Achieving high spatial resolution over a wide field of view (FOV) is the goal of many imaging systems. In a traditional lens-based microscope, designing a complex objective with high numerical aperture (NA) to achieve this goal is a tough and challenging task. The lens-free wide-field imaging method based on phase retrieval provides a new way to bypass the trade-off between the spatial resolution and FOV of conventional microscopy. However, the typical lens-free microscopy usually requires mechanical devices with high precision and repeatability. In this paper, we report a robust and cost-effective pixel super-resolved lens-free imaging method based on dual laterally shifting modulation. A thin diffuser is inserted between the object and the image sensor to be used as the modulator. The diffuser and the object are transversely scanned at the same time to add diversities for phase retrieval and pixel super-resolution, respectively. In this way, the positional shifts of the diffuser and the object can be directly recovered with the registration algorithm, thus addressing the low stability and inaccuracy issues of translation stages. We also propose a pixel super-resolution phase-retrieval algorithm to recover the object and the unknown diffuser. We first use numerical simulations to evaluate the proposed scheme. Then, we validate this approach by imaging a resolution target and a pollen sample, thus achieving an FOV of similar to 30 mm(2) and a half-pitch resolution of 0.78 mu m, which surpasses 2.14 times the theoretical Nyquist-Shannon sampling resolution limit. Finally, the 3D refocusing ability is also verified by imaging a thick mosquito sample. (C) 2020 Optical Society of America
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机译:在广泛的视野下实现高空间分辨率(FOV)是许多成像系统的目标。在一种传统的基于镜头的显微镜中,设计具有高数字孔径(NA)的复杂目标,以实现这一目标是一个艰难而挑战的任务。基于相位检索的无透镜广场成像方法提供了一种绕过空间分辨率和传统显微镜的FOV之间的权衡的新方法。然而,典型的无透镜显微镜通常需要具有高精度和可重复性的机械装置。在本文中,我们报告了一种基于双横向移位调制的稳健且经济高效的像素超分辨透镜成像方法。在物体和图像传感器之间插入薄的漫射器以用作调制器。横向扫描扩散器和对象的同时分别同时扫描,以分别增加相位检索和像素超分辨率的多样区。以这种方式,扩散器和对象的位置偏移可以用注册算法直接恢复,从而解决翻译阶段的低稳定性和不准确问题。我们还提出了一种像素超分辨率相位检索算法,以恢复对象和未知的扩散器。我们首先使用数值模拟来评估所提出的方案。然后,我们通过成像分辨率和花粉样品来验证这种方法,从而实现类似于30mm(2)的FOV和0.78 mu m的半间距分辨率,其超越了理论奈奎斯语 - 香农采样分辨率的2.14倍限制。最后,通过成像厚厚的蚊子样本,还验证了3D重焦能力。 (c)2020美国光学学会
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