A spatial calibration method for master-slave surveillance system

The master-slave surveillance system uses stationary-dynamic camera assemblies to achieve wide-area surveillance and selective focus-of-interest. In such a system, a stationary fish-eye camera monitors a panoramic field of environment from a distance, while a dynamic PTZ (Pan–Tilt–Zoom) dome camera is commanded to acquire high-resolution images from a focused direction and provide multi-scale zoomed-in information. In order to achieve the precise interaction, pre-processing spatial calibration between these two cameras is required. This paper introduces a novel vision based calibration approach to automatically calculate a transformation matrix model between the fish-eye coordinate system and the PTZ dome coordinate system by matching feature points in the scene. The experiment has demonstrated the effectiveness of using this method with high accuracy in short calibration time.     

A distortion correction algorithm for fish-eye panoramic image of master-slave visual surveillance system

A master-slave visual surveillance system is composed of one fish-eye panoramic camera and one dynamic pan-tilt-zoom (PTZ) dome camera. In order to make PTZ dome camera zoom into all targets of interest in panoramic image, the fish-eye panoramic camera is fixed inclining towards the gravity direction, which may cause more obvious distortion. This paper proposed a novel method for the distortion correction of captured panoramic image based on the midpoint circle algorithm (MCA). The method uses incremental calculation of decision parameters to determine the pixel positions along a circle circumference, and both of the vertical and horizontal are rectilinearised. Experimental results show that our correction method based on MCA is efficient and effective. In particular, due to its low computational cost, our method can be applied on embedded camera platform without any extra hardware resources.     

Horizontal parallax distortion in toed-in camera with wide-angle lens for mobile device

An effect of the toed-in camera configuration is keystone distortion, which causes vertical and horizontal parallax in the stereoscopic image. The horizontal parallax is the source of the depth plane curvature. However, if the stereoscopic image captured by the toed-in camera system with fish-eye lens is displayed on mobile device, it is uncomfortable to view because the horizontal parallax contains horizontal parallax distortion occurred by the wide field of view of the lenses. Therefore, in this paper, we propose a novel correction method of the horizontal parallax distortion, which is one of the keystone distortions, in a toed-in camera with fish-eye lenses for mobile device. We have experimented to attest the proposed method. In experiment, we used two charge coupled device cameras, whose field of view is 48.48°. In addition, the captured stereoscopic image was corrected for the barrel distortion and the horizontal parallax distortion. Therefore, the proposed method provides correcting of the horizontal parallax distortion from a toed-in camera system in order that the users can enjoy three-dimensional effects without the visual fatigue. Additionally, the proposed method is able to apply to toed-in camera consisting of any kinds of cameras.     

Design of object surveillance system based on enhanced fish-eye lens

A new method is proposed for the object surveillance system based on the enhanced fish-eye lens and the high speed digital signal processor （DSP）. The improved fish-eye lens images an ellipse picture on the charge-coupled device （CCD） surface, which increases both the utilization rate of the 4：3 rectangular CCD and the imaging resolution, and remains the view angle of 183° The algorithm of auto-adapted renewal background subtraction （ARBS） is also explored to extract the object from the monitoring image. The experimental result shows that the ARBS algorithm has high anti-jamming ability and high resolution, leading to excellent object detecting ability from the enhanced elliptical fish-eye image under varies environments. This system has potential applications in different security monitoring fields due to its wide monitoring space, simple structure, working stability, and reliability.     

Hand gesture pointing location detection

Gesture recognition has been implemented in many systems for different purposes. The way it is used can be different from system to system. Few used them as touch objects using sensors while few use them as pointing object where the camera is in front of the hand, but the location is being pointed by human, can be detected only if the camera is behind that person. This paper presents an automatic system to detect the location on the wall where the user is currently pointing by his hand. This is done with the detection of head and both hands. The shoulders and elbows’ locations are identified using geometry analysis to understand the current gesture of the human and finally the direction where user hand is pointing would be detected. The face was detected using Haar classifier and shoulders were estimated using the rectangle method near the head. This method does not work in poor illumination conditions and is made to detect only one person at a time. Also user is supposed to wear half sleeve or sleeveless shirt for the better segmentation.     

航母中线电视监视系统的设计

研究设计了航母中线电视监视系统。依据照度、对比度及分辨率要求提出了一套基于电子倍增电荷耦合器件（EMCCD）的光电成像系统。分析了航母中线电视监视系统的舰载稳定平台的精度要求,并探讨了该系统可采用的图像处理算法。分析表明：采用主流的AndorIxonEMCCD并配合口径为40mm的光学系统可满足照度、对比度和分辨率的要求;采用Petzval形式初步设计的F／2光学系统,其光学传递函数接近衍射极限;而现有舰载稳定平台技术可以满足指向稳定的需要。最后,分析了形心算法、边缘算子算法在获取着舰机位置和姿态角的应用。该系统具有全天候工作能力,适用于航空母舰的着舰引导。     

车载鱼眼成像系统的运动矢量检测方法

在复合成像侦测系统中,鱼眼成像系统的超大视场突破了"旋转扫描"和"多镜头拼接"的设计常规,采用固定凝视的方式对整个半球空域的目标进行搜索.然而在车载环境下,车体运动将导致输出的图像序列不稳定,影响观察效果,甚至会引起黄斑成像系统跟踪偏差.根据鱼眼成像系统的工作特点,通过利用熵值理论确定出图像信息最为丰富的区域,探讨了一...     

Real-time distortion correction of fish-eye lens based on Bayer image signal

The imaging system based on a fish-eye lens generally has to correct the distortion of fish-eye images. The distortion correction based on the Bayer image signal is valuable, such as reducing the computation burden of image signal processing chips and providing a new imaging system structure of fish-eye lens. In this paper, a distortion correction method of fish-eye lens based on the Bayer image signal is proposed. Firstly, a distortion correction method that focuses on vertical straight lines and processing delay is proposed. Secondly, according to the correlation among color channels of the Bayer image, a novel Hermite interpolation method appropriate for Bayer image signal is proposed. Finally, a prototype system of fish-eye-lens-based imaging is established and the real-time field-programmable gate array (FPGA) implementation of the proposed method is demonstrated. The experiment demonstrates that the proposed distortion correction is not only characteristic of real-time processing and the smaller computation amount, but also applicable to embedded hardware.     

用于监控系统的鱼眼镜头光学设计

为了满足监控系统中单镜头可实现全景监控的需求,运用仿生学原理,在原有鱼眼镜头的基础上结合监控系统的需求,运用ZEMAX软件设计了一款视场为180°,相对孔径为1/1.6的鱼眼镜头.该镜头由9片透镜组成,总长度为68.5mm,采用1/3英寸CCD作为图像接收器件.在120lp/mm时,其MTF曲线在轴上大于0.4,在80...     

Laser imaging and approximation networks for calibration of three-dimensional vision

An automatic calibration technique for three-dimensional vision is presented. This technique determines the vision parameters by means of approximation networks and image processing of a laser line. Also, the network performs the three-dimensional vision based on laser scanning and a mobile camera. The network is built based on the behavior of a laser line and the camera position. Here, an electromechanical device moves the camera during the vision task and the network provides an automatic re-calibration. Thus, the vision is carried out via mobile camera and extrinsic parameters are not passed to the system. Therefore, the accuracy and the performance of the vision procedure are improved. It is because the physical measurements of references are avoided. Thus, a contribution for the calibration of lighting methods is achieved. Additionally to it, the mobile setup provides a high sensitivity and avoids occlusion. The proposed technique is tested with real objects and its results are evaluated based on laser projection methods. To carry it out, a root mean square of error is computed using a contact method as reference. Also, the time processing is described.     

红外热成像鱼眼镜头设计中若干特殊问题的处理

提出鱼眼镜头光阑球差的级数表达式及其基于有限差分的近似计算方法,解决了通常的光阑倒追方法面临的难题;讨论孔径光阑与入瞳的特殊"共轭"关系,分析了光阑彗差和像差渐晕;运用Aitkin插值技术填补"溢出"光线在像面上的落点,以保证像质函数定义的一致性,维持自动优化持续进展,从而克服频繁的光线"溢出"造成的严重困难;提出充分利用像差渐晕改善像面照度均匀性的方法;论述标定轴外光束边界的逐次渐近过程和运用入瞳距离变量实现孔径光阑位置全域优化的技术.     

飞行试验中军用1553B总线的实时采集技术

针对飞行试验中飞机结构件的动态变形测量问题,提出了一种基于图像的测量方法,对其中涉及的关键技术进行了研究。采用10参数模型非线性成像模型补偿摄像机系统误差,引入摄像机动态校准算法,使摄像机标校重投影误差小于0.03pixel;采用编码标志作为测量标志,提高了图像自动识别和匹配效率;采用双像机交会测量计算测量标志位移变形量可达到0.15mm/1m。实验证明,该方法满足飞行试验中飞机结构件动态变形要求。     

稳瞄炮长镜加装CCD摄像机技术分析

分析在炮长镜现有位置基础上加装CCD摄像机的可行性，提出加装CCD 摄像机的原则和方案。通过选择恰当的CCD摄像机安装位置和结构布局，满足了炮长镜潜望高度保持不变，炮长瞄准镜的内部结构改动量较少，加装成本整体降低的要求。借助有关理论，讨论了CCD摄像机选型、光路计算、激光发射光路镀膜的变化等问题。最后指出，炮长瞄准镜在加装CCD摄像机后，若再配备具有数据处理功能的自动跟踪组件，还可实现视频自动跟踪，而其原有的可见光观瞄功能仍然保持不变。     

基于脉冲耦合神经网络的弹簧卡箍缺陷检测

传统的弹簧卡箍缺陷多为产后人工全检,存在漏检与缺陷率上升等现象,这不但会使成本上升、也对人力资源提出了考验。为此实现自动实时在线全检就成为急需解决的课题,设计了基于机器视觉的弹簧卡箍在线自动检测系统,该系统安装在弹簧卡箍流水线两侧,搭建特定光源,通过激光传感器外部触发工业相机对其表面进行图像捕获,送上位机进行缺陷判定与定位,最后通过RS485将判定结果送下位机来控制剔除机制。实验结果显示：该系统采用改进的脉冲神经网络(PCNN)能准确提取目标缺陷区域并对缺陷进行判定,可在0.348 s每个零件的速度下,检测出弹簧卡箍表面大于10像素的缺陷。通过对不同弹簧卡箍进行检测验证实验,证明了PCNN算法对缺陷分割的准确性和有效性。     

面向单向器星轮自动化装配的视觉检测定位

针对传统单向器星轮人工装配效率低下问题,分析了单向器星轮装配过程,构建了基于计算机视觉技术的工业机器人自动化装配方案。首先利用CCD摄像机捕捉星轮表面形貌图像,然后利用Open CV视觉库进行了摄像机标定,再结合图像噪声去除,Hough圆检测,轮廓提取等技术,实现了星轮位姿的非接触式视觉检测。最后以单向器为例验证了该检测方法的有效性,机器人通过视觉获取的星轮位姿信息完成自动化装配。     

An acoustic Maxwell's fish-eye lens based on gradient-index metamaterials

We have proposed a two-dimensional acoustic Maxwell's fish-eye lens by using the gradient-index metamaterials with space-coiling units. By adjusting the structural parameters of the units, the refractive index can be gradually varied, which is key role to design the acoustic fish-eye lens. As predicted by ray trajectories on a virtual sphere, the proposed lens has the capability to focus the acoustic wave irradiated from a point source at the surface of the lens on the diametrically opposite side of the lens. The broadband and low loss performance is further demonstrated for the lens. The proposed acoustic fish-eye lens is expected to have the potential applications in directional acoustic coupler or coherent ultrasonic imaging.     

一种照相机成像平面照度均匀度检测系统

在讨论了照相机成像平面照度均匀度的影响因素的基础上 ,介绍了一种可在单片机的控制下 ,通过GaAsP光电二极管线阵扫描、A/D转换、测量结果输出等环节实现的照相机整机像面照度均匀度自动检测系统 ,并给出了该系统的测试结果。     

一种四路车载视频监控系统的设计与实现

针对目前汽车电子智能辅助系统的现状和市场需求,提出了一种基于多路视频解码复合技术和OSD显示技术的四路车载视频监控系统的设计方案。通过360度无死角四路鱼眼摄像头采集车身监控视频画面,实现多分割自由切换显示。阐述了视频监控系统的原理及软硬件模块的实现方法,重点讨论了视频分割、OSD显示模块的实现。最后,完成了整个系统的设计,并给出了实际运行结果。相比同类型的其他方案,成本下降了约三分之一。     

基于CCD图像的火灾空间定位方法

大空间中火源的空间位置的定位,一直是火灾自动探测与自动扑救中的难点。研究了一种利用单一CCD摄像头进行火灾自动空间定位的方法。根据计算机视觉原理,利用固定在自动消防水炮末端的CCD摄像头随水炮旋转扫描时的角度、位移变化,将CCD摄像头在不同位置所拍摄的图像中火源图像坐标和火源的空间坐标建立联系,从而实现了火源空间位置的自动定位。