A new type of blind watermarking technology , which has the advantage of adopting watermarking embedding algorithm is introduced based on wavelet transform and cosine transform , so the original image isn ' t necessary when picking up watermarking and the transparency and robustness of digital watermarking system is well fulfilled , the attack in the forms of noise , median filtering and compress can be withstood , and high pass filtering and low pass filtering can also be endured 摘要详细介绍了基于一种新型的基于小波变换和余弦变换的盲水印数字水印技术，这种方法的一个显著的优点就是采用水印嵌入算法，提取水印的时候不需要原图象，能够很好的满足了数字水印系统的透明性和鲁棒性，能够经受住加入噪声、中值滤波、压缩等方式的攻击，并且还能够经受住高通滤波和低通滤波。
As the military and industry is developing dramatically , to enhance the low - contrast digital image has become one of the important areas in image processing . there are two traditional methods to enhance the low - contrast digital image : the methods based on frequency and the method based on time . the histogram enhancement , the most popular way to enhance , is representing the latter one ; while the methods based on frequency often uses wavelet transform , ft ( flourier transform ) , dct ( discrete cosine transform ) to enhance 随着军事和工业上的发展需要,低对比度数字图像的增强越来越成为数字图像处理中的一个重要领域,传统的增强方法分为频域法和空域法两大类,其中空域法的代表为直方图增强法,这也是最为流行的增强方法,频域法中用的较多的是基于小波变换,傅立叶变换和离散余弦变换的增强方法,本文介绍的是基于小波神经网络的频域增强法。
Discrete cosine transform ( dct ) is one of common transform encoding technique in common use of image compression . because such advantages as relatively matured theory , arithmetic and hardware ; ease to move relativity ; fit human vision system ; less calculation ( not include plural calculation ) : ease to realize and so on , dct compression is widely used 离散余弦变换( dct )是图像压缩中经常用到的正交变换编码技术，由于理论、算法和硬件相对成熟，去相关性好，适应人眼的视觉特性，计算量不大(没有复数计算) ，易于实现等优点， dct压缩编码的应用非常广泛。
The paper introduces the technique of the recommendation on the basic frame , encoder and decoder ' s main technique and regulation , the syntax and semantics of the bitstream , optional coding algorithm , and etc . in the forth part of the paper , aimed the time - costest and most important technique - discrete cosine transform ( dct ) and motion estimate algorithms , paper analyses the classical and practical algorithms and introduce the theory . then paper sum up all the algorithms character , give out the ameliorated algorithm , and simulate with the c language on the computer . these two algorithm , can be realized using hardware and can be used into the real videophone ' s video module 论文的第四部分，针对可视电话中最耗费计算时间，也是其中最关键的技术? ?离散余弦变换( dct )和运动估计算法进行的仔细的研究，分析了当前出现的经典的实用算法，并对其原理进行了研究和介绍，并总结各种算法的特点和原理，各自提出了其的改进算法，给出了其原理介绍和实现方法，并在计算机上使用c语言进行了仿真试验，并达到了较为满意的效果，这两种算法，完全可以通过硬件得以实现并能应用到实际的可视电话的视频模块压缩算法中去。
This thesis is part of the project of national science foundation of china “ study on color video coding based on four - dimensional matrix ” . a multi - matrix theory model has been established in the project . and the color video is presented into a four dimensional matrix model and the four - dimensional discrete cosine transform ( 4d - mdct ) is applied to reduce the correlation between color components and adjacent pixels 将多个彩色视频帧构建在一个四维矩阵模型中进行运动补偿预测、四维矩阵离散余弦变换和矩阵量化,最后利用基于上下文的变长编码方法进行压缩,以全面去除彩色视频各象素之间、各彩色分量之间以及连续帧之间的相关性,从而实现高信噪比条件下的高倍压缩。
Most of these standards are based on the method of inter - frame motion compensation and two - dimensional discrete cosine transform ( 2d - dct ) and encode and describe the color video in ycbcr 4 : 2 : 0 format , which want to take advantage of human visual system ( hvs ) to save bit expense by decreasing the resolution of two color difference components 当前国际上的压缩标准普遍采用帧间运动补偿加帧内二维离散余弦变换的编码方法,并且将彩色视频序列表示为ycbcr格式,试图利用人眼的视觉特性降低对色差信号的分辨率来节省比特开销。
Applying generalized gaussian distribution to statistical model of the alternating current coefficient of discrete cosine transform , an adaptive blind watermark detection algorithm is presented on the basis of sign detector and linear correlate detector and its probability efficiency is deduced 摘要根据数字图像离散余弦变换域交流系数的广义高斯分布模型，在符号检测器和线性相关检测器的基础上，提出一种盲水印自调节的检测算法，并推导出该检测器有较高的检测效率。
