Attal Benjamin, O'Toole Matthew
IEEE Trans Pattern Anal Mach Intell. 2025 Aug;47(8):6122-6133. doi: 10.1109/TPAMI.2022.3203347.
Coherent diffraction imaging (CDI) is a computational technique for reconstructing a complex-valued optical field from an intensity measurement. The approach is to illuminate an object with a coherent beam of light to form a diffraction pattern, and use a phase retrieval algorithm to reconstruct the object's complex transmittance from the measurement. However, as the name implies, conventional CDI assumes highly coherent illumination. Recent works therefore extend CDI to account for partial coherence and imperfect detection, by modeling light as an incoherent mixture of multiple fields (e.g., multiple wavelengths) and recovering each field simultaneously. In this work, we make strides towards the practical implementation and usage of multi-wavelength diffraction imaging. In particular, we provide novel analysis of the noise characteristics of multi-wavelength diffraction imaging, and show that it is preferable to coherent diffraction imaging under high signal-independent noise. Additionally, we present a compact coded diffraction imaging system and corresponding phase retrieval algorithms to robustly and simultaneously recover complex fields representing multiple wavelengths. Using a novel mixed-norm color prior, our prototype system reconstructs a larger number of multi-wavelength fields from fewer measurements than existing methods, and supports applications such as micron-scale optical path difference measurement via synthetic wavelength holography.
相干衍射成像（CDI）是一种通过强度测量来重建复值光场的计算技术。该方法是用相干光束照射物体以形成衍射图案，并使用相位恢复算法从测量值中重建物体的复透过率。然而，顾名思义，传统的CDI假定为高度相干照明。因此，最近的研究通过将光建模为多个场（例如，多个波长）的非相干混合并同时恢复每个场，将CDI扩展到考虑部分相干和不完美检测的情况。在这项工作中，我们朝着多波长衍射成像的实际实现和应用迈出了步伐。特别是，我们对多波长衍射成像的噪声特性进行了新颖的分析，并表明在高信号无关噪声下，它比相干衍射成像更具优势。此外，我们提出了一种紧凑的编码衍射成像系统和相应的相位恢复算法，以稳健地同时恢复代表多个波长的复场。利用一种新颖的混合范数颜色先验，我们的原型系统比现有方法从更少的测量中重建更多数量的多波长场，并支持诸如通过合成波长全息术进行微米级光程差测量等应用。
