从光栅模式和矢量模式考察图形输入输出方法

一、光栅模式和矢量模式的概念 无论是图形的输入、生成、存储、处理或输出,都是以矢量模式或光栅模式这两种形式来表达图形的。以显示器为例,在随机扫描的CRT中,电子束像一支快速移动的画笔,实际勾画出要显示的图形,电子束根据需要可在荧光屏的任意方向上连续扫描,没有固定扫描线和规定扫描顺序的限制,它描绘的图形只能是单线条图形,故称随机扫描,也称矢量扫描或轨迹扫描。笔式绘图机是典型的矢量设备。 在光栅扫描的CRT中,电子束依照固定的扫描线和规定的扫描顺序,自上而下,从左到右扫描。

基于离轴刻写的FBG包层模式的光纤弯曲传感器

基于光纤光栅(FBG)包层模式,制作了一种弯曲在线监测的全光纤传感器。传感器使用193nm ArF准分子激光器,通过离轴刻栅的方式在15mm单模光纤上刻写的光栅。对该传感器的弯曲和温度变化的响应特性进行了理论分析,并在0~1.2m-1曲率变化范围内,对传感器的弯曲响应特性进行了实验研究,结果表明,随着弯曲曲率的增大,包层模式的强度下降。其对弯曲的响应灵敏度为0.11dB/m-1,线性度为0.996,表现出了它较高的灵敏度和线性度。随着环境温度从25℃变化到60℃,该传感器峰值波长响应灵敏度为0.02nm/℃。结果表明,该型传感器对温度干扰不敏感。由于其结构简单,制作方便,精度高,在油气田管道健康监测领域有较好的应用前景。

基于改进型傅氏变换轮廓术检测螺纹钢肋径

采用改进型傅氏变换轮廓(I FTP)术,提出了一种实用化的非接触式三维测量系统。通过计算机建模仿真,证明了该技术用于三维测量的可行性。采用了一种局部滤波的方法,通过滤波修正测量结果,使得测量精度明显提高。利用该系统对螺纹钢肋径进行实际测量,获得了良好的实验结果,经与实际值对比,并进行误差分析,验证了该系统具有实用价值和开发前景。

DrawDib函数组在图形图象处理方面的应用

介绍DrawDib函数组和StretchDIBits函数在颜色信息表格式、光栅操作模式、视频及动画回放的质量、显示适配器、图象拉伸、压缩图象等处理方面的区别 ,分析DrawDib函数组在图象再现、图象序列、调色板及图象处理时间计算等方面的操作方法 ,并结合实例介绍DrawDib函数组的使用 .

Analytic expression of the chirped sampled function used to produce the equal chirp in the specific reflection channel in uniform period fiber Bragg gratings

The general analytic expression of the chirped sampled function is derived based on coupled mode theory. This function can be used to describe how to use uniform period fiber Bragg grating to produce the equal chirp at will in the specific reflection channel. As an example,the exact sampled function expression that produces a linear chirped at the +4 channel is given. The simulation results by using the transfer-matrix show that the theory is correct.

Multiwavelength Actively Mode-locked Fiber Laser with a Double-ring Configuration and Integrated Cascaded Sampled Fiber Bragg Gratings

A modified multiwavelength actively mode-locked fiber ring laser is proposed and experimentally demonstrated. In this kind of laser, stable multiwavelengths lasing is achieved by integrating cascaded sampled fiber Bragg gratings(SFBGs) into the laser cavity. To implement actively mode-locking technique, a double-ring cavity configuration is used to assure that the cavity lengths for all wavelengths lasing are identical. Thus, simultaneous mode locking of all wavelengths has been successfully achieved by using the same mode-locking signal.

对“利用Adobe Acrobat Professional 8.0软件实现图片型PDF文件到文本型PDF文件的转换”一文的质疑——与李宗红老师商榷

对"利用Adobe Acrobat Professional 8.0软件实现图片型PDF文件到文本型PDF文件的转换"一文中概念笼统和认识片面的内容提出质疑并与该文作者商榷。基于计算机理论知识分析和对各种转换方法的比较,对"图片型"和"文本型"PDF文件的定义与区分、Adobe Acrobat法转换所得PDF文件的特点和注释标记问题以及Fineprint/PDFfactory转换法的不足进行了分析评述,并综合转换效率、转换质量和投入成本等因素,认为GSview法为目前书版PS文件转PDF的最经济、效率最高、转换质量较好的方法。

A novel oil level monitoring sensor based on string tilted fiber Bragg grating

In this paper,we present a novel oil level monitoring sensor based on string tilted fiber Bragg grating(TFBG).The measurement range and sensitivity of oil level monitoring can be modulated via changing the length and number of string tilted fiber gratings.The transmission spectrum of string TFBGs immersed in oil changes obviously with the oil level variation.Experiments are conducted on three 2 cm-length serial TFBGs with the same tilted angle of 10o.A sensitivity of 3.28 dB/cm in the string TFBG sensor is achieved with good linearity by means of TFBG spectrum characteristic with peak-low value.The cladding mode transmission power and the amplitude of high order cladding mode resonance are nearly linear to the oil level variation.This kind of sensor is insensitive to temperature and attributed to be employed in extremely harsh environment oil monitoring.

Non-Geometric Conditional Phase Gate by Quantum Zeno Dynamics in Laser-Excited Nitrogen-Vacancy Centers

Based on the quantum Zeno dynamics,we propose a two-qubit non-geometric conditional phase gate between two nitrogen-vacancy centers coupled to a whispering-gallery mode cavity.The varying phases design of periodic laser can be used for realizing non-geometric conditional phase gate,and the cavity mode is virtually excited during the gate operation.Thus,the fidelity of the gate operation is insensitive to cavity decay and the fluctuation of the preset laser intensity.The numerical simulation with a realistic set of experimental parameters shows that the gate fidelity 0.987 can be within reached in the near future.