数字电视节目中马赛克的检测算法设计与试验

本文提出一种基于马赛克块直线边缘检测并延长使其交叉标识的方法来检测图像中的马赛克。首先,对图像进行边缘识别;其次,对边缘图像进行霍夫变换来识别直线;最后,延长这些直线,通过其相交点来识别马赛克块。本算法基于OpenCV库函数实现,并通过大量计算对比和数据分析来寻找出最佳检测参数,完成预期实验。     

马赛克故障图像的分析与检测

本文提出一种利用差分边缘检测获取灰度图像的边缘特征与色差分量信号特征相结合的检测马赛克故障图像的方法，该方法在保证较低误报的情况下，实现了马赛克检测的功能。     

基于压缩感知的多光谱图像去马赛克算法

针对目前多光谱图像去马赛克算法存在计算量大、效率低的缺点,本文提出一种基于压缩感知的多光谱图像去马赛克算法。首先,分析去马赛克与压缩感知问题的等价性,建立基于压缩感知的去马赛克模型;然后,采用离散余弦变换构建压缩感知的稀疏基,将去马赛克问题转化为压缩感知的信号重构问题;最后,采用改进的光滑0范数和修正牛顿法的重构算法求解去马赛克问题,得到重构的多光谱图像。仿真实验表明,相对于基于克罗内克压缩感知和组稀疏两种算法,本文算法提高了重构的多光谱图像的峰值信噪比,能有效减少对比算法重构多光谱图像中出现的锯齿现象,改善了重构图像具有更好的视觉效果。实验结果验证了本文算法的有效性。     

基于像素组的去马赛克算法

提出一种利用图像的像素组特性的彩色滤镜阵列去马赛克的新算法：实验表明该算法在图像的去马赛克过程中抑制减少了传统方法存在的人工痕迹，有效克服了VNG与LCC算法中的一些不足。     

基于马赛克的低通滤波人脸表情处理

表情在人脸识别中是重要的干扰信号,有效消除表情对人脸识别的影响尤为重要。提出了一种基于马赛克的低通滤波表情处理方法,通过不同的马赛克密度对待识别人脸图像进行处理,有效降低不同表情对人脸识别的影响。实验表明,经过该方法处理后的待识别人脸图像与库存图像的相似度有明显的提高。     

基于马赛克技术的秘密图像共享

在传统的秘密图像共享算法中,通常产生类似噪声的影子图像,极易引起攻击者的注意。针对这一问题,文中根据马赛克技术提出了一种产生有意义的影子图像算法。通过图像相似度的比较,可将秘密图像共享到载体图像中,得到含有秘密图像信息的马赛克图像。然后采用可逆信息隐藏的技术将图像块的位置序列隐藏到马赛克图像中,得到完整的影子图像。通过文中所提算法产生的影子图像,既可避免攻击者的注意又能恢复出无损的秘密图像。     

基于偏振权重局部对比度的目标检测

分焦平面红外偏振探测器输出的是红外偏振马赛克图像,传统处理流程需要进行去马赛克恢复出四个偏振通道的完整图像,然后再实现后续的任务。然而,去马赛克过程会引入误差,而且计算复杂度高、耗时长。针对如何直接在红外偏振马赛克图像上进行目标检测的问题,本文提出了一种偏振权重局部对比度的目标检测方法。首先分析了目标与背景的偏振特性差异;然后设计了红外偏振马赛克图像的斯托克斯矢量计算卷积核;在此基础上提出了基于偏振权重的偏振度显著图,在偏振度显著图上利用自适应阈值操作实现目标检测。此外,利用边缘检测方法进一步优化目标检测结果,得到更加完整的检测结果。最后,使用采集的红外偏振马赛克数据集验证了所提出的目标检测算法在复杂背景以及恶劣天气影响下的鲁棒性。     

基于彩色边缘与十字型加权模板的马赛克检测

为了解决高分辨率视频马赛克检测识别率不高的问题,提出了一种基于彩色边缘与十字型加权模板的视频马赛克检测算法.该算法先通过基于CIELab色彩空间的彩色边缘检测检出更多马赛克边缘,再采用十字型加权模板进行模板匹配以识别出马赛克块.采用本文算法以及传统算法对高分辨率视频进行马赛克检测,实验结果表明本文算法对视频中马赛克检测的识别率高达98.2％,相比于传统算法识别率提高了7.1％.     

JPEG图像盲检测算法的抗滤波攻击性能研究

针对图像在传输过程中遇到的几种典型滤波攻击,分析了高斯低通、二维中值、均值和马赛克等滤波攻击对图像传输质量的影响,在此基础上研究了JPEG图像盲检测算法的抗滤波攻击性能。仿真结果表明,实验所用的盲检测算法能够有效抵抗高斯低通滤波攻击。     

基于CFA去马赛克的图像篡改检测技术研究

图像篡改检测研究中,大多数检测方法需要构建一个复杂的分类器,致使检测效率降低。文章提出一种基于由色彩滤镜阵列(CFA)处理过程中产生的伪影检测技术,包括基于CFA模式个数估计和其他基于CFA噪声分析,该方法通过计算单个特征点和基于分类器简单阈值来实现,通过被篡改后图像改变了CFA去马赛克伪影检测图像篡改,通过成千上万张真实的、篡改的及计算机合成的图片验证,实验结果表明,文章所提方法具有较高的性能。     

Super-resolution mosaicing from MPEG compressed video

In this paper we address the problem of mosaic construction from MPEG 1/2 compressed video for the purpose of video browsing. State-of-the-art mosaicing methods work on raw video, but most video content is available in compressed form such as MPEG 1/2. Applying these methods to compressed video requires full decoding which is very costly. The resulting mosaic is in general too large to display on the screen and is thus inappropriate for the purpose of video browsing. Therefore, we directly extract very low-resolution frames from MPEG 1/2 compressed video for the mosaic construction and then apply a super-resolution (SR) method based on iterative backprojections in order to increase the mosaic resolution and its visual quality. Global motion to be used in the SR method for aligning and warping the frames is estimated from motion information contained in the compressed stream. We also use the estimated global motion in the blur estimation and in the choice of the degradation model used for the restoration in the SR algorithm. The method for the SR mosaic construction from MPEG 1/2 compressed video that we present in this paper is less costly than mosaic construction from full decoded video. Furthermore, the resulting mosaic size is more appropriate for the purpose of video browsing.     

Universal intra coding for arbitrary RGB color filter arrays in HEVC

Compressing mosaic video sequences is necessary for storage and transmission over the internet. However, mosaic video sequences with different red–green–blue (RGB) color filter arrays (CFAs) require different compression schemes. We propose a two-stage universal intra coding scheme for compressing mosaic video sequences with arbitrary RGB-CFAs in high efficiency video coding (HEVC). Based on the associated mosaic structure, the proposed scheme first demosaics the neighboring reference pixels and then predicts the color value of the target pixel using the color values of the identical color components in the demosaiced reference pixels. Experimental results demonstrate that the proposed universal intra coding scheme achieves substantial improvement on bitrate while preserving the quality of the reconstructed video sequences.     

Two-dimensional mesh-based mosaic representation for manipulationof video objects with occlusion

We present a two-dimensional (2-D) mesh-based mosaic representation, consisting of an object mesh and a mosaic mesh for each frame and a final mosaic image, for video objects with mildly deformable motion in the presence of self and/or object-to-object (external) occlusion. Unlike classical mosaic representations where successive frames are registered using global motion models, we map the uncovered regions in the successive frames onto the mosaic reference frame using local affine models, i.e., those of the neighboring mesh patches. The proposed method to compute this mosaic representation is tightly coupled with an occlusion adaptive 2-D mesh tracking procedure, which consist of propagating the object mesh frame to frame, and updating of both object and mosaic meshes to optimize texture mapping from the mosaic to each instance of the object. The proposed representation has been applied to video object rendering and editing, including self transfiguration, synthetic transfiguration, and 2-D augmented reality in the presence of self and/or external occlusion. We also provide an algorithm to determine the minimum number of still views needed to reconstruct a replacement mosaic which is needed for synthetic transfiguration. Experimental results are provided to demonstrate both the 2-D mesh-based mosaic synthesis and two different video object editing applications on real video sequences.     

改进模型估计的无人机侦察视频快速拼接方法

针对提高无人机侦察视频的拼接速度与效果的问题,提出一种改进模型估计的无人机侦察视频快速拼接方法。首先,基于自适应鲁棒性尺度不变的特征检测子对视频各帧进行基于点的特征匹配。其次,提出改进的随机抽样一致性算法进行模型估计,并去除误匹配点。最后,提出侦察影像快速拼接算法,计算各影像变换到正射拼接图的单应性矩阵,完成视频序列拼接。实验结果表明:改进的随机抽样一致性算法在保证鲁棒性的同时,提高了执行速度;侦察影像快速拼接算法提高了拼接速度,同时改善了拼接效果。     

Mosaic视频导航系统的分析

本文主要介绍了基于DVB标准EN300 468的Mosaic视频导航系统。Mosaic是一种利用多个视频图像组合进行节目导航的机制，可以把它看成是一种高级的电子节目指南。文章先介绍了Mosaic节目视频导航机制的原理。然后分析了Mosaic描述符的数据结构，并补充必要的私有描述符，最后给出实现方法概要。     

New methods for dynamic mosaicking

This paper presents a new technique for the creation of a sequence of mosaic images from an original video shot. A mosaic image represents, on a single image, the scene background seen all over the sequence and its creation requires the estimation of the warping parameters and the use of a blending technique. The warping parameters permit one to represent each original image in the mosaic reference. An estimation method, based on a direct comparison between the current original image and the previously calculated mosaic is proposed. A new analytic minimization criterion is also designed to optimize the determination of the blending coefficient used for the update of the mosaic image with a new original image. This criterion is based on constraints related to the temporal variations of the background, the temporal delay and the resolution of the created mosaic images, while its minimization can be analytically performed. Finally, the proposed method is applied to the creation of new video sequences in which the camera point of view, the camera focal, or the image size are modified. This approach has been tested and validated on real video sequences with large camera motion.     

TMS320DM642在视频拼接系统中的应用

提出一套基于TMS320DM642的视频拼接系统,对视频拼接技术、系统的硬件资源选择和工作流程等关键问题进行了详细的讨论.实验结果表明,视频拼接系统可以获得一个满足要求的高分辨率、无缝且大视场图像.     

Near Real-Time Orthorectification and Mosaic of Small UAV Video Flow for Time-Critical Event Response

A method for real-time mosaic of video flow acquired by a small low-cost unmanned aerial vehicle (UAV) has been presented in this paper. The basic procedures of real-time mosaic are as follows: 1) Each video frame is resampled and orthorectified using a developed mathematical model, which can simultaneously solve the video camera's interior orientation parameters and the exterior orientation parameters of each video frame; 2) each orthorectified video frame is mosaicked at real time. A test field located in Picayune, Mississippi, has been established for testing our method. Sixty-minute video data were collected using the UAV and were processed using the proposed method. The results demonstrated that each video frame can be geo-orthorectified and mosaicked together to produce a 2-D planimetric mapping at near real time. Accuracy of the mosaicked video images (2-D planimetric map) is approximately 1–2 pixels, when compared to 55 checkpoints, which were measured by differential GPS surveying.      

一种基于自适应关键帧的视频序列拼接方法

由于视频帧数量较大,视频序列拼接时容易造成拼接误差大、耗时较多,为有效解决此问题,提出一种基于自适应关键帧的视频序列拼接方法。将固定间隔采样帧作为关键帧并对其进行特征点提取,利用特征点匹配结合RANSAC鲁棒估计算法得到关键帧间单映矩阵,依此计算关键帧间重叠区域,按照重叠区域比例结合折半排序方法重新定位关键帧,将此关键帧作为基准帧,重复帧采样、重叠区域确定、定位后续所需关键帧过程,直至关键帧提取完毕,最后,利用级联单映矩阵和加权融合实现视频序列无缝拼接。实验验证了该方法的有效性。