三维控制网技术在BEPCⅡ储存环中的应用研究

介绍了加速器准直测量控制网的特点及BEPCⅡ储存环的控制网, 给出了基于全站仪和激光跟踪仪的三维控制网技术在该工程中的研究和应用情况, 联合利用这两种仪器, 采用三维测量方式建立了一个高精度的测量控制网, 着重分析了三维控制网的优缺点及增加全站仪观测值后对控制网精度的贡献, 并指出三维控制网技术具有较好的应用前景.     

中国散裂中子源准直控制网数据处理方法

以中国散裂中子源CSNS的直线加速器控制网为例,对其数据处理方法进行研究,采用平面与高程二维平差以及三维定向平差两种方式对准直控制网进行处理分析。同时,为了使准直数据处理更加简易便利,提出利用激光跟踪仪的测量软件SA实现三维定向平差的方法。通过不同软件及不同数据处理方法的对比,验证准直控制网数据处理的正确性,最终200 m长直线控制网点位精度优于0.2 mm,这为准直控制网的数据处理提供了指导。     

兰州重离子医疗装置同步环安装控制网设计

介绍了兰州重离子医疗装置（HIMM）建造中准直安装方案里核心的测量控制网设计。同步环准直测量控制网是基于Leica AT401激光跟踪仪和综合测量软件SA建立的三维测量控制网,在控制网设计中采用9个基准柱和2个激光干涉测量得到的基准长度参考,以及Leica DNA03数字水准仪协同测量,使全局三维控制网设计精度达到0.04 mm,最终确保同步环四极磁铁安装精度达到0.10 mm的要求指标,为将来束流的稳定运行做好可靠的保证。     

兰州重离子医疗装置同步环安装控制网设计

介绍了兰州重离子医疗装置(HIMM)建造中准直安装方案里核心的测量控制网设计。同步环准直测量控制网是基于Leica AT401激光跟踪仪和综合测量软件SA建立的三维测量控制网,在控制网设计中采用9个基准柱和2个激光干涉测量得到的基准长度参考,以及Leica DNA03数字水准仪协同测量,使全局三维控制网设计精度达到0.04mm,最终确保同步环四极磁铁安装精度达到0.10mm的要求指标,为将来束流的稳定运行做好可靠的保证。     

激光差拍波等离子体加速装置中约束磁场的计算研究

通过对等离子体发生器建立三维模型,计算得到磁场在该装置中的分布情况。所得结果与实际测量基本一致,从而说明所建模型的合理性。通过调节一些参数,对该模型进一步搞清了导致等离子体发生器中真实磁场较实验设计要求偏低的主要原因,并提出了相应的改进方案。     

激光差拍波等离子体加速装置中约束磁场的计算研究

通过对等离子体发生器建立三维模型,计算得到磁场在该装置中的分布情况。所得结果与实际测量基本一致 ,从而说明所建模型的合理性。通过调节一些参数,对该模型进一步搞清了导致等离子体发生器中真实磁场较实验设计要求偏低的主要原因,并提出了相应的改进方案。     

激光差拍波等离子体加速装置中约束磁场的计算研究

 通过对等离子体发生器建立三维模型,计算得到磁场在该装置中的分布情况。所得结果与实际测量基本一致 ,从而说明所建模型的合理性。通过调节一些参数,对该模型进一步搞清了导致等离子体发生器中真实磁场较实验设计要求偏低的主要原因,并提出了相应的改进方案。     

基于光束法平差的相位测量偏折术镜面面形测量

为了简化相位测量偏折术的系统标定,并减少系统标定和图像噪声对测量精度的影响,提出在相位测量偏折术中引入自由参考系,并在自由参考系内对测量结果进行光束法平差.由于基于梯度恢复面形的相位测量偏折术缺少绝对高度信息,因而不能直接进行光束法平差,自由参考系使入射光线和反射光线处于同一个坐标系内,通过光线三角交会计算自由参考系下...     

冷却储存环主环磁铁的准直测量

采用激光跟踪仪及配套带软件Insight对兰州重离子加速器冷却储存环主环磁铁进行了安装和准直。首先建立全局坐标系，用来确定从源体到实验环各子系统的理论原点的位置；而各个子系统又分别以各自的理论原点为基础建立局部坐标系，用来安装定位本系统内的各个元件；对各个子系统中的每一个元件还采用了元件坐标系。准直测量时，先在每块磁铁上焊接8个测量基准；然后对磁铁上的基准进行测量，以确定其在元件坐标系中的位置；再架设激光跟踪仪，测量主环控制网点，恢复主环局部坐标系，根据元件在主环局部坐标系中的位置及理论坐标，计算出相关的变换参数；转入元件坐标系，采用激光跟踪仪及Insight 软件显示实时测量坐标及其与理论值之差，其精度达到0.15 mm。     

冷却储存环主环磁铁的准直测量

采用激光跟踪仪及配套带软件Insight对兰州重离子加速器冷却储存环主环磁铁进行了安装和准直。首先建立全局坐标系,用来确定从源体到实验环各子系统的理论原点的位置;而各个子系统又分别以各自的理论原点为基础建立局部坐标系,用来安装定位本系统内的各个元件;对各个子系统中的每一个元件还采用了元件坐标系。准直测量时,先在每块磁铁上焊接8个测量基准;然后对磁铁上的基准进行测量,以确定其在元件坐标系中的位置;再架设激光跟踪仪,测量主环控制网点,恢复主环局部坐标系,根据元件在主环局部坐标系中的位置及理论坐标,计算出相关的变换参数;转入元件坐标系,采用激光跟踪仪及Insight 软件显示实时测量坐标及其与理论值之差,其精度达到0.15 mm。     

A new approach for the bundle adjustment problem with fixed constraints in stereo vision

A new approach for the bundle adjustment problem with fixed constraints in stereo vision is described in this paper. Since the direct application of traditional bundle adjustment fails to use the inner constraints completely which are maintained by fixating the orientation and the baseline between the left and right cameras. However, if the fixed constraints are applied to the traditional bundle adjustment, we refine only the left camera extrinsic parameters and 3D points for simplification in stereo pairs. The new method using the fixed constraints has superior theoretical 3D accuracy, and it can reduce the matrix dimension of the covariance matrix so that the total computation time is decreased. Experiments results using synthetic and real data have shown that our method is better than the traditional bundle adjustment algorithm in the 3D accuracy and the convergence rate.     

Generalization of three-dimensional N-ocular imaging systems under fixed resource constraints

The performance of multiview three-dimensional imaging systems depends on several factors, including the number of sensors, sensor pixel size, relative sensor configuration, imaging optics, and computational reconstruction algorithm. Therefore, it is important to compare the performance of such systems under equally constrained resources. In this Letter, we develop a unifying framework to evaluate the lateral and axial resolution of N-ocular imaging systems ranging from stereo (two cameras) to multiple sensors (integral imaging) under fixed resource constraints. The proposed framework enables one to evaluate the system performance as a function of sensing parameters such as the number of cameras, the number of pixels, parallax, pixel size, lens aperture, and focal length. We carry out Monte Carlo simulations based on this framework to evaluate system performance as a function of sensing parameters. To the best of our knowledge, this is the first report on quantitative analysis of N-ocular imaging systems under common resource constraints.     

Research on a fast algorithm of three-dimensional CGH

This paper puts forward a novel fast algorithm of three-dimensional Computer-Generated Hologram (CGH). The algorithm proposed can directly express the two-dimensional Fourier spectrum of a unit square by an analytic function, as well as the light field distribution of the unit square on the holographic plane (the unit square is not parallel to the holographic plane). The computer simulation and photoelectric reconstruction are also performed to verify the algorithm. The experimental results show that the algorithm is quick and simple, providing a good reference to research on three-dimensional CGH.     

三维人脸测量与分割系统研究

三维人脸的测量与分割有着广泛的应用需求,是目前重要的研究方向,但三维人脸数据的庞大、无序等问题制约了其快速发展。首先开发了基于结构光方法的三维人脸测量系统,获得以点云形式存储的高精度三维人脸数据。其次,采用保角变换对三维人脸数据进行了预处理,并采用二维卷积神经网络分割结合三维反映射的思路,实现了三维人脸的分割,解决了三维数据的无序性以及旋转性,降低了三维数据分割的时间消耗。实验结果表明,本文提出的三维人脸测量系统精度可达0.5 mm,三维分割的平均交并比可达0.78,二维分割结合三维反映射的整体效率明显高于直接进行三维分割的效率。     

Research on the propagation properties of hollow laser beams with three-dimensional trap optical distribution

A new kind of hollow beams - hollow laser beams with three-dimension trap optical distribution - was put forward. With the help of the Collins formula in paraxial optical system, the analytical equation of propagation and transformation of the hollow laser beams was deduced. According to the analytical equation, the propagation properties of the kind of hollow beams that transform in free space were simulated. In the experiment, we obtained the hollow laser beams by means of the combinational optical system of reflecting positive-axis and negative-axis pyramids. The intensity of the vertical loop in different distances was tested, which shows that the analytical equation of propagation and transformation is in agreement with the result.     

Research on three-dimensional shape reconstruction of circular cylindrical flaw

In this article, three-dimensional Born inverse scattering method is modified to convenient form for a cylindrical specimen that includes three-dimensional defect. One aluminum cylinder with flaw model is prepared and ultrasonic measurements are carried out. The measurement area in the modified methods is restricted in the plane perpendicular to the axis of cylindrical specimen. That’s to say that the method is modified to convenient form to use measured waveforms in the x₁ − x₂ plane. The measured wave data are fed into the inversion method and cross-sectional images are obtained. Then, three-dimensional shape reconstruction of flaw model in aluminum specimen is performed by piling up the cross-sectional images. At the same time, we get the numerical results from all directions by finite element method.     

Brownian dynamics with constraints

Systems possessing degrees of freedom operating on widely separated timescales, where the effects of those operating on the smaller timescales are relatively unimportant, may be modelled by the use of the Langevin equation. In order to study such systems containing complex polyatomic particles, holonomic constraints may be used. Though there is no lack of published algorithms for the numerical solution of the Langevin equation, few of them have been developed with sufficient rigour to ensure their precision, nor to demonstrate their compatibility with constraints. This study recapitulates an approach based upon Runge-Kutta equations which has the advantage of being perfectible to any desired order in the time-step, and shows how it may be combined with the SHAKE method in order to perform constrained Brownian dynamics simulations. Results are presented for some simple systems with a third order algorithm, and it is found that the correct dynamic and statistical behaviour is recovered.     

百万像素照相手机CMOS模组调焦方法的探讨

简要介绍了CMOS模组调焦的基本原理。在分析传统调焦方法的基础上,提出了用双光源标板进行调焦的新方法,同时测量CMOS中心像场近距离和无穷远处的MTF,调节镜头和CMOS的相对位置使两处的MTF相等时的位置为最佳对焦位置,实验结果证明该方法调焦范围分布窄、调焦精准、检查位置设置合理。对百万像素照相手机CMOS模组调焦、检测有较大的实用价值。     

基于虚拟仪器三维多涡卷混沌电路的研究

介绍了基于虚拟仪器的三维多涡卷混沌系统,给出了三维多涡卷混沌电路的实验方案.利用此方案进行实验,证明此实验系统具有良好的实验效果.