光学扫描全息术及其计算机仿真

提出了一种新的全息术——光学扫描全息术，它是建立在光学扫描之上的光电混合处理技术。阐明了扫描全息术的基本原理，给出了计算机仿真的结果。     

Elimination of the Background Noise of the Decoded Image in Fresnel Zone Plate Scanning Holography

A method of digitally high pass filtering in frequency domain is proposed to eliminate the background noise of the decoded image in Fresnel zone plate scanning holography. The high pass filter is designed as a circular stop, which should be suitable to suppressing the background noise significantly and remain much low frequency information of the object. The principle of high pass filtering is that the Fourier transform of the decoded image is multiplied with the high pass filter. Thus the frequency spectrum of the decoded image without the background noise is achieved. By inverse Fourier transform of the spectrum of the decoded image after multiplying operation, the decoded image without the background noise is obtained. Both of the computer simulations and the experimental results show that the contrast and the signal-to-noise ratio of the decoded image are significantly improved with digital filtering.     

多投影几何校正误差评估分析

近年来,投影拼接显示技术在展览展示、产品发布、虚拟仿真等领域得到了广泛的应用,但是目前还缺少完整的投影拼接几何校正误差评估方法.在深入分析多投影几何校正特点的基础上提出了一套较为完整的误差评估方法,分为自相关投影拼接误差(投影机自身几何校正之后所产生的误差)以及互相关投影拼接误差(多台投影机之间叠加区域的配准误差);首先提出了自相关投影拼接误差的关键参数——重投影误差(描述了每台投影机投影图像中每个像素点与预期投影位置的接近程度),并使用平均重投影误差、最大重投影误差以及关键点配准误差完善自相关投影拼接误差的评估体系;然后提出了互相关投影拼接误差的关键参数——叠加区域误差(表示投影机之间叠加区域对应像素点之间的匹配程度),并使用平均叠加区域误差、最大叠加区域误差完善互相关投影拼接误差的评估体系;最后使用该方法对平面投影、曲面投影、自由表面投影拼接的几何校正误差进行了分析.理论分析和实验结果表明,提出的误差评估方法能够有效地评估投影几何校正的精度.