基于多距离相位恢复的无透镜计算成像技术

Lensfree computational imaging based on multi-distance phase retrieval

迭代相位恢复是一种将算法优越性与成像系统相结合的计算成像技术,它将有助于显微镜的小型化与低成本化。基于多距离相位恢复的无透镜成像技术因其高分辨、大视场以及无相差等特性成为计算成像领域的一个研究热点。多距离相位恢复可通过不同衍射距离下的多幅强度图样迭代重建出样品的完整波前信息。目前,无透镜多距离成像系统存在倾斜照明、收敛迟滞、初始距离无法直接测量、真彩色成像疵病、分辨率受限等问题。文中系统地综述了国内外研究团队针对这些问题的解决措施以及最新研究进展,并给出了相对应的实验验证。

Iterative phase retrieval,as a computational imaging technique,provides a powerful tool that combines the superiority of post-processing algorithm with an optical system,which will facilitate a low-cost and portable implementation for microscope.Lensfree imaging based on multi-distance phase retrieval becomes a focused topic in the domain of computational imaging,due to its high-resolution,wide field and aberration-less propertyies.Multi-distance phase retrieval reconstructs a full wavefront merely with a dataset of defocused intensity patterns related to different diffraction distances.At present,this technique suffers from tilt illumination artifact,convergence stagnation,measurement uncertainty of the sample-to-sensor distance,color imaging artifact and resolution loss with pixelated problem.Different correction methods to solve these problems were proposed in this paper.Experiment was also given to validate the performance of these methods.