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Optical Data Storage by Use of Optical Encryption and its Compression and Transmission

利用光加密的光数据存储及其压缩和传输

基本信息

批准号：
14550039
负责人：
NOMURA Takanori
金额：
$ 1.92万
依托单位：
Wakayama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

项目摘要

We proposed optical data storage by use of optical encryption and its compression and transmission.(1)A secure optical storage based on a configuration of a joint transform correlator by use of a photorefractive material has been presented. A key code designed through the use of an optimized algorithm so that its Fourier transform has a uniform amplitude distribution and a uniformly random phase distribution has been introduced. Original two-dimensional data and the key code are placed side-by-side at the input plane. Both of them are stored in a photorefractive material as a joint power spectrum. The retrieval of the original data can be achieved with the same key code. We can record multiple two-dimensional data in the same crystal by angular multiplexing and or key code multiplexing.(2)An encryption method of a 3D object based on phase modulation of an object wave has been proposed. The phase of the object wave is modulated by a virtual optical random phase mask using a digital holographic technique. The keys of an encryption step are both a phase distribution and a position of the virtual optical phase mask. If either of them is not correct, we can not decrypt the 3D object. Owing to a characteristic of a hologram, we can see some parallax of a reconstructed 3D object. Experimental results have been presented to confirm the proposed method.(3)An encrypted digital holographic data reconstruction method with data compression has been proposed. We show the number of quantization levels of the digital hologram can be reduced. By computer simulations, it is confirmed that the method is especially useful for binary images. For gray-scale images, we propose a bit plane decomposition method. By this method, we have shown both high quality reconstructed image quality and a high compression ratio can be achieved.

提出了基于光学加密的光学数据存储及其压缩和传输。(1)提出了一种基于光折变材料联合变换相关器结构的安全光学存储方案。介绍了一种利用优化算法设计的密钥码，使其傅里叶变换具有均匀的幅度分布和均匀随机的相位分布。原始二维数据和密钥代码并排放置在输入平面上。它们都以联合功率谱的形式存储在光折变材料中。使用相同的密钥代码即可实现原始数据的检索。通过角度复用和/或密钥码复用，可以在同一晶体中记录多个二维数据。(2)提出了基于物波相位调制的三维物体加密方法。物波的相位由使用数字全息技术的虚拟光学随机位相掩模调制。加密步骤的密钥既是虚拟光学相位掩模的相位分布又是虚拟光学相位掩模的位置。如果其中任何一个都不正确，我们就无法解密3D对象。由于全息图的特点，我们可以看到重建的3D对象的一些视差。实验结果验证了该方法的有效性。(3)提出了一种基于数据压缩的加密数字全息数据重建方法。我们证明了数字全息图的量化级数是可以减少的。计算机仿真结果表明，该方法特别适用于二值图像。对于灰度图像，我们提出了一种位平面分解方法。实验结果表明，该方法既能获得高质量的重建图像，又能获得较高的压缩比。