Compressed sampling strategies for tomography
Compressed sampling strategies for tomography
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DOI：
10.1364/josaa.31.001369
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发表时间：
2014-07-01
影响因子：
1.9
通讯作者：
Brady, David J.
中科院分区：
文献类型：
--
作者：
Kaganovsky, Yan;Li, Daheng;Brady, David J.
我们研究新的投影断层扫描的采样策略，使之能够采用更少的测量比预期从经典的采样理论，而没有显着的信息丢失。受压缩传感的启发，我们的方法是基于这样的理解，即许多真实的对象在一些已知的表示中是可压缩的，这意味着定义对象的自由度的数量通常远小于像素/体素的数量。我们提出了一种新的方法基于准随机检测器二次采样，而以前的方法只解决了相对于源位置（视角）的二次采样。不同的采样策略的性能被认为是使用对象无关的品质因数，也基于特定对象的重建，与合成和真实的数据。所提出的方法可以通过分别在源或检测器侧放置编码孔径/掩模来使用被询问对象或检测器阵列的结构化照明来实现。所提出的方法的优点包括（i）对于检测器阵列的结构化照射，其导致较少的检测器像素，并且允许在未使用的空间中集成用于散射辐射的检测器;（ii）对于对象的结构化照射，其导致在医学扫描中患者的辐射剂量减少;（iii）在后一种情况下，射线的阻挡减少了散射辐射，同时在透射射线中保持相同的能量，导致比通过降低曝光时间或源的能量所获得的信噪比更高的信噪比;（iv）与视角子采样相比，它允许对于相同的图像质量使用较少的测量，或者对于相同数量的测量导致更好的图像质量。所提出的方法也可以与视角子采样相结合。(C)2014年美国光学学会
We investigate new sampling strategies for projection tomography, enabling one to employ fewer measurements than expected from classical sampling theory without significant loss of information. Inspired by compressed sensing, our approach is based on the understanding that many real objects are compressible in some known representation, implying that the number of degrees of freedom defining an object is often much smaller than the number of pixels/voxels. We propose a new approach based on quasi-random detector subsampling, whereas previous approaches only addressed subsampling with respect to source location (view angle). The performance of different sampling strategies is considered using object-independent figures of merit, and also based on reconstructions for specific objects, with synthetic and real data. The proposed approach can be implemented using a structured illumination of the interrogated object or the detector array by placing a coded aperture/mask at the source or detector side, respectively. Advantages of the proposed approach include (i) for structured illumination of the detector array, it leads to fewer detector pixels and allows one to integrate detectors for scattered radiation in the unused space; (ii) for structured illumination of the object, it leads to a reduced radiation dose for patients in medical scans; (iii) in the latter case, the blocking of rays reduces scattered radiation while keeping the same energy in the transmitted rays, resulting in a higher signal-to-noise ratio than that achieved by lowering exposure times or the energy of the source; (iv) compared to view-angle subsampling, it allows one to use fewer measurements for the same image quality, or leads to better image quality for the same number of measurements. The proposed approach can also be combined with view-angle subsampling. (C) 2014 Optical Society of America