采用抗混叠移不变Contourlet变换的云图融合(英文)

融合多通道的卫星云图可为监测和预报天气状况提供更加全面可靠的信息。本文提出一种采用抗混叠移不变Contourlet变换(Aliasing-suppression and Shift-invariance Contourlet Transform,ASSICT)的卫星云图融合方法。首先,为了克服原始Contourlet变换的频谱混叠及移变问题,将抗混叠滤波器组与非下采样方向滤波器组相结合,构造出ASSICT;然后,对两通道卫星云图(红外与可见光)采用ASSICT分解成低频及若干高频方向子带,对低频子带系数采取加权区域能量融合规则,而对高频子带系数采取加权区域方差融合规则进行融合处理;最后,对融合后系数进行抗混叠移不变Contourlet逆变换,得到融合云图。实验结果表明,本文方法融合的云图,由于增添了可见光云图的纹理细节信息,不仅提高了原始红外云图的分辨率,而且较好地保留了红外云图的亮温信息。     

离散余弦小波包变换及语音信号压缩感知

针对语音信号压缩感知问题,在研究语音离散余弦变换(Discrete Cosine Transform,DCT)系数和小波包变换(Wavelet Packet Transform,WPT)特性的基础上构造了离散余弦小波包变换(Discrete Cosine Wavelet Packet Transform,DCWPT)。DCWPT首先获取语音信号的DCT域系数,结合语音频谱特性选取部分DCT系数进行WPT变换,从而得到比DCT系数更加稀疏的DCWPT系数。为将此变换直接用于压缩感知,构造了DCWPT的正交稀疏分解矩阵并分析了其稀疏表示性能。结合稀疏表示基优化了正交匹配追踪重构算法,提出了基于DCWPT的语音信号压缩感知框架。通过压缩重构对照实验,采用主客观评价指标,得出该方法优于传统基于DCT的语音压缩感知方法的结论。     

一种改进的边缘检测方法

本文提出了基于小波变换和图像融合的一种改进的边缘检测方法。该方法利用小波变换将数字图像分解为高频和低频分量,对高频和低频分量分别进行边缘检测;再采用局部区域方差准则把高频和低频边缘在小波域进行融合。实验表明,该方法能够有效融合高频、低频边缘图像特征,具有较好的边缘检测功能。     

基于优化分类的机械振动信号压缩感知

针对复杂机械振动信号压缩感知过程中存在的稀疏字典构造困难问题,提出了基于QPSO分类的自适应稀疏字典构造方法。该方法根据信号的分割尺度,将信号进行分块,并利用每一信号块的能量大小,构造能量序列,利用QPSO对能量序列进行优化分类,保证不同类别间能量序列的方差最大,从而实现对信号块的分类,采用K-SVD对不同类信号块分别进行稀疏字典的自适应学习训练,产生与信号相适应的稀疏字典,用于机械振动信号的压缩感知重构过程。通过滚动轴承实测信号在不同状态下的压缩感知实验表明:所提方法能够有效提高信号重构的峰值信号比,改善机械振动信号的重构效果。     

基于混合编码和IWT的医学图像近无损压缩

本文对医学图像先采用DPCM预测变换后,再选择IWT(整数小波变换)对其进行分解,对分解后的低频和高频子带分别作无损Huffman编码和有损矢量量化.根据小波分解后系数的分布特征,能量大部分集中在低频部分,对低频进行无损熵编码,对高频采用量化处理,去除人眼不敏感的冗余信息.最后利用处理过的低频和高频系数进行重构获得压缩后的图像.并与传统的离散小波变换压缩编码,JPEG和JPEG2000进行比较,实验结果表明,利用该方法能得到较高的压缩比和较好的压缩效果.     

基于压缩感知的强鲁棒性彩色图像双水印算法

目的为了解决图像的鲁棒性和透明性之间的矛盾,依据压缩感知理论的计算保密性提出一种基于压缩感知的强鲁棒彩色图像双水印算法。方法首先将水印图像RGB分解后,对G,B分量分块压缩感知获得测量值,再对载体图像G,B分量NSCT分解,对低频分量非重叠分块后LU分解、奇异值分解,将每个分块的水印测量值按不同嵌入强度对应嵌入载体奇异值矩阵中,经过一系列逆变换得到含水印图像。最后用含水印图像R分量分块压缩感知测量值生成零水印,发往IPR中心注册保存。结果该算法在水印的嵌入和提取仿真实验结果中峰值信噪比大于40 d B,重建的水印图像与原图像相似度极高,且能抵抗剪切、高斯噪声、椒盐噪声、高斯低通滤波和JPEG压缩等类攻击。结论算法具有很强的鲁棒性和较好的透明性,实现较简单具有切实的可行性。     

基于QR分解的彩色图像自嵌入全盲水印算法

针对彩色图像的版权保护问题,基于 QR 矩阵分解提出了一种自嵌入全盲水印算法。先将原始图像的G通道分量进行非下采样剪切波变换,再对得到的低频分量分块QR分解,通过判断各子块R矩阵中第一行元素向量的l1范数与所有子块R矩阵第一行元素l1范数均值之间的大小关系生成特征水印。然后对B通道分量DWT变换后的低频分量进行分块QR分解,并通过修改该子块QR分解后R矩阵中第一行最后一列元素来嵌入特征水印。特征水印的生成和嵌入在两个通道内独立完成,水印检测无需原始载体图像,算法无需借助外加水印信息即可完成对图像版权的鉴别。实验结果表明,该算法在经历添加噪声、JPEG压缩、缩放、剪切和行偏移等常见攻击时,具有很强的鲁棒性。     

分块Radon变换在低对比度掌纹特征提取中的应用

特征提取是低对比度掌纹识别的关键步骤.针对掌纹纹理特征明显的特点,本文提出了一种分块Radon变换的掌纹特征提取方法.该方法先对掌纹感兴趣区域进行一级小波分解去噪降维,接着对低频子图像进行分块以圈定局部主要纹理,最后把所有分块后的子图像进行70°～140°Radon变换,所获得的线积分组合在一起构成该图像的特征向量.运...     

基于小波系数邻域特征的CT与MR图像融合方法

提出一种基于小波变换的像素级CT,MR医学图像融合方法,利用离散小波变换分别将两幅源图像进行多尺度分解,再用不同的小波系数邻域特征指导高频分量和低频分量的小波系数的融合,低频分量采用邻域方差指导,高频分量采用邻域能量指导,最后根据融合图像的各小波系数重构融合图像.实验表明:不论从主观感受,还是采用信息熵和平均梯度两项指标作为客观定量评价标准,该方法都优于传统的融合方法,获得的融合图像有效地综合了CT与MR图像信息,能够同时清晰地显示脑部骨组织和软组织.     

基于NSCT和压缩感知的数字图像水印算法

目的依据压缩感知理论具有很好的计算保密性,提出一种基于NSCT和压缩感知的数字图像水印算法,以解决图像的鲁棒性、不可感知性及保密性之间矛盾。方法首先将水印图像分块压缩感知获得测量值,然后再将载体图像NSCT分解,对低频分量Fibonacci置乱后非重叠分块,对每块进行LU分解、奇异值分解,将每个分块的水印测量值按不同的嵌入强度对应嵌入载体奇异值矩阵中,经过一系列逆变换得到含水印图像。结果该算法在水印的嵌入和提取仿真实验结果中峰值信噪比大于40 d B,重建的水印图像与原图像相似度极高,且能抵抗剪切、高斯噪声、椒盐噪声、高斯低通滤波和JPEG压缩等类的攻击。结论该算法既具有很好的鲁棒性又兼有较强的不可见性,具有切实的可行性。     

Effect of Permeable Crystalline Material on Steel Reinforcement Corrosion of Concrete

Permeable crystalline materialcan permeate into pores and cracks of concrete and catalyze the reaction between Ca(OH) 2and unhydrated cement to generate a great quantity needle non-soluble crystals, which can stop up the pores and cracks of concrete, and increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate steel reinforcement corrosion of concrete specimens uncoated and coated with permeable crystalline material as well as mixed with the permeable crystalline material. The properties evaluated for corrosion test were water impermeability, water absorption, compressive strength and potential. The results of water impermeability, water absorption, compressive strength clearly showed that the permeable crystalline material could prohibit water, any soluble salts and moisture from penetrating the concrete to cause corrosion, leaking, and other problems, and it did increase the compressive strength, which was favorable for protection of corrosion of reinforcing steel. Moreover, it was concluded from the potential-time curve that the steel reinforcement of uncoated specimen was in the state of activation whereas that of other specimens coated and mixed with the permeable crystalline material was in the state of inactivation. Above all, it was indicated that the permeable crystalline materialis very effective to protect the steel reinforcement of concrete from corrosion.     

The Research and Application About "Dry Peeling Off" Technology for Airplane Surface Paint Layer

In this paper, the principle of spurting take off lacquer were introduced; and with orthogonal method the unsaturate polyester was prepared ;it was easy to peel airplane paint layer off with this material and equipment.     

Quality Study of Honeycomb Core Shaping Without Wax Stabilization

Sandwich panels utilizing honeycomb cores result in lightweight, high-strength units that are very rigid. Indeed, they give honeycomb panels the best strength-to-weight ratio of any construction type available. Conventionally, the wax is poured into the cell of the core to strengthen the structure and prevent the core from being crushed during milling. Much time and labor is required to wax, mill, and clean the cores. In this study, the process of pouring wax into the core was skipped. In other words, the cutter directly milled the core. Experiments showed that the compressive strength of the core produced without wax stabilization was only 3% lower than that of cores produced using the traditional method. In addition, the drum peel strengths of cores produced without wax stabilization were 38.4% higher than cores produced using the traditional method, in which residual wax seriously polluted the adhesive. It was also found that eliminating the wax process can reduce costs.     

In-process thermal treatment of polylactic acid in fused deposition modelling

Polylactic acid (PLA) is one of the most widely used open source fused filament fabrication materials due to its ease of extrusion, biodegradability, and mechanical strength. The mechanical strength of PLA largely depends on the proper growth of its semi-crystalline structure, which can be severely impaired by a low rate of crystallization, particularly in open source printers. This can be further aggravated by the non-uniform thermal distribution of heat that causes improper curing among the extruded beads of the printing material. As a result, PLA printed on open source printers does not achieve the best mechanical properties. This research, for the first time, proposes an additive-free solution implemented through a detailed set of experimentation to improve the curing rate through in-process temperature variations to cure the joints among the beads. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy is used to confirm the improvements in the bead joints. This work is conducted in two phases of experiments. In the first phase, a full factorial ANOVA is used to investigate various process parameters and the important variables are used in the second phase to print test specimens in four different sets.     

Investigation of the Corrosion Behaviors of HVOF-Sprayed Carbide Cernet Coatings in Molten Al-Zn-Si Alloy Bath

In continuous hot-dip galvanization process the corrosion and chemical stability of the sink roll in the galvanizing bath are important problem which effects on the quality and productivity. In order to protect the sink roll the carbide cermet and/or ceramic coatings were deposited on the surface of the sink roll. The WC-, Cr3 C2-cermet coatings were deposited by high velocity oxygen fuel (HVOF) spray, respectively. The coating samples were immersed in molten Zn-alloy containing 50 wt % aluminum at 833 K for 24 hr and 144 hr, respectively. The inter-diffusion and inter-reaction of Zn, Al and elements in coating and corrosion behaviors of these coatings were investigated by XRD, SEM and EPMA etc. The corrosion mechanisms of the carbide cermet coatings and ceramic coatings in molten High Al-Zn-alloy were approached.     

Fundamental study of adhesion of ice to cooling solid surface (Discussion on influence of copper oxide layer on ice adhesion force)

In many situations, ice often adheres to a cooling solid surface, frequently causing serious accidents. It is critical to clarify the mechanism of ice adhesion to the cooling surface in order to prevent ice adhesion. In a past study, the shearing stresses of two kinds of test plates with a copper surface having the higher thermal conductivity were measured. The shearing stress corresponds to ice adhesion force. Both shearing stresses were significantly different; however, the cause remains unclear.Therefore, the present study focuses on an oxide layer as the main factor causing the difference of both shearing stresses; the influence of the oxide layer formed on shearing stress was discussed. And in the removal and reformation processes of the oxide layer, the time variation of the shearing stress was clarified. Moreover, the relationship between the state of the copper surface and the shearing stress was also clarified by surface analysis.     

＂Three Transformations＂ and Standardization

During his inspection in Henan Province in May, Chinese President Xi Jinping stressed to ＂push forward the transformation from China Speed to China Quality, from Made in China to Created in China, and from Chinese Products to Chinese Brand＂. The ＂Three Transformations＂ are the specific requirements and goal of China＇s national development in the context that market should play a decisive role in the allocation of resources.     

重塑标准推行格局 推动LED照明的普及（英文）

正When you are enjoying the green,energy-saving and healthy lighting of IKEA LED luminaire,you may not realize that most of IKEA’s LED bulbs are produced by the LED luminaire smart manufacturing system of Hangzhou Zhongwei Photoelectricity CO.,LTD(ZVISION).No longer enclosed in the laboratory,the product standards are brought into the factory workshop and even to the entire production process.Thus,the standards are promoted and applied in a favorable way by enterprises,benefitting consumers with high quality products.     

Chinese Experts Contribute to ISO＇s New Toy Standards

正The international standard,ISO 8124-6,Safety of toys–Part 6:Certain phthalate esters in toys and children’s products,was officially issued by ISO worldwide on August 15.It was the first time for Chinese experts to lead the ISO standard development in toys industry.The standard was drafted by a group of Chinese experts from SAC/TC for toys and relevant Chinese departments and finally completed by a dedicated international group of experts.ISO 8124-6 makes a substantive breakthrough in the aspects of the scope of toys,limitation of plasticizer types,control of test cost,accuracy of test,operation convenience,etc.,offering the operational guidance for toy manufactures and testing laboratories.     

SAC Delegation Visits AENOR and Signs Cooperation Agreements

正SAC Administrator Tian Shihong led the Chinese delegation to visit the Spanish Association for Standardization and Certification(AENOR)on September 15,2014.Mrs.Begona Cristeto,the Vice-Minister of Industry,Energy and Tourism of Spain,and Mr.Avelino Brito,the President and CEO of AENOR greeted the delegation.The two sides had a deep and friendly discussion on strengthening the cooperation between China and Spain in the standardization field and promoting the standardization work to support the development of economy and trade in the two countries.