Using digital anaglyphy to improve the relief effect of SEM micrographs of bloodstains

Anaglyphy is a stereoscopic technique based on the superimposition of two images of the same view, taken from slightly different angles as well as in two different colours. This superimposition produces a depth effect when viewed through glasses having one red and one green, blue or cyan lens acting as a colour filter. The nearly flat surface of a chip of grey chert was thin-smeared with peripheral human blood. Two months later, the specimen was fixed to a microscope stub as horizontal as possible, coated with gold, and examined via secondary electrons by a scanning electron microscope (SEM). After obtaining SEM micrographs, anaglyphs were digitally generated. The best results were obtained using pairs of SEM micrographs acquired at 10° differing angle and at SEM-stage tilts that were symmetric from the horizontal plane. The relief effect was more accentuated at low magnification. The most ergonomic colour combination for viewing bloodstain anaglyphs was red–cyan. Digital anaglyphy provides a simple and feasible method to improve the relief effect of SEM micrographs of bloodstains. Moreover, as a first consequence of this improvement, the results obtained in this research reveal that the outermost erythrocyte layer of a thin bloodstain – coinciding, in general, with the smear surface – can be much more uneven than that previously suggested by customary SEM micrographs.     

Generating 3D and 3D-like animations of strongly uneven surface microareas of bloodstains from small series of partially out-of-focus digital SEM micrographs

When dealing with microscopic still images of some kinds of samples, the out-of-focus problem represents a particularly serious limiting factor for the subsequent generation of fully sharp 3D animations. In order to produce fully-focused 3D animations of strongly uneven surface microareas, a vertical stack of six digital secondary-electron SEM micrographs of a human bloodstain microarea was acquired. Afterwards, single combined images were generated using a macrophotography and light microscope image post-processing software. Subsequently, 3D animations of texture and topography were obtained in different formats using a combination of software tools. Finally, a 3D-like animation of a texture–topography composite was obtained in different formats using another combination of software tools. By one hand, results indicate that the use of image post-processing software not concerned primarily with electron micrographs allows to obtain, in an easy way, fully-focused images of strongly uneven surface microareas of bloodstains from small series of partially out-of-focus digital SEM micrographs. On the other hand, results also indicate that such small series of electron micrographs can be utilized for generating 3D and 3D-like animations that can subsequently be converted into different formats, by using certain user-friendly software facilities not originally designed for use in SEM, that are easily available from Internet. Although the focus of this study was on bloodstains, the methods used in it well probably are also of relevance for studying the surface microstructures of other organic or inorganic materials whose sharp displaying is difficult of obtaining from a single SEM micrograph.     

Multichannel method for absolute shape measurement using projected fringes

The multichannel approach is combined with the reduced temporal phase unwrapping scheme for rapid shape measurement. The shape is measured using projected fringes and optical triangulation. Fringes are projected using a colour video projector and recorded by a CCD-camera. Using a colour video projector and a colour video camera makes it possible to use the red, green and blue channels individually. This is the multichannel method. In each channel, the blue, green and red carries fringe maps with different fringe pitch. A short sequence of phase-stepped images is projected and acquired sequentially in time. This reduces measurement time by a factor of three when compared to using one channel. From the acquired images, it is possible to calculate absolute phase using the reduced temporal phase unwrapping analysis scheme. For each channel, it is also possible to calculate fringe contrast and fringe amplitude. Therefore, it is possible to retrieve the colour of an object without acquiring an extra image. The method is demonstrated by measuring the shape of two generally coloured and complex shaped objects.     

印度红花岗石与芝麻白花岗石的光谱的研究

采用了电感耦合等离子体原子发射光谱法、X荧光光谱法测定了印度红花岗石和芝麻白花岗石的组成，测定了它们的X射线谱及红外光谱。印度红花岗中的Fe、Ca和Al、Ti、K、S、P、Mg、Mn的含量分别高于和低于芝麻白花岗石中的Al、Ti、K、S、P、Mg、Mn、Fe、Ca。印度红花岗石的红色是由于它们含有Fe的有色矿物而产生的。     

Apports de la colorimétrie et de la spectroradiométrie à la caractérisation in situ des peintures paléolithiques de la grotte Chauvet (Ardèche,France)

The colour of the Palaeolithic paintings on cave walls has been studied primarily in a qualitative way and, more rarely, from the physical angle. Our approach is based on the production of colorimetric measurements in caves, by means of the acquisition of energy radiance spectra with a portable spectroradiometer that can function without contact, several metres away from the decorated walls being studied, thus respecting the constraints of conservation. The colour of parietal works is an element that needs to be taken into account for their archaeological study and conservation. But observation is insufficient and only the measurement of colour makes it possible to compare distant works on rocky supports with different colourings and surface conditions.This article shows the methodology used, and it takes stock of the experience acquired in the research programme on the Chauvet Cave. It also attempts to show the benefits of taking spectroradiometric measurements on prehistoric artworks. However, the in-situ study of their colour cannot be a substitute for chemical and mineralogical analyses and the characterization of the materials, either sampled or in place. Its interest lies in its capacity for detecting even minimal changes in condition and composition. So our objective has been to establish comparisons between the graphic entities to identify the origins of the variations detected in their optical signatures. These variations can be linked to the nature of the colouring materials, but also to their position on the wall, a consequence of the application methods and sometimes also of later removals through taphonomic processes such as water run-off. Alterations (patinas) and coverings (notably veils of calcite or clay) have also been taken into account in our analysis of the data. Hence, we carried out experiments in calcification of surfaces to evaluate the case – quite frequent in caves – of calcite covering a coloured surface, outside of any other phenomenon of alteration. The first results lead us assume that it is possible to identify the signature of a veil of calcite on given colouring materials and also to present hypotheses about the nature of colouring materials covered by a veil of calcite.     

Ultrasonic dyeing of cationized cotton fabric with natural dye. Part 1: cationization of cotton using Solfix E

The dyeing of cationized cotton fabric with Solfix E using colouring matter extracted from Cochineal dye has been studied using both conventional and ultrasonic techniques. Factors affecting dye extraction such as ultrasound power, particle size, extraction temperature and time were studied. The results indicated that the extraction by ultrasound at 300 W was more effective at lower temperature and time than conventional extraction. The effect of various factors of dye bath such as pH, salt concentration, ultrasound power, dyeing time and temperature were investigated. The colour strength values obtained were found to be higher with ultrasound than with conventional techniques. The results of fastness properties of the dyed fabrics were fair to good. The scanning electron microscope (SEM) images of the morphological and X-ray analyzes were measured for cationized cotton fabrics dyed with both conventional and ultrasound methods, thus showing the sonicator efficiency.     

Using coloured structured light in 3-D surface measurement

The widest used algorithms for 3-D surface measurement using structured fringe patterns are phase stepping and Fourier fringe analysis. The techniques currently employed use mostly monochrome fringe patterns as a tool for phase information measurement and further surface reconstruction. However, the information contained in colour images is much more than that of monochrome, in this case, a new colour technique can be employed to analyse a measured scene with colour fringe patterns.This paper presents a new method for improving the measurement of 3-D shapes by using colour information of the measured scene as an additional parameter. The new method is based on primary colours (red, green and blue) to increase the number of the illuminated fringe patterns, which will remove or significantly reduce the common drawbacks of existing methods. The proposed technique produces a number of coloured structured lighting patterns, which are projected from different angles onto the scene. These patterns are analysed using masking algorithms, a specially adapted multi-colour version of the standard Fourier fringe analysis method and calibration routines. In this way a number of the standard difficulties are overcome.     

Real-time coloured visualization of phase flows by the schlieren method

A coloured real-time visualizer of optical inhomogeneities comprising a bichromatic schlieren system, video camera and colour monitor has been developed. The schlieren system represents a function Foucault-Hilbert transformation provided with an amplitude spatial frequency filter, or a quadrant Foucault knife edge. Two colour-coded complementary Toepler-grams are obtained in the exit plane of this schlieren system. Their summed image is then recorded by the video camera and displayed on the screen of the colour monitor. The schlieren photograph of internal gravity waves, generated by the cylindrical body motion in the reservoir filled with the stratified liquid, is presented.     

宝石辐照的颜色改善

宝石的颜色是其最重要的物理性质之一,也是宝石学界最关切的,提高宝石档次的关键问题之一,本文介绍了宝石致色的一些因素和作为宝石颜色改善的新方法—辐照改色的一些动态. The colour of gem is one of the most important physical properties of gem.Some factorson the colouring of gem and situations of colour improvement by irradiation are introduced in this pa-per.     

基于Land实验的可见红外伪彩色图像融合方法

由Land在研究人类视觉颜色恒定性现象时从所做的某个实验出发,通过对该实验中所用红、绿色滤波片的理想化假设以及光源的等能分布假设,并建立红外图像与红色透明片、可见光图像与绿色透明片的对应关系,得到Land实验启发下的新的伪彩色融合算法。通过与Toet伪彩色融合算法的结果比较,说明了该方法的有效性。进而借鉴Toet算法中强调图像特有成分的思想,使本算法输出更丰富、更逼近真实景物的色彩。     

Simple coherent-optical colour encoder

A simple, coherent-optical processor for the production of colour-encoded images from half-tone screened, black and white transparencies is described. Only one laser is used, and the images generated when different diffracted orders and selected by a spatial filter are picked up by a black and white, closed-circuit television system. The screen of the monitor is photographed successively through appropriate coloured filters to produce a colour-encoded image.     

Compatibility of temporal multiplexed spatial light modulator with optical image processing

The tendency today is to replace high-dynamic light modulators by high-speed binary ones (of which the micromirror is the best example). This kind of spatial light modulators (SLM) fulfils all the present needs in displays. They are used in optical communications as binary systems and also in display applications (video projectors) with temporal multiplexing, in order to generate greyscale or colour images. In optical processing, and in the majority of coherent applications, temporal dithering introduces some distortions. In this paper, this point is studied with simulations. We point out that temporal multiplexing cannot be used in the Fourier plane. In the imaging plane, the distortion is weak if the filter has a positive impulse response.     

Fidelity evaluation of metallic luster in six-band high-dynamic-range imaging

This paper presents subjective evaluation results for images reproducing metallic luster. The images were produced by a six-band high-dynamic-range imaging technique, which provides high color fidelity and the capability of various tone mapping operations. The preferences for images produced by four kinds of tone mapping operations were evaluated by means of a paired comparison method under the conditions that observers could or could not refer to real scenes. The evaluation results indicated that preferences for images depend on tone mapping operations, especially for objects that have the luster changing over a large area with moderately high intensity. In addition, when referring to a real scene, the spatially varying tone compression, which reproduces the color and complex characteristics of metallic luster, was significantly preferable to the tone mappings by other approaches. Without a real scene, the preference was also strong for images produced by simply saturating pixel values at highlights.     

多孔金属薄膜阻尼减振微观机理研究

研究了多孔金属薄膜的阻尼性能和微观机理. 采用分子动力学方法及扫描电镜(SEM) 原位观察实验手段对多孔金属薄膜阻尼进行研究, 得出金属薄膜应变滞后于应力周期性变化以及弹性势能周期性衰减的规律, 并通过应变滞后应力的时间差求得损耗因子; 从微观结构上可看出, 在薄膜孔缺陷附近\langle110angle晶向上经历了位错产生、 并且位错呈阶梯状向前发射的变化; 在SEM原位拉伸、卸载实验中观察到有微裂纹的萌生、斜向阶梯扩展、收缩及消失的周期过程. 结果表明: 在周期载荷作用下, 多孔金属薄膜的孔缺陷附近产生的位错可以挣脱开弱钉扎点并限制在强钉扎点上, 由于位错的变化及附近晶界间的相对滑动产生内摩擦, 消耗了系统的部分弹性势能, 引起金属薄膜的阻尼减振效应, 从而揭示了多孔金属涂层阻尼产生的微观机理.     

360 degree realistic 3D image display and image processing from real objects

A 360-degree realistic 3D image display system based on direct light scanning method, so-called Holo-Table has been introduced in this paper. High-density directional continuous 3D motion images can be displayed easily with only one spatial light modulator. Using the holographic screen as the beam deflector, 360-degree full horizontal viewing angle was achieved. As an accompany part of the system, CMOS camera based image acquisition platform was built to feed the display engine, which can take a full 360-degree continuous imaging of the sample at the center. Customized image processing techniques such as scaling, rotation, format transformation were also developed and embedded into the system control software platform. In the end several samples were imaged to demonstrate the capability of our system.     

Characterisation of inorganic pigments in ancient glass beads by means of Raman microspectroscopy,microprobe analysis and X‐ray diffractometry

Ancient coloured glass beads from Sri Lanka and Oman were analysed by Raman microspectroscopy for non‐destructive identification of inorganic pigments in the glass. Calcium phosphate (Ca₃(PO₄)₂), cassiterite (SnO₂), cuprite (Cu₂O) and a Pb(Sn,Si)O₃‐type lead tin oxide were found to be used as colouring agents. Moreover, a distinction between lead‐based and alkali‐based glass matrices could be made. Electron microprobe analysis and X‐ray diffractometry were performed to show the capability of Raman microspectroscopy in comparison to these methods for answering archaeometric questions. Copyright © 2006 John Wiley & Sons, Ltd.     

EPMA and µ‐SRXRF analysis and TEM‐based microstructure characterization of a set of Roman glass fragments

A set of Roman glass fragments, excavated at Bliesbruck–Reinheim (French–German border), were analysed by electron probe microanalysis (EPMA) and micro‐synchrotron radiation‐induced x‐ray fluorescence (µ‐SRXRF) in order to determine the major, minor and trace chemical composition. Based on this analysis, five classes of mono‐coloured glass could be discerned. However, one piece of this set was not mono‐coloured, but consisted of a mixture of brown and white opaque glass. This fragment was investigated using EPMA and transmission electron microscopy (TEM) in order to gain a better insight into its microstructure. Both colours proved to contain small crystalline inhomogeneities. Structural information reveals the form in which the detected elements are present and helps to explain the appearance (e.g. colour) of the material. Copyright © 2004 John Wiley & Sons, Ltd.     

Reflected light holographic microscopy of moving objects

A holographic system that images front-illuminated, fast-moving microscopic objects is described. Focused micrographs can be generated under circumstances when ordinary microscopy (due to object movements) and transilluminated holographic microscopy (due to object opaqueness) cannot be used. Details of the experimental arrangements, easy-to-use working formulae for obtaining optimum image reproduction, and results from the application of the system to studies of droplet and solid particle suspensions in liquids are presented.     

Comparison of fractal and profilometric methods for surface topography characterization

In this study microstructural and roughness characterization of surface of aluminium foils used in lithographic printing process was performed by contact and non-contact profilometric methods and fractal analysis. Significant differences in roughness parameters values inferred from stylus method in respect to those inferred from the non-contact measurements were observed. The investigation of correlation between various fractal dimensions obtained from gray-scale SEM micrographs and binary images resulting from median filtering of the original SEM micrographs as well as selected relevant roughness parameters shows that there is a strong correlation between certain roughness parameters and particular fractal dimensions. This correlations permit better physical understanding of fractal characteristics and interpretation of the dynamics of surface roughness change through processing. Generally these correlations are more suitable for parameters obtained by stylus method than those inferred from the laser-based measurements.     

Correlation between deformation bleaching and mechanoluminescence in coloured alkali halide crystals

The present paper reports the correlation between deformation bleaching of coloration and mechanoluminescence (ML) in coloured alkali halide crystals. When the F-centre electrons captured by moving dislocations are picked up by holes, deep traps and other compatible traps, then deformation bleaching occurs. At the same time, radiative recombination of dislocation captured electrons with the holes gives rise to the mechanoluminescence. Expressions are derived for the strain dependence of the density of colour centres in deformed crystals and also for the number of colour centres bleached. So far as strain, temperature, density of colour centres, E _a and volume dependence are concerned, there exists a correlation between the deformation bleaching and ML in coloured alkali halide crystals. From the strain dependence of the density of colour centres in deformed crystals, the value of coefficient of deformation bleaching D is determined and it is found to be 1.93 and 2.00 for KCl and KBr crystals, respectively. The value of (D+χ) is determined from the strain dependence of the ML intensity and it is found to be 2.6 and 3.7 for KCl and KBr crystals, respectively. This gives the value of coefficient of deformation generated compatible traps χ to be 0.67 and 1.7 for KCl and KBr crystals, respectively.