Real-time color holographic video reconstruction using multiple-graphics processing unit cluster acceleration and three spatial light modulators

We demonstrate real-time three-dimensional(3D)color video using a color electroholographic system with a cluster of multiple-graphics processing units(multi-GPU)and three spatial light modulators(SLMs)corresponding respectively to red,green,and blue(RGB)-colored reconstructing lights.The multi-GPU cluster has a computer-generated hologram(CGH)display node containing a GPU,for displaying calculated CGHs on SLMs,and four CGH calculation nodes using 12 GPUs.The GPUs in the CGH calculation node generate CGHs corresponding to RGB reconstructing lights in a 3D color video using pipeline processing.Real-time color electroholography was realized for a 3D color object comprising approximately 21,000 points per color.     

一种显示器颜色特性的反向查找新方法

根据实验的数据建立了CRT的设备颜色空间(RGB空间)与标准颜色空间(CIELAB空间)之间的颜色特性转换模型。通过分析大量的实验测量数据,以改进的三维查找表形式建立了RGB和L*a*b*之间的正逆转换关系。其中正向查找表的建立是按照三维线性的插值方法,逆向查找表的建立则利用一种插值和迭代相结合的新方法,使L*a*b*查找到较为准确的RGB值。通过用标准图像的的随机误差检验,其转换的平均色差ΔE为0.9286色差单位。     

Fiber-optic color synthesizer

Full-color synthesis was achieved, for what we believe is the first time, utilizing a novel 3x1 hard polymer-clad fiber coupler along with red, green, and blue (RGB) LED primaries. By using RGB LEDs that are coupled to three input ports, the device rendered full color from the output port with a circular emitting pixel of 135 microm in diameter with an extended color gamut. The proposed fiber-optic color synthesizer can provide a compact waveguide solution for the beam scanning display and the tunable pure white source for LED backlighting.     

Multi-scale underwater image enhancement with optimized homomorphic filter and RGB color correction

Optical Review - We propose a multi-scale underwater image enhancement method with an optimized homomorphic filter and a RGB color correction algorithm. The proposed method includes three steps....     

真实场景的三维视频采集及显示

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.     

彩色滤光膜硅覆液晶微显示器的三维光学建模

本文针对彩色滤光膜(color filter, CF)硅覆液晶(liquid crystal on silicon, LCoS)微显示器件(microdisplay)中的微型彩色像素建立了三维光学模型. 这个三维光学建模主要分为三个过程, 即彩色液晶器件的机电特性分析, 利用扩展琼斯矩阵(extended Jones matrix)计算器件的光反射率, 以及采用标准RGB(standard RGB, sRGB)协议将CF-LCoS微显示阵列中各像素点的光反射特性还原成彩色图像. 通过上述过程建立的三维光学模型用于CF-LCoS的光学特性研究并与实验数据进行比较. 比较结果显示, 模拟得到的CF-LCoS微显示器的光学特性与实验结果非常符合.     

An experimental evaluation method for the performance of a laser line scanning system with multiple sensors

Laser line scanning 3D digitising systems have a wide range of applications. Their working performance is mainly determined by the system calibration procedure and is also affected by the working conditions, CCD camera imperfections, and object surface optical characteristics. Therefore, a comprehensive evaluation of working performance is necessary before and during use. This study proposes an experimental method for the performance evaluation of a laser line scanner (LLS) with 8 scanning sensors developed in our laboratory. This method first obtains the dense point clouds of standard parts composed of disks, cylinders, and squares. Next, the single-layer point clouds located in horizontal planes of different heights are fitted using the least squares method to obtain the enclosed contours S. Three parameters, namely, the standard deviation of the distance distribution between points and S, the mean distance of the distance distribution, and the shape feature sizes, are used to evaluate the performance. The proposed method evaluates both the scanner as a whole and each scanning sensor. Using this method, more comprehensive information can be acquired to evaluate the scanner performance. The experimental results show that the absolute dimension size error and relative error are less than 5 mm and 3%, respectively, and the relative shape error is less than 2%; therefore, the evaluated LLS system can meet the requirements for human anthropometry applications. Although each scanning sensor has different random and systematic error, these errors are the function of measurement depth. These conclusions are helpful for the further use of this scanner system and can be utilised to optimise this LLS system further.     

Holographic imaging of full-color real-existing three-dimensional objects with computer-generated sequential kinoforms

We propose a computational method for generating sequential kinoforms of real-existing full-color threedimensional (3D) objects and realizing high-quality 3D imaging.The depth map and color information are obtained using non-contact full-color 3D measurement system based on binocular vision.The obtained full-color 3D data are decomposed into multiple slices with RGB channels.Sequential kinoforms of each channel are calculated and reconstructed using a Fresnel-diffraction-based algorithm called the dynamicpseudorandom-phase tomographic computer holography (DPP-TCH).Color dispersion introduced by different wavelengths is well compensated by zero-padding operation in the red and green channels of object slices.Numerical reconstruction results show that the speckle noise and color-dispersion are well suppressed and that high-quality full-color holographic 3D imaging is feasible.The method is useful for improving the 3D image quality in holographic displays with pixelated phase-type spatial light modulators (SLMs).     

Color component 3D Arnold transform for polychromatic pattern recognition

We propose a novel method for polychromatic pattern recognition based on color component 3D Arnold transform. Three color components (for example RGB) are first transformed into three chaotic images by the use of 3D Arnold transform. And then any one of the chaotic images is chosen as the input image of the JTC to be recognized. As a result, strong color discrimination capability is achieved and common color images as well as some special color images can be recognized, while still preserving compact system and easier analysis of the output. Numerical results demonstrate the feasibility and effectiveness of the proposed method.     

海面弱小目标高光谱融合技术研究

海面目标受海水扰动影响,难以被宽波段光电传感器探测识别。高光谱传感器可以获取海面目标和水体的光谱数据,利用目标和海水的光谱特性差异可以有效抑制海面扰动影响,提高探测识别能力。针对高光谱数据降维融合容易丢失海面弱小目标问题,研究了弱小目标光谱数据融合方法。通过相似性分类产生类矩阵,由类矩阵主成分变换的降维投影矩阵来投影变换原有光谱数据,获得降维数据矩阵。降维矩阵通过空间变换转换到RGB彩色空间,生成伪彩色融合图像。通过远距离弱小目标和水中鱼群高光谱数据,验证了改进方法的融合性能。实验结果表明:相似性分类融合方法不仅能将高维光谱数据融合成一幅伪彩色图像,还能有效避免弱小目标融合丢失问题,提高了目标探测识别能力。     

Computer-generated kinoforms of real-existing full-color 3D objects using pure-phase look-up-table method

A computational method based on pure-phase look-up-table (LUT) is proposed for generating kinoforms of full-color real-existing three-dimensional (3D) objects. The principle of the pure-phase LUT method is described. 3D depth as well as color information of a full-color 3D object is obtained by the full-color 3D profile measurement approach based on binocular vision. The obtained full-color 3D data is decomposed into red (R), green (G), and blue (B) channels, and kinoforms of each channel are calculated from the depth map and color information of the corresponding channel using the pure-phase LUT method. In order to reduce the speckle noise of reconstructed full-color 3D image, sequential kinoforms of each color channel are generated by adding dynamic-pseudorandom phase factor into the object domain. Numerical reconstruction and optical reconstruction with a phase-only spatial light modulator (SLM) show that, with the proposed method, full-color holographic 3D display of real-existing full-color 3D objects is available.     

基于双光栅成像的RGB模型色彩还原效果的研究

基于双光栅衍射成像的实验方案,利用双光栅的色散和汇合光谱效应特性,用电脑摄像头拍摄作为物体的RGB模型,得到了RGB颜色模型的像。利用Photo shop软件将RGB颜色模型和得到的像进行颜色通道分离,再进行数据化分析处理,探究双光栅的RGB色彩模型色彩还原情况以及不同光栅组合对RGB颜色模型的色彩还原效果的影响。     

Local dimming algorithm and color gamut calibration for RGB LED backlight LCD display

A 32 in RGB LED backlight unit is developed. A local dimming algorithm is designed for the backlight, and grid-noise artifacts in the LC driving signal are successfully removed with consideration of the backlight distribution to provide identical intensity from each LED block. The 32 in RGB LED backlight LCD display has achieved a static display contrast of over 20000:1 and an average power reduction of 30%. We have also obtained the color gamut transformation matrix for transferring a cold cathode fluorescent lamp BLU LCD display gamut system to our RGB LED BLU LCD display gamut system, and extended the color saturation by suppositional color expansion method. As a result, the color has been accurately reproduced in RGB LED BLU LCD display with more richness and more saturation.     

一种色度自适应投影标记点的选取方法

近年来,对物体的颜色显现力、光源光谱功率分布和自身表面反射光谱三者的定量关系方面的研究备受大家关注。在三维扫描测量领域,由于颜色特征具有反映物体材料和纹理等丰富信息的优势,提出了一种主要由彩色相机、投点光源和PC机组成的色度自适应投点仪结构,其中数字微镜(DMD)作为投点光源的核心元件用于调制R,G,B 三个LED光源的光谱功率分布。然而主动式标记点的颜色显现力因受未知反射光谱投影接受面的影响,其颜色特征往往难以识别和区分。为了提高投影标记点与不同反射光谱的投影接收面作为背景的分辨力,描述了一种色度自适应投影标记点的选取方法。在高维线性反射光谱建模的基础上,用光谱响应的方法对彩色投点仪设备特征化,以解决三通道彩色相机设备特征化精度低的问题。并通过样本训练为高维线性反射光谱的求解提供条件约束。继而,在CIE1931色度坐标空间下,选取与投影接收面背景色度坐标欧氏矩最大的色度坐标点。根据投点仪设备特征化结果,推导其LED最优设定值。最后,采用24孟塞尔色卡作为被投影对象,主动标记点与色块的色差作为其颜色显现力的评价参数,通过与激光二极管投点仪做对比性实验。实验结果表明对各不同色度的投点接受面,提出的色度自适应投影标记点的选取方法均有较好表现。     

浅海遥感图片海底研究

利用海洋水色进行浅海水深反演,国内外已经提出了很多方法,并建立了各种模型。在他们的反演系统中,无一例外的要运用不同的水下测试仪器进行某些信息的提取,利用提取的信息确定参数,从而完成水深反演。在脱离任何水下测试仪器的情况下,仅通过卫星图片或航空图片提取浅海水深信息,利用海洋水色变化的基本原理,讨论了辐照度与波长以及水深的关系,模拟了浅海水下地形,并通过三维立体形式演示海底地貌。以遥感图片和数码照片为例,分别模拟了所拍摄地区的浅海海底概貌。结果表明,此方法具有一定的可行性,可以进行更深层次的研究,并可应用于航海安全保证、大陆架遥感测绘和环境检测等多个领域。     

人工神经网络作为打印机色空间转换工具的问题

通过分析大量实测的打印机输入(R,G,B)与输出(L ,a ,b )数据之间的对应关系,发现在一些颜色区域存在着RGB与L a b 之间的二对一甚至多对一的关系。另一方面,一个已知的事实是,当一个神经网络已经建立后,任一个(或一组)输入只能产生一个(或一组)输出。结合以上两个事实得出的结论是,在要求打印机的输出颜色能准确地复现指定颜色的情况下,神经网络不适合作为由指定颜色的L a b 值来寻求打印机的相应输入RGB的工具。     

A Non-symmetric Digital Image Secure Communication Scheme Based on Generalized Chaos Synchronization System

Based on a generalized chaos synchronization system and a discrete Sinai map, a non-symmetric true color （RGB） digital image secure communication scheme is proposed. The scheme first changes an ordinary RGB digital image with 8 bits into unrecognizable disorder codes and then transforms the disorder codes into an RGB digital image with 16 bits for transmitting. A receiver uses a non-symmetric key to verify the authentication of the received data origin, and decrypts the ciphertext. The scheme can encrypt and decz：Fpt most formatted digital RGB images recognized by computers, and recover the plaintext almost without any errors. The scheme is suitable to be applied in network image communications. The analysis of the key space, sensitivity of key parameters, and correlation of encrypted images imply that this scheme has sound security.     

A Non-symmetric Digital Image Secure Communication Scheme Based on Generalized Chaos Synchronization System

Based on a generalized chaos synchronization system and a discrete Sinai map, a non-symmetric true color(RGB) digital image secur e communication scheme is proposed. The scheme first changes an ordinary RGB digital image with 8 bits into unrecognizable disorder codes and then transforms the disorder codes into an RGB digital image with 16 bits for transmitting. A receiver uses a non-symmetric key to verify the authentication of the received data origin,and decrypts the ciphertext. The scheme can encrypt and decrypt most formatted digital RGB images recognized by computers, and recover the plaintext almost without any errors. The scheme is suitable to be applied in network image communications. The analysis of the key space, sensitivity of key parameters, and correlation of encrypted images imply that this scheme has sound security.     

一种可交互的体绘制光学传递函数模型

针对三维数据场可视化过程中兴趣区的交瓦分离问题.给出了基于体绘制光学传递函数的半自动调节方法.该方法从传递函数的光学模型出发,根据三维数据的光强分布,结合体数据的三维梯度场.给出了体数据的颜色及透明度值分离交互凋常的模犁.为了提高本方法的实用性,本文采用了交互模型与现代显卡纹理特性相结合的方法来提高交互速度.实验证明,通过实时调节改进传递函数的相关参量.该模型能以大于每秒30帧的交互速度获得必趣区的最佳视觉分离效果.本方法能在交互体视化的同时实现最佳参量的获取.     

A robust security framework for 3D images

Abstract  

Three-dimensional (3D) visualization of spatial and non-spatial data is a well-established practice having numerous applications. The cheapest and the most efficient way to 3D visualization is 3D images/Anaglyphs. 3D images contain 3D information of the objects present in the image. These images are easily obtained by superimposing left and right eye images in different color in a single image. In this paper, a novel security framework, viz., watermarking scheme, is presented to ensure their security. The proposed security framework is employed in fractional Fourier transform domain of secret color channel followed by the embedding using singular value decomposition. The secret channels (SEC) are obtained by applying reversible integer transform on the RGB channels. The experimental results prove the robustness and imperceptibility of the proposed watermarking scheme.