基于差分时间数字转换光子计数技术的时域扩散光学成像系统研究

刘欣霖; 路光达; 秦转萍; 郭庭航; 刘东远; 高峰

doi:10.37188/CO.2025-0048

基于差分时间数字转换光子计数技术的时域扩散光学成像系统研究

doi: 10.37188/CO.2025-0048

cstr: 32171.14.CO.2025-0048

刘欣霖^{1, 2,},
路光达^{1, 2,},
秦转萍^{1, 2, ,},
郭庭航^{1, 2,},
刘东远^3, ,,
高峰^3,

1.
天津职业技术师范大学自动化与电气工程学院, 天津 300222
2.
天津市信息传感与智能控制重点实验室, 天津 300222
3.
天津大学精密仪器与光电子工程学院, 天津 300072

基金项目: 国家自然科学基金（No. 62205239，No. 62075156）；中国博士后自然科学基金（No. 2023M732600）；天津市信息传感与智能控制重点实验室开放基金课题（No. 2023KFJJ02）

详细信息

作者简介:
刘欣霖（2000—），男，天津人，硕士，研究生，主要从事光学仪器设计、脑机接口等方面的研究。E-mail：LXL7729@126.com

路光达（1978—），男，河北保定人，博士，教授，主要从事机器人机械设计、控制算法等方面的研究。E-mail：lugd1229@163.com

秦转萍（1983—），女，河北邢台人，博士，讲师，主要从事脑机接口、智能医疗机器人等方面的研究。E-mail：qinzhuanping@126.com

郭庭航（1984—），男，山东济宁人，博士，讲师，主要从事智能检测、人工智能等方面的研究。E-mail: guotinghang@tute.edu.cn

刘东远（1990—），男，河北廊坊人，博士，助理研究员，主要从事组织光学成像等方面的研究。E-mail：liudongyuan@tju.edu.cn

高　峰（1963—），男，陕西西安人，博士，教授，主要从事组织光学成像等方面的研究。E-mail：gaofeng@tju.edu.cn

中图分类号: O434
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出版历程
- 网络出版日期: 2025-08-26

A time-domain diffuse optical imaging system based on differential time-to-digital converter photon-counting technology

LIU Xin-lin^{1, 2
,},
LU Guang-da^{1, 2
,},
QIN Zhuan-ping^{1, 2
, ,},
GUO Ting-hang^{1, 2
,},
LIU Dong-yuan^{3
, ,},
GAO Feng^3
,

1.
School of Automation and Electrical Engineering, Tianjin University of Technology and Education, Tianjin, 300222, China
2.
Tianjin Key Laboratory of Information Sensing & Intelligent Control, Tianjin, 300222, China
3.
College of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China

Funds: Supported by

More Information

Corresponding author: qinzhuanping@126.com; liudongyuan@tju.edu.cn

摘要

摘要:
时域扩散光学成像（time domain diffuse optical imaging, TD-DOI）作为一种先进的组织光学成像技术，通过时间相关单光子计数(time-correlated single photon counting, TCSPC)系统可实现生物组织吸收系数与散射系数的定量重建，从而精确评估组织氧代谢、血流灌注等关键生理参数。然而，受限于TCSPC系统固有的硬件复杂性、高成本特性，目前难以实现临床场景下在体多通道动态监测的规模化应用需求。本文发展了一种双通道差分混合触发参考信号策略，通过结合差分时间数字转换（time-to-digital converter, TDC）器件和光子计数技术，构建稳定可靠的时间扩展曲线（time point spread function, TPSF）测量体系，实现了激光同步信号与出射光子信号时间延迟的亚纳秒级精确标定。实验验证数据显示，所发展系统时间分辨率为55 ps，在2.3×10⁴ 光子/s计数率条件下，TPSF波动系数可稳定控制在1.35%以内（积分时间1 s）。针对组织仿体的光学参数反演测试表明，组织光学参数反演精度方面，吸收系数与约化散射系数的平均反演误差分别在5.39%和4.34%以内。该技术方案显著提升了TD-DOI多通道并行检测可行性，特别适用于脑皮层血氧饱和度动态监测等生物医学场景，为开发新一代穿戴式光学脑功能成像设备奠定了技术基础。
- 时域扩散光学成像 /
- 时间相关单光子计数 /
- 时间数字转换 /
- 光学参数反演
Abstract:
As an advanced tissue optical imaging technology, time-domain diffuse optical imaging (TD-DOI) enables quantitative reconstruction of absorption and reduced scattering coefficients in biological tissues through time-correlated single photon counting (TCSPC) systems, thereby allowing precise assessment of critical physiological parameters such as tissue oxygen metabolism and blood perfusion. However, constrained by the inherent hardware complexity and high cost of TCSPC systems, current implementations face challenges in achieving scalable clinical applications requiring in-vivo multichannel dynamic monitoring. This study innovatively proposes a dual-channel differential hybrid trigger reference signal strategy. By integrating differential time-to-digital converter (TDC) devices with photon counting techniques, we have established a stable and reliable time point spread function (TPSF) measurement system that achieves sub-nanosecond precision (±50 ps) in calibrating the temporal delay between laser synchronization signals and emitted photon events. Experimental validation demonstrates that the developed system attains a temporal resolution of 55 ps. Under photon counting rates of 2.3×10⁴ photons/s, the TPSF fluctuation coefficient remains consistently below 1.35% (1 s integration time). Optical properties inversion on tissue phantoms reveal mean reconstruction errors of 5.39% for absorption coefficient and 4.34% for reduced scattering coefficient. This technological advancement significantly enhances the feasibility of multichannel parallel detection in TD-DOI systems. Particularly suited for biomedical applications, such as dynamic monitoring of cerebral cortical oxygen saturation, it establishes a technical foundation for developing next-generation wearable optical brain function imaging devices.
- time domain diffuse optical imaging /
- time-correlated single photon counting /
- time-to-digital converter /
- optical properties inversion

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图 1 基于差分TDC光子计数技术的TD-DOI系统

Figure 1. TD-DOI system based on differential TDC photon-counting technology

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图 2 数据传输时序逻辑图

Figure 2. Timing diagram of the data transmission

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图 3 差分测量方案：（a）测量系统框图；（b）测量时序图

Figure 3. Differential measurement scheme: (a) block diagram; (b) timing diagram

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图 4 测量结果校正

Figure 4. Measurement calibration

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图 5 标准信号输入时的系统稳定性

Figure 5. System stability under standard signal input

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图 6 TPSF曲线稳定性评估实验：（a）实验配置图（仿体尺寸：长85 cm；宽50 cm；高50 cm）；（b）TCSPC与TDC系统的IRF曲线特点对比；（c）TCSPC在不同配置下TPSF曲线；（d）TDC在不同配置下TPSF曲线；（e）TDC在不同配置下FHWM变化规律

Figure 6. Results of the evaluation of TPSF stability in the phantom experiment: (a) Experimental configuration diagram (phantom dimensions: 85 cm (L) × 50 cm (W) × 50 cm (H)); (b) Comparison of the of the IRF between TCSPC and the TDC module; (c) TPSF of TCSPC under different configurations; (d) TPSF curves of TDC module under different configurations; (e) Variation of FWHM of TDC module under different configurations.

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图 7 光学参数反演实验：（a）TCSPC（积分时间为10 s）反演结果；（b）TDC系统（积分时间为20 s）反演结果

Figure 7. Optical properties inversion experiment: (a) TCSPC (integration time: 10 s) inversion results; (b) TDC system (integration time: 20 s) inversion results

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