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A method for depth sensing based on sensing the visibility associated with the coherence function of a laser source is presented. The setup is based on an electronic speckle pattern interferometric (ESPI) setup, where the object depth is encoded into the amplitude of the interference pattern without the need for depth scanning. After performing phase-shifting method, the object three-dimensional (3-D) shape is reconstructed by means as a range image from the visibility of the image set of interferograms and where each gray level represents a given object depth. Experimental results validate the proposed approach for reflective diffuse objects at different measurement distances. 相似文献
104.
Yuan Dong Xi-He Zhang Feng-dong Zhang Guo-Bin Ning Guang-yong Jin Wei Liang Yan-Fei Lü Kai Zhang 《Optik》2010,121(19):1781-1783
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. 相似文献
105.
In this paper, we consider the unilateral obstacle problem, trying to find the numerical solution and coincidence set. We construct an equivalent format of the original problem and propose a method with a second-order in time dissipative system for solving the equivalent format. Several numerical examples are given to illustrate the effectiveness and stability of the proposed algorithm. Convergence speed comparisons with existent numerical algorithm are also provided and our algorithm is fast. 相似文献
106.
Kazuki Yoshida 《Journal of Mathematical Analysis and Applications》2010,369(2):645-657
We consider an inverse acoustic scattering problem for identifying a non-convex penetrable obstacle in three dimensions in a homogeneous medium. We apply the complex geometrical optics solutions with logarithmic phase, which is called complex spherical waves, to reconstruction problem. The reconstruction schemes will be demonstrated in the last section. 相似文献
107.
对大学生学习概率论的障碍因素进行分析,得出影响概率论学习的障碍因素包含三方面:直观能力,概率思维品质,心理因素及情感,并分析了这几方面因素,给出克服这些障碍的相应对策,以期能从根本上改进传统教学方法,更新传统教学理念. 相似文献
108.
Three-dimensional guidance in the neighborhood of collision course, based on a terminal differential game, renders ellipsoidal control sets. As a result, a saddle-point contains singularities. This paper (a) generalizes previous results on linear dynamics with terminal cost and ellipsoidal control sets and (b) applies the results to the above guidance problem to include general missile and target transfer functions. We further demonstrate the construction of the isocost surfaces (tubes). 相似文献
109.
Penalty methods form a well known technique to embed elliptic variational inequality problems into a family of variational equations (cf. [6], [13], [17]). Using the specific inverse monotonicity properties of these problems L ∞-bounds for the convergence can be derived by means of comparison solutions. Lagrange duality is applied to estimate parameters involved. For piecewise linear finite elements applied on weakly acute triangulations in combination with mass lumping the inverse monotonicity of the obstacle problems can be transferred to its discretization. This forms the base of similar error estimations in the maximum norm for the penalty method applied to the discrete problem. The technique of comparison solutions combined with the uniform boundedness of the Lagrange multipliers leads to decoupled convergence estimations with respect to the discretization and penalization parameters. 相似文献
110.