Li Runze, Peng Tong, Liang Yansheng, Yang Yanlong, Yao Baoli, Yu Xianghua, Min Junwei, Lei Ming, Yan Shaohui, Zhang Chunmin, Ye Tong
State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China.
School of Science, Xi'an Jiaotong University, Xi'an 710049, China.
J Opt. 2017 Oct;19(10). doi: 10.1088/2040-8986/aa84dc. Epub 2017 Sep 13.
Focusing and imaging through scattering media has been proved possible with high resolution wavefront shaping. A completely scrambled scattering field can be corrected by applying a correction phase mask on a phase only spatial light modulator (SLM) and thereby the focusing quality can be improved. The correction phase is often found by global searching algorithms, among which Genetic Algorithm (GA) stands out for its parallel optimization process and high performance in noisy environment. However, the convergence of GA slows down gradually with the progression of optimization, causing the improvement factor of optimization to reach a plateau eventually. In this report, we propose an interleaved segment correction (ISC) method that can significantly boost the improvement factor with the same number of iterations comparing with the conventional all segment correction (ASC) method. In the ISC method, all the phase segments are divided into a number of interleaved groups; GA optimization procedures are performed individually and sequentially among each group of segments. The final correction phase mask is formed by applying correction phases of all interleaved groups together on the SLM. The ISC method has been proved significantly useful in practice because of its ability to achieve better improvement factors when noise is present in the system. We have also demonstrated that the imaging quality is improved as better correction phases are found and applied on the SLM. Additionally, the ISC method lowers the demand of dynamic ranges of detection devices. The proposed method holds potential in applications, such as high-resolution imaging in deep tissue.
通过高分辨率波前整形已证明可以透过散射介质进行聚焦和成像。通过在纯相位空间光调制器(SLM)上应用校正相位掩模,可以校正完全混乱的散射场,从而提高聚焦质量。校正相位通常通过全局搜索算法来找到,其中遗传算法(GA)因其并行优化过程和在噪声环境中的高性能而脱颖而出。然而,随着优化的进行,GA的收敛速度会逐渐减慢,导致优化的改进因子最终达到一个平台期。在本报告中,我们提出了一种交错段校正(ISC)方法,与传统的全段校正(ASC)方法相比,在相同的迭代次数下,该方法可以显著提高改进因子。在ISC方法中,所有相位段被分成若干个交错组;在每组段之间单独且顺序地执行GA优化过程。最终的校正相位掩模是通过将所有交错组的校正相位一起应用于SLM而形成的。ISC方法在实践中已被证明非常有用,因为当系统中存在噪声时,它能够实现更好的改进因子。我们还证明,随着找到更好的校正相位并应用于SLM,成像质量会得到改善。此外,ISC方法降低了对检测设备动态范围的要求。所提出的方法在诸如深部组织的高分辨率成像等应用中具有潜力。