共查询到19条相似文献,搜索用时 96 毫秒
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介绍了一种以发光二极管(LED)点光源作为相机标定光源的方法。根据LED点光源的特性,用恒流源给LED点光源提供所需的电流,用光照度计测量LED光源的光强度。由ARM单片下位机控制恒流源;通过串行通讯与上位机交换数据;由计算机作为上位机来管理数控恒流源和光照度计;根据所测光度值来调节电流,直到光度达到预想值。实验分析显示:LED点光源作为标定光源可以达到CCD标定的要求,精度也较高,能够很好地自适应控制LED的光照强度,达到了预期的效果,且系统使用方便灵活,性能稳定可靠。 相似文献
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清晰显示高分辨率画面是LED显示屏图像质量提升领域中亟待解决的关键问题之一.针对LED显示屏分辨率低、成本高、像素排布灵活的特点,研究了亚像素采样技术在LED显示屏中的应用.从信号处理的角度,在RGB颜色空间中对LED显示屏建立了全像素采样和亚像素采样数学模型,在亮度与色度相分离的空间中对两种采样方式进行了频谱分析,证明了应用亚像素采样技术可以将显示系统的亮度混叠转移到了人眼较不敏感的颜色通道上,有效扩展了LED显示系统在各方向上的Nyquist频率限制.物理屏体上的仿真实验表明亚像素采样对LED显示屏的图像显示质量具有改善作用. 相似文献
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基于发光二极管(Light-emitting Diode,LED)的电脉冲响应过程,建立了一个简便计算LED电脉冲响应模型。在此模型基础上研究了采用脉宽调制(Pulse-width Modulation,PWM)控制LED亮度时,由于LED响应延迟所导致的发光强度随占空比的非线性误差的变化情况,并进行了实验测试。结果表明:在PWM频率为2.5MHz时,LED发光强度与占空比的平均非线性误差为10%左右。最后,针对LED电脉冲响应模型,提出了显示屏像素亮度校正方法。该方法有效减小了由LED响应过程所造成的显示屏亮度控制误差,使得LED实际发光强度与所给亮度值近似成线性关系,从而减小了LED显示屏的色彩偏离,增强了显示效果。 相似文献
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《物理学报》2020,(19)
随着显示技术的不断发展,高度微型化和集成化成为显示领域主要的发展趋势.微米发光二极管(lightemitting diode, LED)显示是一种由微米级半导体发光单元组成的阵列显示技术,在亮度、分辨率、对比度、能耗、使用寿命、响应速度和稳定性等方面相比于液晶显示和有机发光二极管显示均具有巨大的优势,应用前景十分广阔,同时也被视为下一代显示技术.目前商用的5G通信技术与显示领域的虚拟现实、增强现实和超高清视频等技术的结合,将进一步推动微米LED显示产业的发展.在面临发展机遇的同时,微米LED显示领域也存在着一些基础科学技术问题需要解决.本文主要总结了微米LED显示从2000年以来的一些研究进展,重点介绍了微米LED显示在外延生长和芯片工艺两方面存在的主要问题和可能的解决方案.在外延生长方面主要介绍了缺陷控制、极化电场控制和波长均匀性等研究进展,芯片工艺方面主要介绍了全彩色显示、巨量转移和检测技术等进展情况,并对微米LED显示在这两方面的发展趋势进行了讨论. 相似文献
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通常情况下,由于计算机在字符显示状态下在内存中存在一个显示代码缓存区,此缓存区存放屏幕上显示内容的ASCⅡ码;因此在LED显示应用上,尤其在需要将控制机显示内容在另一区域的LED屏幕重现时所需要的数据传输方面上,上述代码缓存区具有重要的作用.但是当我们使用象pc-1500这样的机器作LED显示系统的控制机时,由于它无上述的系统有规律的顺序显示代码缓存区,同时鉴于LED与主控机点阵的不同及需传送的数据量等问题,我们在传输屏幕内容上存在一定的困难.本文提出并采用一种布尔变换及解变换方法来解决这个问题. 相似文献
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同时记录与高速事件相关的信息是进行胶片判读处理的必要条件,数据记录系统就是由高速摄影机的同步控制信号控制选通,将与事件相关的信息经特殊处理,由集成数据点阵头记录在胶片上,为此后的胶片判读及对拍摄事件进行更精细的分析处理提供定量、实时的依据。 相似文献
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The variable structure control (VSC) and the stabilizer design by using pole placement technique are applied to the tracking control of the flexible slider-crank mechanism under impact. The VSC strategy is employed to track the crank angular position and speed, while the stabilizer design is involved to suppress the flexible vibrations simultaneously. From the theoretical impact consideration, three approaches including the generalized momentum balance (GMB), the continuous force model (CFM), and the CFM associated with the effective mass compensation EMC are adopted, and are derived on the basis of the energy and impulse-momentum conservations. Simulation results are provided to demonstrate the performance of the motor-controller flexible slider-crank mechanism not only accomplishing good tracking trajectory of the crank angle, but also eliminating vibrations of the flexible connecting rod. 相似文献
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Effect of different bending shapes on thermal properties of flexible light-emitting diode filament 下载免费PDF全文
《中国物理 B》2018,(11)
Heat dissipation is an important part of light-emitting diode(LED) filament research and has aroused constant concern.In this paper, we studied the thermal performance of flexible LED filament by numerical simulation and through experiment.The heat dissipation characteristics of spring-like structure flexible LED filament were computed by finite volume method,and it was found that the chip junction temperature was closely related to the pitch and the bending radius. The effect of inclination angle of lighting LED filament was discussed because it is relevant to the spring-like structure flexible LED filament in geometry. The results demonstrated that the temperature of the filament increases as the inclination angle improves. 相似文献
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针对现有城市路灯控制系统路灯使用寿命短、无法远程操控、不能自动识别故障路灯的问题,提出一种基于GPRS网络技术和ZigBee无线通信技术的节能型LED路灯智能控制系统,使用ZigBee无线网络与LED路灯控制终端通信,并通过GPRS通讯模块接入GPRS网络与远程控制中心相连,实现远程控制LED路灯,此外,通过LED路灯控制终端实时采集路灯电压和电流,实现LED路灯的远程监控。具体阐述了GPRS通讯模块、ZigBee无线网络模块、LED控制终端的硬件设计方案,软件设计流程,系统通信协议和远程控制实现方法。测试结果证明此系统数据传输可靠、响应及时、成本低、易于实现LED路灯的远程控制和远程监控,具有较大的实用性和推广价值。 相似文献
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全彩色LED显示屏可以用来显示电视画面。目前没有专门用于LED彩色大屏幕的图像源及其标准,所以都是将送给CRT显像管的图形信号源送到LED彩色大屏幕进行显示。针对把送给CRT的信号送到LED屏进行显示会引起彩色失真这种情况,本文给出LED大屏幕系统的色度公式,为准确控制LED管的发光亮度提供理论依据,并给出产例。 相似文献
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P.W. LOVEDAYC.A. ROGERS 《Journal of sound and vibration》2002,255(3):417-432
Understanding the influence of the control system on the performance of vibratory gyroscopes is important during the design of such devices. The ability of the control system to reduce the effects of resonator imperfections, on the gyroscope performance, was investigated. The analysis of the control problem presented begins with equations of motion describing the dynamics of a resonator including frequency and damping imperfections. These equations were transformed to slowly varying parameters and averaged. The equations of motion, in this form, provide many insights into the dynamics of the resonator and suggest the control system functions required to effectively operate the resonator as an angular rate sensor. A phase-locked loop-based control system was designed, analyzed and implemented. The control system drives the resonator at resonance to a constant amplitude and nulls the rotation-induced vibrations. It was shown analytically that the first order effects of frequency imperfections can be eliminated by the control system. The effect of damping anisotropy is not reduced by the control system and this is expected to be the major source of error in the closed-loop system. Experimental measurements, of a piezoelectrically actuated and sensed resonator, over a temperature range of 60°C, showed that variation of the zero-rate offset was decreased by an order of magnitude by the force-to-rebalance control. The analytical and experimental results present a convincing argument for the use of force-to-rebalance control in vibratory gyroscopes. 相似文献
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This paper presents a four-dimensional nonlinear dynamical system. By the numerical simulation the hyperchaotic attractor, Lyapunov exponents and Lyapunov dimension are obtained, also it is confirmed that hyperchaos can be driven in the system described by the equation. The control action of the periodic perturbation on the autonomous hyperchaotic system is studied, and a control rule is obtained which indicates the relationship of the control action and the frequency characteristics after degeneration of the system. Finaly the circuit implementation of the dynamical system is given. 相似文献