共查询到18条相似文献,搜索用时 125 毫秒
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利用反射全息实现计算全息三维显示 总被引:4,自引:4,他引:0
计算全息和光学全息都可应用于三维显示,但各有自己的优势和缺陷.将计算全息和光学反射全息相结合,可以突破光学全息对记录物体的限制,进行虚拟物体或自然场景的全息图的制作,同时可以实现白光再现.本文首先用三维扫描仪获得实际物体的三维数据,用"点云算法"模拟得到其菲涅耳全息图透射率数据,采用计算全息打印机将其输出于全息记录介质,得到可光学再现的菲涅耳计算全息图H1.然后将H1作为光学全息的记录物体进行反射全息记录,将平面全息转化为体全息,实现了计算全息白光再现. 相似文献
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提出了一种真实场景三维视频采集及彩色显示的方法.设计了一种采用条纹投影的实时三维成像系统及采用液晶空间光调制器的实时全息彩色三维显示系统.在三维成像系统中采用π相移正弦条纹与编码图案结合实现绝对相位测量,从而可以测量孤立物体.同时对采用数字微镜的投影仪进行改造,实现高速投影,并与高速摄像机配合实现三维视频采集.首先利用实时三维成像系统同时获取三维场景的彩色强度像和距离像;然后根据这些三维成像数据, 设计和制作计算菲涅耳全息图;最后在实时全息彩色三维显示系统中再现.三维信息的采集和显示速度达到了60帧每秒. 相似文献
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应用Matlab语言,结合博奇型计算全息的编码方法,利用计算机分别绘制了菲涅耳全息图和傅里叶变换全息图,实现了计算全息图的快速制作,讨论了制作计算全息图的原理、方法和步骤。利用CGH技术和数字全息技术所生成的全息图再现出原始图像,完成了全息图的数字重现,实现了整个全息记录和再现过程的计算机模拟。与传统的编程语言和绘图方法相比较,该算法在实现上更加简单和快捷,并且带有一系列提高计算全息图质量的措施,有效地消除了零级像和孪生像的影响,获得了清晰的数字再现图像。 相似文献
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《中国光学与应用光学文摘》2005,(2)
O438.1 2005021186 利用菲涅尔波带法计算三维全息=Study of CGH for 3D image using Fresnel zone[刊,中]/张晓洁(浙江大学现代 光学仪器国家重点实验室.浙江,杭州(310027)),刘旭… //光电工程.-2004,31(12).-58-60,67 根据全息理论,从点光源菲涅尔全息图的计算出发, 提出一种利用主菲涅尔波带计算三维物体菲涅尔全息图 的方法。通过读取3DS文件直接获得三维物体表面各点 相似文献
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提出了一种基于计算全息和θ调制的彩色图像光学加密新方法.该方法利用彩色三基色原理和计算全息编码技术,首先将彩色图像的红、绿、蓝三基色分量进行随机相位调制和菲涅耳衍射变换,然后经过θ调制后进行图像叠加并编码为计算全息图,即加密过程是将一幅彩色图像加密为一幅实值的二元计算全息图,得到单幅密文.解密为加密的逆过程,首先将加密的计算全息图置于空间滤波和菲涅耳衍射系统中,经过相位密钥解调和基于滤光片的滤波器滤波,最后通过正确距离的菲涅耳衍射完成解密,得到彩色明文图像.计算机模拟结果证明了该方法的有效性和可行性. 相似文献
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根据全息理论和线性系统理论,采用离轴无透镜傅里叶变换全息记录光路,对利用菲涅耳近似法、基于瑞利—索末菲衍射积分的卷积法以及角谱理论方法数值重建全息图进行了比较研究,并做了计算机模拟验证.结果表明:菲涅耳近似法和角谱方法重建像质比较好,且菲涅耳方法重建速度快;在记录距离极小的情况下,尽管记录距离不满足通常的菲涅耳近似条件,菲涅耳近似公式仍然成立;自由空间脉冲响应的快速傅里叶变换的性质与距离有关,由卷积方法得到的再现像只在某一特定距离下比较理想;对于极小物场、大孔径显微数字全息来说,菲涅耳近似重建方法是较为有效的方法. 相似文献
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Phase-only stereoscopic hologram calculation based on Gerchberg–Saxton iterative algorithm 下载免费PDF全文
A phase-only computer-generated holography(CGH) calculation method for stereoscopic holography is proposed in this paper.The two-dimensional(2D) perspective projection views of the three-dimensional(3D) object are generated by the computer graphics rendering techniques.Based on these views,a phase-only hologram is calculated by using the Gerchberg–Saxton(GS) iterative algorithm.Comparing with the non-iterative algorithm in the conventional stereoscopic holography,the proposed method improves the holographic image quality,especially for the phase-only hologram encoded from the complex distribution.Both simulation and optical experiment results demonstrate that our proposed method can give higher quality reconstruction comparing with the traditional method. 相似文献
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分层角谱算法可用于三维物体全息图的生成计算,在计算时间、占用内存和算法复杂度方面占有优势.本文基于强度图和深度图的分层角谱算法,对多波长采样进行分析,有效抑制混频现象,实现了真彩色物体的计算全息图生成.针对分层角谱算法重建时产生的散斑噪声问题,引入Gerchberg-Saxton(GS)算法,提出基于分层角谱算法的GS算法.通过计算比较引入GS算法前后再现像的均方根误差和峰值信噪比,证明该算法可有效地抑制散斑噪声,提高全息图的再现像质量,更适用于复杂形貌三维物体的计算. 相似文献
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We present an optical method for information watermarking of three-dimensional (3D) objects by digital holography. A hidden image is embedded by double phase encoding in a phase-shift digital hologram of the 3D object. We decode the watermarked hologram to reconstruct the hidden image and the 3D object. We use either the entire hologram or a part of it to decode the hidden image. Experiments are presented to illustrate the ability to recover both the 3D object and the decoded hidden image. Digital holograms of the 3D object are obtained by optical experiments. The watermarking process, 3D object reconstruction, and hidden image recovery are performed digitally. To the best of our knowledge, this is the first report of 3D object watermarking by use of a phase encoding technique and digital holography. 相似文献
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使用计算全息进行三维信息加密的方法研究 总被引:1,自引:0,他引:1
全息加密技术作为一种特殊的加密方法被广泛应用于信息加密和防伪等领域。在全息加密过程中,光波的波长、记录距离和入射角度等参数用做加密密钥和解密密钥被人们深入研究,但所加密的信息几乎都是二维信息。利用一种基于虚拟光学的对三维信息进行加密的方法,将三维物体的大小作为一个新的密钥被引入安全全息加密算法,其安全性能得到了极大提高;在此基础上提出了对再现三维图像进行客观评价的方法,即修正峰值信噪比法(PSNR,PeakSignal-to-Noise Ratio)。模拟实验证明,计算全息方法(CGH,Computer-Generated Hologram)作为一种对三维信息进行加密的方法是可行的,修正PSNR法对再现三维图像的质量进行定量分析是有效的。 相似文献
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《中国光学快报(英文版)》2017,(6)
We propose a simple gradation representation method using a binary-weighted computer-generated hologram(CGH) to be displayed on a high-speed spatial light modulator that can be controlled by the pulse-width modulation technique. The proposed method uses multiple bit planes comprising binary-weighted CGHs with various pulse widths. The object points of a three-dimensional(3D) object are assigned to multiple bit planes according to their gray levels. The bit planes are sequentially displayed in a time-division-multiplexed manner.Consequently, the proposed method realizes a gradation representation of a reconstructed 3D object. 相似文献
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Component object model technology is used to solve problems encountered when using three-dimentional (3D) objects to conduct computer-generated hologram (CGH) fast coding. MATLAB and C/C++ are combined for relevant programming under experimental conditions. The proposed method effectively reduces the time required for holographic encoding of large amounts of 3D object data. The CGH- accelerated computing method based on mixed programming is proven to be highly reliable and practical by testing the 3D data of different data volumes. According to the test results, the proposed method improves the efficiency of holographic encoding. The higher the data volume is, the more significantly the computation speed is improved. 相似文献
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《中国光学快报(英文版)》2017,(11)
The use of a computer-generated hologram(CGH) in interferometric testing provides new methods for highly accurate optical measurement.To fabricate a CGH,polygons are used to approximate the smooth CGH pattern.Because the data size supported by CGH writing machines is limited,the number of polygon vertices must be limited.Therefore,the CGH-encoding method determines the encoding accuracy.To realize a highly accurate optical measurement using CGHs,we propose a CGH-pattern-encoding method based on non-maxima suppression.A self-aligned CGH is designed to verify the accuracy.The experimental result shows that a highly accurate CGH can be fabricated using this method. 相似文献
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Takashi Tsuchitani Sumio Nakahara Hisaharu Tottori Kazuhito Kanazawa Takeyoshi Fujita 《Optical Review》2008,15(1):44-50
We propose and demonstrate a method which constructs large size multicolor images using a holographic technique in limited
spaces, i.e., tunnels. A traffic sign image of the same size and color as an actual traffic sign board is displayed using
many comparative small holograms. Each hologram is composed of a single computer generated hologram (CGH). Though it was necessary
to make many CGHs, we have shortened the hologram production time by putting a reconstructed image on long distance, and using
many reconstruction sources. Moreover, though cross-talk images are caused in a color reconstruction, by adjusting the optical
system it is possible to make sure that drivers see only the appropriate image. Many holograms function as one big hologram,
and it has been confirmed that a large reconstructed image can be displayed in a limited space. 相似文献