共查询到20条相似文献,搜索用时 15 毫秒
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Agustin Ramirez-Agundis Rafael Gadea-Girones Ricardo Colom-Palero Javier Diaz-Carmona 《Journal of Real-Time Image Processing》2007,2(4):271-280
This paper presents a scheme and its Field Programmable Gate Array (FPGA) implementation for a system based on combining the
bi-dimensional discrete wavelet transformation (2D-DWT) and vector quantization (VQ) for image compression. The 2D-DWT works
in a non-separable fashion using a parallel filter structure with distributed control to compute two resolution levels. The
wavelet coefficients of the higher frequency sub-bands are vector quantized using multi-resolution codebook and those of the
lower frequency sub-band at level two are scalar quantized and entropy encoded. VQ is carried out by self organizing feature
map (SOFM) neural nets working at the recall phase. Codebooks are quickly generated off-line using the same nets functioning
at the training phase. The complete system, including the 2D-DWT, the multi-resolution codebook VQ, and the statistical encoder,
was implemented on a Xilinx Virtex 4 FPGA and is capable of performing real-time compression for digital video when dealing
with grayscale 512 × 512 pixels images. It offers high compression quality (PSNR values around 35 dB) and acceptable compression
rate values (0.62 bpp).
相似文献
Javier Diaz-CarmonaEmail: |
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Sequential Monte Carlo (SMC) represents a principal statistical method for tracking objects in video sequences by on-line estimation of the state of a non-linear dynamic system. The performance of individual stages of the SMC algorithm is usually data-dependent, making the prediction of the performance of a real-time capable system difficult and often leading to grossly overestimated and inefficient system designs. Also, the considerable computational complexity is a major obstacle when implementing SMC methods on purely CPU-based resource constrained embedded systems. In contrast, heterogeneous multi-cores present a more suitable implementation platform. We use hybrid CPU/FPGA systems, as they can efficiently execute both the control-centric sequential as well as the data-parallel parts of an SMC application. However, even with hybrid CPU/FPGA platforms, determining the optimal HW/SW partitioning is challenging in general, and even impossible with a design time approach. Thus, we need self-adaptive architectures and system software layers that are able to react autonomously to varying workloads and changing input data while preserving real-time constraints and area efficiency. In this article, we present a video tracking application modeled on top of a framework for implementing SMC methods on CPU/FPGA-based systems such as modern platform FPGAs. Based on a multithreaded programming model, our framework allows for an easy design space exploration with respect to the HW/SW partitioning. Additionally, the application can adaptively switch between several partitionings during run-time to react to changing input data and performance requirements. Our system utilizes two variants of a add/remove self-adaptation technique for task partitioning inside this framework that achieve soft real-time behavior while trying to minimize the number of active cores. To evaluate its performance and area requirements, we demonstrate the application and the framework on a real-life video tracking case study and show that partial reconfiguration can be effectively and transparently used for realizing adaptive real-time HW/SW systems. 相似文献
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《传感器与微系统》2019,(7):82-85
针对良性阵发性位置性眩晕(BPPV)诊断中视频眼震记录仪存在的分辨率低、帧率低、抗干扰能力不足的问题,提出了一种实时的无线高速视频眼震追踪系统。基于ARM Cortex-A7构架和最新5 G WiFi模块设计了高速无线传输的核心控制板,使用MIPI相机接口保证了视频的高速采集,采用H. 265高性能编码技术实现视频的无损压缩,通过RTSP实时网络传输协议完成无线传输网络构建,终端通过无线网络接收眼震视频,进行基于暗瞳的实时眼震追踪算法分析获取眼震信息。在视频分辨率、帧率对系统精度的影响与不同传输方式的抗干扰能力,实验结果表明:提出的高速视频眼震分析系统精度高、抗干扰能力强,能准确获取眼震轨迹,为疾病的诊断奠定了基础。 相似文献
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Wu-Chih Hu Chao-Ho Chen Yi-Jen Su Tzu-Hsing Chang 《Multimedia Tools and Applications》2018,77(5):5107-5127
This paper presents a fast and effective method based on features to obtain real-time video stabilization for vehicle video recorder system. The corresponding feature points are first obtained from two consecutive frames and then optical flows are calculated based on these points. Next, the obtained optical flows are mapped to polar coordinates to obtain clusters and remove incorrect optical flows. These obtained clusters are used to evaluate the global motion and rotation angle. Finally, the obtained global motion and rotation angle are smoothed and then compensated to obtain the stabilized video. Experimental results show that the proposed method has good performance for video stabilization. 相似文献
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提出一种新的人脸快速检测与实时跟踪算法,能够对视频序列中的人脸进行快速、准确地检测和跟踪。算法分为开始状态、目标丢失状态的人脸检测和连续状态的目标跟踪。首先预测人脸两眼之间的中心位置,得到人脸的预测位置并对预测位置处的图像进行模板匹配,快速检测出人脸准确位置。然后利用检测出的人脸修正人脸模板,并在检测出的位置、旋转度、缩放比例等条件下,对后面序列图像进行小位置、小角度的快速跟踪。实验采用了多种环境下的大量视频,结果显示该算法能够快速跟踪视频序列中的人脸并具有很高的准确性、鲁棒性。 相似文献
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针对现有煤矿井下视频传输系统存在视频清晰度低、传输速率不稳定、兼容性差等问题,设计了一种矿用实时视频传输系统。该系统采用960 nm红外激光作为辅助光源,利用MCCD图像传感器采集视频信号,提高了低光照强度或黑暗环境下视频清晰度;通过视频解码模块TVP5150将采集的PAL制式模拟视频信号转换为YUV数字信号,数字信号经多格式编码器进行H.264压缩编码,并在此基础上添加UDP报文头进行RTP封装,提高了视频数据传输的时效性;通过Live555流媒体服务器进行数据流化,使用ONVIF标准封装RTSP视频流,通过Socket网络编程实现实时视频流数据网络传输,提高了系统兼容性和传输速率稳定性。测试结果表明,该系统视频传输速率为2.190 Mbit/s,丢包率约为1.256%,达到实时视频传输要求。 相似文献
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《Journal of Manufacturing Systems》1987,6(3):241-245
The concept of a real-time seam tracking system for welding automation and the initial design for building a prototype is presented. The Adaptive Real-time Intelligent Seam Tracker (ARTIST) uses a robot held, laser based vision system for automation of arc welding processes, and is currently under development at the Applied Research Laboratory of the Pennsylvania State University. The design of ARTIST builds upon the concept of a zero-pass technique. The 3D information of seam geometry is collected and processed for real-time guidance and control of the welding torch trailing behind the laser based vision sensor. This zero-pass concept eliminates the need for preprogramming of the weld path and thus, potentially enhances the welding cycle time for small batches. The ARTIST is designed to support multipass arc welding and to handle any tack welds which are encountered during the seam welding operation. 相似文献
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Ju Wang Author Vitae Jonathan C.L. Liu Author Vitae Mbonisi Masilela Author Vitae 《Computers & Electrical Engineering》2009,35(2):395-414
Real-time watermarking for streaming video (such as VOD service) requires significant amounts of computing resources. To address this issue, we present a scalable watermarking scheme integrated in a parallel MPEG-2 engine. A content-based block selection algorithm is proposed to efficiently embed the pseudo-random watermark signatures into DCT blocks. Our watermark scheme also provides a robust way to synchronize the watermarked video to the original source at detectors and is very resilient against cumulative and temporal attack.We optimize the parallel watermark engine to achieve real-time watermarking performance. We found that the system throughput could suffer significant degradation when processing high-level MPEG-2 video (such as HDTV) due to inefficient management of memory space. Therefore, we investigated an efficient buffer management scheme consisting of two methods: First we reduced the transmission buffer in slave nodes by frames sharing between frames in the Group-of-Picture (GOP) level. Then we further reduce the buffer space by a dynamic on-demand allocation on the slave side. By solving the memory-shortage bottleneck, the proposed system can support real-time watermarking for multiple high-resolution (up to 1404 × 960) video. 相似文献
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Autonomous video surveillance and monitoring has a rich history. Many deployed systems are able to reliably track human motion in indoor and controlled outdoor environments. However, object detection and tracking at night remain very important problems for visual surveillance. The objects are often distant, small and their signatures have low contrast against the background. Traditional methods based on the analysis of the difference between successive frames and a background frame will do not work. In this paper, a novel real time object detection algorithm is proposed for night-time visual surveillance. The algorithm is based on contrast analysis. In the first stage, the contrast in local change over time is used to detect potential moving objects. Then motion prediction and spatial nearest neighbor data association are used to suppress false alarms. Experiments on real scenes show that the algorithm is effective for night-time object detection and tracking. 相似文献
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针对当前视频捕获设备驱动模式各不相同的现状,提出了一种能够应用于多种不同驱动模型视频捕获设备的视频采集方案.该方案可以对不同驱动模型的视频捕获设备统一进行参数设置.利用DirectShow技术实现了实时课堂教学系统中视频采集模块.在实现视频采集时,研究了对于不同硬件DirectShow构建的Filter Graph的差别.实验测试显示,实现的视频采集模块能够对不同的硬件设备进行参数设置,提高了实时课堂教学系统的硬件兼容性. 相似文献
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为了解决有线网络视频监控的布线问题和工作人员的移动化监控问题,设计并实现了一种支持IP摄像头、DVR、3G手机作为视频数据采集前端,兼容H.264和MPEG4等编码标准和支持PC和3G手机进行客户端监看的实时视频监控系统,该系统实现视频的采集、压缩、传输、解码、显示、控制、录像、事件通知、电子地图等功能,该系统支持前端采集设备的多流输出和高并发访问,适应了3G手机的带宽,提高了服务器使用效率,达到了利用手机进行移动视频监控的目的。 相似文献
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《Journal of Network and Computer Applications》2012,35(3):1067-1073
A tracking object must present a proper field of view (FOV) in a multiple active camera surveillance system; its clarity can facilitate smooth processing by the surveillance system before further processing, such as face recognition. However, when pan–tilt–zoom (PTZ) cameras are used, the tracking object can be brought into the FOV by adjusting its intrinsic parameters; consequently, selection of the best-performing camera is critical. Performance is determined by the relative positions of the camera and the tracking objects, image quality, lighting and how much of the front side of the object faces the camera. In a multi-camera surveillance system, both camera hand-off and camera assignment play an important role in automated and persistent tracking, which are typical surveillance requirements. This study investigates the use of automatic methods for tracking an object across cameras in a surveillance network using PTZ cameras. An automatic, efficient continuous tracking scheme is developed. The goal is to determine the decision criteria for hand-off using Sight Quality Indication (SQI) (which includes information on the position of the object and the proportion of the front of object faces the camera), and to perform the camera handoff task in a manner that optimizes the vision effect associated with monitoring. Experimental results reveal that the proposed algorithm can be efficiently executed, and the handoff method for feasible and continuously tracking active objects under real-time surveillance. 相似文献
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设计了一种以WinCE操作系统和ARM硬件平台为核心的对公交车进行监控的实时系统.通过无线网络把视频数据传输到存储显示端来实现分析、存储和显示等功能. 相似文献