基于数据挖掘技术的网络化无损检测系统

介绍了基于交变磁场测量技术的无损检测仪器的工作原理和测量方法,并在此基础上提出了基于数据挖掘技术的网络化无损检测系统,本套系统利用数据挖掘技术从无损检检测仪器的数据服务器的海量数据中提出有用的信息,并结合模式识别技术和神经网络技术建立自适应的缺陷识别模型,利用网络实时修正系统中仪器的检测模型,提出了网络化无损检测仪器的结构,并阐述了网络化仪器的发展状态和前景。     

数据采集系统输入信号多参数检测仪

本文根据固体火箭发动机试验数据采集系统检测特点,在分析国内外数据采集系统的设计组成现状后,研制新型的数据采集系统输入信号多参数检测仪。该检测仪的作用是:输入信号检测;点火系统性能检测;手控同步检测;数据采集系统输入信号过压保护及接口功能;发动机点火同步控制功能;该检测仪适用于固体火箭发动机试验数据采集系统中,是数据采集系统的最佳配套仪器,是个多功能式检测控制仪器。 本文介绍了该仪器的设计原理,工作原理,应用及分析,技术指标。为正确的设计数据采集系统和选择配套仪器提供了参考依据;对于设计数据采集输入接口控制电路提供了参考作用。     

圆孔阵列对“猫眼”目标成像质量的影响分析

利用圆孔阵列光强调制作用可以有效减弱光学窗口的“猫眼”效应,同时也会对“猫眼”目标成像质量产生一定不利影响.考虑到利用调制传递函数(MTF)可对光电仪器成像质量进行综合评价,分别给出了测试望远系统和微光夜视系统MTF的数学模型,利用自行研制的光学仪器MTF数字化检测系统,实现了这两种典型“猫眼”目标MTF的数字化检测.结果表明,圆孔阵列在全空间频率上均使“猫眼”目标的MTF有所下降,且孔径较小、孔阵较密的圆孔阵列对“猫眼”目标MTF的影响较小,这为合理设计圆孔阵列结构以减小对“猫眼”目标成像质量的影响提供了可靠的实验数据.     

交通水运工程测绘仪器计量检定现状探索

交通水运工程测绘仪器计量检定工作相对复杂,精度要求较高。主要内容就是针对涉及水运工程测绘仪器的各种具体参数进行详细的检定,确保其设计达到了一定的要求,并且能够根据具体的检定结果进行适当的参数校正,确保相应的检测仪器能够准确的工作,为今后的水运工程勘察测绘工作提供精确的数据支持。因此,该项工作在一定程度上能够促进我国水运工程建设的顺利开展,保障了航运的顺利进行。     

电子经纬仪的基础性调校

基础性调校是电子经纬仪也即全站仪的测角部分进行检定或测量前必须进行的工作,介绍了基础性调校的内容以及进行机械部分硬件调整与电子部分软件调整的方法,针对新旧型号的仪器校正方法进行了对比,统计了仪器进行电子部分软件校正前和校正后的各项指标,表明进行前期的基础性调校工作,可以保证仪器检定结果和测量数据的可靠性。     

液晶投影显示颜色均匀性的测量及校正系统

根据二维面阵 CCD 能够快速采集二维图像的特点,提出了一套由视频测试信号发生器、投影屏幕、CCD 摄像机和计算机组成的液晶投影显示颜色均匀性测量及校正系统。该系统利用面阵 CCD 对液晶投影图像三色分量的二维亮度分布进行分时测量,并根据测量及分析得到的校正数据对输出的三色亮度比例进行修正,实现了对液晶投影显示系统颜色均匀性的校正。实验表明,校正后屏幕上各个区域的色坐标和平均色坐标的偏差的标准差为 5.23×10-4,仅为校正前的 10.46%,色均匀度提高了一个量级。     

氮气中乙烯标准气体的研制

叙述了用于仪器、仪表校正和产品质量检测使用的氮气中乙烯气体标准样品的制备,以气相色谱法对其各项性能进行考核,确保其数据准确可靠。     

氮气中乙炔标准气体的研制

叙述了用于仪器、仪表校正和产品质量检测使用的氮气中乙炔气体标准样品的制备,以气相色谱法对其各项性能进行考核,确保其数据准确可靠。     

氮气中二氧化碳标准气体的研制

叙述了用于仪器、仪表校正和产品质量检测使用的氮气中二氧化碳气体标准样品的制备,以气相色谱法对其各项性能进行考核,确保其数据准确可靠.     

筛分法和激光粒度法联合测定陆源碎屑岩粒度

用筛分法和激光粒度法联合测定陆源碎屑岩粒度,对激光粒度法的分析数据进行了校正,以保证两种方法的分析数据配套衔接。通过对比不同地质年代沉积岩的岩心校正前后概率累积频率曲线,校正后的曲线能更好地表征碎屑岩粒度的分布。对影响马尔文Mastersizer 2000激光粒度仪背景测量的进样器搅拌转速A、泵速B、超声强度C三个因子进行L9(34)正交优化设计,筛选出最优的测量条件是A取600r/min,B取2000r/min,可使背景测量稳定,并得出它们对背景测量影响程度可用B>A>误差>C表示。用仪器自带的9个标准物质校正了粒度标准曲线,粒度标准曲线与仪器标准曲线的加权残差小,在0.795%～2.934%之间。该方法相对标准偏差在0.24%～0.33%之间,适用于各种地质年代陆源碎屑岩的粒度分析。     

A Review of Current Image-Evaluation Techniques

The characteristics of image-evaluation techniques are reviewed in relation to their use in the design and testing of photographic systems. Each technique has advantages and limitations; no one technique can serve all purposes. Resolving power takes account of many factors that affect image quality, hence it can be a significant measure of system performance; for the same reason it is inaccurate and inherently unsuitable for measuring the performance of lenses. The MTF is potentially more accurate than resolving power, but by itself lacks significance because it omits important factors in the system. Nevertheless the MTF is an invaluable aid in design and analysis as well as in research. The importance of adequate calibration of MTF equipment and of standardization of resolving power targets is stressed. The possibilities of a calculated resolving power based on the MTF and a signal to noise ratio are mentioned. Problems of evaluating the MTF in practically significant ways, and the advantages of the single bar target for interpreting it in spatial terms, are discussed.     

An Afocal-system OTF Test Standard

Several standard test lenses for evaluating the accuracy of OTF measuring equipment have been described in the literature. However, these are not generally suitable for evaluating the equipment and test procedures used for afocal systems which differ from those used with normal lenses in several significant ways. A special afocal system in the form of a straight-through telescope has been designed and built for this purpose. The paper describes the design and construction of this telescope and compares the calculated and experimentally measured values for the MTF of the system. A particular feature of the MTF calculations is that they have been carried out, not only for the usual radial and tangential azimuths, but also for several intermediate azimuths. Thus it has been possible to determine the value of a range of different MTF-based criteria which relate to measuring equipment where the MTF is measured at a single spatial frequency in all azimuths.     

GRACoL7工业应用方法浅析

GRACoL 7是商业胶版印刷检测方法的新规范,是实施国际胶印印刷标准ISO 12647-2的基本要求,它针对CTP为基础的商业印刷流程,设定灰平衡、中性印刷密度曲线、亮度等概念的定义和测试方法,最终获得准确的数据,依此调整CTP制版机或照排机的RIP输出校正曲线,从而在保证系统重复性工作基础上,改善印刷品的阶调和彩色再现质量。本文对此作系统介绍。     

Atmospheric modulation transfer function in the infrared

In high-resolution ultranarrow field-of-view thermal imagers, image quality over relatively long path lengths is typically limited by atmospheric degradation, especially atmospheric blur. We report our results and analyses of infrared images from two sites, Fort A. P. Hill and Aberdeen Proving Ground. The images are influenced by the various atmospheric phenomena: scattering, absorption, and turbulence. A series of experiments with high-resolution equipment in both the 3-5- and 8-13-microm regions at the two locations indicate that, as in the visible, image quality is limited much more by atmosphere than by the instrumentation for ranges even of the order of only a few kilometers. For paths close to the ground, turbulence is more dominant, whereas for paths involving higher average elevation, aerosol modulation transfer function (MTF) is dominant. As wavelength increases, turbulence MTF also increases, thus permitting aerosol MTF to become more dominant. A critical role in aerosol MTF in the thermal infrared is attributed to absorption, which noticeably decreases atmospheric transmission much more than in the visible, thereby reducing high-spatial-frequency aerosol MTF. These measurements indicate that atmospheric MTF should be a basic component in imaging system design and analysis even in the infrared, especially as higher-resolution hardware becomes available.     

Investigation of possible methods for equipment self-tests in digital radiology

Quality control in digital radiology can be time-consuming. Equipment self-tests may significantly decrease staff workload. The two most essential parameters for radiology systems are image quality and patient dose. Concerning patient dose, information on the dose-area product (DAP) values generally forms the basis for assessment of patient dose. DAP-values can be measured using a transmission ionisation chamber or calculated from equipment settings. In the present study, various image quality parameters were derived using a contrast-detail (C-D) phantom. The investigation included a computer-aided assessment of C-D images, which produced various parameters, and also parameters based upon scoring by human observers. In addition, another parameter was calculated from modulation transfer function (MTF) measurements. The automatically calculated parameters showed good correlation with human readings, although the number of X-ray systems studied is still limited. We propose a combined evaluation of DAP and automatically calculated C-D or MTF parameters for equipment self-tests.     

Modulation Transfer Function Measurement Using Three- and Four-bar Targets

Modulation-transfer-function (MTF) measurement often involves the use of three- and four-bar resolution targets. In the conversion of three- and four-bar image data to MTF, biased results can occur when we use series-expansion techniques appropriate for square-wave targets of infinite extent. For systems where the image data are digitally recorded, a convenient and accurate conversion of bar-target data to MTF can be performed using a Fourier-domain method.     

Design, assembly, and optical bench testing of a high-numerical-aperture miniature injection-molded objective for fiber-optic confocal reflectance microscopy

The design, analysis, assembly methods, and optical-bench test results for a miniature injection-molded plastic objective lens used in a fiber-optic confocal reflectance microscope are presented. The five-lens plastic objective was tested as a stand-alone optical system before its integration into a confocal microscope for in vivo imaging of cells and tissue. Changing the spacing and rotation of the individual optical elements can compensate for fabrication inaccuracies and improve performance. The system performance of the miniature objective lens is measured by use of an industry-accepted slanted-edge modulation transfer function (MTF) metric. An estimated Strehl ratio of 0.61 and a MTF value of 0.66 at the fiber-optic bundle Nyquist frequency have been obtained. The optical bench testing system is configured to permit interactive optical alignment during testing to optimize performance. These results are part of an effort to demonstrate the manufacturability of low-cost, high-performance biomedical optics for high-resolution in vivo imaging. Disposable endoscopic microscope objectives could help in vivo confocal microscopy technology mature to permit wide-scale clinical screening and detection of early cancers and precancerous lesions.     

Development and application of programs to measure modulation transfer function, noise power spectrum and detective quantum efficiency

This project aimed to produce programs to calculate the modulation transfer function (MTF), noise power spectrum (NPS) and detective quantum efficiency (DQE) of digital X-ray systems, given a suitable digital image. The MTF was calculated using the edge technique and the NPS was calculated from a flat field image. Both programs require a suitably edited DICOM image as input. The DQE was then calculated from the output of MTF and NPS programs. This required data external to the DQE program to estimate the number of quanta per mm2 in the beam which formed the NPS image. All three programs run independent of each other on a PC and require no special software to be installed. Results for MTF, NPS and DQE for a Philips AC3 CR system are presented. In addition, the results for MTF from a Siemens Duo CT scanner with a specially designed PTFE edge are also shown.     

投影机镜头的MTF实时检测系统

目前还没有标准的方法来检测投影机镜头的MTF,为此我们提出了一种基于图像分析的投影机镜头MTF实时测试系统.本系统使用CCD作为成像接收器,采用基于图像分析的方法,通过分析单个像素成像同时获得投影镜头子午和弧矢两个方向上的调制传递函数(MTF).阐述了整个测试系统的构造及理论框架,着重分析了系统参数标定的重要性以及如何正确地进行系统参数标定;全面分析了影响测试结果的因素以及如何正确快速地修正噪声的影响.检测了质量合格与质量不合格的投影机镜头,并将结果同设计值的进行比较,实验结果表明了本系统及其处理方法的有效性.