微波辐射计定标

对微波辐射计的两种定标方法进行了介绍,即分步定标法和整体定标法。分步定标法需要测量的中间参数较多,故误差来源多,定标精度低。整体定标一次完成,没有中间环节,因此定标精度较高,缺点是要求有一个提供给天线的准确、可靠的噪声环境,成本较高。本文在现有的实验条件下,分别对５．４ＧＨｚ和３７ＧＨｚ微波辐射计进行了整体定标和接收机定标,并对定标结果进行了对比。     

Multi-camera calibration based on an invariant pattern

In this paper we present a method for the calibration of multiple cameras based on the extraction and use of the physical characteristics of a one-dimensional invariant pattern which is defined by four collinear markers. The advantages of this kind of pattern stand out in two key steps of the calibration process. In the initial step of camera calibration methods, related to sample points capture, the proposed method takes advantage of using a new technique for the capture and recognition of a robust sample of projective invariant patterns, which allows to capture simultaneously more than one invariant pattern in the tracking area and recognize each pattern individually as well as each marker that composes them. This process is executed in real time while capturing our sample of calibration points in the cameras of our system. This new feature allows to capture a more numerous and robust set of sample points than other patterns used for multi-camera calibration methods. In the last step of the calibration process, related to camera parameters' optimization, we explore the collinearity feature of the invariant pattern and add this feature in the camera parameters optimization model. This approach obtains better results in the computation of camera parameters. We present the results obtained with the calibration of two multi-camera systems using the proposed method and compare them with other methods from the literature.     

Methods for geometrical video projector calibration

In this paper we present two methods to geometrically calibrate a video projector using a markerless planar surface. The first method assumes a partial knowledge on the camera parameters, whereas the second method consists in an auto-calibration method with no assumption on the parameters of the camera. Instead, the auto-calibration is performed by identifying a roughly fronto-parallel pose of the camera w.r.t. the projection surface. The fact that camera calibration is not needed increases the usability of the methods and at the same time eliminates one potential source of inaccuracy, since errors in the camera calibration would otherwise inevitably propagate through the projector calibration. Not using a printed pattern as most existing methods do is another gain in accuracy and ease of use. As depicted by our experiments, both methods enjoy a good stability and give good results when compared against existing methods.     

基于现场观测的星载雷达高度计定标方法进展

综述了截至目前的高度计定标相关进展。简要论述了星载雷达高度计的发展历史，高度计的主要误差来源，并以此引出并重点论述了用以校正这些误差来源并获得定标参数的3种基于现场观测的高度计定标方法，分别为依据GPS浮标、锚系压力验潮仪阵列以及沿岸验潮仪进行现场观测方法。同时论述了高度计定标场的历史发展，分析了国际高度计定标场的建设现状，重点介绍了国际上4个主要的业务化高度计定标场：Harvest石油平台、Bass海峡定标场、Corsica岛定标场、Gavdos岛定标场与我国为HY-2定标建设中的珠海万山定标场。通过对定标方法与国际业务化定标场的介绍，将为我国HY-2系列星载高度计万山定标场建设提供一定的思路。     

基于现场观测的星载雷达高度计定标方法进展

综述了截至目前的高度计定标相关进展。简要论述了星载雷达高度计的发展历史,高度计的主要误差来源,并以此引出并重点论述了用以校正这些误差来源并获得定标参数的3种基于现场观测的高度计定标方法,分别为依据GPS浮标、锚系压力验潮仪阵列以及沿岸验潮仪进行现场观测方法。同时论述了高度计定标场的历史发展,分析了国际高度计定标场的建设现状,重点介绍了国际上4个主要的业务化高度计定标场：Harvest石油平台、Bass海峡定标场、Corsica岛定标场、Gavdos岛定标场与我国为HY-2定标建设中的珠海万山定标场。通过对定标方法与国际业务化定标场的介绍,将为我国HY-2系列星载高度计万山定标场建设提供一定的思路。     

材料试验机同轴度检测方法及影响因素分析

材料试验机同轴度是影响其试验力传递效率的重要指标。各级计量部门按照检定规程规定的方法开展对试验机同轴度指标的周期性检测工作，而检测过程中存在多方面因素会影响结果的准确性从而影响其合格性判定结果。当前试验机同轴度检测所依据的检定规程中给出了多种检测方法，多种方法的差异性、适用性和可比性也往往会引起疑惑。通过比较分析，对几个相关标准文件规定的几种同轴度检测方法进行了适用性阐述，通过算法对比和仿真分析得出引伸计式同轴度测量方法和应变计式同轴度测量方法的差异，并从安装定位、初始拉力、夹持长度等方面，对影响检测结果的几个因素进行分析探讨，为完善同轴度检测操作方法，提升数据的准确性和可比性提供参考依据。     

背投式多投影系统中各向异性问题的研究

目的 针对背投式多投影系统中存在的各向异性问题,提出一套行之有效的解决方案.方法 首先,为了解决以静态观众为主体的多投影系统各向异性问题,基于反馈机制提出了以特定位置为中心的“最佳观测域”,并在该区域内实现了真正的视觉无缝画面校正;然后,基于视觉人体跟踪技术进一步提出了以特定交互者为中心的“动态最佳观测域”框架,并结合模糊预测控制思想从人体重心检测、跟踪和投影仪亮度实时补偿等3个方面对该框架内的各个组成模块的关键技术进行了阐述.结果 实验结果显示,利用交互者运动的时空连续性优化后的动态最佳观测域算法,具有较好的鲁棒性和实时性.同时,与其他类似方法相比获得了更好的视觉无缝校正效果,其中观测距离为1 m、3 m和5 m时,对应的亮度样本标准差分别为17.11、13.17和9.2.结论 提出的各向异性解决方案,将实时反馈信号引入校正过程中,有效提高了输出画面质量.通过实验测试和性能评估,验证了文中方法的可行性.     

摄像机标定方法简述

文章首先介绍了摄像机标定的基本原理以及对摄像机标定方法的分类.通过对最优化标定法、双平面标定法、两步法等传统摄像机方法的具体分析,给出了各种方法的优劣对比;同时对多种自标定方法的研究现状、发展情况以及存在问题进行了探讨.最后给出了发展传统摄像机标定方向、提高摄像机自标定精度的一些参考建议.     

Methodology for materiality: interaction design research through a material lens

Increasingly, human–computer interaction (HCI) is acknowledging the material dimensions of our subject. In doing so, a wide repertoire of methods is currently being explored for conducting interaction design research through a material lens. These methods range from material studies and studies in material cultures to methods borrowed from craft, designerly approaches to interaction design, sketching in hardware approaches, and so on. While we acknowledge these important attempts to approach the material dimensions of interaction design, it should also be noted that there is a lack of more systematic studies of methods that are, can be, or have been applied within HCI and interaction design to specifically explore interaction design through a material lens. So, there is a need for a methodology that acts as a guideline to material-centered interaction design research. In this paper, we address this need. More specifically, this paper contributes to this current state by presenting a methodology for methodological explorations in material-centered interaction design research. The development of this proposed methodology takes a point of departure in the methods available and applied so far. With grounding in design theory, this paper organizes these methods into a four-dimensional structure to guide deliberate choices of methods in different phases of interaction design research projects—that is, it serves as a framework for research design. The organizing structure for the proposed methodology follows the simple dialectic tradition in design to work back and forth between details and wholeness, materials and textures. In this paper, we describe the four dimensions of our framework and how these can be useful to guide research design aimed at advancing our understanding of the material dimensions of HCI. We illustrate how the proposed structure can be practically useful—both in advancing our studies of interaction design through a material lens and show how it brings us back to the roots of our profession—that is, back to a focus on the materials, the fundamental components of any computational composition.     

Multiple consumer-grade depth camera registration using everyday objects

The registration of multiple consumer-grade depth sensors is a challenging task due to noisy and systematic distortions in depth measurements. Most of the existing works heavily rely on large number of checkerboard observations for calibration and registration of multiple depth cameras, which is tedious and not flexible. In this paper, we propose a more practical method for conducting and maintaining registration of multi-depth sensors, via replacing checkerboards with everyday objects found in the scene, such as regular furniture. Particularly, high quality pre-scanned 3D shapes of standard furniture are used as calibration targets. We propose a unified framework that jointly computes the optimal extrinsic calibration and depth correction parameters. Experimental results show that our proposed method significantly outperforms state-of-the-art depth camera registration methods.     

AFM微悬臂梁探针弹性常数各种标定方法的比较与分析

微悬臂梁探针是基于原子力显微镜(AFM)的微纳尺度力学测试中重要的力传感元件,其弹性常数的准确程度直接影响力学测量结果的可靠性。但是,目前已有的众多标定微悬臂梁探针弹性常数的方法都有各自的局限性,且准确性各异,因此需要对各种方法进行对比来选择出最佳方法。选取三种商用悬臂梁探针利用本实验室搭建的基于天平法的可溯源微悬臂梁探针弹性常数标定仪对其法向弹性常数进行标定,之后再将相同悬臂梁用三种常用标定方法（尺寸参数法,Sader法,热噪声法）进行再次标定。对不同方法测量结果进行比较,分析并详细讨论每种方法的优缺点与适用范围。结果表明相比于其他方法,微悬臂梁探针弹性常数标定仪（天平法）可测范围广,精度高,可溯源,可成为精确标定各种悬臂梁探针弹性常数的最佳方法之一。     

一种新的基于直线特征的摄像机自标定方法

通过引入场景的几何约束,提出了一种新的基于直线的摄像机自标定方法。利用射影几何中平行直线投影的交点与光心的连线平行于该平行直线的性质,给出了摄像机内参数的线性求解方法。只假设场景中存在垂直的平行直线,相对于文献［1］而言,其适用的情况更为广泛。实验结果验证了方法的有效性。     

一种新的单点标定视线估计方法

在单相机单光源条件下,针对现有视线估计方法标定过程复杂的问题,提出一种新的单点标定视线估计方法. 该方法预先建立屏幕中多个点的视线估计统计模型,进而通过插值估计用户在屏幕中的视点. 主要创新工作有:1） 提出一种基于统计的单点标定视线估计模型,降低了标定过程的复杂度;2） 采用增量学习方法进一步更新模型,提高模型对不同用户以及头部运动的适应性. 实验证明,本文方法在设备简单、允许头部运动的前提下,只需单点标定就能够取得较高精度.     

A novel fabrication method of fiber-optical planar transmission sensors for monitoring pH in concrete structures

Monitoring concrete structures requires robust, long-term stable, and low-cost sensors. We introduce a new technique for producing a fiber-optical planar transmission sensor setup using a wafer saw for cutting the sensitive zone, which can monitor in situ pH in concrete. The sensitive zone of the fiber-optical sensor setup is filled with a sensing material, which color varies reversibly upon change of pH. Analyzing the characteristic changes in absorption of this material is done by a micro spectrometer. Our fabrication method is suited for industrial mass production because no cost-intensive adjustment of fibers is necessary. In this paper we will present beside our fabrication method the calibration of pH sensors produced with this method.     

一种简单快速的相机标定新方法

本文提出了一种新的相机自标定方法,该方法要求摄像机在3个(或3个以上)不同方位摄取一个包含其内接正三角形的圆的新型标定模板的图像.首先,从模板图像中推导得到圆环点的像点坐标;然后通过得到的圆环点像点坐标,可线性求解摄像机内参数.与传统方法不同的是,该方法避免了复杂的椭圆拟合和直线拟合,降低了计算复杂度,提高了标定速度和...     

模糊化神经网络在摄像机标定中的应用

摄像机标定是精确的视觉系统的前提。该文提出了基于双目视觉的一种新型模糊化神经网络摄像机标定法。神经网络已经成功的运用于无参摄像机标定技术当中。由于镜头的畸变主要由径向畸变引起，且图像中点总的径向畸变正比于该点到图像中心距离的平方，所以通过对神经网络的输入层进行径向模糊化，可以进一步精确标定结果。通过与普通神经网络摄像机标定法、分割区间双神经网络摄像机标定法的仿真比较，证明了模糊化神经网络摄像机标定法的有效性。     

Implicit and explicit camera calibration: theory and experiments

By implicit camera calibration, we mean the process of calibrating a camera without explicitly computing its physical parameters. Implicit calibration can be used for both three-dimensional (3-D) measurement and generation of image coordinates. In this paper, we present a new implicit model based on the generalized projective mappings between the image plane and two calibration planes. The back-projection and projection processes are modelled separately to ease the computation of distorted image coordinates from known world points. A set of constraints of perspectivity is derived to relate the transformation parameters of the two calibration planes. Under the assumption of the radial distortion model, we present a computationally efficient method for explicitly correcting the distortion of image coordinates in frame buffer without involving the computation of camera position and orientation. By combining with any linear calibration techniques, this method makes explicit the camera physical parameters. Extensive experimental comparison of our methods with the classic photogrammetric method and Tsai's (1986) method in the aspects of 3-D measurement (both absolute and relative errors), the prediction of image coordinates, and the effect of the number of calibration points, is made using real images from 15 different depth values     

机械臂绝对定位精度标定关键技术综述

目前我国飞机和卫星装配仍主要采用人工装配,装配技术陈旧、机器人绝对定位精度低等问题难以满足飞机和卫星高精度、高性能的要求,阻碍了工业机器人在航空制造行业的发展,因此,在机器人柔性自动化装配过程中,如何提高机械臂绝对定位精度的标定技术已成为学术界和工业界广泛关注的焦点。为了系统地分析和总结现有的研究成果,对绝对定位精度标定方法进行了分类探讨,归纳了国内外机械臂标定技术的研究现状,详细分析了误差不确定性、冗余参数的消除及最优测量结构选择性等关键技术,并对机械臂绝对定位精度标定技术的未来发展趋势进行了构想和展望。