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超短脉冲激光选通电子学全息成象系统研究 总被引:1,自引:0,他引:1
本文介绍了最早到达光概念,分析了超短脉冲激光电子学全息实现选通最早到达光成象的原理.用超短脉冲激光拍摄全息图,相当于用多色光记录全息图,当用单色光再现这种全息图时,会给再现象造成一个模糊量.在一般全息理论中,只讨论了采用单色光记录全息图,复色光再现所造成的模糊量.因此,本文中讨论的是一个与此相反的问题,即用多色光记录全息图,单色光再现的情况,并且着重讨论了超短脉冲激光记录全息图的情况.最后得出结论,在用超短脉冲激光拍摄全息图时,最好采用象面全息术. 相似文献
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模压全息图的再现过程 总被引:1,自引:0,他引:1
本文就模压全息图的再现过程进行了论述。由于模压全息图的特殊性,本文论述了模压全息图再现时的一些现象,这对于设计2D/3D模压全息图有一定的参考意义。 相似文献
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体积全息图机制的再认识 总被引:6,自引:0,他引:6
提出了一种有关体积全息图机制的新看法,与以往的布拉格衍射模型不同,认为体积全息图由法布里-珀罗干涉仪构成,多光束干涉的优点是形成体积全息图特征的基础,基于这种新看法的计算机模拟给出了非常好的反射全息图的衍射光谱。 相似文献
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明胶全息图环境稳定性的研究 总被引:4,自引:2,他引:2
参照Naik对明胶全息图环境性的考察工作,对双敏感中心红敏明胶材料中所记录的全息图的环境稳定性进行了实验考察,结果表明,用DC-MBDCG记录的全息图比各酸明胶全息图有高的多的环境稳定性。本文还对实验结果的机理进行了讨论,并给出了一种明胶全息图抗水涂层制备新工艺。 相似文献
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重铬酸盐明胶全息图的吸水退化模型 总被引:1,自引:0,他引:1
在有前明胶材料吸水机理的基础上,结合明胶全息图退化的有关实验结果,提出重铬酸盐明胶全息图的吸水退化模型,并对明胶全息图稳定性的实验结果从机理上进行解释。结果表明,这一模型对现有析实验有给出满足的解释,因此是进一步提高明胶全息图稳定性和具有一定的理论指导意义。 相似文献
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一种制作多色彩全息图的新方法 总被引:2,自引:0,他引:2
本文首先提出了一种制作二维透射物彩虹全息图的新方法,即利用一专门设计的全息光学元件──色编码板,采用单光束制作所需物体的彩虹全息图;在此基础上,通过对色编码板的进一步理论设计,制作了一组对应不同主波长的色编码板,实现了记录物体的多色彩虹再现全息图。实验结果表明,此方案简便易行,光路布置灵活性高,且能有效地消除纵向色差的影响,特别适合于模压全息图制造中母全息图的拍摄,并降低了对环境稳定性的要求。 相似文献
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Xiao-ou Cai 《Optik》2014
As one of the most important 3-D display technique, reduction of speckle noise in the reconstructed image of digital holography should be grounded on the digital hologram itself. Based on the whole process of the recording and reconstruction of digital holography, the optical distributions of recorded object and reconstructed image of digital holography have been studied. It has been proposed that the root formation cause of speckle noise in its reconstructed image is the speckle noise formed on the recorded object surface when illuminated by coherent light because of its optical roughness. A novel approach has been presented to reduce speckle noise in digital holography by changing the interference structure of hologram itself. First, by reducing the speckle noise in the reconstructed image, the distribution of ideal reconstruction light with reduced speckle noise is acquired. Then in turn, taking the ideal reconstruction light with reduced speckle noise as ideal object light, a new hologram can be rebuilt, which can reconstruct the ideal object light. The experimental results are given to confirm the proposed method. Therefore, it offers a brand-new thought and practical way to reduce the speckle noise in the reconstructed image of digital holography. 相似文献
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Masahiro Yamaguchi Toshio Honda Nagaaki Ohyama Jun Ishikawa 《Optics Communications》1994,110(5-6):523-528
A new method for rainbow and multicolor holographic stereograms is described using the technique of multidot recording, which was originally developed for the syntheses of full-parallax holographic stereograms. Instead of recording vertical parallax, an image of horizontal slit is synthesized for rainbow holography. It becomes possible to obtain large images by a compact optical system, since the hologram is composed of many small elementary holograms. Multicolor image is also produced by the same system introducing a simple image processing. Experimental results of three-dimensional and color imagery are demonstrated. 相似文献
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Ding Wang 《Optics Communications》2006,267(1):79-82
A true color stereoscopic hologram is made with one-wavelength laser. Under illuminating incandescent lamp, a true color stereoscopic image can be seen from the hologram. A diffused reference light and a project object light are used in the recording of the hologram. The three primary color images of natural scenery are encoded on a white-and-black film. With the help of the encoded film, a true color hologram is recorded on a plate by single exposure and a true color stereoscopic by two exposures. The simplification of this method is apparent. Further more, it largely decreases the scattering noise of the hologram and averts the problem of color lack fidelity of the holographic image. 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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A new type of hologram that elaborates upon the simplest (Gabor) on-axis hologram is suggested. The new approach makes it
possible to eliminate the projected image distortions typical of the Gabor hologram. Specifically, based on a reference-free
thick hologram, an on-axis holographic screen that does not transmit the zeroth order is prepared. In addition, this screen
does not produce a halo and the conjugate image. It allows for recording in one spectral range and reconstruction in another,
thereby greatly simplifying the choice of a light-sensitive record medium. With this screen, a color image can be projected. 相似文献
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We propose a new method for color image encryption by wavelength multiplexing on the basis of two-dimensional (2-D) generalization of 1-D fractional Hartley transform that has been redefined recently in search of its inverse transform. A color image can be considered as three monochromatic images and then divided into three components and each component is encrypted independently with different wavelength corresponding to red, green or blue light. The system parameters of fractional Hartley transform and random phase masks are keys in the color image encryption and decryption. Only when all of these keys are correct, can the image be well decrypted. The optical realization is then proposed and computer simulations are also performed to confirm the possibility of the proposed 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
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描述一种用非干光制作二维彩虹模压全息图母版的新技术。该技术用紫外灯作为记录光不原,记录系统中不用任何光学元件。记录过程不需防振条件,色彩编码 狭缝像的“彩虹版”上进行条纹复制而获得。彩虹版可以无数次重复使用,所以全息图母版的记录十分简单。该技术投资少、效率高,制出的全息图质量好,对大批量模压全息图制造有很高的实用价值。 相似文献
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Digital holography for quantitative phase-contrast imaging 总被引:19,自引:0,他引:19
We present a new application of digital holography for phase-contrast imaging and optical metrology. This holographic imaging technique uses a CCD camera for recording of a digital Fresnel off-axis hologram and a numerical method for hologram reconstruction. The method simultaneously provides an amplitude-contrast image and a quantitative phase-contrast image. An application to surface profilometry is presented and shows excellent agreement with contact-stylus probe measurements. 相似文献