Use of 3D field simulators in the synthesis of waveguide capacitive iris coupled lowpass filters

This paper presents the generalized lowpass filter design method of Levy based on three‐dimensional electromagnetic analysis and discontinuity modeling using commercially available full‐wave electromagnetic simulators. It shows how to use Levy's method for very accurate theoretical design of a waveguide capacitive iris lowpass filter, using modern 3D EM field‐solvers based on the finite element method (FEM), the mode matching method (MM), and the transmission line matrix (TLM) analysis method. This is the first time that design curves and equations, based on full electromagnetic modeling, have been presented for constant thickness capacitive iris filters. We will demonstrate our approach by designing a number of waveguide capacitive iris filters. This paper also demonstrates the generality of the method. This method can be applied to many other types of waveguide lowpass and bandpass filters. © 2000 John Wiley & Sons, Inc. Int J RF and Microwave CAE 10: 190–198, 2000.     

宽带3dB混合环基本原理的研究

阐述了宽带3dB混合环的基本原理以及支线交接不连续性对混合环设计的影响,提出了修正公式,并介绍了3dB混合环等效成的波导魔T的结构。     

基于神经网络的仿人跑步机器人步态规划

为了快速生成仿人机器人跑步运动轨迹,研究了一种用于仿人机器人跑步步态生成的步态规划器.采用三维弹簧倒立摆模型描述跑步过程中仿人机器人质心运动规律,奔跑时机器人质心轨迹及落脚点位置可以由四个步态参数来确定,从而将步态规划问题转化成步态参数优化问题,求解了500余种不同运动状态下的步态参数.建立了基于三层BP神经网络的步态...     

Structure from Motion: Beyond the Epipolar Constraint

The classic approach to structure from motion entails a clear separation between motion estimation and structure estimation and between two-dimensional (2D) and three-dimensional (3D) information. For the recovery of the rigid transformation between different views only 2D image measurements are used. To have available enough information, most existing techniques are based on the intermediate computation of optical flow which, however, poses a problem at the locations of depth discontinuities. If we knew where depth discontinuities were, we could (using a multitude of approaches based on smoothness constraints) accurately estimate flow values for image patches corresponding to smooth scene patches; but to know the discontinuities requires solving the structure from motion problem first. This paper introduces a novel approach to structure from motion which addresses the processes of smoothing, 3D motion and structure estimation in a synergistic manner. It provides an algorithm for estimating the transformation between two views obtained by either a calibrated or uncalibrated camera. The results of the estimation are then utilized to perform a reconstruction of the scene from a short sequence of images.The technique is based on constraints on image derivatives which involve the 3D motion and shape of the scene, leading to a geometric and statistical estimation problem. The interaction between 3D motion and shape allows us to estimate the 3D motion while at the same time segmenting the scene. If we use a wrong 3D motion estimate to compute depth, we obtain a distorted version of the depth function. The distortion, however, is such that the worse the motion estimate, the more likely we are to obtain depth estimates that vary locally more than the correct ones. Since local variability of depth is due either to the existence of a discontinuity or to a wrong 3D motion estimate, being able to differentiate between these two cases provides the correct motion, which yields the least varying estimated depth as well as the image locations of scene discontinuities. We analyze the new constraints, show their relationship to the minimization of the epipolar constraint, and present experimental results using real image sequences that indicate the robustness of the method.