结果起锐化作用,并不能进一步提高成像分辨率。

The lighting mode has great influence on the resolution of optical imaging system.Based on the coherence theory of light field,the main factor which influence the imaging resolution of first-order autocorrelation imaging and the second-order autocorrelation imaging of intensity fluctuation via multi-frame speckle illumination are studied.The theory and numerical simulation results show that the transverse coherence length of speckle on the object plane and the resolution of first-order autocorrelation imaging and the second-order autocorrelation imaging of intensity fluctuation are not monotonic relationship.In addition,compared with the traditional incoherent imaging,the firstorder autocorrelation imaging and the second-order autocorrelation imaging of intensity fluctuation can only slightly improve the imaging resolution.The result of second-order autocorrelation imaging of intensity fluctuation is just the sharpening of the result of first-order autocorrelation imaging,which can′t further improve the imaging resolution.