Detection of kinematics parameters of index finger movement with high-speed video camera

Synergic movement of finger's joints provides human hand tremendous dexterities,and the detection of kinematics parameters is critical to describe and evaluate the kinesiology functions of the fingers.The present work is the attempt to investigate how the angular velocity and angular acceleration of the joints of index finger vary with respect to time during conducting a motor task.A high-speed video camera has been employed to visually record the movement of index finger,and miniaturized(5-mm diameter) reflective markers have affixed to the subject's index finger on the side close to thumb and dorsum of thumb at different joint landmarks.Captured images have been reviewed frame by frame to get the coordinate values of each joint,and the angular displacements,angular velocities and angular acceleration can be obtained with triangle function.The experiment results show that the methods here can detect the kinematics parameters of index finger joints during moving,and can be a valid route to study the motor function of index finger.

The Calibration of High-Speed Camera Imaging System for ELMs Observation on EAST Tokamak

A tangential fast visible camera has been set up in EAST tokamak for the study of edge MHD instabilities such as ELM. To determine the 3-D information from CCD images, Tsai＇s two-stage technique was utilized to calibrate the high-speed camera imaging system for ELM study. By applying tiles of the passive stabilizers in the tokamak device as the calibration pattern, transformation parameters for transforming from a 3-D world coordinate system to a 2-D image coordinate system were obtained, including the rotation matrix, the translation vector, the focal length and the lens distortion. The calibration errors were estimated and the results indicate the reliability of the method used for the camera imaging system. Through the calibration, some information about ELM filaments, such as positions and velocities were obtained from images of H-mode CCD videos.

Investigation of condition-induced bubble size and distribution in electroflotation using a high-speed camera

In the flotation process, bubble is a key factor in studying bubble-particle interaction and fine particle flo- tation. Knowledge on size distribution of bubbles in a flotation system is highly important. In this study, bubble distributions in different reagent concentrations, electrolyte concentrations, cathode apertures, and current densities in electroflotation are determined using a high-speed camera. Average bubble sizes under different conditions are calculated using Image-Pro@ Plus （Media Cybernetics@, MD, USA） and SigmaScan@ Pro （Systat Software, CA, USA） software. Results indicate that the average sizes of bubbles, which were generated through 38, 50, 74, 150, 250, 420, and 1000 μm cathode apertures, are 20.2, 29.5, 44.6, 59.2, 68.7, 78.5, and 88.8 μm, respectively. The optimal current density in electroflotation is 20 A/m2. Reagent and electrolyte concentrations, current density, and cathode aperture are important factors in controlling bubble size and nucleation. These factors also contribute to the control of fine- Particle flotation.

基于USB Video Camera的自动对焦系统

介绍一种应用于USB video camera中的自动对焦系统。由USB video camera获取的视频图像经计算机进行FFT运算或微分运算,得到其频谱幅值数据或微分幅值数据,计算机根据所得数据判断USB video camera中的镜头是否处于离焦位置并控制电机将镜头移到对焦位置。文章还进一步讨论了提高自动对焦准确度的措施。实验结果表明该自动对焦系统能很好地实现USB video camera的自动对焦,该系统将使具有USB接口的video camera使用更简单方便。

Neural Network Method for Colorimetry Calibration of Video Cameras

To transfer the color data from a device (video camera) dependent color space into a device? independent color space, a multilayer feedforward network with the error backpropagation (BP) learning rule, was regarded as a nonlinear transformer realizing the mapping from the RGB color space to CIELAB color space. A variety of mapping accuracy were obtained with different network structures. BP neural networks can provide a satisfactory mapping accuracy in the field of color space transformation for video cameras.

基于Video Port的Camera Link的图像采集接口设计

通过视频接口和Channel Link芯片实现了数字信号处理芯片TMS320DM642与Camera Link线扫描相机的无缝连接。解决了图像数据输出速度为40 MB/s的高速图像数据采集系统中,前端采集与后端输出的速度匹配问题。系统可实时、高速地采集大量的图像数据。

Color compensation for multi-view video coding based on diversity of cameras

A novel color compensation method for multi-view video coding (MVC) is proposed, which efficiently exploits the inter-view dependencies between views with the existence of color mismatch caused by the diversity of cameras. A color compensation model is developed in RGB channels and then extended to YCbCr channels for practical use. A modified inter-view reference picture is constructed based on the color compensation model, which is more similar to the coding picture than the original inter-view reference picture. Moreover, the color compensation factors can be derived in both encoder and decoder, therefore no additional data need to be transmitted to the decoder. The experimental results show that the proposed method improves the coding efficiency of MVC and maintains good subjective quality.

Visualization of High-Speed Impact of Projectile in Granular Sheet with Destructive Collision of Particles

The impact and penetration of a projectile in a particle-laden space, which are expected to have frequently occurred during the formation of the solar system and will occur in the case of an impact probe for future planetary exploration, were experimentally simulated by using the ballistic range. A two-dimensional sheet made from small glass beads or emery powder was formed by the free-falling device through a long slit in the test chamber evacuated down to about 35 Pa. A polycarbonate projectile of a hemi-sphere-cylinder or sphere shape with the mass and diameter about 4 g and 25 mm, respectively, was launched at the velocity up to 430 m/s, and the phenomena were observed by the high-speed camera at 20,000 fps. From a series of images, the bow-shock-wave-like laterally facing U-shaped pattern over the projectile and the absence of particles in the trail behind it were clearly seen. At the impact of the particles on the projectile surface, fine grains were formed due to the destructive collision and injected outward from the projectile. The images obtained by different lighting methods including the laser light sheet were compared. The effects of the particle diameter, its material and the impact velocity were also investigated.

Visualization of High-Speed Impact of Penetrator into Icy Target

For application to exploration under the surface of icy objects in the solar system, the penetration of an impact probe into an icy target was experimentally simulated by using the ballistic range. Slender projectiles with a cylindrical body and various nose shapes were tested at the impact velocity 130 - 420 m/s. The motion of the penetrator, fragmentation of ice and crater forming were observed by the high-speed camera. It revealed that the crown-shaped ejection was made for a short time after the impact and then the outward normal jet-like stream of ice pieces continued for much longer time. The concave shape of the crater was successfully visualized by pouring the plaster into it. The two-stage structure, the pit and the spall, was clearly confirmed. The rim was not formed around the crater. Observation of the crater surface and the ice around the trace of the penetrator shows that both crushing into smaller ice pieces and recompression into ice blocks are caused by the forward motion of the penetrator. In case of a body with a flow-through duct, ice pieces entering the inlet at the nose tip were ejected from the tail, resulting in relaxation of the impact force. The correlation of the penetration distance and the crater diameter with the impact velocity was investigated.

基于Cyclone IV的Camera Link-HDMI高清视频转换器设计

针对实际项目需求,在充分了解Camera Link接口协议和HDMI接口协议的基础上,给出了基于FPGA的Camera Link-HDMI高清视频转换器设计方案。选用Altera公司的Cyclone IV系列FPGA器件,完成了转换器的电路设计和性能测试。结果表明,图像转换实时性好,色彩和图形无失真,满足设计要求。该方案是一种解决Camera Link-HDMI转换的有效方法,为相似的技术设计问题提供了有益的参考。

基于FPGA实现由多路复合信号传输到Camera Link传输的研究

针对传统的复合视频信号直接传输图象信息具有抗干扰能力差,噪声大等缺点,提出了一个视频信号传输方式变换的新方案,利用Camera Link通信协议在数字信息领域具有传递距离远、抗干扰能力强的优点,实现了由4路实时的复合视频信号转换为1路高速的Camera Link格式的信号。这种方法改变了传统的复合视频信号直接传输图象信息的思维,从而为数字信息领域远距离多路实时视频信号的快速传送和处理提供了平台。

Camera Link Full至HD-SDI接口的高清传输显示系统

为实现远距离、高可靠性传输,并减小复杂度,对Camera Link Full接口数据的HD-SDI传输显示进行了深入研究。采用FPGA作为核心处理器,考虑相机输出具有多种帧频,采取帧频检测及充分降频策略,并通过3个SRAM进行缓存以实现帧频转换,以满足HD-SDI帧频25Hz的要求。考虑到SRAM数据宽度,采取FIFO行缓存策略将Camera Link Full80输出的10tap、80bits图像数据转换成单通道的8bits图像数据。最后,完成系统设计并进行实验验证。实验结果表明:系统实现了图像数据从50Hz、100Hz、500 Hz等多种帧频的Camera Link Full80到25帧HD-SDI接口1080i的格式转换及实时显示,且图像层次丰富,无失真。

基于异步FIFO的Camera Link数字图像光纤传输技术

为满足数字图像的远距离传输需求,设计用于传输Camera Link接口数字图像的光纤通讯系统。系统分为发送和接收两个部分,分别负责Camera Link数字图像到光信号的转化以及相应的逆变换过程。采用Cyclone I EP1C12 FPGA作为发送和接收板卡的逻辑控制核心。在发送板卡的FPGA内设计逻辑控制模块,操纵两个异步FIFO(先入先出队列),将接收到的数字图像缓存,用本地时钟读取后再进行串行化转换。在不改变数字图像时序关系的前提下,用本地时钟替换原有的像素时钟,消除像素时钟不稳定性对后续传输影响。实验表明,利用该技术可以有效提升光纤传输系统的适应性、稳定性,改善、消除由像素时钟抖动造成的传输图像抖动现象。

高速Camera Link工业相机视频采集研究

高速工业相机在图像采集过程中产生的大量数据,导致采集和传输困难,针对此种情况本文提出了高速工业相机图像采集系统方案。详细介绍了系统各个结构,对相机迸发的大量数据进行传输、转存和显示进行了研究,本系统采用中级配置模式,并行传输4路像素数据、时钟信号及控制信号。实验结果表明,图像采集系统能够完成对分辨率1280×1024、帧频400f/s、位宽8bit高速视频图像的实时采集及显示。

Pano Video:摄像机运动建模及从视频估计摄像机运动参数的一种方法

通过给摄像机平移、旋转与变焦等运动建模，并把运动模型与基于象素点亮度变化的方法相结合来估计摄像机运动参数。用得到的运动参数可以把视频构造成一幅全景图，全景图可广泛应用于视频压缩与检索。实验表明，该方法可成功地应用于视频会议系统中的视频压缩与视频检索。

基于FPGA的Camera Link视频信号分配系统设计

在给出标准CameraLink视频信号协议的基础上,设计基于FPGA的视频分配系统,实现视频信号一分三,扩展Camer-aLink信号接口,提供给后续图像处理、存储等设备。实验表明视频分配系统可以正确的将CameraLink视频信号进行一比三分配,系统工作稳定,信号传输质量良好。

基于Video for Linux内核的USB摄像头视频信号采集实现

Video for Linux是Linux中关于视频设备的内核驱动,本文介绍了在Video for Linux内核基础上,利用其提供的接口函数、数据结构完成对USB摄像头驱动进行设计,并实现在Linux下对视频信号的采集。

基于IP Camera的网络视频监控系统的设计

设计了一种基于IP Camera的网络视频监控系统,系统通过各种不同的接入服务,提供了C/S、Web、ClickOnce等多种访问方式,实现了多种平台下对视频终端的监控。系统采用类似于DNS的目录服务,将所有物理节点、逻辑节点均统一编码,并存储到本地配置数据库或文件中,实现了视频终端、客户监控端、视频数据文件等信息的管理和访问。系统在有线和无线两种不同的传输方式下,根据不同的网络传输特点,分别采用了TCP和UDP两种不同的通信方式和通信机制向外部提供视频数据服务,提高了视频流畅性。