利用DFT幅度和相位构建矢量空间数据水印模型

针对矢量空间数据的特征,提出了利用离散傅里叶变换 (DFT)幅度和相位构建矢量空间数字水印模型的方法. 首先将矢量空间数据进行DFT,将水印信息嵌入DFT系数的幅度和相位中;然后做逆变换,得到嵌入水印的矢量空间数据,对其进行攻击后提取水印;实验结果证明,该模型能够保证数据的精度,对数据平移、一定比率的随机删点、旋转、格式转换、缩放等具有稳健性.     

The influence of sweeteners in probiotic Petit Suisse cheese in concentrations equivalent to that of sucrose

As in the case of probiotic functional foods in recent years, demand has increased notably for light or diet foods with added sweeteners. However, little is known about the effect of different sweeteners on the microorganisms present. Thus, the objective of the current study was to establish the ideal sucrose concentration and equivalent concentrations of different sweeteners and to determine, by microbiological analyses, the influence of these compounds on the viability of the starter and probiotic cultures used in the production of strawberry-flavored Petit Suisse cheese during its shelf life. The ideal sucrose concentration was determined using the just-about-right (JAR) scale, and the equivalent concentrations of the sweeteners were subsequently determined by the magnitude estimation method. Microbiological analyses were also carried out to check the viability of the cultures during the product’s shelf life. The results showed that the compounds Neotame (NutraSweet, Chicago, IL) and stevia presented, respectively, the greatest and least sweetening power of the sweeteners tested. None of the sweeteners used in this study exerted a negative effect on the viability of the starter or probiotic cultures, and thus we were able to obtain a probiotic, functional food with reduced calorie content.     

旋转压缩机定子与壳体过盈配合有限元计算

本文应用有限元分析软件ANSYS对旋转压缩机定子与壳体过盈配合方式在两种工况下进行模拟计算,得到定子与壳体变形规律与定子外形结构密切关系。并对两种工况下定子、壳体变形,两者接触装配压力及抱紧力随过盈量变化关系进行比较分析。分析方法对过盈量选择提供了理论依据,同时对定子结构设计与优化具有重要指导意义。     

壳体凸台挤压模

详细说明壳体凸台挤压模的模具结构及工作过程 ,并介绍了凸台成形中产生的缺陷和防范措施     

基于噪声估计和双加权的彩色图像矢量中值滤波

针对彩色图像椒盐噪声滤除中保护色彩和细节这个关键问题,提出了一种基于噪声估计和双加权的滤波新算法.噪声估计采用二级估计策略,第1级基于灰度最大、最小值进行粗估计,第2级采用加权方向算子进行精估计.对非噪声点保持像素灰度不变,对噪声点设计了空间和灰度双加权的矢量中值滤波算法(VMF).实验结果表明,新算法对低、中密度的彩...     

Image quality assessment based on Prewitt magnitude

The goal of image quality assessment (IQA) research is to use computational models to calculate the quality of images consistently with subjective evaluations. In this paper, we propose a new image quality assessment (IQA) algorithm by combining Prewitt magnitude and regional mutual information (RMI) in HSV color space. The Prewitt operator is usually used for edge detection and can extract vertical edge more accurately than other operators. The HSV color space encapsulates information about a color in terms that are more natural and intuitive to humans. The proposed method PMRMI first transforms reference and distorted images from RGB color space into HSV color space and Prewitt magnitude is introduced to extract key edge features of each channel. Then the regional mutual information is calculated to measure the similarity of the two images. After that, a weighting method is utilized for better consistency with subjective evaluations. Therefore we get a single quality score. Experiments on various image distortion types demonstrate that the proposed algorithm can achieve better consistency with the subjective evaluations than PSNR and SSIM.     

基于梯度幅值的自适应边缘检测算法

提出了一种新的边缘检测算法.根据所提出的梯度幅值计算方法求出整幅图像的梯度幅值均值和图像中所有像素点的梯度幅值相对与均值的方差.由图像的梯度幅值均值和方差计算出图像的最佳阈值.然后根据提出的噪声剔除方法对由最佳阈值判定的初始边缘中的噪声进行剔除.实验结果表明所提出的算法在精确定位边缘的同时也较好地抑制了噪声.     

改进的基于梯度幅值的自适应边缘检测算法

分析文献[1]给出的算法.针对其中存在的问题和不足,给出了一个改进算法.实验结果表明,改进算法弥补了原文算法中的缺陷,在获取连续边缘的同时也较好地抑制了噪声,在运算效率方面有了明显的提升,并节省了大量的内存空间.     

星等能量检测系统设计

空间目标场景模拟器是在实验室环境下进行星等探测能力评价和定标的设备,该系统的关键是对弱星等的标定要求很高,最高检测星等为16等星。本文设计了基于光电倍增管的单光子计数器作为模拟星的能量检测设备,给出了光电倍增管的选择方法及其分压器的设计原理,最后通过实验验证了该单光子计数器的测量精度能够满足定标的要求。     

循环AMDF及其语音基音周期估计算法

基音周期是语音压缩、合成以及识别中的一个重要参数.传统的基于AMDF的基音估计算法容易导致估计的基音周期加倍.本文针对该现象,分析了AMDF函数的特性及其用于基音检测时存在的不足,提出了新的CAMDF函数.CAMDF有效地克服了AMDF函数的不足,简化了基音检测过程.在此基础上,本文给出了新的基于CAMDF的基音检测算法.该算法不仅简化了基音检测过程,而且降低了误判率,提高了估计精度.大量实验表明其性能优于其它AMDF或LVAMDF的方法.