Imaging through strongly scattering media noninvasively faces a key challenge: reconstructing the object phase spectrum. Speckle correlation imaging (SCI) effectively reconstructs the amplitude spectrum but struggles with stable and accurate phase spectrum reconstruction, particularly in variable or background-light-interfered scenarios. In this study, we proposed a speckle spectrum autocorrelation imaging (SSAI) approach for complex strongly scattering scenarios. SSAI employs the spectrum autocorrelation of centroid-aligned speckle images for independent and stable reconstruction of the object phase spectrum, markedly reducing interference from medium dynamics and object motion. Then, SSAI reconstructs the object spectrum by combining the object phase spectrum with the object amplitude spectrum recovered from the speckle autocorrelation. In the experimental validation, we compared SSAI and SCI in reconstructing stationary and moving objects hidden behind dynamic media, both with and without background light interference. SSAI not only exhibits stability and fidelity superior to SCI but also functions in scattering scenarios where SCI fails. Furthermore, SSAI can reconstruct size-scaling objects hidden behind dynamic scattering media with high fidelity, showing significant scalability in complex scenarios. We expect this lensless and noninvasive approach to find widespread applicability in biomedical imaging, astronomical observations, remote sensing, and underwater detection.

针对Gerchberg-Saxton（GS）算法对初始相位敏感、光斑内部均匀性差，以及混合区域振幅自由度（MRAF）算法的低衍射效率和非信号区域散斑严重等问题，提出了一种改进的GS算法。首先，采用泽尼克多项式作为初始相位的基础形态，引入权重系数Z值，并通过迭代寻优算法获取最佳Z值，以生成初始相位。其次，在改进算法的前半部分使用GS算法优化初始相位，以确保其与目标光斑的适配性并维持高衍射效率，随后使用MRAF算法提升光斑内部的均匀性并降低误差。最后，基于输出面实际光强分布的反馈构建了一种优化机制，以获得最佳的DOE相位分布。针对三角形、方形和圆形光斑进行了优化设计，并开展了模拟仿真和光路实验，结果表明改进算法实现了超过98.30%的衍射效率和低于1.10%的均方根误差，并有效抑制了非信号区域的散斑，展现出强大的图形泛化能力。

A cross air‬–water interface hydroacoustic signal detection method based on microvibration detection at the air–water interface is proposed. Laser speckles modulated by water surface acoustic waves are recorded and used as an information carrier. Phase correlation and multichannel fusion algorithms are used to extract and enhance hydroacoustic signals. Wide frequency range (200 Hz to 20 kHz) underwater acoustic signals are detected with a frequency relative error smaller than 0.5%. Several common artificial and natural hydroacoustic signals are used as source signals and correctly reconstructed. The average intelligibility of recovered humpback whale signals evaluated with the normalized subband envelope correlation algorithm is 0.52 ± 0.02.

Structured illumination, a wide-field imaging approach used in microscopy to enhance image resolution beyond the system's diffraction limits, is a well-studied technique that has gained significant traction over the last two decades. However, when translated to endoscopic systems, severe deformations of illumination patterns occur due to the large depth of field (DOF) and the 3D nature of the targets, introducing significant implementation challenges. Hence, this study explores a speckle-based system that best suits endoscopic practices to enhance image resolution by using random illumination patterns. The study presents a prototypic model of an endoscopic add-on, its design, and fabrication facilitated by using the speckle structured illumination endoscopic (SSIE) system. The imaging results of the SSIE are explained on a colon phantom model at different imaging planes with a wide field of view (FOV) and DOF. The obtained imaging metrics are elucidated and compared with state-of-the-art (SOA) high-resolution endoscopic techniques. Moreover, the potential for a clinical translation of the prototypic SSIE model is also explored in this work. The incorporation of the add-on and its subsequent results on the colon phantom model could potentially pave the way for its successful integration and use in futuristic clinical endoscopic trials.