墙地砖边缘检测中的小波去噪

在墙地砖的边缘检测过程中,噪声的引入是不可避免的,有效地消除噪声而不影响检测结果是检测过程中需要解决的关键问题。本文采用了小波去噪方法—对图像进行去噪后再进行边缘检测的方法,其检测结果较好地满足了检测要求。     

墙地砖边缘检测中的几种去噪复原方法

在墙地砖的质量检测过程中，边缘检测是一项重要内容，而在检测过程中，图像噪声的引入不可避免。本文就这一内容讨论了在母地砖检测过程中的四种图像去噪复原方法，并将各种去噪复原方法的边缘检测结果进行了比较。     

基于快速曲波变换的陶瓷显微图像处理

陶瓷内部结构信息对于陶瓷质量分析、生产工艺控制是非常重要的。由于陶瓷显微图像在采集和传输过程中不可避免地要受到光照分布不均匀、电子噪声等干扰因素的影响而使得图像的质量变差。需要首先对其进行去噪、增强处理,然后才能进行图像分析。曲波变换是在小波变换的基础上发展起来的一种新的多尺度分析方法,比小波更加适合分析二维图像中的曲线或直线状边缘特征,而且具有更高的逼近精度和更好的稀疏表达能力。快速曲波变换理论的提出也使得其理论更易理解和实现。因此,提出了一种基于快速曲渡变换的图像去噪、增强方法,并将其引入陶瓷显微图像的处理中,然后按照分水岭算法进行粒度分割,得到陶瓷粒度分布的统计结果。实验结果表明,该方法是可行的,并且效果良好。     

结合无下采样Shearlet模极大值和改进尺度积的有噪图像边缘检测

为从噪声污染的图像中提取出更为清晰、连续的边缘,进一步改善边缘检测效果,本文提出了一种基于无下采样Shearlet模极大值和改进尺度积的边缘检测方法。首先对含噪图像进行多尺度、多方向无下采样Shearlet变换(Non-subsampled Shearlet Transform,NSST),得到图像在NSST域的高频系数;然后选取相邻的两个较大尺度的高频系数进行改进的尺度积运算,并经NSST模极大值处理得到边缘二值图像;最后使用区域连通方法去除二值图像中的孤立点,得到准确的边缘图像。大量实验结果表明,与小波模极大值、小波尺度积、基于无下采样Contourlet变换(Non-subsampled Contourlet Transform,NSCT)模极大值和尺度积、NSST模极大值等4种边缘检测方法相比,本文提出的方法具有更强的抗噪能力,且有效地避免了纹理的影响,检测出的边缘完整清晰,连续性好。     

基于二进小波变换的多尺度边缘细化检测

对采用小波变换多尺度边缘检测得到的图像进行细化,并与传统的5种边缘检测算法的检测结果进行比较。选取不同小波变换的尺度,将图像信噪比作为评价指标对边缘检测算法进行度量。实验结果表明:基于二进小波变换的多尺度边缘细化检测算法在存在噪声干扰时可取得满意的边缘提取效果,在边缘信噪比方面优于传统边缘检测算法。     

基于小波门限去噪法在提高ROI重合度的研究

在无接触式充电系统中,为了保证充电的效率,最终达到高效的充电,对于初次级线圈重合度有着十分严格的要求。本文采用了一种空间自适应小波门限去噪法来进行视觉定位系统的研究。实验表明:在有噪声的情况下,该算法对于去除单帧图像小波去噪后残留的噪声和去噪时引入的类似脉冲噪声的伪细节有较大的改进。     

数字图像去噪处理方法研究与实现

针对目前图像在传输过程中会受到多种噪声影响和干扰的问题,本文通过MATLAB仿真平台,分别采用邻域平均法、中值滤波法以及小波阈值法对图像进行去噪处理,同时比较几种去噪方法的优缺点,找到对图像质量影响最小,且去噪性能最好的方法。     

基于小波去噪的阈值函数改进方法分析

首先介绍了两种国内外比较有代表性的小波阈值改进方法,并在传统软、硬阈值函数的基础上提出了一种新的改进阈值函数,通过对小波系数的阈值处理,使得去噪后的信号在过分平滑与边缘振荡现象之间达到合理的平衡。对一段压气机台架实验数据的仿真分析表明:该方法在去噪的同时减少了有用信息的损失,在信噪比增益和最小均方差误差方面的性能指标要优于传统软、硬阈值法,同时在3种改进阈值函数方法中具有最佳的去噪性能。     

基于小波变换尺度相关性去噪算法的改进

在基于小波变换尺度相关性去噪的基础上,本文提出一种连续迭代的相关性去噪改进算法,克服了通常相关性去噪算法中小波系数对偏移敏感的缺点,引入小波窗口的方法来计算相关系数和迭代的方法连续去噪。数值试验结果表明,该方法易于重构,且重构信号可以较大限度地恢复原来的信号。     

一种基于频域变换的无监督车身漆膜缺陷检测算法

针对现有的2D汽车漆膜缺陷检测算法不能很好地检测出颜色暗、对比度低和较小的漆膜缺陷的问题,提出了一种基于频域变换的漆膜缺陷检测算法。首先通过对其主频率进行零掩码来消除图像背景中频谱显示较高梯度值分量的图像背景噪声。然后使用小波收缩法对傅里叶逆变换后的图像进行去噪。通过小波系数进行阈值修改,提取缺陷的高频信息,最后对重建后的图像使用阈值分割法分割出缺陷区域。对不同尺度和类型缺陷样本进行实验的结果表明,该算法检测准确率为95.01%,且具备良好的鲁棒性。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。