基于折射定律的摄像机标定模型

传统的摄像机标定是基于针孔模型,把镜头简化为凸透镜,得出的是光学元件的集总参数,精确度低.为提高精度,根据折射定律提出基于折射定律的摄像机标定模型.上述模型细化了摄像机镜头的组成,把镜头分为三个透镜部分,并且应用折射定律定性研究光线在透镜边界面的折射情况.改进模型充分考虑了摄像机镜头的透镜组成,大大提高了标定的精确度.仿真结果表明,新模型与针孔模型相比,平均误差值明显降低.并且比较了摄像机与物体的距离不同时,误差值的变化,确定了标定时的最佳距离.     

离心球铁管承口部气孔缺陷分析

分析了离心球铁管承口针孔及其成因。结果表明，来自树脂粘结剂中的Ｎ２，Ｈ２等气体是导致针孔的主要气体。氧化夹杂物作为气泡生核的核心，并使之生长。若铸件凝固速度等于气泡逸出速度，针孔生成。     

Optimization of screen-printing parameters of SN9000 ink for pinholes using Taguchi method in chip on film packaging

The influence of pinholes on the chip on film (COF) in screen-printing was studied in this paper. Yield improvement is the most challenging part of COF manufacturing in view of its processing complexity, mainly in the screen-printing process. The process parameters such as ink capacity, origin control distance, angle of the squeezer, method of mixing, freshness of ink, speed of printing, and speed of scraper are considered to improve the pinholes. In Taguchi method, a two level orthogonal array is used to determine the signal-to-noise (S/N) ratio. Analysis of variance and the F-test values are used to determine the most significant process parameters affecting the pinholes. Confirmation analysis tests with the optimal levels of process parameters are carried out. The results of the experiment show that Taguchi method is a very suitable approach with regard to solving quality problems related to such pinholes.     

基准离焦偏差控制技术

一种新的采用基准离焦信号的针孔调焦方案,用于激光直写的自动对焦子系统。通过在离焦曲线上提取参考离焦信号,建立基准离焦判据,它能容易地区分前离焦或后离焦,有效地克服了原有针孔调焦方案难于根据离焦信号来分辨离焦方向的弱点。借助微处理器和模拟电路实现了这一方案,并因此获得了均匀的1靘线宽的线条。     

The pinhole SPECT for animal model of bone metastasis with SPC-A-1BM human pulmonary adenocarcinoma bone metastasis cell line

The study was to investigate the role of pinhole single photon emission computed tomography （SPECT）, the human pulmonary adenocarcinoma bone-seeking metastasis cell line SPC-A-1BM was used. These cells form typical osteolytic bone metastases when inoculated into the arterial circulation of NIH-Beige-Nude-XD （BNX） mice v/a the left ventricle. In order to evaluate the irradiation impact of ^99mTc-MDP versus X-ray on cells growth, we used six groups of SPC-A-IBM cells in our imaging scheme and irradiated by various doses of ^99mTc-MDP （37, 74, 111, 370, 740 MBq） and X-ray（40 kV, 2 mA, 6 s） respectively. The cell＇s number of each group was well recorded in different exposure time（ 4, 8, 12, 24, 48, 72, 96 hours ）. After that, SPC-A-1BM cells （1×106） were inoculated into the mice via left ventricle. We compared the results obtained with those different doses of ^99mTc-MDP using pinhole SPECT and conventional X-ray skeletal surveys. The data show that the cell-survival number of 111 MBq group has insignificant difference with that of X-ray and the dose is adequate to have an ideal image. Besides, it is important that the chromosome of the cells in the group of 111 MBq showed no irradiation-related damages in our test. These results implied that ^99mTc-MDP pinhole SPECT may provide another way other than conventional X-ray skeletal surveys in detecting bone metastasis of pulmonary adenocarcinoma in BNX mice.     

电流密度和润湿剂对Ni镀层组织与形貌的影响

采用普通型瓦特液,按照不同的工艺参数在铜材表面电镀镍,通过SEM对镀层表面进行扫描观察和使用XRD测试对镀层表面进行检测,并且对不同样品数据进行对比和分析,从而达到研究电流密度及润湿剂对镀层沉积速度、表面显微形貌和晶粒尺寸的影响的目的.实验结果表明,电流密度的影响非常显著,不同电流密度下的镀层表面形貌和晶粒尺寸存在相应的差别.适量的润湿剂对镀层的沉积具有促进作用,对防止针孔的生成及细化晶粒具有明显的效果.     

Passivation of pinhole defect microelectrode arrays in ultrathin silica films immobilized on gold substrates

Nanoscopic defects present in ultrathin (~ 6 nm) silica films covalently attached to gold substrates through a gold oxide layer exhibit a voltammetric response consistent with a random array of ultramicroelectrodes. These pinholes can be passivated via electrochemical polymerization of phenol to create insulating poly(phenylene) oxide plugs as documented by atomic force microscopy and infrared reflectance-absorbance spectroscopy. Passivation of pinholes is ~ 99.5% complete after 550 voltammetric cycles of oxidative electropolymerization.     

Camera calibration for a mobile robot prototype

Stereovision is an effective technique to use a CCD video camera to determine the 3D position of a target object from two or more simultaneous views of the scene. Camera calibration is a central issue in finding the position of objects in a stereovision system. This is usually carried out by calibrating each camera independently, and then applying a geometric transformation of the external parameters to find the geometry of the stereo setting. After calibration, the distance of various target objects in the scene can be calculated with CCD video cameras, and recovering the 3D structure from 2D images becomes simpler. However, the process of camera calibration is complicated. Based on the ideal pinhole model of a camera, we describe formulas to calculate intrinsic parameters that specify the correct camera characteristics, and extrinsic parameters that describe the spatial relationship between the camera and the world coordinate system. A simple camera calibration method for our CCD video cameras and corresponding experiment results are also given. This work was presented in part at the 7th International Symposium on Artificial Life and Robotics, Oita, Japan, January 16–18, 2002     

Pinhole imaging to observe spatial jitters of a triple-pulse X-ray source on the Dragon-Ⅱ LIA

In high-energy flash radiography,scattered photons degrade the acquiring image,which limits the resolving power of interfaces and density of dense object.The application of large anti-scatter grid can reduce the scattered photons remarkably,but this requires a stable source position in order to reduce the loss of signal photons in the grid structure.The pinhole imaging technique is applied to observe spatial jitters of a triple-pulse radiographic source of a linear induction accelerator.Numerical simulations are conducted to analyze the imaging performance with the same or close parameters of the pinhole object and experimental alignment.Experiments are carried out to observe spatial jitters of the source between different measurements.Deviations of the source position between different pulses are measured in each experiment.     

新型机器人视觉系统准直相干光束的获取

论述了一种新型的机器人视觉系统所用激光准直光束的获取方法，分析了半导体激光束的像散椭圆高斯光束特性，设计了光束准直系统的光学结构，利用光斑法对准直度进行了检验。实验证明利用这种方法获取的直光束符合该视觉系统的要求。