TWAIN协议在医用扫描仪驱动源中的应用

由EPSON、HP、RICOH和科达等企业联合提出的TWAIN协议是静态图像系统中图像获取设备与应用程序间的通信接口.其具有一致性好,兼容性强的特性,且系统架构简单健壮,稳定性高.文中从组成元素、系统架构和通信规范3个方面论述了TWAIN协议,并应用此协议设计和实现医用扫描仪设备驱动的通信模块,试验证明,此通信模块能够很好的满足实际需求.     

TWAIN协议及其在VB中的应用

TWAIN协议可以方便地实现计算机与图像获取设备（扫描仪、数码相机）之间的通讯，使应用程序获取图像。本文介绍在VB应用程序中通过EZTwain使用TWAIN协议的方法，并附以示例。     

TWAIN的原理及其应用开发

随着计算机科学技术的飞速发展，声音，图形，图像以其直观的形象越来越受到人们的重视和喜爱，在多媒体世界中扮演着重要角色，如何在应用程序中简单方便地将图形，图像输出到计算机中，已成为一个非常普遍的问题，采用光电扫描仪是解决这一问题的有效途径。着重介绍扫描仪驱动接口－TWAIN的原理，使用和开发应用规范。     

基于TWAIN接口的图像测量系统的设计

介绍了TWAIN接口的标准,并分析了开发基于TWAIN接口的应用程序的方法.建立了基于TWAIN接口的图像测量系统,并分析了其测量的原理及标定的方法.位移测量的实验结果证明图像测量系统可应用于位移、长度、直径等工件尺寸的测量.     

基于灰度图像的扫描仪模型研究

为了能够更好地模拟扫描仪对图像的扫描过程,在分析现有打印机和扫描仪模型的基础上,提出了一种改进的扫描仪模型,主要为改进模拟扫描仪采集数据点过程的线性滤波器.经实验结果证实,该扫描仪模型比现有模型模拟扫描仪扫描输出的图像误差小.     

办公室/家用1200dpi最佳画质——HP ScanJet 5300C

HP ScanJet 5300C在办公室/家用1200dpi扫描仪中,得到极高的整体评价,一方面图像品质不错,扫描速度也相当快速,附赠的软件及扫描TWAIN界面的功能也都相当优秀,重要的是售价低,且将来的扩充性佳。整体算下来,无论是1200dpi或是600dpi的办公室/家用扫描仪,HP     

Epson GT-10000——网络扫描仪

作为打印机知名厂商的EPSON近来对扫描仪领域也在持续不断地开发。PC Computing中国易用性实验室日前评测了该公司新近推出的A3幅面扫描仪——GT-10000。 GT-10000是专门针对网络化高效商务办公需要而设计的。它的最大特点是,客户端的计算机只需安装EPSON TWAIN Pro Network驱动程序软件,就可以非常方便地共享这台高效扫描仪,而且就像使用本地扫描仪     

线阵CCD图像采集系统综述

文中介绍了CCD发展现状及工作原理、USB2．0协议、CPLD相关知识以及TWAIN协议,总结了线阵CCD图像采集系统的组建方法。     

当月精选

随着扫描仪市场竞争的日益加剧,扫描仪厂商逐渐意识到高速度、高分辨率不再是扫描仪产品的唯一衡量指标。如何能够贴近用户的应用需求才是扫描仪产品生命力的保证。近日,国内数码影像领导厂商上海中晶科技有限公司推出的纷腾V6扫描仪,它拥有3200dpi的光学分辨率、真正48-bit色彩位深,能够获取281万亿种色彩,更为重要的是,它实现了“零边距” (Zero-margin)的扫描功能,使一般扫描仪无法顾及的厚本杂志夹缝处的文字与图像也能实现无变形扫描。     

红外扫描仪高速图像采集系统的设计与实现

介绍了基于USB 2.0的高速图像采集系统的解决方案.采用一片CPLD控制从多通道的高速锁存器的数据读出、FIFO控制时序以及和USB芯片CY7C68013的握手逻辑.此外,采用FIFO缓存,使得采集系统的结构得以简化和易于实现,并保证数据在传输过程中不丢数据,起到性能稳定和优化的结果.已经研制出一套完整的红外扫描仪高速红外图像采集系统,实验结果表明,该系统能够满足系统的指标要求.     

Noise Evaluation and Filter Design in CT Images

Filtering CT images to remove noise, and thereby enhance the signal-to-noise ratio in the images, is a difficult process because CT noise is of a broad-band spatial-frequency character, overlapping frequencies of interest in the signal. We present a measurement of the noise power spectrum of a CT scanner and show that some form of spatially variant filtering of CT images can be beneficial if the filtering process is based upon the differences between the frequency characteristics of the noise and the signal. For evaluating the performance, we used a percentage standard deviation, an index representing contrast, a frequency spectral pattern, and several CT images processed with the filter.     

基于回光强度的平面标靶自动识别方法

平面标靶在中长距离三维激光扫描仪的检校、数据采集、单点测量等环节中发挥着重要作用,而平面标靶的高精度、自动化识别是在其使用中面临的一个关键问题.在分析扫描数据特点的基础上,提出一种基于回光强度的平面标靶自动识别方法.具体的步骤为:改正回光强度以消除距离的影响;基于回光强度进行阈值分割以得到平面标靶点云;提出一种基于扫描...     

Development of a High-Performance Stamped Character Reader

A high-performance optical character reader (OCR) capable of reading low-quality stamped alphanumeric characters, on a metal rod, is described in this paper. Reliable and precise recognition is achieved by means of a special scanner and dedicated recognition module. The scanner revolves around the metal rod and detects characters, thus avoiding rotation of the heavy and long rod. Diffused illumination which produces a clear image, a powerful pattern-matching method?the Multiple Similarity Method (MSM)?implemented by the recognition module, and the use of adaptive rescan control results in a correct recognition rate of 99.93 percent. One recognition module can process images from up to five different scanners. The processing speed is about 1.5 s/rod. The design and industrial application of the system are discussed.     

基于Hough变换的倾斜文本图像的检测

在OCR图像扫描输入的过程中,扫描图像经常会出现某种程度的倾斜,这种倾斜会给下一个字符的切割造成困难,影响字符识别的精度。正是出于检测倾斜文本图像角度的目的,提出了一种基于Hough变换的检测图像倾斜度的方法,可以有效地克服几何失真对文字识别系统的影响,为了克服Hough变换计算量大的缺点,该方法采用了提取图像特征点的方法。实验结果表明,该方法能快速准确地测出各类文本图像的倾斜角度,并且具有很好的适应性。     

Reduction of artifacts induced by misaligned geometry in cone-beam CT

The quality of computed tomography (CT) images frequently suffers from artifacts caused by scanner misalignments. In this paper, we discuss the results of our improved approximate cone-beam reconstruction formula, which corrects for the mechanical misalignment of the scanner. Based on the general filtered back-projection (FBP) algorithm proposed by Feldkamp, the new formula reduces the artifacts in reconstructed images. Six parameters are employed to describe the scanner misalignment. Experimental results show that the images reconstructed by using the new formula are clearer than those reconstructed by using the general FBP algorithm in a misaligned system. Through the new formula, we have reduced the artifacts caused by misalignment.     

计算全息光栅扫描器的研制

给出了反射式圆盘型计算全息光栅扫描器的位相方程、条纹位置方程及参数结构方程式 ,利用新的加工工艺制作出能实现两行扫描 即二维扫描 的光栅 ,给出由于加工工艺的改进和设计上的充分考虑而带来的明显实验效果及达到提高一级衍射能量和抑制零级衍射能量的目的 ,从而得出计算全息光栅扫描器的多行快速直线扫描和复制时成本低的特点能够满足有这种需要的领域 .最后分析总结出研制实用型计算全息光栅扫描器的有效途径 .     

Composition of a Dewarped and Enhanced Document Image From Two View Images

In this paper, we propose an algorithm to compose a geometrically dewarped and visually enhanced image from two document images taken by a digital camera at different angles. Unlike the conventional works that require special equipments or assumptions on the contents of books or complicated image acquisition steps, we estimate the unfolded book or document surface from the corresponding points between two images. For this purpose, the surface and camera matrices are estimated using structure reconstruction, 3-D projection analysis, and random sample consensus-based curve fitting with the cylindrical surface model. Because we do not need any assumption on the contents of books, the proposed method can be applied not only to optical character recognition (OCR), but also to the high-quality digitization of pictures in documents. In addition to the dewarping for a structurally better image, image mosaic is also performed for further improving the visual quality. By finding better parts of images (with less out of focus blur and/or without specular reflections) from either of views, we compose a better image by stitching and blending them. These processes are formulated as energy minimization problems that can be solved using a graph cut method. Experiments on many kinds of book or document images show that the proposed algorithm robustly works and yields visually pleasing results. Also, the OCR rate of the resulting image is comparable to that of document images from a flatbed scanner.     

Fully automatic luminal contour segmentation in intracoronary ultrasound imaging--a statistical approach

In this paper, a fully automatic method for luminal contour segmentation in intracoronary ultrasound imaging is introduced. Its principle is based on a contour with a priori properties that evolves according to the statistics of the ultrasound texture brightness, which is generally Rayleigh distributed. The main interest of the technique is its fully automatic character. This is insured by an initial contour that is not set by the user, like in classical snake-based algorithms, but estimated and, thus, adapted to each image. Its estimation combines two pieces of information extracted from the a posteriori probability function of the contour position: the function maximum location (or maximum a posteriori estimator) and the first zero-crossing of its derivative. Then, starting from the initial contour, a region of interest is automatically selected and the process iterated until the contour evolution can be ignored. In vivo coronary images from 15 patients, acquired with the 20-MHz central frequency Jomed Invision ultrasound scanner, were segmented with the developed method. Automatic contours were compared to those manually drawn by two physicians in terms of mean absolute difference. The results demonstrate that the error between automatic contours and the average of manual ones is of small amplitude, and only very slightly higher (0.099 +/- 0.032 mm) than the interexpert error (0.097 +/- 0.027 mm).     

用于采集交通数据的激光扫描器技术研究

针对交通数据采集应用,设计了一种符合一级激光安全等级的中短距离、高速、高精度脉冲激光扫描器(Laser Scanner)。为了解决激光扫描器的快速、高精度测距问题,提出了一种数字化全波形脉冲检波方法。该方法通过脉冲波形前沿拟合判定激光脉冲的达到时刻,以模拟数字转换器(Analog to Digital Converter, ADC)的采样时钟作为计数器,对回波延时进行计算;再根据回波信号的强度对测距结果进行补偿修正,显著减小了测距幅相误差。扫描器的信号处理基于高速ADC和FPGA实现。测试结果显示,激光扫描器的测距频率达到50000点/s,单点测距精度为±4 cm,能够满足车型自动分类、交通流量调查和客流密度检测等系统的数据采集需求。