数字印刷技术及其设备(十四) 第二部分:数字印前技术及其设备——图文数字化处理及其设备

图像信息采集和转换及其设备1.扫描技术及设备③平面型扫描仪:平面扫描仪是应用最为广泛的图像扫描仪。从办公,商用到印前处理,广泛用其对图像进行数字化采集。A.组成和结构:平面扫描仪由扫描平台,扫描光源,光学成像系统,光电转换器件(CCD)、图像信号处理器,接口,机械驱动系统等组成。大多数平面扫描仪的扫描平台     

CCD工作原理介绍

随着科学技术的飞速发展，光电转换功能的设备更新速度越来越快，数码复印机、扫描仪、数码照相机及数码摄像机等光电转换设备都用到了具有光电转换功能的CCD器件。有必要对CCD进行简单介绍，使大家对它有一定的了解。     

数字印刷技术及其设备(十六) 第二部分:数字印前技术及其设备——图文数字化处理及其设备

图像信息采集和转换及其设备3光电转换技术①电荷耦合器件光电转换技术:电荷耦合器件简称CCD(Charge Coup led Device)具有光电转换功能。其作用是将拍摄到的图像光信号转变为模拟电信号。在平面扫描仪、数字照相机和数字摄像机上广泛采用CCD。A.电荷耦合器件由光敏单元组成,根据CCD光敏单元的连接方式,CCD通常分为线阵型CCD和面阵型CCD两     

基于BP网络的扫描仪色彩空间转换模型的研究

本文提出了一种基于BP网络的扫描仪色空间转换的方法。它既解决了RGB色空间到CIELab色空间的非线性转换,又可用于其它的色空间转换。实验结果表明,利用BP网络建立扫描仪色空间转换模型取得了很好的效果。     

基于三维测量的数字化服装应用研究综述

三维人体测量技术是以现代光学技术为基础,融光电子学、计算机图像学、信息处理、计算机视觉、软件应用技术和传感技术等多种科学技术为一体的测量技术.国际上对三维测量设备的研究始于20世纪50年代,目前,国际先进的三维人体扫描仪主要以光电和激光技术为基础,如英国的Model WBX人体扫描仪、美国TC2公司的NX - 16 3D三维扫描仪、德国的Vitus三维扫描仪等.     

扫描仪的动态范围

<正>30年前谁能想象扫描仪可以进入寻常百姓之家,那时即使办公室也很难买得起。数字技术的发展和旺盛的市场需求大大加快了光电转换技术应用于扫描领域的进程。今天的人们只要有兴趣,购买一台扫描仪都不在话下,区别仅在于等级     

非电量电测法讲座——第三讲 回转速度和瞬时速度的测量

测量高速回转体的转速,在现代化的测量方法中均采用非接触式的光电转换原理。特别是测量精度要求高,被测对象为微小零件时,采用光电转换的非接触或较为理想。测量瞬时速度时,其频率响应的要求更高,应用光电转换更能显示出它的优越性。     

电脑平面设计及印前图文处理问答(十三)

139.滚筒扫描仪比平台扫描仪的扫描精度高、质量好,是什么原因? 答:滚筒扫描仪比平台式扫描仪好、精度高,从市场售价上可以窥见一斑.一般平台式扫描仪价格在几千到几万元之间,而滚筒式扫描仪一般在十几万元到几十万元之间.当然,随着CCD技术的发展,平台式扫描仪近些年来发展也很快,与滚筒扫描仪的性能也越来越接近,高档的平台式扫描仪现在也售价高达几十万元.从本质上来说平台扫描仪是用CCD(光电耦合器)技术,而滚筒扫描仪用的是PMT(光电倍增管)技术,它没有相邻的光线反射后的干扰,只是光点处的光被接受,而其它地方没有光反射或透射,所以它的清晰度和色彩准确度比较好.另外,滚筒式扫描仪的光学分辨率也比平台式要高.由于集成技术的提高,CCD的集成度也越来越高,平台式扫描仪的分辨率比以前已经不可同日而语了.图片分色质量除了与硬件有关之外,在很大程度上还依赖于分色软件的优劣、色彩管理系统的完善,所以这些都是不容忽视的,一味地强调滚筒扫描仪扫出来的产品一定比平台式好是片面的.     

雪崩光电二极管器件信噪比分析与计算

雪崩光电二极管具有光电转换能力强、耗电低、感光精度高及可以在更大的频谱范围内工作的优点,在光电通信的应用地位越来越重要。雪崩效应是由二极管内高电压产生光电流迅速增加引起的。该文详细分析和计算APD雪崩光电二极管工作噪声的来源和光电转换信噪比的变化。雪崩效应造成的光电二极管的内部增益不仅会扩大接收信号的噪音,还会扩大原始噪音,使人们很难收集和提取外部的微弱信号,输出信号中的噪音是影响雪崩光电二极管信噪比的主要原因,因此要提高雪崩光电二极管的性能,必须减少噪音。     

浅谈图像颜色校正技巧

<正>扫描仪和数字相机是印前处理中常用的两种图像输入设备。由于扫描仪光源、滤色片和光电转换元件的误差,扫描输入的图像经常会存在一定程度的颜色偏差;同样,用数字相机采集图像时也可能因为光照条件或曝光时间的不合适以及CCD的颜色响应误差而引起图像的色偏。因此,为了得到颜色复制准确的彩     

Comparison of different body measurement techniques: 3D stationary scanner, 3D handheld scanner,and tape measurement

Body measurements play an import role in pattern generation and size determination. Traditionally, body measurements were captured with tape measures. The tape measure technique is often time-consuming. Nowadays, three-dimensional (3D) stationary whole-body scanners are widely used in the apparel industry to collect body measurements. The stationary scanner has good performance on efficiency, validity, and reliability. However, it is not suitable for home use due to its high cost. Occipital’s Structure Sensor, as a representation for low-price handheld 3D scanners, is a 3D scanner for mobile devices. This research focused on studying whether the Structure Sensor could be used to capture body measurements for the apparel industry or not. Its performance was compared to a whole-body stationary scanner and the tape measurement. It was found that the Structure Sensor could be used to collect body measurements data with relatively low reliability if corresponding measurement extraction software was developed.     

Simulated yield in a sawmill using different measurement technologies

Pinus silvestris ) logs and 106 Norway spruce (Picea abies) logs was used in the study. These shapes are measured manually and the operation of the different scanners, that is, the measurements and the shape predictions leading to a decision on the sawing pattern, is simulated. Different technological situations as whether the bark has or has not been removed by the time of scanning, and whether the rotation of the logs at sawing is random, fixed or optimized, are considered. The performances of the scanners in the different situations are given in terms of the average main yields. The results show that there is a yield increase of ca. 0.5 percentage points when replacing a 1-axis shadow scanner with a 2-axis shadow scanner. There is a further potential yield increase in introducing a 3-d scanner or an X-ray scanner, however, in order to get a substantial improvement using these scanners one has to control the orientation at sawing. The difference in yield of the 3-d scanner between random and optimized orientation is ca. 2 percentage points when measuring on bark and ca. 4 percentage points when measuring under bark.

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Non-destructive wood density distribution measurements using computed tomography

Two computed tomography scanners have been used to acquire density profiles from five wooden test pieces. These test pieces had annual growth ring widths varying between about 0.6 mm and 3.5 mm. The two scanners employed were a medical scanner, a GE 9800 Quick scan system, and a purpose built microscanner constructed around a Rigaku D-Max II diffractometer. The results demonstrated that the annual growth rings could be resolved and density measurements could be reliably determined using the microscanner when the annual growth rings were about 0.9 mm or greater in width. The medical scanner could not satisfactorily measure density in carlywood or latewood resions even in samples where the annual growth ring width was of the order of 3.5 mm. A small difference in density measurements could be observed between the two scanners for the same specimens. The difference is attributed to calibration differences, the reconstruction algorithms used and the different geometries of the two systems; particularly in relation to the detector apertures. The larger detector size in the medical system results in too high or too low density values in the carlywood or the latewood respectively due to spatial averaging. However, the medical scanner provides satisfactory density accuracy in specimens where the density is very uniform or as long as measured areas include both carlywood and latewood. An accuracy of ±2–6 kg/m³ at 95% confidence level can then be expected.     

纹织CAD中的颜色量化算法研究

经过扫描仪输入的图像,所包含的颜色很多,真彩色图像有成千上万种颜色,八位图像也有256种颜色,而实际的纹织图像花样设计中所涉及到的颜色数目屈指可数.因此,在进行进一步处理前,需要对图像进行颜色量化,将扫描图像中的颜色归并为少数几种颜色.利用改进了的"变球法"颜色量化算法进行颜色量化,满足了在纹织CAD设计中,设计人员因为工艺或者设计的需要,保留原图片上几种特定颜色的要求.仿真结果表明运用该算法的颜色量化效果好,误差小,基本接近原图.     

Developing novel 3D measurement techniques and prediction method for food density determination

Density is a physical characteristic which depends on the experimental technique used and structural properties of food. True, apparent, and bulk are different types of densities based on the way volume is measured. For porous foods such as grain food products, accurate measurement of density is challenging. Current measurement techniques for food density are inconsistent and nutrient databases do not have sufficient density data. Computed tomography (CT) and magnetic resonance imaging (MRI), laser scanners are non-destructive diagnostic tools for characterizing food microstructure. The objectives of this study were to 1) optimize the parameters of CT, MRI, and laser scanner to determine food density and compare the corresponding values with other traditional techniques, and 2) to develop neural networks as a prediction method for apparent and bulk densities. MicroCT 40 (Scano Medical Inc.), Lightspeed QX/i clinical CT (GE Healthcare), and 3 Tesla Signa HDx MRI (GE Healthcare) were used to acquire 3D images of foods for true density. A 3D laser scanner (NextEngine, Inc) was used to scan the foods items for apparent density. Neural networks were used in conjunction with the data collected from laser scanner and using food composition and processing conditions to generate a black-box prediction scheme. The results of CT, MRI, and laser scanner showed great potential to estimate density in comparison to traditional techniques. Porosity was estimated from the CT and MRI scanned image data. Laser scanner was successful in acquiring 3D images and calculating apparent density. Neural networks provided reliable density prediction power and were comparable to the other empirical equations in terms of accuracy. The ability to predict food density based on composition and processing conditions is necessary to fill gaps in nutrient databases and account for new foods.     

Identification of Sicilian landraces and Canadian cultivars of lentil using an image analysis system

Seed colour and size determine the appearance of grain legumes such as lentils (Lens culinaris Medik.). Currently, these characteristics are assessed by visual inspection of grain; it is slow and subjective, for this reason an objective imaging system was developed in Canada to measure bulk seeds lentil colour and size in a consistent manner for lentil quality colour grading.The Canadian imaging method, using image captured by a flatbed scanner, was modified in collaboration with the Stazione Sperimentale di Granicoltura (Research Institute in Sicily) to measure seed size, shape and mean colour on individual seeds; each seed imaging data were computed with a Linear Discriminant Analysis (Classifier) to identify five Sicilian landraces of Lens culinaris Medik., precisely Aragona, Bronte, Leonforte, Ustica and Villalba and three common Canadian accessions, cv Laird, cv Crimson and cv Eston.The performance of the classifier was 99.8% for the training sets and 97.1% for the independent test set. In addition to commercial international trade, lentil seed characterisation is very important to identify and catalogue in a biodiversity conservation program.     

Scanner colorimetric characterization for concentration estimation in single-component dyeing systems

Today, scanners are often promoted for color measurement applications. With a color scanner, it is possible, to some extent, to measure the color of objects if they are properly calibrated and characterized. The object of the present work is to study concentration estimation in single-component dyeing systems using a scanner. A new method is presented based on Cohen and Kappauf and single-constant Kubelka–Munk theories. The results showed a nonlinear transformation of the fundamental color stimulus that benefits from a good scalability could be applied for the aims of this study in specified illumination and viewing conditions with an adequate error range.     

利用OPC技术实现成品烟发货扫描

使用手持无线扫描仪对发货的成品烟进行扫描,该方式劳动强度大,且容易出错。为此,通过在成品发货输送轨道两侧安装固定扫描器,利用RS-232串口通讯技术、OPC技术等解决了传统发货扫描效率低、易出错的问题。改进后扫描速度由25件/min提高到40件/min,返工重扫率由5%下降至0.1%,极大地提高了成品烟的发货效率。     

Optimization of a scanner imaging technique to accurately study oil migration kinetics

The aim of this study was to refine an image analysis technique that was developed in our laboratory in order to study oil migration in confectionery products (Marty, S., Baker, K., Dibildox-Alvarado, E., Neves Rodrigues, J., & Marangoni, A. G. (2005). Monitoring and quantifying of oil migration in cocoa butter using a flatbed scanner and fluorescence light microscopy. Food Research International). The migration of a nile red stained oily phase (soft fat) was monitored in tempered cocoa butter matrices kept at 18 °C for about 75 days. Oil migration kinetics was quantified using a common flatbed scanner followed by image processing and analysis. The most reliable parameter derived from this analysis is the position of the dye front (I₁₀) where the intensity of the dye is 10% of maximum. The determination of the amount of dye migrated from pixel intensity measurements was found to be highly affected by cocoa butter structure at times greater than 28 days, but I₁₀ was not. The determination of a model-independent oil migration rate (I₁₀/tⁿ) using this method was found to be highly reproducible and accurate. Due to the observed non-linearity of the oil migration process and the effects of matrix structure on the determination of pixel intensity (and thus mass of dye migrated), the quantification of oil migration using the simplified version of Fick’s second law is not recommended.     

Photo-scanning colorimetry of wood and transparent wood coatings

Although conventional spectrophotometers are well-known to give very accurate and reproducible measuring results of the wood surface colour, the areal resolution of this method is limited due to the fixed aperture size. In this study, the applicability of a colour calibrated flatbed scanner for areal-resolved colorimetry was investigated. For this purpose, the colorimetric values of several wood species calculated from images of a colour calibrated photo-scanner were correlated with those obtained by a conventional spectrophotometer. Further, this method was used to evaluate the discoloration of earlywood and latewood of Siberian larch (Larix sibirica) during Xenon arc exposure as a demonstration of the potential application of this method. In addition, an investigation concerning the possibility of image analysis for the evaluation of the colour change as a consequence of the application of transparent coatings was done. Good correlation among the measured methods could be found by applying relative colour values ΔL* Δa*, Δb* and ΔE*, whereas absolute colour values L*, a* and b* obtained rather weak correlations. The investigation of the relative discoloration of earlywood and latewood of Siberian larch showed a higher amount of discoloration in the earlywood. The investigation concerning the colour change induced by the application of transparent coatings showed that it is possible to evaluate the discoloration by the coating for earlywood and latewood separately. This could be the basis for a more quantitative comparison of quality parameters of coatings like the visual contrast enhancement effect, known as wet-look or “Anfeuerung” of transparent coatings. It was concluded that when evaluating colour changes on wood the use of a calibrated photo-scanner is a valuable addition to conventional spectrophotometry.