红外与激光工程
2023, 52(11): 20230229
Author Affiliations
Abstract
1 School of Integrated Circuits, Huazhong University of Science and Technology, Wuhan 430074, China
2 Hubei Yangtze Memory Laboratories, Wuhan 430205, China
Sparse coding is a prevalent method for image inpainting and feature extraction, which can repair corrupted images or improve data processing efficiency, and has numerous applications in computer vision and signal processing. Recently, several memristor-based in-memory computing systems have been proposed to enhance the efficiency of sparse coding remarkably. However, the variations and low precision of the devices will deteriorate the dictionary, causing inevitable degradation in the accuracy and reliability of the application. In this work, a digital-analog hybrid memristive sparse coding system is proposed utilizing a multilevel Pt/Al2O3/AlOx/W memristor, which employs the forward stagewise regression algorithm: The approximate cosine distance calculation is conducted in the analog part to speed up the computation, followed by high-precision coefficient updates performed in the digital portion. We determine that four states of the aforementioned memristor are sufficient for the processing of natural images. Furthermore, through dynamic adjustment of the mapping ratio, the precision requirement for the digit-to-analog converters can be reduced to 4 bits. Compared to the previous system, our system achieves higher image reconstruction quality of the 38 dB peak-signal-to-noise ratio. Moreover, in the context of image inpainting, images containing 50% missing pixels can be restored with a reconstruction error of 0.0424 root-mean-squared error.
forward stagewise regression in-memory computing memristor sparse coding Journal of Semiconductors
2023, 44(10): 104101
1 浙江大学材料科学与工程学院硅材料国家重点实验室，杭州 310027
2 中国建筑第四工程局有限公司， 广州 510665
随着机器学习技术的不断发展和玻璃材料数据的逐步积累，基于数据驱动的组分设计方法已成为玻璃新材料开发的一种有力手段。本文采用随机森林回归算法构建了包含56种氧化物的玻璃组分与性能预测模型，并采用SHAP分析等方法进行了可解释性研究，实现了在高维组分空间对线膨胀系数、密度及弹性模量的准确预测。利用该预测模型在Si-Al-B-Ca-Mg-Na六元氧化物组分空间中对约118万个玻璃配方进行快速预测，并对优选的4组硼硅酸盐玻璃样品进行测试。结果表明，样品的线膨胀系数分布在(5200~5800)×10-7℃-1，密度分布在234~239 g/cm3，弹性模量分布在6700~74.00 GPa，与模型预测结果相符，且优于相关规范要求。
机器学习 数据驱动 幕墙玻璃 硼硅酸盐氧化物玻璃 组分设计 machine learning data driving glass curtain wall borosilicate oxide glass composition design
1 School of Integrated Circuits, School of Optical and Electronic Information, Wuhan National Laboratory for Optoelectronics, Optics Valley Laboratory, Huazhong University of Science and Technology, Wuhan 430074, China
2 Hubei Yangtze Memory Laboratories, Wuhan 430205, China
3 AI Chip Center for Emerging Smart Systems, InnoHK Centers, Hong Kong Science Park, Hong Kong, China
4 School of Integrated Circuits, Peking University, Beijing 100871, China
5 School of Integrated Circuits, Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing 100084, China
6 Frontier Institute of Chip and System, Fudan University, Shanghai 200433, China
7 School of Electronic Science and Engineering, and Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing 210093, China
Frontiers of Optoelectronics
2022, 15(2): s12200
1 武汉理工大学 材料科学与工程学院, 湖北 武汉 430070
2 武汉理工大学 三亚科教创新园, 海南 三亚 572019
随着地震勘探的深度越来越大, 地震反射波不断向低频段发展, 迫切要求开发低频传感器。该文设计制备了PZT-5H基压电纤维复合材料(MFC)悬臂梁式传感器, 并将其应用于低频传感领域。通过有限元仿真模拟, 力-电耦合分析探明了MFC悬臂梁结构中基板材料及结构尺寸参数对MFC电输出性能的影响规律, 进而优化结构参数, 研制了低频振动监测用MFC悬臂梁传感元件。对其传感性能进行了测试研究。测试结果表明, MFC悬臂梁可很好地感知低频振动加速度的变化, 在低频段(5~190 Hz)时加速度灵敏度可达205 mV/g(g=9.8 m/s2)。
压电纤维复合材料 悬臂梁 有限元模拟 低频传感 macro fibre composite(MFC) cantilever beam finite element simulation low frequency sensing
1 徐州工程学院材料与化学工程学院，徐州 221018
2 北京航空航天大学杭州创新研究院，杭州 310051
石墨相氮化碳(g-C3N4)的研究已成为光催化领域热点。本文以三聚氰氨为前驱体，采用甲醇回流法制备Er掺杂的g-C3N4催化剂。利用扫描电镜(SEM)、X射线光电子能谱(XPS)、X射线衍射仪(XRD)、紫外-可见-近红外分光光度计(UV-Vis-NIR DRS)、傅里叶红外光谱仪(IR)、荧光光谱(PL)、物理吸附(N2-physisorption)及共聚焦显微镜(CLSM)等手段对Er/g-C3N4催化剂进行系统表征。结果表明，稀土金属Er高分散于g-C3N4上，促使氮化碳表面氮空穴的产生。Er掺杂优化了氮化碳的能带结构，增强了其对可见光的吸收，提升电子-空穴对的分离效率，此外还发现Er/g-C3N4具有较强的上转换能力。在660 nm红光LED照射下，对罗丹明B的水溶液进行光催化降解，发现Er/g-C3N4的降解速率是g-C3N4的2.0倍，且发现超氧自由基为该体系中的主要活性物种。
铒掺杂 甲醇回流法 光催化 红光 上转换 降解活性 g-C3N4 g-C3N4 Er doped methanol-refluxing method photocatalysis red light upconversion degradation activity
长春职业技术学院 信息技术学院, 长春 130000
为了可以同时获取多谱段光谱信息, 并且多测试数据同步处理, 设计了一种基于现场可编程门阵列+数据信号处理器的同步采集与处理系统。采用非均匀快速傅里叶变换(NUFFT)算法对包含目标信息的谱段采样进行了针对多谱段数据非均匀采样的理论分析和实验验证。针对632nm, 880nm和980nm 3种不同激光波长同时实验测试, 分别采用本系统与传统光谱分析算法进行了对比。结果表明, 本系统在3个波长峰值位置上的信噪比分别是31.6dBm,36.3dBm和32.5dBm, 而传统光谱仪的信噪比仅为20.1dBm,25.4dBm和23.7dBm, 采用本系统硬件设计配合NUFFT算法可以有效增强多谱段光谱信息获取过程中的信噪比。本系统的处理速度更快, 在多光谱快速处理方面具有一定的应用价值。
测量与计量 非均匀快速傅里叶变换 多光谱数据处理 现场可编辑程门阵列+数据信号处理器 measurement and metrology non-uniform fast Fouriter transform multi-spectral data processing field-programmable gate array+digital signal proce
Author Affiliations
Abstract
1 Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong, University of Science and Technology, Wuhan, Hubei 430074, P. R. China
2 MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P. R. China
3 Department of Clinical Laboratory, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P. R. China
4 Department of Pathology, Hubei Maternal and Child Health Hospital, Wuhan, Hubei 430072, P. R. China
Computer-assisted cervical screening is an effective method to save the doctors' workload and improve their work e±ciency. Usually, the correct classification of cervical cells depends on the nuclear segmentation effect and the extraction of nuclear features. However, the precise nucleus segmentation remains a huge challenge, especially for densely distributed nucleus. Moreover, previous cellular classification methods are mostly based on morphological features of nucleus size or color. Those individual features can make accurate classification for severe lesions, but not for mild lesions. In this paper, we propose an accurate instance segmentation algorithm and propose cognition-based features to identify cervical cancer cells. Different from previous individual nucleus features, we also propose population features and cognition-based features according to the Bethesda System (TBS) for reporting cervical cytology and the diagnostic experience of the cytologists. The results showed that the segmentation achieves better success in complex situations than that by traditional segmentation algorithms. Besides, the cell classification via cognition-based features also help us find out more about less severe lesions' nuclei than that based on conventional features of individual nucleus, meaning an improvement of classification accuracy for cervical screening.
Cervical cancer instance segmentation nucleus classification lesion cognition Journal of Innovative Optical Health Sciences
2020, 13(1):
为了高速采集并反演光谱数据, 采用 FPGA设计了一种高速光谱反演系统。由 FPGA控制 CCD驱动模块, 使 CCD高速采集干涉条纹数据并传输给 FPGA处理模块。设计了高速数据采集与处理的 FPGA硬件结构, 通过仿真数据分析了采集模块与处理模块的时序逻辑关系。为了同时满足系统光谱反演精度与速度的要求, 对比了 8 bit、10 bit和 12 bit数据位深条件下的频谱分布, 实验结果显示, 位深越小速度越快, 但其会降低光谱反演的对比度; 而位深越大光谱反演的对比度越好, 但处理速度越慢, 综合考虑本系统采用 10 bit位深结构。实验针对中心波长为 975 nm的激光进行光谱反演, 并与 MATLAB反演数据进行对比分析。结果显示本系统检测精度符合要求, 且速度更快。
高速光谱反演 干涉条纹 位深设置 high-speed spectral inversion, interference fringe FPGA
1 国防科技大学 信息通信学院, 武汉 430010
2 军事科学院 系统工程研究院, 北京 100141
3 武警河北总队参谋部综合信息保障中心, 石家庄 050073
文章对双向混沌保密通信方式进行了设计和研究, 提出了一种双向混沌同步的理论模型及系统架构, 并证明了其通信的可行性和安全性, 利用通信双方系统的对称性, 提高了混沌同步对色散和非线性效应的鲁棒性。最后, 仿真证明了相互耦合的激光混沌系统可实现通信双方的抗截获保密通信。
混沌同步 保密光通信 抗截获 chaos synchronization secure communication anti-interception
