Author Affiliations
Abstract
1 College of Computer Science and Electronic Engineering, Hunan University, Changsha 410082, China
2 School of Computer Science, Hubei University of Technology, Wuhan 430068, China
The array spatial light field is an effective means for improving imaging speed in single-pixel imaging. However, distinguishing the intensity values of each sub-light field in the array spatial light field requires the help of the array detector or the time-consuming deep-learning algorithm. Aiming at this problem, we propose measurable speckle gradation Hadamard single-pixel imaging (MSG-HSI), which makes most of the refresh mechanism of the device generate the Hadamard speckle patterns and the high sampling rate of the bucket detector and is capable of measuring the light intensity fluctuation of the array spatial light field only by a simple bucket detector. The numerical and experimental results indicate that data acquisition in MSG-HSI is 4 times faster than in traditional Hadamard single-pixel imaging. Moreover, imaging quality in MSG-HSI can be further improved by image stitching technology. Our approach may open a new perspective for single-pixel imaging to improve imaging speed.
single-pixel imaging array spatial light field measurable speckle gradation Chinese Optics Letters
2024, 22(3): 031104
1 中国科学院上海光学精密机械研究所量子光学重点实验室，上海 201800
2 中国科学院大学材料与光电研究中心，北京 100049
3 宇航智能控制技术国防科技重点实验室，北京 100089
4 自然资源部第二海洋研究所卫星海洋环境动力学国家重点实验室，浙江 杭州 310012
5 中国科学院大学杭州高等研究院物理与光电工程学院，浙江 杭州 310024
针对水下鬼成像重构质量下降、分辨率退化的问题，分析水体对散斑场传播的作用，提出在重构计算前将参考臂散斑进行校正的方法，以实现对物臂散斑场的退化补偿，进而提高水下鬼成像的成像质量。首先根据近似的S-S（Sahu-Shanmugam）散射相函数和Wells模型推导得到调制传递函数，用来描述水体对散斑的退化作用；然后对参考臂散斑场进行校正补偿，使参考臂散斑与物臂散斑具有相同的退化程度以恢复关联性；最后采用校正后的参考臂散斑进行图像重构。从理论上证明了所提方法在二阶关联计算中会使得图像退化加剧，而在基于伪逆的重构计算中则可以有效提高图像分辨率、改善图像质量。通过仿真和实验验证了理论模型的正确性，该研究为远距离水下目标鬼成像图像恢复提供了新的思路。
海洋光学 水下鬼成像 散斑场退化补偿 水体调制传递函数 二阶关联 伪逆
1 南京航空航天大学机电学院，江苏 南京 210000
2 中航西安飞机工业集团股份有限公司复合材料厂，陕西 西安 710089
针对数字剪切散斑干涉技术在检测过程中得到的包裹相位图中存在噪声干扰的问题，本文提出了一种基于同态滤波的正余弦全变分融合降噪的激光散斑图像噪声抑制方法。首先对同态滤波后的包裹相位图进行正余弦分解，然后在分解的基础上通过全变分滤波来抑制噪声，最终通过散斑抑制指数的变化自适应地判断滤波是否完成。通过仿真与实验对所提方法的有效性进行了验证。首先向仿真包裹相位图中添加噪声并采用所提方法进行噪声抑制，根据散斑抑制指数验证所提方法的可行性；然后对预制缺陷的复合材料试件进行检测，并采用所提方法进行噪声抑制；最后通过散斑抑制指数和相位展开结果对所提方法的滤波效果进行验证。结果表明：采用所提方法得到的散斑抑制指数相较于传统的正余弦全变分滤波方法约降低了10.7%，同时有效地保护了相位信息不被破坏。
测量 融合滤波 数字剪切散斑干涉术 散斑图像 噪声抑制
Author Affiliations
Abstract
1 Department of Pain Management, The First Affiliated Hospital, Jinan University, Guang Zhou, Guangdong 510630, P. R. China
2 Department of Pain Management, The First People’s Hospital of Foshan, Foshan City, Guangdong 528000, P. R. China
Temporary spinal cord stimulation (tSCS) can effectively reduce the pain and severity of postherpetic neuralgia (PHN). However, there are no effective and objective methods for predicting the effects of tSCS on PHN. Laser speckle contrast imaging (LSCI) is frequently used in neurology to evaluate the effectiveness of treatment. To assess the accuracy of LSCI in predicting the impact of tSCS on PHN, 14 adult patients receiving tSCS treatments for spinal nerve-innervated (C6-T2) PHN participated in this observational study. Visual analog scale (VAS) assessments and LSCI blood flow images of the fingers were recorded after the tSCS procedure. The results showed that the VAS scores of all patients decreased significantly. Moreover, the blood flow index (BFI) values were significantly higher than they were before the procedure. Increased blood flow and pain alleviation were positively correlated. The findings indicated that spinal nerve PHN (C6-T2) was significantly reduced by tSCS. Pain alleviation by tSCS was positively correlated with increased blood flow in the hand. The effect of tSCS on PHN may thus be predicted using an independent and consistent indicator such as LSCI.
Laser speckle contrast imaging temporary spinal cord stimulation postherpetic neuralgia Journal of Innovative Optical Health Sciences
2024, 17(1): 2350014
Author Affiliations
Abstract
1 School of Biomedical Science, Huaqiao University, Quanzhou 362021, China
2 College of Engineering, Huaqiao University, Quanzhou 362021, China
We propose a laser speckle contrast imaging method based on uniting spatiotemporal Fourier transform. First, the raw speckle images are entirely transformed to the spatiotemporal frequency domain with a three-dimensional (3D) fast Fourier transform. Second, the dynamic and static speckle components are extracted by applying 3D low-pass and high-pass filtering in the spatiotemporal frequency domain and inverse 3D Fourier transform. Third, we calculate the time-averaged modulation depth with the average of both components to map the two-dimensional blood flow distribution. The experiments demonstrate that the proposed method could effectively improve computational efficiency and imaging quality.
uniting spatiotemporal Fourier transform laser speckle contrast image fluctuation modulation 3D Fourier transform Chinese Optics Letters
2024, 22(1): 011701
Author Affiliations
Abstract
1 CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei 230027, China
2 Shenzhen Key Laboratory of Intelligent Optical Measurement and Detection, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
A new electronic speckle pattern interferometry method is proposed to realize in situ deformation measurements. The feature of the method is the combination of a high-speed camera and multiple laser Doppler vibrometers (LDVs) for synchronous measurements. The high-speed camera is used to record and select effective interferograms, while the LDVs are used to measure the rigid body displacement caused by vibrations. A series of effective interferograms with known shifted phase values are obtained to calculate the deformation phase. The experimental results show that the method performs well in measuring static and dynamic deformations with high accuracy in vibrating environments.
speckle pattern interferometry laser Doppler vibrometers in situ deformation measurements Chinese Optics Letters
2024, 22(1): 011202
红外与激光工程
2023, 52(12): 20230348
中国海洋大学物理与光电工程学院，山东青岛 266101
激光散斑会严重影响图像的质量，降低图像的对比度和分辨率，为了抑制激光投影散斑，基于人眼视觉暂留特性和漫散射体散斑抑制原理，搭建了一套基于运动循环胶质溶液的散斑抑制装置，该装置体积小，并能有效抑制散斑，实现散斑对比度低于人眼观测阈值 5%的抑制效果，光的透过率可达 65%以上，同时该装置比起振动扩散器，在降低噪声及价格上具有明显的优势，具有一定的实用推广价值。
激光投影 散斑 漫散射 散斑对比度 扩散器 laser projection speckle diffuse scattering speckle contrast scatter
邓林宵 1,2,3杨雨桦 1,2,3姚昞晖 1,2,3朱立全 1,2,3[ ... ]许立新 1,2,3,*
1 中国科学技术大学 核探测与核电子学国家重点实验室，合肥 230026
2 中国科学技术大学 物理学院 安徽省光电子科学与技术重点实验室，合肥 230026
3 先进激光技术安徽省实验室，合肥 230026
为了探究多基色激光显示系统的彩色散斑特性，采用蒙特卡洛的统计方法模拟了彩色散斑的空间分布。在CIE-u′v′色品图中，定义了彩色散斑椭圆的简化模型，描述了显示系统的彩色散斑空间分布，分析了不同基色数目和波长组合对彩色散斑的影响。结果表明，该椭圆随着基色数目的增加而缩小，彩色散斑严重程度下降; 三基色系统的椭圆面积为16.0×10-4，而六基色系统的椭圆面积为6.81×10-4,其中绿基色对彩色散斑的影响最大; 在多基色显示系统中，对于给定白平衡点的各基色亮度配比不唯一，因此在颜色表现和散斑现象之间存在权衡，当减小散斑对比度值较大的基色亮度的权重时，将减弱彩色散斑现象。该研究为多基色激光显示系统的彩色散斑评估提供了理论指导。
激光技术 彩色散斑 三刺激值 多基色显示 白平衡点 激光显示 laser technique color speckle tristimulus values multi-primary display white point laser display
