负压波法适合碳捕获、利用与封存(carbon capture utilization and storage,CCUS)技术的CO_(2)管道泄漏定位检测,但超临界CO_(2)管输周边环境及管内高压产生的噪声,影响了定位的准确性。为此,选择小波变换对含噪声的压力信号进行分解降...负压波法适合碳捕获、利用与封存(carbon capture utilization and storage,CCUS)技术的CO_(2)管道泄漏定位检测,但超临界CO_(2)管输周边环境及管内高压产生的噪声,影响了定位的准确性。为此,选择小波变换对含噪声的压力信号进行分解降噪,采用TGNET模拟软件建立CO_(2)管道泄漏模型,通过对比Botros的激波管泄放试验验证了泄漏模型的可行性。使用该泄漏模型对含噪声的压力信号进行小波降噪,再对降噪后的数据进行压差转化和互相关分析,最终得到各组压力传感器接收到压力信号的具体时间差。该泄漏模型还应用到了延长油田360000 t/a超临界CO_(2)管输方案,对人为设定的泄漏口压力噪声进行小波降噪和互相关分析。研究表明,经小波降噪后的压力信号更为稳定、精确,能够得到准确的时间差,为后续负压波法精确定位泄漏点位置提供了依据。展开更多
It is revealed that the dynamic stability of 2-D recursive continuous-discrete systems with interval parameters involves the problem of robust Hurwitz-Schur stability of bivariate polynomials family. It is proved that...It is revealed that the dynamic stability of 2-D recursive continuous-discrete systems with interval parameters involves the problem of robust Hurwitz-Schur stability of bivariate polynomials family. It is proved that the Hurwitz-Schur stability of the denominator polynomials of the systems is necessary and sufficient for the asymptotic stability of the 2-D hybrid systems. The 2-D hybrid transformation, i. e. 2-D Laplace-Z transformation, has been proposed to solve the stability analysis of the 2-D continuous-discrete systems, to get the 2-D hybrid transfer functions of the systems. The edge test for the Hurwitz-Schur stability of interval bivariate polynomials is introduced. The Hurwitz-Schur stability of the interval family of 2-D polynomials can be guaranteed by the stability of its finite edge polynomials of the family. An algorithm about the stability test of edge polynomials is given.展开更多
提出一种改进的基于Gabor小波变换和二维主分量分析2DPCA(2-Dimensional Principal component analysis)的掌纹识别。2DPCA克服了传统Gabor小波变换后直接进行主分量分析PCA(Principal component analysis)遇到的维数灾难问题,并且将PCA...提出一种改进的基于Gabor小波变换和二维主分量分析2DPCA(2-Dimensional Principal component analysis)的掌纹识别。2DPCA克服了传统Gabor小波变换后直接进行主分量分析PCA(Principal component analysis)遇到的维数灾难问题,并且将PCA与Fisher线性判别FLD(Fisher Linear Discriminate)结合起来,利用了以前仅用于降维的PCA特征和FLD特征相融合进行掌纹识别。基于PolyU掌纹库的实验结果表明,该方法不仅有更高的识别率,而且维数更低。展开更多
With the advancement of content-based retrieval technology, the importance of semantics for text information contained in images attracts many researchers. An algorithm which will automatically locate the textual regi...With the advancement of content-based retrieval technology, the importance of semantics for text information contained in images attracts many researchers. An algorithm which will automatically locate the textual regions in the input image will facilitate the retrieving task, and the optical character recognizer can then be applied to only those regions of the image which contain text. In this paper a new text location method based wavelet is described, which can be used to locate textual regions from complex image and video frame. Experimental results show that the textual regions in image can be located effectively and quickly.展开更多
该文基于小波域多状态隐马尔科夫树(HMT)模型,引入一种新的文本分割方法。该分割方法是在H.Choi et al.(2001)工作的基础上,将文本按纹理分为背景、文字与图片3种类型,分别建立多状态HMT模型。另外,基于平滑图像将上述方法又作了进一步...该文基于小波域多状态隐马尔科夫树(HMT)模型,引入一种新的文本分割方法。该分割方法是在H.Choi et al.(2001)工作的基础上,将文本按纹理分为背景、文字与图片3种类型,分别建立多状态HMT模型。另外,基于平滑图像将上述方法又作了进一步的改进,引入了多状态IHMT分割方法,最后通过实例阐明了方法的有效性。展开更多
为了实现基于FPGA的CCSDS图像压缩算法,在提升小波变换结构的基础上,提出了一种改进的基于行的并行3级2-D整数9/7小波变换实现结构。结构充分利用流水线设计技术,对于每一级2-DDWT,结构包含2个行处理器同时处理2行数据,借助10个行缓存...为了实现基于FPGA的CCSDS图像压缩算法,在提升小波变换结构的基础上,提出了一种改进的基于行的并行3级2-D整数9/7小波变换实现结构。结构充分利用流水线设计技术,对于每一级2-DDWT,结构包含2个行处理器同时处理2行数据,借助10个行缓存存储变换的中间数据,实现了行、列变换的并行运算。同时对于3级小波变换,也采用了流水线结构,减少了存储器的使用量和对其访问造成的时间延迟,提高了变换速度。本结构完成分辨率为N×N灰度图像的3级小波分解所用的时钟周期约为O(N2/2)。采用Altera的Stratix II FPGA实验,结果表明,本整数小波变换结构具有较高的吞吐率和变换速度,可以工作在86.5MHz的频率下,实现1024×1024灰度图像100fps的图像实时变换。展开更多
基金This project was supported by National Natural Science Foundation of China (69971002).
文摘It is revealed that the dynamic stability of 2-D recursive continuous-discrete systems with interval parameters involves the problem of robust Hurwitz-Schur stability of bivariate polynomials family. It is proved that the Hurwitz-Schur stability of the denominator polynomials of the systems is necessary and sufficient for the asymptotic stability of the 2-D hybrid systems. The 2-D hybrid transformation, i. e. 2-D Laplace-Z transformation, has been proposed to solve the stability analysis of the 2-D continuous-discrete systems, to get the 2-D hybrid transfer functions of the systems. The edge test for the Hurwitz-Schur stability of interval bivariate polynomials is introduced. The Hurwitz-Schur stability of the interval family of 2-D polynomials can be guaranteed by the stability of its finite edge polynomials of the family. An algorithm about the stability test of edge polynomials is given.
文摘提出一种改进的基于Gabor小波变换和二维主分量分析2DPCA(2-Dimensional Principal component analysis)的掌纹识别。2DPCA克服了传统Gabor小波变换后直接进行主分量分析PCA(Principal component analysis)遇到的维数灾难问题,并且将PCA与Fisher线性判别FLD(Fisher Linear Discriminate)结合起来,利用了以前仅用于降维的PCA特征和FLD特征相融合进行掌纹识别。基于PolyU掌纹库的实验结果表明,该方法不仅有更高的识别率,而且维数更低。
文摘With the advancement of content-based retrieval technology, the importance of semantics for text information contained in images attracts many researchers. An algorithm which will automatically locate the textual regions in the input image will facilitate the retrieving task, and the optical character recognizer can then be applied to only those regions of the image which contain text. In this paper a new text location method based wavelet is described, which can be used to locate textual regions from complex image and video frame. Experimental results show that the textual regions in image can be located effectively and quickly.
文摘该文基于小波域多状态隐马尔科夫树(HMT)模型,引入一种新的文本分割方法。该分割方法是在H.Choi et al.(2001)工作的基础上,将文本按纹理分为背景、文字与图片3种类型,分别建立多状态HMT模型。另外,基于平滑图像将上述方法又作了进一步的改进,引入了多状态IHMT分割方法,最后通过实例阐明了方法的有效性。
文摘为了实现基于FPGA的CCSDS图像压缩算法,在提升小波变换结构的基础上,提出了一种改进的基于行的并行3级2-D整数9/7小波变换实现结构。结构充分利用流水线设计技术,对于每一级2-DDWT,结构包含2个行处理器同时处理2行数据,借助10个行缓存存储变换的中间数据,实现了行、列变换的并行运算。同时对于3级小波变换,也采用了流水线结构,减少了存储器的使用量和对其访问造成的时间延迟,提高了变换速度。本结构完成分辨率为N×N灰度图像的3级小波分解所用的时钟周期约为O(N2/2)。采用Altera的Stratix II FPGA实验,结果表明,本整数小波变换结构具有较高的吞吐率和变换速度,可以工作在86.5MHz的频率下,实现1024×1024灰度图像100fps的图像实时变换。
