Computed tomography using level set method and algebraic reconstruction technique

In this paper, a novel reconstruction technique based on level set method and algebraic reconstruction technique is proposed for multiphase flow computed tomography (CT) system. The curvature-driven noise reduction method is inserted into the conventional iteration procedure of algebraic reconstruction technique to improve the image quality and convergence speed with limited projection data. By evolving the image as a set of iso-intensity contours after each updation, the sufficient number of iterations for acceptable results is reduced by 80%-90%, while the image quality is enhanced obviously. Quantitative evaluation of image quality is given by using both relative image error and correlation coefficient. The resultant images can be utilized to detect flow regimes for monitoring industrial multiphase flow. Laboratory results demonstrate the feasibility of the proposed method. Phantoms of four typical flow regimes can be reconstructed from few-view projection data efficiently, and the corresponding image errors and correlation coefficients are acceptable for the cases tested in this paper.     

Length-based vehicle classification in multi-lane traffic flow

For the realtime classification of moving vehicles in the multi-lane traffic video sequences, a length-based method is proposed. To extract the moving regions of interest, the difference image between the updated background and current frame is obtained by using background subtraction, and then an edge-based shadow removal algorithm is implemented. Moreover, a thresholding segmentation method for the region detection of moving vehicle based on location search is developed. At the estimation stage, a registration line is set up in the detection area, then the vehicle length is estimated with the horizontal projection technique as soon as the vehicle leaves the registration line. Lastly, the vehicle is classified according to its length and the classification threshold. The proposed method is different from traditional methods that require complex camera calibrations. It calculates the pixel-based vehicle length by using uncalibrated traffic video sequences at lower computational cost. Furthermore, only one registration line is set up, which has high flexibility. Experimental results of three traffic video sequences show that the classification accuracies for the large and small vehicles are 97.1% and 96.7% respectively, which demonstrates the effectiveness of the proposed method.     

彩色图像的数字水印系统设计

针对数字产品的版权保护问题,利用二维离散整数小波变换的快速性,结合人类视觉系统特性,开发了一种基于彩色图像新的、简单的、鲁棒性盲水印嵌入系统.系统可以将水印信息嵌入到不同整数小波分解级数下的彩色载体图像中去,具有嵌入速度快、安全性高的特点.首先将彩色载体图像由RGB彩色空间转换到YUV空间,再对y分量进行多级整数小波分解,然后分别将有意义的二值图像和字符串作为水印嵌入到不同级数小波分解后的低频域(LLn).算法选择了合适的水印嵌入位置,实验结果证明:系统使图像的不可见性好,所嵌入的水印对一般的图像处理攻击,如噪声、滤波、旋转、压缩等有较强的鲁棒性,系统实用性较强.     

一种基于Harris角点特征精确匹配的图像拼接方法

提出了一种基于Harris角点特征的精确匹配方法。该方法首先提取参考图像及待拼接图像中各自的Harris角点点集,并计算出这2个点集间每对点的圆形邻域图像的相关系数;再通过提取各个角点邻域的Hu矩特征,获得了该特征下每对点的相似程度。将不同特征下的相似度进行归一化并融合,构造出2个点集间,每对点的相似度表。在此表的基础上,优化匹配结果,使得匹配点对的总体相似程度高,从而得到精确匹配。由于Hu矩特征具有旋转及尺度不变性,因此提取出的角点特征能够较好地抵抗常见的图像变换。最后,实现了一套包括图像预处理、图像对齐与匹配等诸多模块的图像拼接系统。通过实际操作表明,该方法的图像拼接效率较高,有较好的鲁棒性。     

“竹帘”背后的中国——1949-1971年《时代》周刊的中国报道评析

1949.10.1-1971.4.9《时代》周刊的报道中所呈现的中国,是一个极度负面的＂风雨飘摇的邪恶帝国＂的形象,这一形象与中国的实际情况相距较远,其报道存在比较明显的不准确和片面的成分。导致这一时期《时代》周刊对中国的报道不太客观公正的原因主要有二：一是其持有强烈的＂反共主义＂意识形态;二是其将中国视为严重威胁美国国家利益的敌人。     

论曹操反面形象的生成

曹操是一个历来被争议颇多的人。历史上,他为结束三国纷争,晋统天下做了不朽贡献;但他又毕竟"篡了汉",在成就功业的过程中,其权术的使用令许多人为之不爽,至口诛笔伐。因此,谈论曹操,褒者说其智,贬者说其奸,千百年来,论说难以盖棺定之。文章针对大众对曹操的一般看法,从一些对曹操耳熟能详的评论来展开,结合史书和文学作品,分析其对曹操反面形象的塑造。     

天使与巫女共舞——评《德莫福夫人》中的女性形象

《德莫福夫人》是亨利？詹姆斯女性命运的早期作品之一。文中众多女性被塑造成两个固定的模式：无欲无求的天使和蛊魅人心的巫女。文章运用西方女性主义文学批评理论,分析文本中所有女性在男人＂凝视＂下的形象,从而进一步揭开那层扭曲了女性形象的神秘面纱。     

高职院校实训基地建设的思考

实训基地建设是提高高职院校教学质量和教学水平的关键要素。实训基地要建成便于教师组织教学,利于学生接受形象思维知识,多元化发展综合性的实训基地;要建成与区域资源共享,产学研相结合的生产性实训基地,才能产生效益,促进实训基地不断发展。     

注重大学生职业形象塑造,提升高职人才就业竞争力

本文阐述了职业形象的概念及重要意义,并且强调了在高职院校中注重大学生职业形象塑造有利于提升高职人才的就业竞争力,同时对如何提高大学生职业形象设计水平给出了看法,也提出了高职院校在职业形象设计指导过程中存在的问题和解决思路。     

基于图像处理的工件检测

研究了基于图像处理的工件轮廓检测技术的流程及算法,通过图像滤波、图像增强、阈值分割、边缘检测、边缘定位和参数测量及拟合等一系列算法,可以测出被检测工件是否符合要求及其误差范围。