Barrett H H, Horrigan F A
Appl Opt. 1973 Nov 1;12(11):2686-702. doi: 10.1364/AO.12.002686.
The use of a Fresnel zone plate as a coded aperture for imaging incoherent radiation such as gamma rays has been previously reported. The coded image is in many respects similar to a hologram and can be decoded or reconstructed with a coherent optical system. In this paper, the general theory of coded-aperture imaging is presented, first for an arbitrary code and then for an on-axis zone plate, an off-axis zone plate, and a one-dimensional zone plate (or linear chirp). With the on-axis plate, a matched imaging condition is suggested as a guide to optimizing image contrast. With the off-axis zone plate and the linear chirp, it is necessary to use a half-tone screen to spatially heterodyne the object spectrum into the passband of the aperture. In all three cases, expressions for the resolution, depth of field, field of view, and relative efficiency are derived. A simplified noise analysis is presented, and some practical system constraints are discussed.
此前已有报道将菲涅耳波带片用作编码孔径来对诸如伽马射线等非相干辐射进行成像。编码图像在许多方面类似于全息图，并且可以用相干光学系统进行解码或重建。本文介绍了编码孔径成像的一般理论，首先针对任意编码，然后针对同轴波带片、离轴波带片和一维波带片（或线性啁啾）。对于同轴波带片，提出了一种匹配成像条件作为优化图像对比度的指导。对于离轴波带片和线性啁啾，有必要使用半色调屏将物体光谱在空间上外差到孔径的通带中。在所有这三种情况下，都推导出了分辨率、景深、视场和相对效率的表达式。给出了简化的噪声分析，并讨论了一些实际的系统限制。
