Scalable Unified Transform Architecture for Advanced Video Coding Embedded Systems

A novel high throughput and scalable unified architecture for the computation of the transform operations in video codecs for advanced standards is presented in this paper. This structure can be used as a hardware accelerator in modern embedded systems to efficiently compute all the two-dimensional 4 × 4 and 2 × 2 transforms of the H.264/AVC standard. Moreover, its highly flexible design and hardware efficiency allows it to be easily scaled in terms of performance and hardware cost to meet the specific requirements of any given video coding application. Experimental results obtained using a Xilinx Virtex-5 FPGA demonstrated the superior performance and hardware efficiency levels provided by the proposed structure, which presents a throughput per unit of area relatively higher than other similar recently published designs targeting the H.264/AVC standard. Such results also showed that, when integrated in a multi-core embedded system, this architecture provides speedup factors of about 120× concerning pure software implementations of the transform algorithms, therefore allowing the computation, in real-time, of all the above mentioned transforms for Ultra High Definition Video (UHDV) sequences (4,320 × 7,680 @ 30 fps).     

FPGA上基于Hausdorff距离的图像匹配并行算法设计与实现

基于Hausdorff距离的图像匹配算法鲁棒性较好,但计算代价较大,软件实现方案很难满足实时性要求。为了解决这个问题,本文在基于局部Hausdorff距离的图像匹配算法基础上提出了一种鲁棒而实时的FPGA实现方案。为了充分有效利用FPGA的硬件资源,首先对传统串行算法进行并行性分析,提出了一个并行算法;然后以此为基础设计了一种三段式粗粒度流水体系结构,并将其映射到FPGA上进行实现。实验结果表明,该系统在性能上优于其它相关工作,与PC(Pentium42.8GHz)上的软件实现方案相比可以达到接近50倍的加速比。     

一种改进的三维递归搜索视频去隔行算法

提出了一种改进的三维递归搜索（3DRS）视频去隔行算法，该算法使用双向参考运动估计，消除了原始算法中的误差传递现象，并采用多分辨率分析的思想，根据视频内容自适应的调节误差匹配块尺寸，提高了运动估计的准确度。实验结果表明，对于大多数测试序列，该算法在实验效果上取得了优于原始的3DRS算法的性能。     

基于FPGA的多路视频合成与去噪设计

在嵌入式视频处理领域,针对视频实时性要求高的特点,提出一种基于现场可编程门阵列(FPGA)的多路视频合成和去噪方法,包含四路视频合成一路视频的具体实现方案,以及对合成后的一路视频进行中值滤波的去噪算法,使用DDR2SDRAM作为视频的帧缓存,设计中值滤波算法的硬件结构和逻辑结构。系统设计采用Verilog语言进行描述,并在Xilinx的FPGA上进行逻辑综合和硬件测试。实验结果表明,该方法利用FPGA实现了硬件并行和流水线技术,可保证视频的实时处理。     

嵌入式设备高效卷积神经网络的电力设备检测

随着大型图像集的出现以及计算机硬件尤其是GPU的快速发展，卷积神经网络（CNN）已经成为人工智能领域的一种成功算法，在各种机器学习任务中表现出色.但CNN的计算复杂度远高于传统算法，嵌入式设备上有限资源的限制成为制造高效嵌入式计算的挑战性问题.在本文中，我们提出了一种基于嵌入式设备的高效卷积神经网络用于电力设备检测，根据处理速度评估这种高效的神经网络.结果表明，该算法能够满足嵌入式设备实时视频处理的要求.     

基于SoC的小型集成化视频采集处理系统研究

由于传统视频采集和处理系统很难解决小体积、低功耗与高数据带宽和处理速度之间的矛盾,同时针对智能武器装备、工业自动化生产等领域对视频采集与处理系统小型化、集成化发展需求,基于Xilinx公司高性能Zynq-7000系列SoC芯片,搭建了一种小型化、集成化、通用化视频采集处理平台系统。通过充分发挥SoC芯片集成ARM处理器软件可编程和FPGA硬件可编程优势,提出了利用HLS工具将图像预处理算法快速打包生成IP核,在FPGA中实现图像算法硬件加速的设计方法,不仅保证了视频采集和处理的实时性,而且实现了视频处理设备小型化、集成化、低功耗设计。对系统软硬件设计和各组成部分原理进行了介绍,并以Sobel边缘检测算子为实例,对系统功能和性能与传统处理方法进行了对比测试,验证了系统的有效性。     

一种带运动检测的去隔行中值滤波算法

视频格式转换(VFC)技术可以较好地解决不同格式的视频信号之间信息不易交流的难题。而去隔行又是视频格式转换的一项关键技术。该文提出了一种新的带运动检测的中值滤波算法。该算法能区分图像的运动和静止部分而分别采用不同的算法进行去隔行。对静止部分,采用场复制的算法;而对运动部分,采用综合的中值滤波算法,这样就充分利用了视频信号在空间和时间上的相关信息,克服了原来算法去隔行时图像边缘不够平滑,出现锯齿,甚至有断点等不足。软件仿真表明,图像的测评效果良好,且该算法的硬件成本较低,极具实用价值。     

基于TMS320DM6467的监控视频去雾算法实现

有雾天气情况下拍摄的视频成像质量退化严重,极大地影响了安防监控、视觉导航等系统的整体性能.面向DSP嵌入式平台,提出一种实时监控视频去雾系统实现方案.首先在暗通道先验单幅图像去雾的基础上,提出了一种监控视频去雾算法;其次,基于TMS320DM6467处理器的硬件资源,对视频格式转换、除法运算、透射率计算、数据搬移等环节进行代码优化,最终在硬件平台上实现了整体系统.实测结果表明,对于D1格式的视频,在兼顾去雾质量的同时,达到了实时处理要求.     

Implementation of an RBF neural network on embedded systems: real-time face tracking and identity verification

This paper describes a real time vision system that allows us to localize faces in video sequences and verify their identity. These processes are image processing techniques based on the radial basis function (RBF) neural network approach. The robustness of this system has been evaluated quantitatively on eight video sequences. We have adapted our model for an application of face recognition using the Olivetti Research Laboratory (ORL), Cambridge, UK, database so as to compare the performance against other systems. We also describe three hardware implementations of our model on embedded systems based on the field programmable gate array (FPGA), zero instruction set computer (ZISC) chips, and digital signal processor (DSP) TMS320C62, respectively. We analyze the algorithm complexity and present results of hardware implementations in terms of the resources used and processing speed. The success rates of face tracking and identity verification are 92% (FPGA), 85% (ZISC), and 98.2% (DSP), respectively. For the three embedded systems, the processing speeds for images size of 288 /spl times/ 352 are 14 images/s, 25 images/s, and 4.8 images/s, respectively.     

CASM: a content-aware protocol for secure video multicast

Information security has been a critical issue in the design and development of reliable distributed communication systems and has attracted significant research efforts. A challenging task is how to maintain information security at a high level for multiple-destination video applications with the huge volume of data and dynamic property of clients. This paper proposes a novel Content-Aware Secure Multicast (CASM) protocol for video distribution that seamlessly integrates three important modules: 1)a scalable light-weight algorithm for group key management; 2) a content-aware key embedding algorithm that can make video quality distortion imperceptible and is reliable for clients to detect embedded keys; and 3) a smart two-level video encryption algorithm that can selectively encrypt a small set of video data only, and yet ensure the video as well as the embedded keys unrecognizable without a genuine key. The implementation of the CASM protocol is independent of the underlying multicast mechanism and is fully compatible with existing coding standards. Performance evaluation studies built upon a CASM prototype have demonstrated that CASM is highly robust and scalable in dynamic multicast environments. Moreover, it ensures secure distribution of key and video data with minimized communication and computation overheads. The proposed content-aware key embedding and encryption algorithms are fast enough to support real-time video multicasting.     

嵌入式视频采集系统的设计与实现

较为理想的嵌入式视频采集系统是基于DSP的视频采集系统,本文重点阐述了嵌入式视频采集系统的硬、软件设计环节以及开发中的一些关键技术问题。首先以TMS320DM642构建视频采集的硬件系统,详细介绍了TVP5150、SAA7121以及所设计的视频采集系统原理,该系统在Xc2s300控制下能实时将视频像进行采集、编码和传输;最后提出嵌入式系统的开发流程并分析嵌入式系统开发中的一些问题。     

视频服务器拥塞控制算法的研究与实现

分析现有网络拥塞控制算法的优缺点,在此基础上,根据多媒体数据和嵌入式设备的特点提出改进的基于视频服务器的拥塞控制算法。此算法以UDP协议为基础,通过控制传输速率来降低丢包率和网络时延,提高了嵌入式设备的多媒体数据传输质量。同时,将此算法应用于基于TMS320DM6467T硬件开发平台和Linux操作系统的视频服务器上,并通过实验验证了算法的可靠性与实用性。     

A real-time near infrared image acquisition system based on image quality assessment

This paper presents a real-time image acquisition system with an improved image quality assessment module to acquire high-quality near infrared (NIR) images. Thermal imaging plays a vital role in a wide range of medical and military applications. The demand for high-throughput image acquisition and image processing has continuously increased especially for critical medical and military purposes where executions under real-time constraints are required. This work implements an NIR image quality assessment module, which utilizes improved two-dimensional entropy and mask-based edge detection algorithms. The effectiveness of the proposed image quality assessment algorithms is demonstrated through the implementation of a complete finger-vein biometric system. The proposed model is implemented as an embedded system on a field programmable gate array prototyping platform. By including the image quality assessment module, the proposed system is able to achieve a recognition accuracy of 0.87 % equal error rate, and can handle real-time processing at 15 frames/s (live video rate). This is achieved through hardware acceleration of the proposed image quality assessment algorithms via a novel streaming architecture.     

一种新型运动自适应去隔行算法

在分析了现有的各种去隔行算法特点的基础上,提出了一种新型的运动自适应去隔行算法。该算法充分结合了中值滤波算法及边沿保护插值算法的优越性,能区分图像的静止和运动部分,采用不同的算法进行去隔行。同时对运动部分采用的边沿保护插值去隔行算法进行了改进,大大简化了运动检测。软件仿真表明,去隔行处理后的逐行图像测评效果良好,该算法占用硬件资源少,结构简洁,极具实用价值。     

Harris角点结合金字塔光流法的目标跟踪算法设计研究

针对现存很多跟踪算法在速度和准确度方面很难满足嵌入式跟踪开发的需要,提出一种基于Harris角点和金字塔光流法的快速跟踪算法,并详细给出了DSP-FPGA的硬件设计。首先,使用Harris角点提取目标角点特征;然后,使用金字塔光流法为后续视频帧匹配角点;最后,基于角点的质心跟踪算法用于匹配目标的重心,确定目标的位置,重心跟踪算法可以较好地抵消由于旋转或扭曲带来的形变问题。在硬件实现过程中,FPGA方便电路设计,使用硬件描述程序语言实现硬件算法、逻辑控制和外部接口,DSP则运行目标跟踪算法。实验结果验证了本文硬件实现算法的有效性,相比于AVT21开发板的质心跟踪算法、相位相关跟踪算法和金字塔相关性跟踪算法相比,本文算法在平均重叠和平均中心误差方面具有一定优势,在720p的视频流上可以满足25fps。     

基于工业以太网的H.264煤矿视频监控系统

在分析视频监控系统网络化趋势和实时性要求的基础上，采用DSP TMS320C6416和ARM微控制器，设计并实现了支持煤矿井下工业以太网传输的嵌入式H.264视频编码器。给出了系统结构原理及硬件设计，实现了DSP编码算法和面向RTP/UDP/IP的NAL接口。测试表明，系统能够进行高质量的视频网络化传输。     

加权边沿自适应的场内插值去隔行方法*

为实现隔行扫描图像到逐行扫描图像的扫描格式转换,提出了一种基于空间加权和边沿自适应的场内插值去隔行算法。该算法包括LRV（left right vertical）评估和边沿自适应插值。相比传统的去隔行算法,LRV评估可以有效地消除伪边沿插值;在边沿自适应插值中增加预插值判断进行插值方向初步估计,可以抑制反向插值错误;在边沿方向搜索中增加空间权值,可以提高插值的准确率。实验结果表明,该算法在处理图片和视频流时的图像质量均要优于传统的算法。     

基于μClinux的嵌入式导盲系统

提出一种为盲人或视弱人群提供导航的基于盲道识别的嵌入式系统的设计方案。结合高性能定点DSP ADSP-BF533 和视频解码芯片SAA7113,设计图像处理硬件平台,移植嵌入式操作系统并给出算法实现与优化方法。实验结果表明,该系统在自然盲道情况下达到必需的处理实时性和判断的准确性要求,可较好地服务于盲人的独立出行。     

De-interlacing technique based on total variation with spatial-temporal smoothness constraint

This paper introduces a new method of converting interlaced video to a progres- sively scanned video and image. The new method is derived from Bayesian framework with the spatial-temporal smoothness constraint and the MAP is done by minimizing the energy functional. The half-quadratic regularization method is used to solve the corresponding partial differential equations (PDEs). This ap- proach gives the improved results over the conventional de-interlacing methods. Two criteria are proposed in the paper, and they can be used to evaluate the per- formance of the de-interlacing algorithms.     

基于改进的H.264的视频监控系统

嵌入式技术的飞速发展推动了视频采集领域的技术革新,使得视频监控系统越来越朝着小型化、智能化、嵌入式化、远程化的方向发展. 文中以基于S3C6410处理器的ARM板为硬件平台,采用Linux为嵌入式操作系统,建立了一个视频采集服务器;以PC机为客户端,实时地远程显示视频---建立了一个远程视频监控系统. 系统利用Linux内核提供的视频数据采集接口V4L2控制USB摄像头来采集图像,利用网络套接字将编码后的图像数据传输至客户端;在客户端将图像解码并转化为RGB格式后,利用GTK把转化后的图像显示出来. 针对H.264运动估计算法的两点不足,提出了动态搜索范围策略和搜索点分组策略. 实验结果证明： 在不影响重建图像质量和编码码率的前提下,改进的算法有效地降低了算法的编码时间和运动估计时间,提高了编码过程的实时性. 通过本文的设计方案能够获得稳定清晰的图像,实现了远程视频监控.