Chen Michael, Tian Lei, Waller Laura
Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA 94720, USA.
Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA 94720, USA; Department of Electrical & Computer Engineering, Boston University, Boston, MA 02215, USA.
Biomed Opt Express. 2016 Sep 9;7(10):3940-3950. doi: 10.1364/BOE.7.003940. eCollection 2016 Oct 1.
We demonstrate 3D phase and absorption recovery from partially coherent intensity images captured with a programmable LED array source. Images are captured through-focus with four different illumination patterns. Using first Born and weak object approximations (WOA), a linear 3D differential phase contrast (DPC) model is derived. The partially coherent transfer functions relate the sample's complex refractive index distribution to intensity measurements at varying defocus. Volumetric reconstruction is achieved by a global FFT-based method, without an intermediate 2D phase retrieval step. Because the illumination is spatially partially coherent, the transverse resolution of the reconstructed field achieves twice the NA of coherent systems and improved axial resolution.
我们展示了从使用可编程LED阵列源捕获的部分相干强度图像中进行三维相位和吸收恢复。通过四种不同的照明模式对图像进行离焦捕获。利用一阶玻恩近似和弱物体近似（WOA），推导了线性三维微分相衬（DPC）模型。部分相干传递函数将样品的复折射率分布与不同离焦处的强度测量联系起来。通过基于全局快速傅里叶变换（FFT）的方法实现体积重建，无需中间的二维相位检索步骤。由于照明在空间上是部分相干的，重建场的横向分辨率达到了相干系统数值孔径的两倍，并且轴向分辨率得到了提高。
