Recording Fractional Fourier Transform Hologram Using Holographic Zone Plate

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光互连中二元计算全息算法的研究

二元计算全息(BCGH)是光学信息处理中一个重要元件,其在动态光互连中被广泛使用.为了更好地在光互连中应用BCGH,本文设计改进了二元计算全息的选代算法,比较了几种内能函数下的迭代算法所设计的BCGH,对其象质的不同指标进行了分析.结果表明,用迭代搜索算法是光互连应用中设计BCGH的一种较理想算法.     

Digital watermarking technique for holography interference patterns in a transform domain

A digital holography interference pattern generated by a computer calculation (computer generated hologram, CGH) is one of the most expensive contents and its usage is being expanded. Thus, it is highly necessary to protect the ownership of a digital hologram. This paper introduces a watermarking scheme, a method to protect the ownership of digital holograms using the DCT domain data as the ones to be watermarked. This scheme shows very high imperceptibility and strong robustness against the anticipated attacks. We expect that the conclusions of this paper will be a very useful basis for further work in the area of electronic watermarking schemes for the digital holograms.     

计算机制全息图的二值化噪声及取样影响

对用于超大规模集成电路光学互连的计算机制全息图(CGH)的量化噪声及取样影响进行了分析.CGH透过率函数的二值化将带来一些噪声,但仍可得到高的信噪比.在光学互连CGH的结构是菲涅耳波带片的条件下,对Nyquist和Whittaker-Shannon两种取样方法进行了分析和比较.结果表明,在小偏转角和高取样频率条件下,用Whittaker-Shannon取样方法得到的衍射效率比用Nyquist取样方法所得到的衍射效率大.     

真彩色全息图的制造新方法

提出采用特殊制作的色编码板，结合空间分离取样技术及彩色荧光屏发光混合原理和方法，仅用单束光，制造一般二维物体的真彩色全息图，文中还叙述对掩膜的制作方法，及高质量色编码板的参数选取和制备方法。最后给出了实验结果。     

相干性对X光全息图分辨率的影响

分析计算了Ｘ光束的相干性对Ｘ光全息图分辨率的影响，结论是Ｘ光无透镜傅里叶变换全息术所要求的相干长度和分辨率与样品尺雨戌二次线型关系；Ｘ光同轴全息术所要求的相干长度和分辨率的平方以及样品到全息图的距离成正比。     

一种菲涅尔全息图的快速算法

通过分析菲涅尔全息图计算模型,发现大量的平方运算和三角函数运算是计算速度的瓶颈,提出了一种菲涅尔全息图的快速计算方法.根据菲涅尔全息图的数学模型,利用三角函数的和差化积公式,将全息图的数学模型变换为由仅与水平或垂直方向有关的独立分量,通过四则运算来表示.在菲涅尔全息图的计算中,用少量的三角函数、平方运算和大量的四则运算代替原来大量的三角函数和平方运算,减少了全息图的运算量.实验表明,采用该算法后全息图的计算速度提高了9倍以上.     

全息图的计算机模拟及重现

根据光学全息原理,分析了在计算机模拟中把物光、参考光和再现光离散化的方法,并对基元全息和无透镜傅里叶全息进行模拟,实验结果逼真,这有助于学生更好地理解全息摄影的相关理论,为光学全息的理论和实验教学提供了可视化的验证。     

Feature tracking for projection registration in laboratory-scale reflective tomography laser radar imaging

In range-resolved reflective tomography laser radar imaging system, for accurate image reconstruction, all projections must be aligned to the center of target rotation. Due to the unknown location of the axis of rotation and random target translation, the center of target rotation in each projection cannot be measured accurately and images reconstructed based on range-resolved projections without registration would be dislocated. Here, we apply a feature tracking method to align projections data for tomographic reconstruction in laboratory-scale laser radar imaging. The target was placed on a spin table with an unknown and fixed axis, and the oscillatory motion of the target translation was simulated by a second order inertia filter to accord with the real satellites vibrations. The experimental simulation results demonstrate the effectiveness of this method to improve images reconstruction equality. The application of this method to actual radar imaging in remote distance was discussed and the differences were compared with the lab setups.