Application of bacteriorhodopsin films in an adaptive-focusing schlieren system

The photochromic property of bacteriorhodopsin films is exploited in the application of a focusing schlieren optical system for the visualization of optical phase information. By encoding an image on the film with light of one wavelength and reading out with a different wavelength, the readout beam can effectively see the photographic negative of the original image. The potential advantage of this system over previous focusing schlieren systems is that the updatable nature of the bacteriorhodopsin film allows system adaptation. I discuss two image encoding and readout techniques for the bacteriorhodopsin and use film transmission characteristics to choose the more appropriate method. I demonstrate the system principle with experimental results using argon-ion and He-Cd lasers as the two light sources of different wavelengths, and I discuss current limitations to implementation with a white-light source.     

基于CIECAM02色貌模型的数码相机色彩管理

为改进数码相机应用ICC色彩管理只考虑光源对呈色影响的缺陷,将色貌模型引入了数码相机色彩管理。在ICC色彩管理的基础上,用VC++开发了"从色度值到色貌值"的转换模型,以拍摄色貌值与显示色貌值颜色属性(色貌)一致为目标,利用软件生成并编辑了特性文件,应用色貌色差公式作为评价特性文件的标准,确定了3种典型光源(D65,D50,A)环境下,数码相机的特性文件,达到了人眼视觉上色彩的准确复制。     

Broadband light profile microscopy: a rapid and direct method for thin film depth imaging

Light profile microscopy (LPM) is a recently developed technique of optical inspection that is used to record micrometer scale images of thin film cross-sections on a direct basis. This technique uses a novel right-angle imaging geometry that shows outstanding contrast for subtle interface structures and morphologies that are invisible to conventional methods of inspection. When laser sources are used for sample illumination, image contrast is provided by luminescence and elastic and/or inelastic scatter. When a white-light excitation source is used for LPM, primary contrast is obtained from elastic scatter, while secondary contrast results from refraction, secondary transmission, and secondary reflection from material phases. We term this mode of inspection broadband light profile microscopy (BB-LPM). It is implemented with a compact, easily aligned apparatus and minimal sample preparation, and it shows outstanding interface contrast similar to laser LPM. In this work we demonstrate BB-LPM as a method for direct imaging of the layers structures of a variety of thin film samples of industrial and manufacturing interest.     

利用积分球对CCD线性和面均匀性的标定

积分球对CCD(Charge-coupled Device)的标定,主要是利用积分球光源具有较好的均匀性、稳定性以及精度高的特点,通过CCD采集积分球光源的图片,将积分球光源亮度转换为CCD拍摄图像的灰度,通过对采集图片灰度信息的提取,得出了CCD标定的各项参数。CCD线性标定试验的结果表明:在CCD快门值固定时,光源亮度的变化和图像灰度呈线性关系,并且在转换后的不同灰度值区段,线性度有一定的差别:在中值区,线性度最好,低值区次之,高值区最差;在光强一定的情况下,CCD快门值的改变和采集图像的灰度也呈线性关系。均匀性标定的试验结果表明:CCD的光电响应的非均匀性是随着快门值和灰度的增加而减小的,但最终趋于一个较稳定的值。     

基于游戏引擎技术视角下的电影影像创作表述机制

对于影视创作者而言,虚拟图像不再是对目标场景的再现与模拟,更多是依据虚拟与现实环境的对应逻辑关系建立创作主体与创作对象的直接或间接表述机制.游戏引擎技术与电影影像制作观念的结合,使电影影像的创作表述不再是以影像内部空间为中心的"预演化"判定,转而围绕整体创作空间与创作空间中所有可见的造型元素之间的电影影像创作机制下的视...     

Optical Processing of Bubble Chamber Photographs

Purely optical methods of spatial pulse width coding for coherent optical densitometry are described. The proposed coding scheme correlates the image intensity with the orientation of one edge of triangular or trapezoidal pulses. One encoding technique employs a contact screen similar to those used for half-tone printing. The image to be coded is copied through this contact screen onto hard-limiting film. This method is limited to the encoding of images with density distributions varying only slowly across the area of one pulse. A holographic encoding technique overcomes these drawbacks, utilizing the storage redundancy of holograms recorded with diffuse object beams. An array of identical holograms is reconstructed with a beam spatially modulated by the image transparency to be encoded. The array of reconstructed real images is recorded on hard-limiting film and renders a pulse-modulated version of the original image. The limiting conditions for the pulse size and the size of details in the image imposed by diffraction effects and speckle pattern are derived.     

A novel automatic color transfer algorithm between images

Abstracts

A color transfer algorithm between images intends to modify the colors in the source image by borrowing the color characteristics from the target image. In this paper, we present a novel automatic color transfer algorithm between images. This algorithm is able to proceed on color transfer with no user intervention, and produce visually plausible resultant images. To the best of our knowledge, our algorithm is the first to achieve this kind of automation. Our technique consists of an image segmentation algorithm, a swatch merging algorithm, and a pattern recognition algorithm. The image segmentation algorithm generates a number of swatches with different features in the source and target images. The swatch merging algorithm merges a particular swatch with its neighbors in the source image when it fails to pass the normality test. The pattern recognition algorithm then automatically matches these swatches for color transfer. We develop a boundary transition algorithm to make possible a consistent transition between two boundaries of patches. Experimental results demonstrate that, without any user intervention, our technique performs color transfer results with good visual realism. The technique is superior to the original user‐intervention color transfer algorithm.     

数码红外线彩色图像的合成与分析应用

红外线彩色照相有普通彩色照相和黑白红外线照相所不具备的优异性，但是也存在一些无法克服的缺点。为此，根据红外线彩色照相的感光原理和色彩再现过程，利用计算机技术和Photoshop 7．0图像处理软件，对数码照相机拍摄的数码彩色图像和红外线图像进行合并，生成新的数码红外线彩色合成图像，并通过试验阐述操作步骤和方法。最后，对合成图像的色彩再现结果进行分析，说明合成图像与红外线彩色照相的色彩效果是相同的，同时，指出在文件检验中的应用。     

Self-referencing substrates for optical interferometric biosensors

Optical interference is a powerful technique for monitoring surface topography or refractive index changes in a thin film layer. Reflectance spectroscopy provides label-free biosensing capability by monitoring small variations in interference signature resulting from optical path length changes from surface-adsorbed biomolecules. Spectral reflectance data can be acquired either by broad wavelength illumination and spectroscopy at a single point, thus necessitating scanning, or by varying the wavelength of illumination and imaging the reflected intensity allowing for acquisition of a spectral image of a large field of view simultaneously. In imaging modalities, intensity fluctuations of the illuminating light source couple into the detected signal, increasing the noise in measured surface profiles. This article introduces a simple technique for eliminating the effects of illumination light power fluctuations by fabricating on-substrate self-reference regions to measure and normalize for the incident intensity, simplifying the overall platform for reflection or transmission-based imaging biosensors. Experimental results demonstrate that the sensitivity performance using self-referencing is equivalent or better than an optimized system with an external reference.     

一种灰度图象的二值表示方法─—半色调技术

半色调技术是一种将具有多灰度等级的图象转换成二值图象的方法，它利用人类视觉系统的特点重构一幅灰度图象，主要应用于图象的硬拷贝上。本文提出了一种半色调处理的算法，它结合了误差分散技术及半色调模对应方法来生成半色调图象。在文章的是后我们给出了一个算法应用的例子。     

基于OSA-UCS数据的CIECAM02图像复制色差评价

目的为了改进彩色图像复制时在不同观测环境下的误差,将优化后的色貌模型引入色彩信息转换。方法在分析CIECAM02-Jab用于彩色图像复制的色彩评价的基础上,提出利用OSA-UCS数据集建立新的优化色貌空间实验方案。利用线性回归的方法,调整原始颜色空间中的明度和彩度,构建出新的均匀颜色空间J_xa_xb_x。结果经过检验发现新的优化色貌空间J_xa_xb_x色差的离散程度减轻,空间更趋均匀,更加符合均匀性标准。结论新的优化色貌空间J_xa_xb_x修正了均匀颜色空间的均匀性,比CAM02初始色貌空间有了一定程度的提高,对彩色图像复制的色差评价取得了一定的效果。     

Improvement of color reproduction in color digital holography by using spectral estimation technique

We propose a color digital holography by using spectral estimation technique to improve the color reproduction of objects. In conventional color digital holography, there is insufficient spectral information in holograms, and the color of the reconstructed images depend on only reflectances at three discrete wavelengths used in the recording of holograms. Therefore the color-composite image of the three reconstructed images is not accurate in color reproduction. However, in our proposed method, the spectral estimation technique was applied, which has been reported in multispectral imaging. According to the spectral estimation technique, the continuous spectrum of object can be estimated and the color reproduction is improved. The effectiveness of the proposed method was confirmed by a numerical simulation and an experiment, and, in the results, the average color differences are decreased from 35.81 to 7.88 and from 43.60 to 25.28, respectively.     

大面积印刷纳米金刚石薄膜的场致发射的研究

研制了特定比例的纳米金刚石浆料,采用了丝网印刷工艺在石墨衬底上大面积印制了纳米金刚石场发射薄膜,实验探索了石墨衬底纳米金刚石薄膜的烧结工艺和后处理过程,利用扫描电镜(SEM)观察了纳米金刚石膜的表面形貌,经后处理的薄膜中纳米金刚石露出薄膜表面,纳米金刚石的棱角是天然的发射体.采用本课题组研制的多功能场发射测试台在10-6Pa的真空条件下进行了场发射特性的测试,结果发现石墨上低成本大面积印刷的纳米金刚石薄膜具有均匀稳定的场发射特性,作为电子器件的理想冷阴极发射,可在宇宙飞船、原子反应堆等恶劣条件下工作的平面显示器中得到应用.     

Resolution matching in a retinal scanning display

In a retinal scanning display an image of a light source is scanned over the retina and at the same time modulated in intensity to form an image. To attain a retinal image most resembling the corresponding original image, the resolution of the modulating graphics board must be at least twice the maximum optical resolution possible. This paper describes how this relationship, which is based on the theorem of Shannon, is derived and what differences in contrast can be observed between the horizontal and the vertical scanning direction. It appears that for a relatively large field of view the resolution of the graphics board is inadequate, so that the maximum optical resolution will have to be decreased.     

复合材料多尺度分析方法与典型元件拉伸损伤模拟

复合材料具有多尺度特性,多尺度模拟方法能够考虑细观损伤、演变对宏观材料性能和力学行为的影响,是复合材料响应分析的一种重要方法和手段。基于多尺度渐进展开理论,对复合材料弹性问题控制方程进行尺度分解,推导了细观尺度与宏观尺度的控制方程,建立了复合材料宏观和细观尺度响应之间的关联。基于协同多尺度计算策略,利用通用有限元软件的用户子程序与脚本二次开发,在宏观模型计算中实时调用细观模型进行多尺度渐进损伤模拟,实现了宏观和细观尺度的信息传递与反馈。建立的复合材料多尺度数值模拟方法可以快速集成细观损伤模型以及宏观唯象强度理论,具有良好的通用性。碳/碳复合材料拉伸模拟算例结果与试验结果吻合较好。     

X-ray reflection tomography: a new tool for surface imaging

We report here a novel technique of surface imaging by X-ray reflection tomography utilizing an ordinary laboratory X-ray source. The technique utilizes the line projection, at different rotation angles, of the reflected beam from a highly reflecting patterned sample at grazing incidence. Filtered back-projection algorithm is applied to the line projection data to reconstruct an image of the pattern on the sample surface. Spatial resolution currently obtained is ~1.6 mm. Nonetheless, we have achieved high correlation between the original image and the reconstructed image. This work is the first step in future efforts of nondestructive X-ray imaging for buried surfaces and interfaces.     

Phase-shifting digital holography with a low-coherence light source for reconstruction of a digital relief object hidden behind a light-scattering medium

Hiding image data with a light-scattering medium is effective as a basic data protection technique. The hidden image data can be observed only by using a low-coherence interference technique and is thus protected from unauthorized access. Unlike an intensity-distributed object, a digital relief object has no intensity distribution, making it possible to hide its existence by using a dilute light-scattering medium. To reconstruct the digital relief object through the light-scattering medium, we developed phase-shifting digital holography with a low-coherence light source. The experimental performance, including the spatial resolution and phase error of the reconstructed image, is estimated.     

激光偏振特性对分光镜分光比影响的实验研究

在强度调制型光纤传感器的应用中,光源的功率波动是影响传感器精度的关键。采用分光镜设置参考光路的强度补偿技术虽然理论上可以实现高精度的补偿,但是由于分光镜分光比会因激光光源的偏振特性变化而改变。在分析光源偏振方向的变化对分光镜分光比影响的基础上,用仿真和系统实验进行了验证。理论及实验结果的吻合证明了分光比受光源偏振特性影响成周期性变化的结论。     

Scanning confocal near-infra-red microscopy: a new microscopytechnique for three-dimensional histopathology

To image microstructures within tissue in detail using conventional light microscopy it is necessary to process the tissue and obtain thin (≈5 μm) physical sections by using destructive physical sectioning techniques. This article describes a microscopy technique, using near-infra-red light (700-1500 nm) as the source, which is able to image thin sections of thick-tissue specimens nondestructively. Images of contiguous two-dimensional thin sections obtained serially can be combined to generate a three-dimensional image of the structures being imaged     

C+L波段掺铒光纤光源模拟算法

提出了利用打靶法模拟双级双程泵浦结构掺铒光纤宽带光源的算法,该算法通过对打靶法的初值校正部分进行改进,加入了阻尼因子与下降因子,并把这两个因子同时应用到初值校正中,从而克服了传统打靶法在铒纤长度较长时校正矩阵奇异造成的算法不收敛的缺点.结合宽带光源的理论模型,给出了算法的实际过程,模拟得到了在光纤最佳长度处的C L波段输出谱型,并通过实验证实了模拟与实验结果相符合.最后讨论了导致宽带光源输出谱型不是最佳的因素,随着光纤长度增加导致的损耗,以及两端泵浦功率的比值,并给出了在泵浦功率比是最佳和不是最佳两种情况下的实验谱型.