散射介质光学系统成像性质研究  

Research on imaging properties of scattering medium optical systems

作　　者：郭振翔 沙刘 鲍海宇 孙文卿 吴泉英[1,2] Guo Zhenxiang;Sha Liu;Bao Haiyu;Sun Wenqing;Wu Quanying(School of Physical Science and Technology,Suzhou University of Science and Technology,Suzhou 215009,China;Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application,Suzhou 215009,China)

机构地区：[1]苏州科技大学物理科学与技术学院,江苏苏州215009 [2]江苏省微纳热流技术与能源应用重点实验室,江苏苏州215009

出　　处：《激光与光电子学进展》2024年第20期220-227,共8页Laser & Optoelectronics Progress

基　　金：国家自然科学基金(62375196,62275187);“十四五”江苏省重点学科(2021135);江苏省高等学校自然科学研究项目(22KJA140002)。

摘　　要：由于散射现象的存在,传统的光学系统无法直接对随机介质后的目标物进行观测,只能采集到散斑图像,而从中恢复目标的质量不仅与算法参数有关,还受到散射距离以及光学成像系统的制约。为提高散斑图像恢复质量,研究了焦距、物距和图像恢复质量之间的关系,提出了最佳成像参数模型,通过改变镜头焦距,调节相机获得的目标频谱信息,采集清晰的散斑图,再根据散斑相关原理与相位恢复算法,实现物体通过散射介质后的散斑图像恢复。仿真及实验结果表明,当散射距离为0.5 m,焦距调节范围从18~55 mm时,随着焦距逐渐增大,镜头的有效孔径变大,物体频谱信息保留得更完整,目标物结构相似度由0.3824上升至0.7829,恢复效果更好。虽然通过调整算法参数来优化短焦距镜头采集的散斑重建质量,但当焦距为45 mm时,结构相似度由0.6341上升至0.7626,仍未能实现更理想的恢复效果。随着散射距离增加,图像重建效果迅速下降,只有更长焦距的镜头才能实现散射介质成像。Due to the existence of scattering phenomena,traditional optical systems can’t directly observe the target object behind a random medium,and can only collect speckle images.The quality of recovering the target from it is not only limited by algorithm parameters,but also by scattering distance and optical imaging systems.To improve the quality of speckle image restoration,this paper studies the relationship between focal length,object length,and image restoration quality,and proposes the optimal imaging parameter model.By changing the lens focal length,adjusting the target spectrum information obtained by the camera,clear speckle images are collected,and then based on the principle of speckle correlation and phase restoration algorithm,speckle image restoration of objects passing through scattering media is achieved.The simulation and experimental results show that when the scattering distance is 0.5m and the focal length adjustment range is from 18 to 55mm, as the focal length gradually increases, the effectiveaperture of the lens becomes larger, and the spectral information of the object is preserved morecompletely. The similarity of the target object structure increases from 0.3824 to 0.7829, resultingin better recovery effect. Although the quality of speckle reconstruction in short focal length lensacquisition was optimized by adjusting algorithm parameters, when the focal length is 45mm, thestructural similarity increased from 0.6341 to 0.7626, but still failed to achieve a more idealrestoration effect.As the scattering distance increases, the image reconstruction effect rapidlydecreases, and longer focal length lenses can achieve imaging of scattering media.

关 键 词：散射介质成像 散斑自相关 相位恢复算法 镜头焦距 

分 类 号：O436[机械工程—光学工程]