利用激光结构光进行焊缝跟踪时,在存在强弧光干扰的情况下稳定地获取跟踪信息是非常关键一个问题。采用模板匹配的方法实时地计算得到当前图像中的感兴趣区域,并且利用重心法结合改进的一维K a lm an滤波的方法准确的提取出强弧光干扰...利用激光结构光进行焊缝跟踪时,在存在强弧光干扰的情况下稳定地获取跟踪信息是非常关键一个问题。采用模板匹配的方法实时地计算得到当前图像中的感兴趣区域,并且利用重心法结合改进的一维K a lm an滤波的方法准确的提取出强弧光干扰下感兴趣区域内激光结构光的中心线,最后利用中心线上各点的横坐标计算加权系数对纵坐标进行加权累积,稳定并且准确地获得了能够体现出整条结构光变化的跟踪点信息。实验表明,该文提出的算法具有很强的抗干扰能力,可以在实际的焊缝跟踪系统中得到应用。展开更多
A weighted algorithm for watermarking relational databases for copyright protection is presented. The possibility of watermarking an attribute is assigned according to its weight decided by the owner of the database. ...A weighted algorithm for watermarking relational databases for copyright protection is presented. The possibility of watermarking an attribute is assigned according to its weight decided by the owner of the database. A one-way hash function and a secret key known only to the owner of the data are used to select tuples and bits to mark. By assigning high weight to significant attributes, the scheme ensures that important attributes take more chance to be marked than less important ones. Experimental results show that the proposed scheme is robust against various forms of attacks, and has perfect immunity to subset attack.展开更多
文摘利用激光结构光进行焊缝跟踪时,在存在强弧光干扰的情况下稳定地获取跟踪信息是非常关键一个问题。采用模板匹配的方法实时地计算得到当前图像中的感兴趣区域,并且利用重心法结合改进的一维K a lm an滤波的方法准确的提取出强弧光干扰下感兴趣区域内激光结构光的中心线,最后利用中心线上各点的横坐标计算加权系数对纵坐标进行加权累积,稳定并且准确地获得了能够体现出整条结构光变化的跟踪点信息。实验表明,该文提出的算法具有很强的抗干扰能力,可以在实际的焊缝跟踪系统中得到应用。
基金Supported by the Aeronautics Science Foundation of China (02F52033), the High-Technology Research Project of Jiangsu Province (BG2004005) and Youth Research Foundation of Qufu Normal Univer-sity(XJ02057)
文摘A weighted algorithm for watermarking relational databases for copyright protection is presented. The possibility of watermarking an attribute is assigned according to its weight decided by the owner of the database. A one-way hash function and a secret key known only to the owner of the data are used to select tuples and bits to mark. By assigning high weight to significant attributes, the scheme ensures that important attributes take more chance to be marked than less important ones. Experimental results show that the proposed scheme is robust against various forms of attacks, and has perfect immunity to subset attack.
