基于小波变换和数据融合技术的弱小目标检测

鉴于弱小目标检测所固有的难点及常用的单一分辨率下的检测方法还不能准确稳定地检测出目标，提出了一种弱小目标检测新方法。考虑到实际应用中的复杂背景和大量干扰噪声，运用数据融合技术，先对图像进行小波多分辨率分解，然后将不同分辨率下的子图进行最优加权平均融合来检测弱小目标。用实地拍摄的空中弱小目标红外和可见光图像分别进行实验验证，实验图像取256×256像素点阵大小，其中目标占10×10像素左右。结果表明该方法能够准确稳定地检测弱小目标，为后续的跟踪作了很好的铺垫。

Inclusion damage mechanisms of optical glass under laser irradiation

Based on the theory of thermal elasticity of spherical symmetry, the laser-induced temperature rise and stress in silica glass or K9 glass, which contain high laser-absorptive platinum inclusion, are calculated from heat conduction and thermal stress equations. Phase change of the inclusion is considered. The optical glass containing inclusion is found to be damaged mainly by either thermal stress or the pressure resulted from boiling of the inclusion. Because of the difference in thermal and mechanical properties between silica glass and K9 glass, the thermal stress in silica glass will not be enough to make it damage before the inclusion vaporizes, and only the pressure due to the inclusion's boiling will serve as the main damage source. While in K9 glass, before the inclusion boils, thermal stress exceeds the materials' mechanical strength, leading to mechanical damage; if the inclusion is vaporized, the resulted pressure furthers the damage. The effect of inclusion size is studied. With the increase of the inclusion's size, the glass's damage threshold in terms of laser energy density decreases firstly, then increases. So a hazardous inclusion size is found, which determinds the lowest laser damage threshold.