透过散射介质的光阑识别及其分辨率研究

Study on the recognition of aperture hidden behind a scattering medium and the resolution

光束经过光阑后产生衍射图样,通过分析衍射图样可得到光阑的形状和尺寸等信息.当光束的传输路径中存在散射介质,散射介质的随机散射效应将导致光场变为随机的散斑场,无法直接从中获取光阑的信息.本文基于强度相关理论,实现了通过散斑场对光阑进行检测.实验结果表明,该方法可以有效地获得光阑轮廓信息.散斑重构的光强分布图的像素间距与实际物体的物理间距之间存在线性关系,能够利用重构图像对目标光阑进行定量测量,本实验散斑重构图像的最高分辨率为396.8μm/lp.

Diffraction pattern is generated by the light transmitting through an aperture. The shape and size of aperture can be acquired by the analysis of the diffraction pattern. When a scattering medium is located in the optical path, the random scattering effect produces the speckle field, from which the information of the aperture cannot be recovered directly. A method is provided in this paper to measure the aperture by the speckle field based on the intensity correlation theory.The experimental result proves that our method is effective for acquiring the profile of the aperture. According to the linear relationship between the pixel pitch of the light intensity distribution reconstructed by speckle and the physical pitch of the aperture, the size of the aperture can be quantitatively measured with the maximum resolution of 396.8 μm/lp.