Using digital colour to increase the realistic appearance of SEM micrographs of bloodstains

Although in the scientific-research literature the micrographs from scanning electron microscopes (SEMs) are usually displayed in greyscale, the potential of colour resources provided by the SEM-coupled image-acquiring systems and, subsidiarily, by image-manipulation free softwares deserves be explored as a tool for colouring SEM micrographs of bloodstains. After acquiring greyscale SEM micrographs of a (dark red to the naked eye) human blood smear on grey chert, they were manually obtained in red tone using both the SEM-coupled image-acquiring system and an image-manipulation free software, as well as they were automatically generated in thermal tone using the SEM-coupled system. Red images obtained by the SEM-coupled system demonstrated lower visual-discrimination capability than the other coloured images, whereas those in red generated by the free software rendered better magnitude of scopic information than the red images generated by the SEM-coupled system. Thermal-tone images, although were further from the real sample colour than the red ones, not only increased their realistic appearance over the greyscale images, but also yielded the best visual-discrimination capability among all the coloured SEM micrographs, and fairly enhanced the relief effect of the SEM micrographs over both the greyscale and the red images. The application of digital colour by means of the facilities provided by an SEM-coupled image-acquiring system or, when required, by an image-manipulation free software provides a user-friendly, quick and inexpensive way of obtaining coloured SEM micrographs of bloodstains, avoiding to do sophisticated, time-consuming colouring procedures. Although this work was focused on bloodstains, well probably other monochromatic or quasi-monochromatic samples are also susceptible of increasing their realistic appearance by colouring them using the simple methods utilized in this study.     

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.     

三维显微图像复原及点扩散函数的研究

三维显微图像去卷积计算量巨大,运算时间长。评价和分析了三维点扩散函数、散焦像、光学切片以及不同三维点扩散函数去卷积的复原图像,进一步证明了散焦光信息对焦面像的干扰,主要来自于焦面像两侧附近的散焦像。提出了折中选择三维PSF的空间大小,可以获得良好的复原效果,并且减少运行时间。提出了频谱图均值的新概念,作为评价图像清晰及模糊程度的标准,并运用于散焦像、光学切片以及复原结果图的评价。     

Recent advances in 3D SEM surface reconstruction

The scanning electron microscope (SEM), as one of the most commonly used instruments in biology and material sciences, employs electrons instead of light to determine the surface properties of specimens. However, the SEM micrographs still remain 2D images. To effectively measure and visualize the surface attributes, we need to restore the 3D shape model from the SEM images. 3D surface reconstruction is a longstanding topic in microscopy vision as it offers quantitative and visual information for a variety of applications consisting medicine, pharmacology, chemistry, and mechanics. In this paper, we attempt to explain the expanding body of the work in this area, including a discussion of recent techniques and algorithms. With the present work, we also enhance the reliability, accuracy, and speed of 3D SEM surface reconstruction by designing and developing an optimized multi-view framework. We then consider several real-world experiments as well as synthetic data to examine the qualitative and quantitative attributes of our proposed framework. Furthermore, we present a taxonomy of 3D SEM surface reconstruction approaches and address several challenging issues as part of our future work.     

3DSEM++: Adaptive and intelligent 3D SEM surface reconstruction

Structural analysis of microscopic objects is a longstanding topic in several scientific disciplines, such as biological, mechanical, and materials sciences. The scanning electron microscope (SEM), as a promising imaging equipment has been around for decades to determine the surface properties (e.g., compositions or geometries) of specimens by achieving increased magnification, contrast, and resolution greater than one nanometer. Whereas SEM micrographs still remain two-dimensional (2D), many research and educational questions truly require knowledge and facts about their three-dimensional (3D) structures. 3D surface reconstruction from SEM images leads to remarkable understanding of microscopic surfaces, allowing informative and qualitative visualization of the samples being investigated. In this contribution, we integrate several computational technologies including machine learning, contrario methodology, and epipolar geometry to design and develop a novel and efficient method called 3DSEM++ for multi-view 3D SEM surface reconstruction in an adaptive and intelligent fashion. The experiments which have been performed on real and synthetic data assert the approach is able to reach a significant precision to both SEM extrinsic calibration and its 3D surface modeling.     

3D surface topography from the specular lobe of scattered light

Scattered light from a surface contains a huge amount of information including surface slope, roughness, pattern, texture, etc. In this paper, the relationship between the intensity distribution of scattered light from a surface and the 3D surface topography will be investigated. From the geometrical point of view the intensity distribution of scattered light from a surface may be modelled with three components, the specular spike, specular lobe and diffuse lobe. In the situation when light is scattered from a relatively smooth surface whose roughness is much larger than the wavelength of the incident light, the scattered light intensity distribution will consist of only a diffuse lobe and a specular lobe, which are well described by a combination of the Lambertian and Torrance–Sparrow geometrical models. Based on the light scattering phenomenon, in this paper a scanning method capable of measuring the 3D surface topography with 500 mm scanning width, high scanning speed, and micron resolution is presented. The 3D topography measurement is implemented by using a linear photodiode array to measure scattered light intensity distribution at different angles against the surface normal. Then the specular lobe of the scattered light will be extracted at each scanning point to calculate the surface normal distribution. Sequentially, the 3D surface topography is obtained by using gradient integration techniques.     

基于白光数字莫尔的三维数字成像系统

提出一种基于数字莫尔的三维光学数字成像系统,此系统采用了非相干光投影和空间相移算法以及混合模板相位复原技术来重构连续位相分布图。给出一种光学几何灵敏度的确定方法并由此区得空间自由表面的三维数字图像。文中还给出由该光学数字化系统得以的真实人体面部的三维数字图像的实验结果。     

Exchanging digital video of laryngeal examinations

Laryngeal examinations, especially stroboscopic examinations, are increasingly recorded using digital video formats on computer media, rather than using analog formats on videotape. It would be useful to share these examinations with other medical professionals in formats that would facilitate reliable and high-quality playback on a personal computer by the recipients. Unfortunately, a personal computer is not well designed for reliable presentation of artifact-free video. It is particularly important that laryngeal video play without artifacts of motion or color because these are often the characteristics of greatest clinical interest. With proper tools and procedures, and with reasonable compromises in image resolution and the duration of the examination, digital video of laryngeal examinations can be reliably exchanged. However, the tools, procedures, and formats for recording, converting to another digital format ("transcoding"), communicating, copying, and playing digital video with a personal computer are not familiar to most medical professionals. Some understanding of digital video and the tools available is required of those wanting to exchange digital video. Best results are achieved by recording to a digital format best suited for recording (such as MJPEG or DV),judiciously selecting a segment of the recording for sharing, and converting to a format suited to distribution (such as MPEG1 or MPEG2) using a medium suited to the situation (such as e-mail attachment, CD-ROM, a "clip" within a Microsoft PowerPoint presentation, or DVD-Video). If digital video is sent to a colleague, some guidance on playing files and using a PC media player is helpful.     

Wavelet processing of topographic high dynamic range images

For a 6H-SiC single crystal, experimental results of the digital processing of topographic images with various dynamic ranges are given. In this case, wavelet analysis was used. The images were obtained by x-ray topography based on the Borrmann effect and were presented in 8-, 16-, and 32-bit formats. It is shown that, on eliminating the experimental contrast granularity, 32-bit images turn out to be more convenient for decoding and contain more useful information about structure defects of a single crystal under study as compared to the 8- and 16-bit images. The wavelet analysis efficiency increases considerably for the digital processing of separate topogram fragments and depends on the choice of the region and the size of the reference image.     

Synthesis of TiO2 nanorods by oriented attachment using EDTA modifier: a novel approach towards 1D nanostructure development

The synthesis of TiO₂ nanorods with anatase structure has been achieved from the necking of truncated nanoparticles by oriented attachment using titanium ethylenediaminetetraacetic acid (EDTA) chelated complex as a molecular precursor. The preparation was carried out under mild conditions using a simple solvothermal process. The influence of EDTA over the growth of nanocrystallites and the various other factors which contribute to the development of 1D TiO₂ nanostructure are investigated. At a relatively lower temperature, titania nanopowders are obtained, and the anatase phase crystallization is verified by wide angle X-ray diffraction. The evolution of rod-shaped TiO₂ with tapered edges has been confirmed by transmission electron micrographs. The well aligned lattice fringes of TiO₂ nanorod towards [001] direction is investigated by HRTEM. The SEM images show the surface configuration of overall aggregates of titania crystallites consisted of primary particles which are densely packed in an orderly texture. The moderate shift in the absorption band towards higher energy region of the absorption spectrum confirms the weak carrier confinement effect in the sample.     

一种色彩向量的降维表示方法

提出了一种依据人眼的颜色视觉机制对真彩色显微生物图像进行分割的色彩向量的降维表示方法。该方法将由红绿蓝三色彩刺激经Karhunen Lo埁ｖｅ变换得到的Ｉ1I2 I3 色彩空间中的I1强度信息摒弃 ,将色彩特征由三维I1I2 I3 色彩空间向量降维为二维I2 I3 色彩向量。并以此I2 I3 色彩向量作为图像的色彩表示特征 ,运用反向传播网络对真彩色显微生物图像进行了分割实验。实验表明该方法应用于分割真彩色显微生物图像时 ,与采用I1I2色彩向量的降维方法相比 ,可优化色彩表示特征 ,加快网络的收敛速度 ,提高图像分割的正确率     

电化学法涂层导体CeO_2缓冲层外延生长研究

电化学沉积法制备高温超导YBa2Cu3O7-δ涂层导体缓冲层具有工艺简单、设备要求低、易于连续化批量制备等优点。采用电化学沉积法,在双轴织构的Ni-5at.%W(Ni-5W)金属基带上成功制备出了具有良好c轴取向的CeO2缓冲层薄膜。利用X射线衍射、极图、扫描电子显微镜和原子力显微镜等对上述氧化物薄膜的织构、表面形貌等进行表征。重点研究了薄膜厚度、退火温度、退火时间等工艺对薄膜外延生长及其表面形貌的影响,结果表明:电化学沉积方法制备的CeO2缓冲层具有很好的双轴织构、表面平整、均一,粗糙度低,表现出良好的缓冲层性质。结合金属有机化学溶液超导层的制备技术,本工作展示了一条全化学法制备第二代高温超导带材的技术路线,具有很好的应用前景。     

The gigapixel image concept for graphic SEM documentation. Applications in archeological use-wear studies

In this paper, we propose a specific procedure to create gigapixel-like images from SEM (scanning electron microscope) micrographs. This methodology allows intensive SEM observations to be made for those disciplines that require of large surfaces to be analyzed at different scales once the SEM sessions have been completed (e.g., stone tools use-wear studies). This is also a very useful resource for academic purposes or as a support for collaborative studies, thus reducing the number of live observation sessions and the associated expense.     

Wavelength-scanning digital interference holography for optical section imaging

We propose and experimentally demonstrate a simple digital holographic method that allows reconstruction of three-dimensional object images with a narrow depth of focus or axial resolution. A number of holograms are optically generated by use of different wavelengths spaced at regular intervals. The holograms are recorded on a digital camera and reconstructed numerically. Multiwavelength interference of the holograms results in images of the contour plane whose thickness can be made arbitrarily narrow. Objects at different distances from the hologram plane are imaged clearly and independently, with complete suppression of the out-of-focus images. The technique is available only in digital holography and should have useful applications in holographic microscopy.     

基于Vega的红外图像仿真

介绍了红外成像仿真的基本理论,讨论了利用Vega传感器模块将输入的可见目标图像生成红外图像的技术。该技术使用Creator软件进行三维几何建模和纹理映射,使用TMM软件进行红外材质建模;然后,用Mat软件进行大气衰减的计算;最后,用SensorWorks软件进行传感器特性建模,通过光电转换生成红外图像。以阿帕奇AH6直升机为例进行了红外图像仿真,结果表明,利用Vega传感器模块进行传感器建模,建模效果较好,成本低,易于工程实现。     

Sequential method for high 3-D resolution imaging in nuclear medicine

A sequential method is developed to obtain a high resolution 3-D image distribution of the activity of a radioactive tracer. Two different types of reconstruction are presented. The first method, related to X or γ ray motion tomography, yields reconstructed objects slices (tomograms) containing superimposed out-of-focus blurred planes. The second method, utilizing computer processing, generates each plane (slice) separately, free from out-of-focus images, as in X-ray scanner transaxial tomography. This approach avoids calculations of the tomograms and improves the restitution of low spatial frequencies. A method of spatial filtering for quantum noise reduction is also proposed.     

Uncertainty studies of topographical measurements on steel surface corrosion by 3D scanning electron microscopy

Pitting corrosion is a damage mechanism quite serious and dangerous in both carbon steel boiler tubes for power plants which are vital to most industries and stainless steels for orthopedic human implants whose demand, due to the increase of life expectation and rate of traffic accidents, has sharply increased. Reliable methods to characterize this kind of damage are becoming increasingly necessary, when trying to evaluate the advance of damage and to establish the best procedures for component inspection in order to determine remaining lives and failure mitigation. A study about the uncertainties on the topographies of corrosion pits from 3D SEM images, obtained at low magnifications (where errors are greater) and different stage tilt angles were carried out using an in-house software previously developed. Additionally, measurements of pit depths on biomaterial surfaces, subjected to two different surface treatments on stainless steels, were carried out. The different depth distributions observed were in agreement with electrochemical measurements.     

Towards a quantitative analysis of magnetic force microscopy data matrices

Fast and efficient software tools previously developed in image processing were adapted to the analysis of raw datasets consisting of multiple stacks of images taken on a sample interacting with a measuring instrument and submitted to the effect of an external parameter. Magnetic force microscopy (MFM), a follow-up of atomic force microscopy (AFM), was selected as a first testbed example. In MFM, a specifically developed ferromagnetic scanning tip probes the stray magnetic field generated from a ferromagnetic specimen. Raw scanning probe images taken on soft patterned magnetic materials and continuous thin films were used, together with synthetic patterns exploited to assess the absolute performance ability of the proposed texture analysis tools. In this case, the parameter affecting the sample-instrument interaction is the applied magnetic field. The application discussed here is just one among the many possible, including, e.g., real-time microscopy images (both optical and electronic) taken during heat treatments, phase transformations and so on. Basically any image exhibiting a texture with a characteristic spatial or angular dependence could be processed by the proposed method. Standard imaging tools such as texture mapping and novel data representation schemes such as texture analysis, feature extraction and classification are discussed. A magnetic texture stability diagram will be presented as an original output of the entropic analysis on MFM datasets.