壁纸机预套准系统研究

预套准是印刷机套准系统的前提。在预套准过程中,当"零位"标志靠近接近开关时,接近开关就会发出的脉冲信号,这个信号经过DSP和FPGA分析处理,可以控制伺服电机使每个色组单元达到预定的位置,为自动套准做好准备并且提高套准精度。预套准是精确套准的重要前提。     

接近开关的原理及应用

接近开关是一种无需与运动部件进行机械接触就可以进行检测的位置开关,这种接近开关不需要机械接触和施加任何压力即可动作,从而驱动执行机构或给采集装置提供信号.文中简要介绍了接近开关的工作原理和分类,给出了接近开关在自来水厂清污机以及刮沙机上的应用实例和具体方法.     

JK系列集成电路接近开关

JK系列集成电路接近开关是上海奉贤县精明电器厂研制生产的一种电感式(即高频振荡型)接近开关。是一种把位量(如定位、定向、位移、转速等)转变为以电量形式的开关量信号的电子传感器件。它的作用原理是利用开放型电感配以电容产生一高频振荡当金属体靠近电感时,将在金属体内产生涡流损耗,使振荡回路Q值下降,从而破坏了振荡条件,迫使振荡停止,产生控制信号。它被广泛应用于工业自动化的控制中。     

视音频信号同线传输调制解调器

视频切换开关在电视系统中应用非常广泛。视频切换开关目前有两种形式 ,一种是普通的视频切换开关 ,结构简单 ,但日后升级困难 ,不能进行远程控制 ,价格便宜。另一种是计算机控制的切换开关 ,今后更新换代方便 ,能进行远程控制 ,输入端和输出端可随意组合 ,而且可以编程控制 ,目前 ,多媒体计算机内视频卡开关只是视频开关 ,不能同时进行视音频的同步切换。为了能同时切换视音频信号。我们研制了视音频信号同线传输的调制器和解调器。1调制解调器的原理视音频同线传输调制和解调器的原理及系统部分的框图 ,如图 1所示。音频信号经预加重电路…     

一种带预加重的开关电流源LVDS驱动器

低压差分信号传输(LVDS)是一种重要的信号传输技术。本文设计了一种集成开关双电流源的结构的LVDS驱动电路,能工作在低电源电压的条件下,并实现了预加重功能以提高其抗干扰能力。     

一种用于背板传输的6.25 Gbps均衡和预加重电路设计

利用0.35μm SiGe BICMOS工艺,设计了一种接收均衡和发送预加重电路。均衡部分采用2级级联的连续时间线性均衡器,补偿由于传输通道损耗带入的信号高频分量衰减。预加重部分采用了一种新型的开关电容式,电流注入结构进行比特位预加重,对高频信号进行预补偿,以降低由于信道衰减造成的ISI。测试结果显示该电路速率范围可达DC~6.25Gbps,均衡器最大可补偿-14dB@3.125GHz的信号衰减,驱动器输出预加重比例为6dB。     

注入子脉冲的Q开关Nd:YAG振荡器的单轴模工作

单轴模工作的Q开关高峰值功率的Nd:YAG激光器对非线性和光谱研究是一种非常有效的功率源。以前已报道由注入外部信号到非稳腔的Nd:YAG振荡器得到稳定的单轴模工作。本文介绍通过注入外部信号到Q开关Nd:YAG激光振荡器的单轴模选择的理论和实验上的讨论。一、理论模型图1示出通过注入外部信号的子脉冲到Q开关或增益开关激光振荡器单轴模选择过程的概念。注入的外部信号频率为ω_i,带宽比单轴模间隔窄,接近一个子振荡器的单轴模频     

解决准方波谐振电源的谷底跳频问题

准方波谐振转换器也称作准谐振(QR)转换器,使反激式开关电源(SMPS)设计的信号电磁干扰(EMI)更低及满载能效更高。然而,由于负载下降时开关频率升高,必须限制频率漂移,避免额外的开关损耗。     

低时间抖动的增益开关型被动调Q激光器

被动调Q激光器的输出抖动一般较大,为了降低这一输出时间抖动,同时实现激光器的小型化,可以根据增益开关工作原理,利用电源控制抽运功率密度变化,实现被动调Q情况下的增益开关.根据这一原理研制了环形激光二极管(LD)抽运增益开关调Q激光器.这种新型被动调Q激光器的输出能量为30 mJ,输出脉冲宽度约16 ns.实验中将传统的两套抽运源减少为一套,通过控制电源波形直接形成抽运功率的增益台阶脉冲,减少了影响时间跳动的因素.多发次统计测量结果表明,激光脉冲与电源输出外触发信号的时间抖动小于1 μs.根据测量的抽运预脉冲功率稳定性和阶跃脉冲的瞬时抽运功率计算的输出抖动与实验结果基本相符.     

2003年全国大学生电子设计竞赛一等奖液体点滴速度监控装置

方案一：使用电容式接近开关。电路集成度高，使用继电器输出，输出信号标准，电路简单。但其工作原理是根据电容中介质的改变对外产生开关量，经过调试发现由于瓶中液体和周围环境随时会发生变化，很容易触发传感器，而使系统采集到错误的信号。     

Image registration based on lifting process: an application to digital subtraction radiography.

In this paper, a digital subtraction radiology scheme is presented based on a new method for the automatic registration of dental radiographs acquired with or without rigorous a priori standardization. The scheme is comprised of an automatic registration method and a subtraction process. The proposed registration method can be considered as an object-based registration method without imposing the prerequisite of image segmentation in order to detect the boundary of the objects of interest or the automatic detection of matching landmarks. This is achieved by augmenting the dimensionality of the problem from two-dimensional gray-level matching to three-dimensional surface matching using the process of lifting in combination with a surface-matching technique. The pseudo three-dimensional affine transformation that matches the lifted images incorporates advantageous characteristics including spatial alignment of the surfaces, anisotropic correction of brightness/contrast differences, and stable convergence of the similarity function to its optimal value. The performance of the proposed automatic registration method is assessed against a manual method based on the projective transformation. The qualitative and quantitative assessments of the experiments have shown advantageous performance of the proposed automatic registration method against the manual one. Finally, the proposed registration method has been further improved in terms of execution time by the implementation of a surface decimation process.     

遥感影像的半自动配准

图像的半自动配准是当前比较先进的图像配准技术。该方法基于初步定位基础,利用模板相关的匹配方法,根据遥感图像之间灰度分布的相关性,选取数量丰富的配准控制点,利用相关系数准则进行图像间的相似性度量,可达到较高的配准精度。实验结果表明,该匹配方法用于遥感图像的配准能够有效提高图像处理的速度以及校正图像的定位精度。     

Monocular camera and 3D lidar joint calibration

Joint calibration of sensors is an important prerequisite in intelligent driving scene retrieval and recognition. A simple and efficient solution is proposed for solving the problem of automatic joint calibration registration between the monocular camera and the 16-line lidar. The study is divided into two parts: single-sensor independent calibration and multi-sensor joint registration, in which the selected objective world is used. The system associates the lidar coordinates with the camera coordinates. The lidar and the camera are used to obtain the normal vectors of the calibration plate and the point cloud data representing the calibration plate by the appropriate algorithm. Iterated closest points (ICP) is the method used for the iterative refinement of the registration.     

Automatic correction of registration errors in surgical navigation systems

Surgical navigation systems are used widely among all fields of modern medicine, including, but not limited to ENT- and maxillofacial surgery. As a fundamental prerequisite for image-guided surgery, intraoperative registration, which maps image to patient coordinates, has been subject to many studies and developments. While registration methods have evolved from invasive procedures like fixed stereotactic frames and implanted fiducial markers toward surface-based registration and noninvasive markers fixed to the patient's skin, even the most sophisticated registration techniques produce an imperfect result. Due to errors introduced during the registration process, the projection of navigated instruments into image data deviates up to several millimeter from the actual position, depending on the applied registration method and the distance between the instrument and the fiducial markers. We propose a method that allows to automatically and continually improve registration accuracy during intraoperative navigation after the actual registration process has been completed. The projections of navigated instruments into image data are inspected and validated by the navigation software. Errors in image-to-patient registration are identified by calculating intersections between the virtual instruments' axes and surfaces of hard bone tissue extracted from the patient's image data. The information gained from the identification of such registration errors is then used to improve registration accuracy by adding an additional pair of registration points at every location where an error has been detected. The proposed method was integrated into a surgical navigation system based on paired points registration with anatomical landmarks. Experiments were conducted, where registrations with deliberately misplaced point pairs were corrected with automatic error correction. Results showed an improvement in registration quality in all cases.     

RF MEMS开关的设计分析

针对具有低损耗、高隔离度性能的微机电系统(Micro-Electro-Mechanical System,MEMS)开关,介绍了串联DC式和并联电容式的开关结构模型,并对并联电容式MEMS开关的工作原理、等效电路模型和制造工艺流程进行了描述,利用其模型研究了开关的微波传输性能,设计了一款电容耦合式开关并进行了仿真。由仿真结果可得,开关"开态"时的插入损耗在40 GHz以内优于-0.3 dB;开关"关态"时的隔离度在20～40 GHz相对较宽的频带内优于-20 dB。     

继电器延迟时间测量电路的研究与设计

由于继电器触点开关“吸合”“释放”时要产生延时参数。此延时给自动控制带来麻烦。本文论述了继电器触点“开”“关”延迟理论。设计了一种简单可靠的延时测试电路。用此电路对市场上两种继电器抽检测试结果,均符合继电器技术条件要求。论文从理论上计算了它的延迟时间,并与测试结果进行了分析。本电路可应用于对继电器有延时要求的设计师和工厂检验人员制作检测装置或设备使用。     

多传感器误差配准研究

多传感器组网信息融合时,需要对组网中各传感器系统误差进行估计和补偿,以消除各传感器系统误差对融合性能的影响。研究了雷达组网系统误差配准模型,并对最小二乘算法 (LS)、广义最小二乘算法(GLS)、递推最小二乘算法(RLS)、修正 EX 算法等误差配准算法进行对比分析,同时给出了扩维配准模型用于解决多传感器组网配准问题,针对实际工程应用中算法收敛情况难以判断的问题,提出了一种误差配准收敛性判定的方法。根据仿真结果对误差配准算法性能进行分析,同时验证了扩维配准和收敛性判定方法的有效性,支撑配准系统应用。     

基于梯度相位相关的自动图像配准方法

图像配准是超分辨率重建、图像融合的基础。提出了非迭代的基于梯度相位相关的图像自动配准方法。首先分析了图像梯度和相位相关的理论,证明了提出方法的正确性;然后给出了图像配准的过程,并利用人工平移图像配准对该方法进行了实验验证。实验表明,该方法配准精度高,能有效地实现图像的自动配准。     

一种精确的预警机误差配准算法

误差配准是多传感器数据融合的先期处理过程。介绍了载机雷达所用坐标系,在考虑载机机动的前提下,给出了预警机系统到地面融合中心的基于地心地固坐标系(ECEF)高精度坐标转换算法。分析了由于载机机动导致的转换偏差,给出了误差补偿模型,然后用卡尔曼滤波实时估计出预警机对地面融合中心的系统偏差,从而实现对预警机的误差配准。计算机仿真结果证明了算法的正确性和有效性。     

NRST及其在需求过程调度中的应用

网络式软件作为基于Internet这一开放环境运行的软件的一个典型代表,其全开放运行机制使得需求过程的自动调度尤为重要.为此,首先将网络式软件的需求状态(NRS)划分为6个状态,并利用网络式软件需求状态跟踪(NRST)图刻画出了各个需求状态之间的转化.最后,利用NRST,有效地实现了网络式软件需求过程的自动转换与调度,使得整个需求分析过程能够在Internet网上无须人的过多干预,而由计算机自动完成.