CCD相机实时自动调光系统

为了实时调整高帧频CCD相机,获得高质量图像,提出了一种基于分档电子快门控制和增益控制相结合的复合控制方法,实现了快速、高精度调光.其算法主要由三部分构成:二次均值灰度权值的累加, 基于分段二次函数的自动快门控制和基于数据分析的自动增益控制.采用共享的乒乓缓存策略来保证算法在自行设计的硬件平台得到有效验证并连续显示.实验结果表明,该算法具有良好的图像质量,捕获的视频图像在各种条件下,均具有快速的收敛性和适应性.     

Time-resolved spectra of dense plasma focus using spectrometer, streak camera, and CCD combination

A time-resolving spectrographic instrument has been assembled with the primary components of a spectrometer, image-converting streak camera, and CCD recording camera, for the primary purpose of diagnosing highly dynamic plasmas. A collection lens defines the sampled region and couples light from the plasma into a step index, multimode fiber which leads to the spectrometer. The output spectrum is focused onto the photocathode of the streak camera, the output of which is proximity-coupled to the CCD. The spectrometer configuration is essentially Czerny-Turner, but off-the-shelf Nikon refraction lenses, rather than mirrors, are used for practicality and flexibility. Only recently assembled, the instrument requires significant refinement, but has now taken data on both bridge wire and dense plasma focus experiments.     

不同光照条件下数字CCD相机响应不均匀性研究

数字CCD相机光电输入输出响应不均匀特性是其用于光束远近场能量分布测量的重要参数,因此研究数字CCD相机的响应不均匀性,是保障激光参数测量系统测量精度的关键技术环节。从理论上分析了数字CCD相机光电响应不均匀性的原因,通过建立数字CCD相机响应不均匀性测试系统和三维模型,推导出了数字CCD相机相应不均匀性的计算公式,对数字CCD相机的响应不均匀性进行测量与分析,给出了测试系统的结构框图和部分测试结果。     

采用外触发方式实现CCD摄像机的全自动调光控制

针对传统的CCD摄像系统自动调光方法在工程使用中存在的不足,提出一种新型的CCD摄像系统的全自动调光方法。它采用外触发电子快门和可变光阑相组合进行调光,外触发电子快门调光为主,可变光阑调光为辅。采用外触发方式实现CCD摄像机的电子快门时间调节,由单片机控制电机调节可变光阑的通光口径,以使像面照度适中。反馈控制量由图像目标区域的均值电平获得,从而实现最佳全自动调光。简要叙述了新型调光系统的组成和工作原理。Matlab仿真结果表明,与传统调光方法相比,新型调光方法调光拍摄的图像对应的直方图分布更宽广且更均匀,功率谱幅值也更高,达到7.5dB以上。其图像更清晰,对比度更高,目标层次对比也更加明显,满足现代CCD摄像系统的最佳全自动调光要求。     

利用照片建立虚拟现实模型

虚拟现实技术有着广泛的应用背景,建立实体模型是其首要步骤。传统的几何建模方法费时、而且难以表现实体表面的真实特征。这里提出、实现了一种便捷的虚拟现实建模方法。首先对待建模对象进行用摄像,并将照片输入到计算机内,经过特征匹配、相机标定及纹理映射等步骤,最终得到具有表面纹理的实体模型。此方法简单易行,文中给出了建模实例,验证了所提出的方法。     

Study on automatic control of arc gap in robotic TIG welding

This paper presents a method for automatic control of arc length in tungsten inert gas (TIG) welding process using the arc voltage. By using this method, the role of operator in arc length control is played by an automatic control system based on a predefined arc voltage value for any special welding operation. A dynamic model for feed-rate mechanism and the relation between variations of arc length and voltage are described in details. Using a proportional-integral controller, variations of arc length in welding path is compensated with an automatic feed-rate mechanism in a normal direction to the welding path. By keeping the voltage constant during the process, a stable weld with higher quality and better appearance is obtained specially in welding of uneven surfaces. Theoretical and practical investigations show that the suggested method is able to control the TIG welding process successfully. Test results show that an accurate weld is obtained without the interference of the operator, and by comparing the predefined values of arc voltage with what is practically obtained, the welding gap is automatically adjusted.     

机械臂倒液任务中透明容器的液位高度视觉检测与控制

针对包含多类透明容器与多种液体的机械臂倒液任务,提出了一种不需要相机标定与标尺辅助的液位相对高度视觉检测方法与闭环控制方案。首先,分析了服务机器人倒液任务的特点,使用计算机视觉中的目标检测方法同时检测液体与容器,利用液体与容器的高度比例关系得到相对液位高度,避免了测量液位绝对高度所需的繁杂标定过程。其次,利用小孔成像模型对所提的相对液位高度检测方案进行几何建模与分析,推理出典型情形下测量的误差规律;再次,采集多种液体、多类容器的图像作为训练集来训练YOLOv5s,用于检测目标物以获得液位相对高度。测试结果验证了所提的液位检测方法的有效性,新方法对于训练集中未出现的新形状容器中的新液体的平均配对检出精度为86.7%;最后,为了避免求解或估计视觉伺服理论中复杂的雅可比矩阵,将求得的相对液位高度与PD控制结合组成液位闭环控制系统。系统使用相同的PD控制器参数在两种倒液平台上的多类倒液任务中均取得成功,验证了液位闭环控制方案的有效性与鲁棒性。     

Developments of low-cost procedure to estimate cloud base height based on a digital camera

Cloud height, wind speed and direction at cloud height play an important role in air safety. This paper presents a low-cost system based on digital cameras to estimate cloud base height. It is shown that both wind speed and direction can also be obtained with this system. The method is based on triangulation and uses image registration to identify common cloud features in photographs taken from different positions. The wind speed and direction is obtained from two time-lapsed pictures taken from the same position. The measurement results are compared with LIDAR measurements performed on site.     

Electromagnetic arc path control in robot plasma welding

Arc welding has always presented a challenge to robot operation. Variations in joint fit-up, positional welding requirements and the high levels of welder skill demanded by transient changes in operating conditions are just some of the variables with which any arc welding robot must cope. The article examines how an inertia-less high-frequency weaving technique using a novel deflector system can solve many of these problems even for high speed seam tracking.     

利用数码相机建立轿车数字模型库

在工业设计或建筑设计中,积累丰富的素材是成功作品的必要条件。随着计算机辅助设计技术的普及,建立数字化的素材库显得尤为重要;在汽车设计领域,现有的素材库多为2维的数字图像,而非3D模型。这里基于计算机视觉原理,利用数码相机,设计了一套轿车车型快速数字化系统,通过对轿车仿真模型的旋转、摄像来获取车身的3D信息。文中给出了两种国产轿车的设计实例,效果令人满意。     

利用数码相建立轿车数字模型库

在工业设计或建筑设计中，积累丰富的素材是成功作品的必要条件。随着计算机辅助设计技术的普及，建立数字化的素材加显得尤为重要；在汽车设计领域，现有的素材库多为2维的数字图像，而非3D模型。这里基于计算机视觉原理，利用数码相机，设计了一套轿车车型快速数字化系统，通过对轿车仿真模型的旋转、摄像来获取车身的3D信息。文中给出了两种国产轿车的设计实例，效果令人满意。     

焊接逆变电源数字控制的分析

针对传统电焊机的交流电压的频率为电网频率50Hz的工作特点,其工作效率低,焊接效果差,耗电多等缺点.本文设计了焊接逆变电源的数字控制,通过数字控制实现电焊机逆变电源输出交流电压的频率,其实现方法是通过改变单相逆变器SPWM的调制波的频率,从而改变输出交流电压的频率.通过理论分析和DSP数字控制实验验证了该控制系统的稳定性和可靠性,并能适时的改变逆变电源输出交流电压的频率,该方法能提高焊接的效率、降低能源,提高焊接质量.     

天文观测CCD相机中Smear效应的消除

为了有效消除帧转移型相机的Smear效应,针对其成像机理及特性,提出了一种基于背景估计的适用于序列图像中Smear效应的消除方法.该方法通过对含有Smear效应的原始图像灰度分布进行统计分析,自适应判定Smear效应的发生位置;然后,采用截尾均值滤波(ATMF)技术高精度估计Smear效应的强度;最后,通过差分的方式消...     

基于开放式体系结构的弧焊机器人控制系统设计和实现

主要是结合具体的课题工作，探讨在开放式体系结构下构建一种机器人控制系统的软、硬件模型，以适应生产实践中对现有控制系统更新、改造或二次开发的要求。     

空间相机大功率CCD器件的热设计与热试验

对空间相机大功率CCD器件进行了热设计以解决其散热问题,为了验证热设计的合理性进行了CCD焦面组件的热试验.首先,介绍了以传导为主要散热措施的CCD器件热设计方案,CCD器件的热量主要通过热管传递到冷源;然后,针对整个焦面组件进行了试验规划,特别对模拟冷板进行了专门设计;最后,在真空环境下进行了综合试验.试验结果显示,...     

弧焊机器人自适应轨迹跟踪控制仿真

针对多关节机械手具有非线性和耦合性等特点,常用的PD控制难以达到现场作业的要求。以弧焊机器人为研究对象,运用拉格朗日法建立该机器人的动力学模型,并在进行动力学仿真的基础上求得两关节机器人的简化模型,然后采用鲁棒自适应算法与PD控制结合的算法实现轨迹跟踪控制,最后在MATLAB/Simulink中进行算法仿真。仿真结果表明,机器人能有效抑制外界扰动对跟踪轨迹的影响,动态性能和误差收敛性良好,为实现多关节机器人的轨迹跟踪控制提供了理论基础。     

科学级CCD相机的噪声分析及处理技术

为了降低科学级CCD相机的噪声,提高相机的成像质量,针对不同的噪声源,根据相应的噪声产生原理,设计了实用的噪声抑制电路和处理电路.应用于选用DALSA IL-E2型TDI-CCD 图像传感器自己开发的科学级CCD 相机,有效地降低了暗电流噪声,消除了复位噪声对真正信号的影响,使相机的成像质量得到提高.通过实验证明,该科学级CCD相机的输出信噪比能达到50 dB.     

Prevention of critical events combination in robotic welding

The problem of minimizing critical events, the combination of which lead to accident situations in robotic welding as part of man–machine production control systems has been considered. The statement of the problem has been adduced, and models, algorithms, and software and hardware tools for solving it have been developed. The solution of this problem will improve the accuracy and quality of operations and reduce losses from the downtime of the welding equipment.     

Noise in off-axis type holograms including reconstruction- and CCD camera parameters

Phase and amplitude images as contained in digital holograms are commonly extracted via a process called “reconstruction.” Expressions for the expected noise in these images have been given in the past by several authors; however, the effect of the actual reconstruction process has not been fully appreciated. By starting with the Quantum Mechanical intensity distribution of the off-axis type interference pattern, then building the digital hologram on an electron-by-electron base while simultaneously reconstructing the phase/amplitude images and evaluating their noise levels, an expression is derived that consistently describes the noise in simulated and experimental phase/amplitude images and contains the reconstruction parameters. Because of the necessity to discretize the intensity distribution function, the digitization effects of an ideal CCD camera had to be included. Subsequently, this allowed a comparison between real and simulated holograms which then led to a comparison between the performance of an “ideal” CCD camera versus a real device. It was concluded that significant improvement of the phase and amplitude noise may be obtained if CCD cameras were optimized for digitizing intensity distributions at low sampling rates.     

Noise in off-axis type holograms including reconstruction and CCD camera parameters

Phase and amplitude images as contained in digital holograms are commonly extracted via a process called “reconstruction”. Expressions for the expected noise in these images have been given in the past by several authors; however, the effect of the actual reconstruction process has not been fully appreciated. By starting with the Quantum Mechanical intensity distribution of the off-axis type interference pattern, then building the digital hologram on an electron-by-electron base while simultaneously reconstructing the phase/amplitude images and evaluating their noise levels, an expression is derived that consistently describes the noise in simulated and experimental phase/amplitude images and contains the reconstruction parameters. Because of the necessity to discretize the intensity distribution function, the digitization effects of an ideal CCD camera had to be included. Subsequently, this allowed a comparison between real and simulated holograms which then led to a comparison between the performance of an “ideal” CCD camera versus a real device. It was concluded that significant improvement of the phase and amplitude noise may be obtained if CCD cameras were optimized for digitizing intensity distributions at low sampling rates.