Liao Weiqing, Luan Tianxiang, Yue Yuanli, Wang Chao
Photonics Information Innovation Center and Hebei Provincial Center for Optical Sensing Innovations, College of Physics Science & Technology, Hebei University, Baoding 071002, China.
School of Engineering, University of Kent, Canterbury CT2 7NT, UK.
Sensors (Basel). 2025 Jun 15;25(12):3738. doi: 10.3390/s25123738.
Swept-source optical coherence tomography (SS-OCT) is a widely used imaging technique, particularly in medical diagnostics, due to its ability to provide high-resolution cross-sectional images. However, one of the main challenges in SS-OCT systems is the nonlinearity in wavelength sweeping, which leads to degraded depth resolution after Fourier transform. Correcting for this nonlinearity typically requires complex re-sampling and chirp compensation methods. In this paper, we introduce the first ultrafast time-stretch optical coherence tomography (TS-OCT) system that utilizes reservoir computing (RC) to perform direct temporal signal analysis without relying on Fourier transform techniques. By focusing solely on the temporal characteristics of the interference signal, regardless of frequency chirp, we demonstrate a more efficient solution to address the nonlinear wavelength sweeping issue. By leveraging the dynamic temporal processing capabilities of RC, the proposed system effectively bypasses the challenges faced by Fourier analysis, maintaining high-resolution depth measurement without being affected by chirp-introduced spectral broadening. The system operates by categorizing the interference signals generated by variations in sample position. This classification-based approach simplifies the data processing pipeline. We developed an RC-based model to interpret the temporal patterns in the interferometric signals, achieving high classification accuracy. A proof-of-the-concept experiment demonstrated that this method allows for precise depth resolution, independent of system chirp. With an A-scan rate of 50 MHz, the classification model yielded 100% accuracy with a root mean square error (RMSE) of 0.2416. This approach offers a robust alternative to Fourier-based analysis, particularly in systems prone to nonlinearities during signal acquisition.
扫频光学相干断层扫描(SS-OCT)是一种广泛应用的成像技术,特别是在医学诊断领域,因为它能够提供高分辨率的横截面图像。然而,SS-OCT系统的主要挑战之一是波长扫描中的非线性,这会导致傅里叶变换后深度分辨率下降。校正这种非线性通常需要复杂的重采样和啁啾补偿方法。在本文中,我们介绍了首个超快时间拉伸光学相干断层扫描(TS-OCT)系统,该系统利用储层计算(RC)来执行直接的时间信号分析,而无需依赖傅里叶变换技术。通过仅关注干涉信号的时间特性,而不考虑频率啁啾,我们展示了一种更有效的解决方案来解决非线性波长扫描问题。通过利用RC的动态时间处理能力,所提出的系统有效地绕过了傅里叶分析所面临的挑战,在不受啁啾引入的光谱展宽影响的情况下保持高分辨率深度测量。该系统通过对由样品位置变化产生的干涉信号进行分类来运行。这种基于分类的方法简化了数据处理流程。我们开发了一个基于RC的模型来解释干涉信号中的时间模式,实现了高分类准确率。一个概念验证实验表明,这种方法能够实现精确的深度分辨率,与系统啁啾无关。在A扫描速率为50 MHz的情况下,分类模型的准确率达到100%,均方根误差(RMSE)为0.2416。这种方法为基于傅里叶的分析提供了一种强大的替代方案,特别是在信号采集过程中容易出现非线性的系统中。