车牌识别嵌入式系统的软硬件设计

作为交通信息服务系统的重要手段,车牌识别技术避免了人工操作存在的各种弊端。文中设计了车牌识别嵌入式系统的软硬件,该系统的整体框架主要包含3个模块,分别是OV7670摄像头、STM32单片机和TFT显示屏。为满足任务需求,设计了最小系统和电源模块等硬件;为解决传统投影法误差较大的问题,该系统在字符分割前会先对车牌区域进行识别,并采用上下投影的方式在有效区域内进行字符分割。实验表明,该系统可以实现车牌识别功能,且精确度较高。     

Tuning the band gap of the CIGS solar buffer layer Cd1-xZnxS (x=0—1) to achieve high efficiency

To evaluate the impact of zinc sulfate (ZnSO4) concentration on the structural properties of the films, Cd1-xZnxS thin films were formed on glass substrates using chemical bath deposition (CBD) in this study. The effect of ZnSO4 precursor concentration on the surface morphology, optical properties, and morphological structure of the Cd1-xZnxS films was investigated. To study the impact of zinc doping content on the performance metrics of Cu(In1-xGax)Se2 (CIGS) cells in the experimental group and to improve the buffer layer thickness, simulations were run using one-dimensional solar cell capacitance simulator (SCAPS-1D) software.     

Analysis of light propagation characteristic in the aero-optic flow field of cone-headed vehicle with side window

Aero-optic imaging deviation research is carried out for infrared-guided vehicle with cone-head side window, with a focus on the propagation characteristics of light in an aero-optic flow field. When the light entering the aero-optic flow field from the free-stream should be close to the normal, numerous data indicate that the light is refracted away from the normal. This paper divides the aero-optic flow field into two parts and uses the gas density distribution in the aero-optic flow field to ...     

能量注量对钛板激光着色的颜色变化影响研究北大核心CSCD

各种激光工艺参数共同作用影响激光彩色打标的结果,不同参数之间相互关系比较复杂。为了获得更优质颜色和基于TA2钛板上更全的激光着色色谱,本实验选用波长为1064 nm、最大输出功率为20 W的MOPA光纤激光器进行试验,通过分光测色仪对彩色样品的色彩、可见光谱进行采集分析。结果表明,通过简化参数间关系,以能量累计注量的变化量dQ产生的色差为依据,调节扫描速度、线间距、功率变化量dP来改变dQ大小,能够获得更丰富的颜色。     

Blood cell counting based on U-Net++ and YOLOv5

Clinical information about a variety of disorders is available through blood cell counting, which is usually done by manual methods. However, manual methods are complex, time-consuming and susceptible to the subjective experience of inspectors. Although many efforts have been made to develop automated blood cell counting algorithms, the complexity of blood cell distribution and the highly overlapping nature of some red blood cells (RBCs) remain significant challenges that limit the improvement of analytical accuracy. Here, we proposed an end-to-end method for blood cell counting based on deep learning. Firstly, U-Net++ was used to segment the whole blood cell image into several regions of interest (ROI), and each ROI contains only one single cell or multiple overlapping cells. Subsequently, YOLOv5 was used to detect blood cells in each ROI. Specifically, we proposed several strategies, including fine classification of RBCs, adaptive adjustment for non-maximal suppression (NMS) threshold and blood cell morphology constraints to improve the accuracy of detection. Finally, the detection outcomes for each ROI were combined and superimposed. The results show that our method can effectively address the issue of high overlap and precisely segment and detect blood cells, with a 98.18% accuracy rate for blood cell counting.     

嵌入式电子助力转向系统研究

电子转向助力技术能够有效驱动汽车转向,为提高其转向控制的稳定性和准确性,本文设计了一种基于嵌入式的电子助力转向系统。首先针对传统的电子助力转向系统,利用牛顿第二定律建立其动力学模型,为控制器设计及构建硬件环境奠定基础。其次,针对典型电子转向助力系统的动力学模型,为降低其运动副间的摩擦对控制性能的影响,设计了自适应摩擦前馈补偿控制器,并根据Lyapunov稳定性原则确定了自适应控制率解析表达式。再次,本文以STM32F407嵌入式控制器为核心,搭建系统硬件平台并设计软件流程。最后,基于此平台展开试验验证,系统通过跟踪阶跃指令和正弦指令对比分析了传统PID算法和自适应摩擦前馈补偿算法,试验结果表明自适应前馈补偿算法可提高系统稳态精度和动态响应能力,并验证所设计的基于嵌入式的电子助力转向系统的正确性和完整性。     

Partial Quenching of Parametrical Tetragonality of a Chromium(III) Complex by Pressure Tuning

The ligand-field spectrum of [Cr(NH(3))(4)F(2)]AsF(6) has been pressure-tuned up to 100 kbar. The parametrical analysis shows that the absolute values of the two independent tetragonalities of the chromophoric ion both decrease with increasing isotropic pressure so that the molecular ion becomes more isotropic. Moreover, the Cr-N single bonds appear to be more compressible than the Cr-F bonds, for which it is parametrically clear that they have a partial multiple-bond character. While the spectrochemical parameter for F(-), Delta(F), increases with pressure, its two components Delta(sigma)(F) and Delta(pi)(F) decrease. It is confirmed that nephelauxetism increases with pressure.