Shi Daxin, Anastasio Mark A
Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, Illinois 60616, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2006 Jan;73(1 Pt 2):016612. doi: 10.1103/PhysRevE.73.016612. Epub 2006 Jan 23.
Inverse scattering theories are available that permit tomographic reconstruction of the complex-valued refractive index distribution of weakly scattering objects from knowledge of intensity measurements. These imaging methods are valuable in applications that involve high-frequency optical wavefields, in which direct wavefield phase measurements can be difficult experimentally. The so-called in-line holographic imaging geometry has been well-studied, in which two measurements of the forward scattered wavefield intensity are acquired on distinct parallel detector planes that are perpendicular to the direction of the illuminating wavefields. In this work, based on the principles of intensity diffraction tomography, a reconstruction theory for off-axis holographic tomography with diffracting scalar wavefields is developed and investigated. A distinct feature of the method is that, at each tomographic view angle, the object is illuminated by use of two plane waves that propagate in different directions. The intensities of the forward scattered wavefields are measured on a single detector behind the object. This permits the direction of the probing wavefield to be varied for acquisition of the necessary measurement data, rather than the detector placement as required by conventional in-line holographic methods. The developed image reconstruction method is validated and investigated by use of computer-simulation studies.
逆散射理论可用于从强度测量数据中对弱散射物体的复值折射率分布进行层析重建。这些成像方法在涉及高频光波场的应用中很有价值，因为在高频光波场中，直接测量波场相位在实验上可能很困难。所谓的同轴全息成像几何结构已经得到了充分研究，即在与照明波场方向垂直的不同平行探测器平面上获取前向散射波场强度的两次测量值。在这项工作中，基于强度衍射层析原理，发展并研究了一种用于具有衍射标量波场的离轴全息层析的重建理论。该方法的一个显著特点是，在每个层析视角下，物体由两个沿不同方向传播的平面波照明。前向散射波场的强度在物体后方的单个探测器上测量。这使得可以改变探测波场的方向来获取必要的测量数据，而不是像传统同轴全息方法那样需要改变探测器的位置。通过计算机模拟研究对所发展的图像重建方法进行了验证和研究。
