摘要
从标量衍射理论出发,对基于阵列抽样的相干衍射成像中物波抽样针孔大小和图像传感器有效记录孔径对重现物波的影响进行了理论分析,给出了描述抽样孔径和记录孔径对波前再现像影响的数学公式。理论分析表明,在抽样波前的重现过程中记录孔径的有限大小会导致相邻抽样孔径间发生串扰;这种串扰效应是产生波前重现误差及由此引起的成像噪声的主要来源。通过数值分析串扰次函数极大幅度随记录孔径的变化情况,发现这种串扰效应随着记录孔径的增大振荡减弱。基于该理论分析,给出了最佳记录孔径的定义及其计算公式。并通过一个实验测量实例进一步验证了当记录孔径大小等于最佳记录孔径时得到的衍射像的信噪比最大。
The influence of the sampling pinholes and recording aperture on imaging quality in coherent diffractive imaging based on sampling array is analyzed using scalar diffraction theory. A mathematical formula for describing the influence is derived. The theoretical analysis shows that the limited size of the recording aperture can result in a crosstalk between adjacent sampling pinholes. This crosstalk effect is the main source of the wavefront reconstruction error and the imaging noise. Through digital analysis of the changes of the sub maximum of the crosstalk function under different recording aperture conditions, it is found that the sub maximum does not descend monotonously when the size of the recording aperture increases, while it oscillatorily decreases with enlargement of the recording aperture. An optimal size of the recording aperture is defined and an analytical formula is given. Further experimental results show that the background noise will descend to its minimum when the radius of the recording aperture is just equal to the optimal size.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2014年第3期100-105,共6页
Acta Optica Sinica
基金
国家自然科学基金(11074152
10934003)
关键词
衍射
相干成像
衍射成像
抽样
diffraction
coherent imaging
diffractive imaging
sampling
