共查询到20条相似文献,搜索用时 21 毫秒
1.
Summary In this note we describe the image acquisition system realized as a part of an experiment designed to record high-spectral-resolution
solar images in the visible part of the spectrum. The system is based on a Charge Coupled Device Thomson THX31159. The electronics
for driving the sensor and for the amplification and conditioning of the video signal has been designed and built in the laboratory,
while a VME-bus-based computer has been used for the timing of operations, for the signal A/D conversion and for image presentation
and storage.
Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990. 相似文献
2.
3.
4.
A fast imaging method in a contact-mode atomic force microscope (AFM) is examined for its principle and performance, where
the image is acquired by combining a cantilever signal and a feedback signal applied to a piezotube. The frequency component
of the feedback signal is restricted in the lower frequency region to keep the linear relationship between the feedback signal
and the displacement of the piezotube. It is shown that the image is basically independent of the feedback details since a
wide detection bandwidth is certified by the cantilever response much faster than by the feedback response, allowing a fast
scanning. The fast scanning, however, enhances the distortion in the transient region where surface height changes abruptly.
This influence can be reduced by choosing the scan line direction for the data acquisition. The combination procedure also
reduces the low-frequency noise in the feedback signal. A 512×512-pixel image was obtained in 90 s without sacrificing the
resolution.
Received: 24 November 1998 / Accepted: 31 March 1999 / Published online: 2 June 1999 相似文献
5.
边缘增强新方法及在联合变换相关器中的应用 总被引:3,自引:2,他引:1
基于耦合理论定义并推导出耦合增益系数g,分析耦合增益系数g随TL和r的变化.提出图像边缘增强的新光学系统,该系统利用背景信号增强边缘信号,具有高输出效率和高亮度的优点.设计并构建出该光学系统,并利用CCD获得手骨的边缘增强图像.论证了光相关原理,模拟边缘增强和非边缘增强字母E的三维相关分布,并比较了两种相关器的分辨率Iac和半高宽(FWHM).分析表明:边缘增强预处理能有效提高相关器的性能. 相似文献
6.
磁共振成像信号的数字化接收系统设计 总被引:3,自引:3,他引:0
磁共振成像信号的采集是磁共振成像系统当中最重要的环节之一,设计性能良好的信号接收系统直接关系到成像质量的好坏. 本文根据磁共振信号强度弱、频率高、带宽窄的特性对接收系统进行了统一设计. 详细地对可控增益放大、高速A/D、数字解调以及抽样滤波器等几个部分进行了讨论,给出一整套设计方案,尤其对多级抽样滤波器,根据磁共振成像的性能需求和滤波器的不同特性给出了抽样系数分配和滤波器设计的一般方法. 根据该方案设计出的磁共振信号接收系统有较高的信噪比,已经应用在临床医疗诊断当中. 相似文献
7.
8.
9.
搭建了紫外单光子成像系统,详细介绍了该系统的组成、工作原理和分辨率性能测试.由汞灯发出的紫外光经过大气散射、多块减光片得到了紫外单光子流.单光子直接打在微通道板上,微通道板产生的倍增电子由楔条形阳极收集,电荷灵敏前置放大器将阳极输出的电荷信号转变为电压信号,主放大器对前放信号进行滤波整形.利用高速数据采集卡连续采集主放大器的输出波形,通过软件对采集波形进行处理,采用图像处理技术得到了紫外单光子10min的计数图像,并对图像进行了畸变校正.此外,通过自己设计的分辨率板,测得该系统的分辨率可达150μm.该系统在极微弱光探测成像,生物发光,空间环境探测等方面具有广泛应用.
关键词:
单光子计数成像
阳极探测器
楔条形阳极
分辨率 相似文献
10.
Small target detection in infrared image with complex background and low signal–noise ratio is an important and difficult task in the infrared target tracking system. In this paper, a principal curvature-based method is proposed. The principal curvatures of target pixels are negative and their absolute values are larger than that of background pixels and noise pixels in a Gaussian-blurred infrared image. The proposed filter takes a composite function of the curvatures for detection. An approximate model is also built for optimizing the parameters. Experimental results show that the proposed algorithm is effective and adaptable for infrared small target detection in complex background. Compared with several popular methods, the proposed algorithm demonstrates significant improvement on detection performance in terms of the parameters of signal clutter ratio gain, background suppression factor and ROC. 相似文献
11.
12.
13.
14.
针对像素不匹配的数字全息存储器中出现的莫尔条纹现象,提出了利用莫尔条纹进行全息存储光路精确调整来实现像素匹配的方法.通过对CCD像面图像中莫尔条纹的周期和角度进行分析,得到光学系统需要的精确调整参数.实验中, 实现了空间光调制器和光电耦合器阵列512×512像素的1∶1像素匹配,该方法能提高读取速度并降低误码率. 相似文献
15.
针对像素不匹配的数字全息存储器中出现的莫尔条纹现象,提出了利用莫尔条纹进行全息存储光路精确调整来实现像素匹配的方法.通过对CCD像面图像中莫尔条纹的周期和角度进行分析,得到光学系统需要的精确调整参数.实验中,实现了空间光调制器和光电耦合器阵列512×512像素的1:1像素匹配,该方法能提高读取速度并降低误码率. 相似文献
16.
The spatial and temporal evolution of an automotive hollow-cone-type spray was investigated with laser-based imaging diagnostics.
Optical conditions of an IC engine were emulated with a test cell that was built from an engine cylinder head to hold a high-pressure
gasoline-fuel injector. The use of iso-octane fuel that was doped with 3-pentanone allowed measurements of laser-induced fluorescence
(LIF) after excitation with a KrF excimer-laser beam. A versatile optical filter system was designed and built that permits
simultaneous measurements of Mie-scattering and laser-induced-fluorescence images using a single laser-light sheet and a single
intensified CCD camera. The influence of background signals, caused by reflection of signal light from surfaces, laser-sheet
intensity attenuation and signal decrease by scattering, was characterized. Mass distributions showed a distinct pre-spray
phase, more so than the Sauter mean diameter (SMD) that was determined from the ratio of LIF to Mie signals using single pulse
as well as averaged image pairs. Significant changes in SMD distributions were found after the spray had impinged on a flat
surface. The impingement also led to the buildup of a liquid film whose thickness was quantitatively determined from LIF images.
Received: 5 December 2000 / Revised version: 28 February 2001 / Published online: 23 May 2001 相似文献
17.
调焦系统在各种光学测量及侦察设备中起着十分重要的作用。本文介绍了光学系统自动调焦的方法和图像法调焦的相关评价函数,利用TMS320DM642数字信号处理芯片为平台设计了图像法自动调焦系统。采用TI公司针对其开发的DSP芯片设计了实时多任务系统DSP/BIOS,完成了软件设计。该实时操作系统为实现调焦过程中任务的调度和实时调焦提供了保障。文中还提出了在实现调焦系统过程中需要注意的一些问题及解决方案。本文所设计的系统能在4~5步(大约2S内)找到像面,满足实际应用的需要。 相似文献
18.
研究并设计了基于FPGA的亚像元图像融合系统,该系统能够在接收到亚像元相机输出的两路CCD图像信号后,实时地将其融合并显示.搭建了亚像元图像融合实验平台,介绍了系统的组成以及主要电路的实现方法,并进行了实验验证.结果表明,图像融合效果好,设计方案可行. 相似文献
19.
设计一种高分辨率中波红外成像制导光学系统。采用折射一次成像的结构形式,初始结构为远摄型物镜组。所设计的系统共用3个光学元件,通过引入非球面和二元光学衍射元件,增加光学设计的自由度,全视场达到10,系统总长为49 mm,焦距为70 mm。并且系统在-40℃~60℃温度范围内具有良好的消热差作用,成像质量接近衍射极限,最大弥散斑直径小于15 m。适用于像元数为640512,像元尺寸为15 m,F数为2的红外焦平面探测器。系统具有成像分辨率高、视场大且体积小等优点,可用于小型红外导引头中。 相似文献
20.
基于UV光谱技术的高压电晕放电检测 总被引:5,自引:3,他引:2
通过分析高压电晕放电的光谱特性,提出应用紫外光+可见光的双光谱实时视频图像处理系统来探测高压电晕放电.该双光谱系统以高性能数字信号处理器TMS320DM642为核心,为了采集紫外信号而设计了光路、光谱转换和图像增强等技术,同时采用多种优化设计的硬件结构、快速融合算法及管理多进程的嵌入式实时操作系统DSP/BIOS,实现具备手动像素平移配准功能的双通道数字图像的实时融合处理.系统可以实时检测和定位高压电晕放电紫外信号,且具有响应速度快、作用距离远、不受日光和雨雾的干扰等优点. 相似文献