一种低形状失真度的VSnakes算法

提出了一种低形状失真度的VSnakes算法。定义了两项新的能量表达式,其中一项使得轮廓控制点的分布更均匀,另一项增强了对候选轮廓曲率的约束,使其不仅仅保持与当前轮廓的形状相似,而且轮廓曲线更加平滑,从而降低了最终收敛轮廓的形状失真度。同时对轮廓松弛过程进行了简化,降低了算法复杂度。

室外场景的多视角视频拼接

扩展式摄像机系统的多视角视频图像拼接因角度因素容易产生形状失真、深度失真和运动失真。为此,对现有视频图像拼接方法加入角度约束进行改进。分离视频中的运动区域与静止区域,分别采用现有方法和改进方法加以实验验证,通过对比分析,选取拼接效果最好的APAP+角度约束方法和APAP+SPHP+角度约束方法进行拼接,将拼接后的静止区域和运动区域融合成宽视野的视频图像。实验结果表明,该方法能有效减少多视角视频图像拼接中的形状失真、深度失真和运动失真现象。

机械CAD中按给定尺寸精确绘图的方法

本文介绍一种在机械CAD及中小型应用程序中,按给定的几何尺寸精确绘图的方法。该法在IBMPC及其兼容机上进行试验,结果表明,所绘图形严格满足给定尺寸的精度要求。该法简便易行,易于推广。

立体电影摄影的基本规律及立体电影摄影机(一)

本文从分析立体电影的基本规律出发 ,推导了立体电影摄影基本参数的相互关系及立体影像空间形状失真的定量表征方法 ;在此基础上提出了立体电影摄影基本参数的计算方法 ,并分析了几种常见的影像空间形状失真 ;最后阐述了对立体电影摄影机的主要技术要求 ,以及提高我国立体电影摄影机性能的途径。

Calibration of split Hopkinson pressure bar system with special shape striker

In order to present basic guidance for system calibration of split Hopkinson pressure bar(SHPB) with the special shape striker,wave characteristics and dynamic responses of SHPB under striker impact were analyzed.Stress generated by the special shape striker tends to have a half-sine waveform and has little wave dispersion during its propagation.Impact velocities of the special shape striker and peak values of generated stress still have linear relation but with a different coefficient from that of cylindrical strikers.From stress histories on the surfaces of the input bar impacted by the special shape striker off-axially and obliquely,it is found that the misalignment impacts usually trigger wave distortion and amplitude decrease,which can be used to identify the poor system adjustment.Finally,the system calibration of SHPB with the special shape striker can be classified into four steps:system adjustment,wave distortion identification,measurement calibration and transmission calibration,where the measurement calibration factor and transmission calibration factor are elaborated and redefined.