马尔可夫随机场在纸病检测中的应用研究

纸病检测是造纸生产过程中重要的环节,现有的纸病检测系统一般采用阈值算法或边缘检测算法对图像进行分割。为解决阈值分割和边缘检测分割方式中存在的误分以及过度分割问题,本研究提出了基于马尔可夫（MarKov）随机场的纸病图像分割方法。通过MarKov随机场理论对纸病图像纹理进行分析得到纹理特征参数,利用纹理特征参数以及最大差值对正常背景和纸病区域进行分割。结果表明,相比于其他分割算法,基于MarKov随机场的纸病图像分割方法可有效提取出纸病图像的纹理细节和轮廓特征,提高分割的准确度。     

基于数学形态学算法的纸病检测及IDL应用

本文介绍了采用数学形态学算法从纸样图像中提取纸病的方法。运用第四代计算机语言IDL（Interactive Data Language）完成了数学形态学的膨胀、腐蚀及梯度运算,并实现了纸样图像中纸病边缘的检测．结合阈值分割方法得到纸病检测和分割结果     

基于粒子群优化算法与形态学的纸病图像检测方法

针对传统边缘检测算子对纸病图像检测的不足,提出了一种基于粒子群优化算法和数学形态学的边缘检测方法。首先通过粒子群优化算法得到图像最优分割阈值,将图像二值化,然后利用数学形态学中的腐蚀运算对纸病图像进行边缘检测。仿真结果表明,相比传统算法,该方法的检测结果更真实地反映了纸病图像的形态特征,且边缘定位准确,取得了较为理想的检测效果。     

基于阈值分割及分形特征的纸病图像识别算法研究

针对脏点、孔洞、褶子和裂口等常见的典型纸病识别问题,在分析纸病图像灰度特征及分形特征基础上,提出了一种基于图像双阈值分割盒维数特征的纸病识别算法,该算法采用灰度阈值分割提取纸病区域及二值数字图像分形盒维数计算结果,确定纸病类型.实验结果表明,该算法识别率较高,且简单迅速.     

基于几何及灰度特征的纸病检测算法研究

针对当前纸病在线检测系统实时性强和信息量大的特点,提出了一种高效、灵活的基于几何及灰度特征的纸病检测算法.首先采用邻域均值法对纸病图像去噪,然后根据灰度直方图选取合适阈值将图像二值化,并运用边界跟踪法检测出纸病边缘,最后提取出纸病的几何及灰度特征并分析其特征量将纸病分类.按照该算法依次对常见5种纸病进行检测,结果表明,基于几何及灰度特征的纸病检测算法能够准确地检测并分类常见纸病.     

基于RPCA的纸病图像分割算法

针对实际纸病检测应用中采集到的图像分辨率越来越高,在图像处理过程中出现数据维数过大的问题,提出一种基于鲁棒主成分分析法(Robust Principal Component Analysis,RPCA)的纸病图像分割算法,该算法将纸病图像对应的矩阵分解成稀疏矩阵和低秩矩阵。在后续检测中只需选取稀疏矩阵对应的图像进行检测就可以满足纸病检测的要求,有效减少了计算量,最终节省了整个纸病检测环节的检测时间。仿真结果表明,该方法可用于纸病图像的分割,并且具有良好的分割效果。     

基于FPGA的纸病提取系统的设计

研究并设计了一种基于FPGA的纸病提取系统,实现造纸过程中纸病部位图像的提取。通过FPGA内部硬件电路进行图像采集、预处理和纸病提取,借助NIOS II软核处理器实现纸病数据的发送,使用计算机从网络接收数据并重组图像,最后得到只含有纸病部位图像的数据。该系统可根据不同的纸机要求灵活配置,在不影响整体性能的前提下,增强系统数据处理能力。经测试,该系统能够稳定可靠地实现纸病提取功能,与纸病识别系统相结合即可实现纸病检测,为纸机的日常维护提供保障。     

基于相位一致性的低对比度纸病识别算法研究

针对机器视觉检测低对比度纸病,存在常规的阈值分割会引起低对比度纸病信息丢失以及边缘检测存在鲁棒性差的问题,本课题提出了一种基于相位一致性算法识别低对比度纸病的方法,并与常规的阈值分割以及边缘检测中具有代表性的canny算子进行了对比分析。结果表明,当识别低对比度纸病时,本课题提出的方法不仅保留的有用信息较常规阈值分割的多,而且鲁棒性较canny算子的边缘检测好。     

基于位平面的纸病检测算法研究

针对当前纸病检测算法存在抗干扰能力差、定位不准确和运算复杂等问题,提出一种基于位平面的纸病检测算法。首先,采用自适应中值滤波算法对纸病图像进行滤波,然后,对滤波后的图像进行位平面分解,并运用格雷码对位平面加以增强,最后,使用数学形态学对其进行边缘检测,得到最终的纸病检测结果。仿真结果表明：该方法运算简单,能够较好地检测出纸病缺陷,并具有较好的抗干扰性和定位准确性。     

一种基于分块思想的多纸张缺陷一次提取算法

为了解决纸张缺陷检测中多个纸病区域的提取实时性问题,提出了一种采用“先分块、后合并”思想直接对实时图像数据流进行处理的并行化纸病提取算法。该算法充分利用现场可编程门阵列（FPGA）的并行处理特性,在跨时钟域对图像数据进行传输的同时,在另一个分支流程中并行地对分块缺陷连通域进行标记以获取每个缺陷的相对位置坐标,最后以包围盒的形式提取出纸张缺陷区域。该算法基于分块思想,分支处理过程不需要消耗主流程额外的处理时间且硬件资源占用率极小。实验结果表明,该算法能够准确、快速地提取出各种常见纸张缺陷,具有很强的灵活性和实时性,能够满足在线纸病检测的实时性要求。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.