Study on near-infrared spectroscopic and laser properties of Pr-dped fluoride crystals

掺Pr3+:YLF晶体具有声子能量低，优异的热光特性，丰富的可见光荧光谱线等特点，成为可见光波段下转换激光器的首选工作物质之一，并得到了广泛的研究。以InGaN半导体激光器或光泵半导体激光器为泵浦源，Pr3+:YLF晶体可以产生红光、橙光、绿光以及深红光等波段的可见光激光。本论文的研究表明，Pr3+:YLF晶体除了可以发出可见光激光以外，还可以产生864nm至936nm的近红外激光，峰值波长为915nm。此外，Pr3+:YLF晶体还可以产生670nm的红光激光，此为Pr3+:YLF晶体该波长的首次激射。在晶体光谱理论研究方面，1962年Judd与Ofelt两人发表了利用掺稀土离子的晶体的吸收光...Owing to the low phonon energy, excellent optical-thermal properties and capability of emitting multiband spectra in the visible light region, Pr3+-doped LiYF4 (Pr3+:YLF) crystal has become one of the most favorable laser materials which can emit visible light through down-conversion directly, and, thus, investigated extensively. Pumped by the InGaN-LD or the optical pumped semiconductor laser (OP...学位：工学博士院系专业：信息科学与技术学院_物理电子学学号：2312012015392

A Shadow Detection Algorithm Research Based on HSV Space Features and Texture Features

为了提高检测和跟踪算法的准确性,提出了一种基于阴影在HSV空间下的特点和纹理特征的阴影检测与去除算法。该算法针对阴影区域覆盖的地面和未被阴影区域覆盖的地面纹理特征基本不变的特点,先检查序列图像中的运动区域,然后在运动区域内,根据阴影在HSV空间下的特点和纹理特征对阴影进行检测与去除,为运动目标的后续处理排除阴影干扰。实验结果表明,该算法能够很好地抑制噪声,有效检测、去除图片中运动目标的阴影。In order to improve the accuracy,this paper proposes a shadow detection and removal algorithm based on the features of HSV space and texture.Either the area is covered by the shadow or not,it always has the same texture feature.Based on this point,the algorithm firstly detect the moving area in series images,and then in moving area,based on the different characteristics of shadow when in HSV space and its texture feature,it is detected from the moving target and it is removed disturbance for the following processing.Experimental results show that the proposed algorithm can detect the noise and shadow and remove them effectively