Discrete cosine transform (DCT) is frequently used in image and video signal processing due to its high energy compaction property. Humans are able to perceive and identify the information from slightly erroneous imag...Discrete cosine transform (DCT) is frequently used in image and video signal processing due to its high energy compaction property. Humans are able to perceive and identify the information from slightly erroneous images. It is enough to produce approximate outputs rather than absolute outputs which in turn reduce the circuit complexity. Numbers of applications like image and video processing need higher dimensional DCT algorithms. So the existing architectures of one dimensional (1D) approximate DCTs are reviewed and extended to two dimensional (2D) approximate DCTs. Approximate 2D multiplier-free DCT architectures are coded in Verilog, simulated in Modelsim to evaluate the correctness, synthesized to evaluate the performance and implemented in virtexE Field Programmable Gate Array (FPGA) kit. A comparative analysis of approximate 2D DCT architectures is carried out in terms of speed and area.展开更多
In this paper, for color image copyright protection application, a new and blind color image watermarking algorithm based on quantitation method in three dimensional discrete cosine transform (3D-DCT) is proposed. Fir...In this paper, for color image copyright protection application, a new and blind color image watermarking algorithm based on quantitation method in three dimensional discrete cosine transform (3D-DCT) is proposed. Firstly, the original RGB color image is divided into non-overlapping blocks sized 8 × 8 × 3, and then performs 3D-DCT transform on each block. Secondly, embed a bit watermarking signal into each block’s 3D-DCT direct-current (DC) coefficient by quantization method. The results show that the proposed scheme has very good imperceptibility and robustness against the common image processing attacks. Compared with similar algorithm, the proposed scheme has better robustness performance for most attacks.展开更多
遥传技术是随钻测量(MWD,measurement while drilling)系统中的一项关键技术,目前大多数MWD系统均采用泥浆脉冲方式进行数据传输。钻井现场噪声环境复杂,特别是泥浆泵的泵冲干扰,其强度较大,如果其频率落入脉冲信号的带内,则会对地面接...遥传技术是随钻测量(MWD,measurement while drilling)系统中的一项关键技术,目前大多数MWD系统均采用泥浆脉冲方式进行数据传输。钻井现场噪声环境复杂,特别是泥浆泵的泵冲干扰,其强度较大,如果其频率落入脉冲信号的带内,则会对地面接收信号造成严重干扰。因此若不能对脉冲信号带内的泵冲干扰进行很好的抑制,则会限制遥传系统对各种工况的适应能力。提出了一种基于二维离散余弦变换(2D-DCT)的泵冲干扰消除方法,该方法将地面接收到的一维泥浆压力信号转换为二维信号,然后进行2D-DCT变换,从而能在变换域进行泵冲干扰的消除处理。展开更多
Recently,securing Copyright has become a hot research topic due to rapidly advancing information technology.As a host cover,watermarking methods are used to conceal or embed sensitive information messages in such a ma...Recently,securing Copyright has become a hot research topic due to rapidly advancing information technology.As a host cover,watermarking methods are used to conceal or embed sensitive information messages in such a manner that it was undetectable to a human observer in contemporary times.Digital media covers may often take any form,including audio,video,photos,even DNA data sequences.In this work,we present a new methodology for watermarking to hide secret data into 3-D objects.The technique of blind extraction based on reversing the steps of the data embedding process is used.The implemented technique uses the features of the 3-D object vertex’discrete cosine transform to embed a grayscale image with high capacity.The coefficient of vertex and the encrypted picture pixels are used in the watermarking procedure.Additionally,the extraction approach is fully blind and is dependent on the backward steps of the encoding procedure to get the hidden data.Correlation distance,Euclidean distance,Manhattan distance,and the Cosine distance are used to evaluate and test the performance of the proposed approach.The visibility and imperceptibility of the proposed method are assessed to show the efficiency of our work compared to previous corresponding methods.展开更多
提出了一种对角离散余弦变换(Discrete Cosine Transform,DCT)和二维主元分析(Two-Dimensional Principal Component Analysis,2DPCA)相结合的人脸识别方法。该算法首先将人脸图像转换成对角图像,同时利用DCT压缩并重建人脸图像;然后通...提出了一种对角离散余弦变换(Discrete Cosine Transform,DCT)和二维主元分析(Two-Dimensional Principal Component Analysis,2DPCA)相结合的人脸识别方法。该算法首先将人脸图像转换成对角图像,同时利用DCT压缩并重建人脸图像;然后通过2DPCA进行特征提取得到人脸识别特征;最后运用最近邻分类器进行识别。基于ORL(Olivetti Research Laboratory)、受污损ORL及Yale人脸数据库的实验结果证明了该算法的有效性。展开更多
文摘Discrete cosine transform (DCT) is frequently used in image and video signal processing due to its high energy compaction property. Humans are able to perceive and identify the information from slightly erroneous images. It is enough to produce approximate outputs rather than absolute outputs which in turn reduce the circuit complexity. Numbers of applications like image and video processing need higher dimensional DCT algorithms. So the existing architectures of one dimensional (1D) approximate DCTs are reviewed and extended to two dimensional (2D) approximate DCTs. Approximate 2D multiplier-free DCT architectures are coded in Verilog, simulated in Modelsim to evaluate the correctness, synthesized to evaluate the performance and implemented in virtexE Field Programmable Gate Array (FPGA) kit. A comparative analysis of approximate 2D DCT architectures is carried out in terms of speed and area.
文摘In this paper, for color image copyright protection application, a new and blind color image watermarking algorithm based on quantitation method in three dimensional discrete cosine transform (3D-DCT) is proposed. Firstly, the original RGB color image is divided into non-overlapping blocks sized 8 × 8 × 3, and then performs 3D-DCT transform on each block. Secondly, embed a bit watermarking signal into each block’s 3D-DCT direct-current (DC) coefficient by quantization method. The results show that the proposed scheme has very good imperceptibility and robustness against the common image processing attacks. Compared with similar algorithm, the proposed scheme has better robustness performance for most attacks.
文摘遥传技术是随钻测量(MWD,measurement while drilling)系统中的一项关键技术,目前大多数MWD系统均采用泥浆脉冲方式进行数据传输。钻井现场噪声环境复杂,特别是泥浆泵的泵冲干扰,其强度较大,如果其频率落入脉冲信号的带内,则会对地面接收信号造成严重干扰。因此若不能对脉冲信号带内的泵冲干扰进行很好的抑制,则会限制遥传系统对各种工况的适应能力。提出了一种基于二维离散余弦变换(2D-DCT)的泵冲干扰消除方法,该方法将地面接收到的一维泥浆压力信号转换为二维信号,然后进行2D-DCT变换,从而能在变换域进行泵冲干扰的消除处理。
文摘Recently,securing Copyright has become a hot research topic due to rapidly advancing information technology.As a host cover,watermarking methods are used to conceal or embed sensitive information messages in such a manner that it was undetectable to a human observer in contemporary times.Digital media covers may often take any form,including audio,video,photos,even DNA data sequences.In this work,we present a new methodology for watermarking to hide secret data into 3-D objects.The technique of blind extraction based on reversing the steps of the data embedding process is used.The implemented technique uses the features of the 3-D object vertex’discrete cosine transform to embed a grayscale image with high capacity.The coefficient of vertex and the encrypted picture pixels are used in the watermarking procedure.Additionally,the extraction approach is fully blind and is dependent on the backward steps of the encoding procedure to get the hidden data.Correlation distance,Euclidean distance,Manhattan distance,and the Cosine distance are used to evaluate and test the performance of the proposed approach.The visibility and imperceptibility of the proposed method are assessed to show the efficiency of our work compared to previous corresponding methods.
基金广东省自然科学基金(the Natural Science Foundation of Guangdong Province of China under Grant No.032356)北京大学视觉与听觉信息处理国家重点实验室开放课题基金项目(No.0505)
文摘提出了一种对角离散余弦变换(Discrete Cosine Transform,DCT)和二维主元分析(Two-Dimensional Principal Component Analysis,2DPCA)相结合的人脸识别方法。该算法首先将人脸图像转换成对角图像,同时利用DCT压缩并重建人脸图像;然后通过2DPCA进行特征提取得到人脸识别特征;最后运用最近邻分类器进行识别。基于ORL(Olivetti Research Laboratory)、受污损ORL及Yale人脸数据库的实验结果证明了该算法的有效性。
基金supported by the National Scientific Equipment Development Project,"Deep Resource Exploration Core Equipment Research and Development"(Grant No.ZDYZ2012-1)06 Subproject,"Metal Mine Earthquake Detection System"and 05 Subject,"System Integration Field Test and Processing Software Development"
