Differentiation of human hair by colour and diameter using light microscopy,digital imaging and statistical analysis

This research introduces and evaluates a novel method that offers the potential of providing objective criteria to forensic microscopical hair comparisons. The method combines hair diameter with numeric characterisations of red, green, and blue colour content as determined with the use of digital imaging at defined locations of the hair. Thirty hairs were collected from each of twenty participants, all with naturally coloured brown hair. The hairs were examined with an Olympus BX53® polarising light microscope and digital images were viewed with an Olympus DP72® camera under 400× magnification. Using Olympus cellSens^? Entry software, hair diameter was measured at 1000, 1500 and 2000 m from the base of the root. The Olympus cellSens^? Entry software uses a red, green and blue (RGB) colour model to quantitatively define the colour of each pixel on an image based on its composition of these three principal colour components. This software was used to collect numerical characterisations of hair colour at each distance interval. The diameter and colour values for each hair were compared using discriminant analysis (DA) and principal component analysis. Although a large amount of intrapersonal variation was observed, the degree of interpersonal variation was greater and enabled the statistical model to differentiate between the hair samples from each participant. The DA model achieved sample reclassification with an error rate of 7.33%. A validation study was conducted on a subset of hair samples from which 18 of the 20 were correctly assigned to the participant from whom they originated. These results support the potential of this method to provide an objective addition to current microscopical hair comparison practices.     

Atomic force microscopy of human hair

The atomic force microscope (AFM) was used to investigate the surface architecture of the entire lengths of cleaned human head hairs. Many features previously seen with the scanning electron microscope (SEM) were identified. However, the AFM has provided much greater detail and, in particular, the hair's cuticular surfaces appear not to be as smooth as had been previously supposed. A consistent feature was of step discontinuities or "ghosts" on the scale surfaces. These delineated the original location of each overlying scale before its edge had been chipped away. There was a change in the longitudinal angular presentation of the surfaces about each ghost. This means the distal ends of each cuticle cell have been synthesised in the follicle to be thicker than where that same cuticle cell is bounded on both sides by other cuticle cells. The undamaged outer cuticular surfaces at the root end of each hair were covered everywhere by longitudinal ridges (striations). Where the hair surface was worn, the striations terminated at a scale edge ghost. The ridges were approximately 9 nm high and were in parallel array with a lateral repeat spacing of about 350 nm. The striations are evidently formed on the outer surface of each cuticle cell following earlier contact in the hair follicle with the inner root sheath. The study of stained transverse sections of hairs in the transmission electron microscope (TEM) is suggested as a means for throwing some light on the underlying structure and chemistry of the striations. Finally, our AFM studies have revealed that the surface of the freshly emergent hair gradually changes over a distance of about 20 mm and that the surface of the hair for most of its length is quite different from that near the root. This is likely to be of import to those engaged in the hair toiletries industry.     

Cilia in the head of hornets: form and function

In the head of the Oriental hornet, beneath the cuticle, there are plaques of hair cells. These are distributed throughout the upper front part of the head; to wit: in the region of the vertex (i.e., around and behind the ocelli), in the genae around and behind the compound eyes (the ommatidia), and in the region of the forehead or frons. These hair cells are arranged with their thin whip-like part (i.e., cilia) directed outward and morphologically fall into three distinct groups: type (a) thin elongated cilia connected to each other alongside by side-links; type (b) thin elongated cilia of which two or more interconnect at their distal ends via a delicate nerve fiber bearing a knob at its center; and type (c) shorter and thicker cilia that roughly resemble a triangular thorn and are also interconnected by a thin thread, which, however, bears a ball rather then a knob at its center. The knob in the one case and the ball in the other vary in their diameter, but in both instances the interconnecting elements, be they nerve fibers or threads, are seemingly multidirectional. Beneath the frons, in the region of the coronal suture, the hair cells (cilial plaques) are inwardly directed and bear a large trachea at their center. Presumably, the "weighted" cilial cells that are directed toward the exterior of the body aid the hornet in navigation and gravity determination whereas the inwardly directed ciliary cells may possibly serve in acoustic communication. Another element worthy of mention within the hair cells are yellow granules (yg). These yg's originate from the whip-like portion of the ciliary cells that are distributed beneath the frons plate, and also in the yellow stripes of the gastral cuticle. Conceivably, these yellow granules, in both cases, may play a role in the absorption and storage of solar energy. In summary, ciliary structures are involved in the hornet in gravity sensing, in acoustical communication and in light sensing, i.e., with some similarity with what happens in vertebrates in the inner ear and in the photoreceptor.     

具有电磁阀微喷功能的3D打印机构建及应用

3D打印技术已经在生物医学、传感器制造等领域得到广泛应用。然而,传统3D打印机由于自身工作方式的不同,适用范围不同,难以同时兼容生物制备和传感器制备。因此,以电磁阀作为3D打印机的喷头,自主设计并构建具有独特工作方式的3D打印机,将高精度液滴分配方式应用于3D结构打印。研究料筒气压、电磁阀开关时间、喷头高度对打印液滴直径的影响,并对点、线、网、面图案的打印质量进行评估;利用所构建的打印机制备具有真皮乳头结构的组织工程皮肤和阵列式柔性压力传感器,测试组织工程皮肤的细胞活性及压力传感器的压-阻转换特性。结果表明,打印液滴直径尺寸与料筒气压、喷头开启时间、喷头高度均成正相关;3D打印机对点、线、网、面图案的打印效果较为理想;可成功应用于具有真皮乳头结构的组织工程皮肤和柔性压力传感器的制备。所构建的3D打印机融合喷墨式打印机和挤出式打印机的优势,对打印墨水有较好的兼容性,具有打印方式简单、打印速度快、成型质量高的优点,对组织工程皮肤及柔性压力传感器的研究具有重要意义,为实现具有感知功能仿生皮肤的制备奠定基础。     

Channelling optics for high quality imaging of sensory hair

A long distance microscope (LDM) is extended by a lens and aperture array. This newly formed channelling LDM is superior in high quality, high-speed imaging of large field of views (FOV). It allows imaging the same FOV like a conventional LDM, but at improved magnification. The optical design is evaluated by calculations with the ray tracing code ZEMAX. High-speed imaging of a 2 × 2 mm(2) FOV is realized at 3.000 frames per second and 1 μm per pixel image resolution. In combination with flow sensitive hair the optics forms a wall shear stress sensor. The optics images the direct vicinity of twenty-one flow sensitive hair distributed in a quadratic array. The hair consists of identical micro-pillars that are 20 μm in diameter, 390 μm in length and made from polydimethylsiloxane (PDMS). Sensor validation is conducted in the transition region of a wall jet in air. The wall shear stress is calculated from optically measured micro-pillar tip deflections. 2D wall shear stress distributions are obtained with currently highest spatiotemporal resolution. The footprint of coherent vortical structures far away from the wall is recovered in the Fourier spectrum of wall shear stress fluctuations. High energetic patterns of 2D wall shear stress distributions are identified by proper orthogonal decomposition (POD).     

Time of flight secondary ion mass spectrometry: a powerful high throughput screening tool

Combinatorial materials libraries are becoming more complicated; successful screening of these libraries requires the development of new high throughput screening methodologies. Time of flight secondary ion mass spectrometry (ToF-SIMS) is a surface analytical technique that is able to detect and image all elements (including hydrogen which is problematic for many other analysis instruments) and molecular fragments, with high mass resolution, during a single measurement. Commercial ToF-SIMS instruments can image 500 microm areas by rastering the primary ion beam over the region of interest. In this work, we will show that large area analysis can be performed, in one single measurement, by rastering the sample under the ion beam. We show that an entire 70 mm diameter wafer can be imaged in less than 90 min using ToF-SIMS stage (macro)rastering techniques. ToF-SIMS data sets contain a wealth of information since an entire high mass resolution mass spectrum is saved at each pixel in an ion image. Multivariate statistical analysis (MVSA) tools are being used in the ToF-SIMS community to assist with data interpretation; we will demonstrate that MVSA tools provide details that were not obtained using manual (univariate) analysis.     

Elemental and molecular imaging of human hair using secondary ion mass spectrometry.

Secondary ion mass spectrometry (SIMS) is used to image the spatial distribution of elemental and molecular species on the surface and in cross sections of doped human hair using a magnetic sector SIMS instrument operated as an ion microprobe. Analysis of electrically insulating, non-planar hair samples requires one of two different methods of charge compensation to be used depending on the polarity of the sputtered secondary ions. For detection of positive secondary ions, the hair is imaged using a approximately 0.5 micron diameter, 19.5 keV impact energy, O- microbeam with no auxiliary electron bombardment. For detection of negative secondary ions, a approximately 0.2 micron diameter, 14.5 keV impact energy Cs+ microbeam is used in conjunction with normal incidence, low-energy electron bombardment. Both of these methods allow submicrometer spatial resolution elemental and molecular secondary ion images to be obtained from hair samples without metallic coating of the sample surface prior to analysis. Several examples are presented that reflect potential application areas for these analytical methods.     

用于高速测量的CCD激光位移传感器的研究

介绍了一种用于高速测量的CCD激光位移传感器测量系统,可用于高速、实时地测量运动物体的位移或高速振动。传感器测量系统由光学系统、具有7500像元的高速线阵CCD、转换速率达40MHz的高速ADC、高速缓存FIFO、比较器筛选电路、CPLD时钟驱动电路、像元脉冲计数器和数字信号处理器DSP构成。在系统中采用自适应控制方法,通过调节激光的发射频率和输出电流强度来调节发射激光光强,从而适应各种被测对象和外界环境条件。采用特殊设计的比较器筛选电路来控制FIFO对高速AD采样数据的存储和DSP对高速FIFO中数据的读取,使 FIFO只存储CCD输出的有效像元信号,从而减轻了DSP数据处理的负担,实现对CCD传感器信号的采集与处理同时进行,以满足高速测量的需要。实验表明数据转换速率可达40M,最小采样间隔时间为0.1ms。     

检测纳米微粒粒径方法的研究

用光子相关法、原子力显微镜和扫描电镜三种测试方法测定了同一标准样品的粒径，比较了三种测试方法在纳米粒径检测方面的特点。光子相关法给出纳米微粒的平均粒径和多分散系数，而原子力显微镜和扫描电镜在测定粒径的同时直接观察到微粒的外貌。     

微波等离子体炬原子发射光谱法测定人发中的六种微量元素

采用干法消解处理样品、微波等离子体炬（MPT）原子发射光主普法测定了人发中锌、锰、镁、铜、钙和铝等6种重要元素的含量,讨论了实验参数的最佳化。用本法对国家标准物质人发样品（GBW09101）中相应元素的含量也进行了测定,测量结果与推荐值符合较好,回收率在85％－115％之间,精密度均小于3％。本方法具有灵敏度高,样品用量少（＜4mL）,维持费用低,分析速度快等特点,仅需4min即可完成一个样品中6种元素含量的测定。     

Methods for Digital Particle Image Sizing (DPIS): Comparisons and improvements

This paper explores the accuracy of particle image sizing using direct processing of digitally recorded images. Traditional methods for particle image sizing were considered and, four new algorithms were developed to deliver improved accuracy and robustness. Statistical error analysis was performed using Monte Carlo simulations in order to quantify the dependence of these methods on noise, discretization, and particle size distribution. The performance of these methods were compared against Phase Doppler Analyzer measurements of spray atomization.We introduce a novel two-dimensional four-point Gaussian estimator and an alternative Gaussian estimator based on a local least squares (LLS) fit. These methods were further advanced to account for pixel discretization effects using integral formulations (continuous methods). All new methods were compared against conventional pixel counting and the established three-point Gaussian estimator. The new methods significantly reduced the total error in the diameter estimation compared to the three-point Gaussian estimator and pixel counting. The least squares Gaussian estimator and its continuous version demonstrated almost identical results and superior performance for diameters over 4 pixels. For smaller diameters, the continuous four-point Gaussian estimator delivered the highest accuracy. For uniform particle size distribution between 2–14 pixels image diameter, the least squares estimators delivered error less than 5% with respect to the true diameter for 80% of the particles. The remaining methods demonstrated error of 5% (or better) for less than 60% of the particles. Validation in an experiment of high-pressure spray atomization showed that the Gaussian local least squares methods and the continuous four-point method delivered similar particle size distribution compared to PDA. The particle mean diameter estimated by the two methods differed only by 3% and 6% respectively with respect to the PDA measurements.The novel particle image sizing schemes developed here can deliver accurate, robust, and computationally efficient apparent diameter measurement, thus providing a viable, simple and inexpensive solution for performing sizing on conventional particle image velocimetry images. This capability enables simultaneous measurements of both velocity and particle size for a wide range of multi-phase flows.     

Measurement of electron probe beam diameter by digital image processing

The present report illustrates a computerized method for precise measurement of the diameter of an electron beam. The value of this measurement extends beyond simply providing an accurate estimate of resolution. Other salient areas which will benefit include quantitative X-ray microanalysis, energy loss spectroscopy, diffraction studies, and electron beam lithography. The biological sciences as well as the material sciences will gain enormously from improved accuracy in measurement (control) of beam diameter. It is anticipated that most or all of the mathematical manipulations outlined in this paper will be incorporated into digital electronic packages which will perform the functions automatically for setting the electron beam diameter to the scientist's choice. The purpose of the present report is to indicate some of the principles involved so that as electron microscopy becomes more computerized and automated, the user will have some understanding of what the electronics are doing rather than simply depressing a button or two and ignoring the power of what resides within the walls of the instrument. The performance of a scanning electron microscope (SEM) and a scanning transmission electron microscope (STEM) is roughly determined by the incident electron probe beam size (diameter) involving a sufficient electron current. In the present paper, the diameter of an ultrafine electron beam is measured indirectly from the information given by the blurring of an edge in a STEM or a SEM image of a crystalline specimen with fine, sharp edges. The obtained data were processed by digital image processing methods which give an accurate value of the beam diameter. For confirming the validity of this method, a suitable simulation based on the convolution theorem was performed. By using this measurement, we could measure the diameter of an ultrafine electron beam down to 2 nm, which could not be measured easily by previous techniques.     

螺纹参数自动检测系统设计

针对传统的螺纹检测方法检测误差大、效率低等特点,开发一种基于数字图像处理的螺纹参数自动检测系统。首先,通过CCD摄像机获取螺纹外轮廓的数字图像;然后对图像数据进行加工和处理;最后计算得到螺纹联接的相关几何参数,并对标准螺纹试件的螺纹夹角、螺距和中径等参数进行了测量。测量结果表明,螺纹参数符合测量精度要求。该系统可以实现螺纹的高精度检测,扩大了视觉检测的应用范围。     

发动机缸体视觉图像定位方法研究

针对发动机缸体孔系实现在线自动测量的难题,提出了基于视觉图像的发动机缸体定位方法。通过面阵CCD获取发动机缸体定位销孔图像信息,利用图像处理提取定位销孔中心位置,以此建立每个被测缸体的测量基准。使用环形双峰阈值法与中值滤波对图像进行预处理,有效地解决了定位销孔具有倒角影响图像边缘提取精度的问题。为验证此定位方法的准确性与可行性,分别进行了发动机缸体定位孔直径与位置度重复性测量与发动机缸体上表面孔组直径与位置度重复性测量实验。实验结果表明所提出的视觉定位方法稳定可靠,实现了发动机缸体的快速、精确定位,为实现发动机缸体的在线检测打下了可靠基础。     

Automatic measurement of scanning beam diameter using an on-line digital computer

A method for the measurement of electron probe beam diameter by digital image processing has recently been published. The purpose of the present report is to describe the development of an automatic system for beam diameter measurement. To complete this system, a method based on a theory which combines automation and high-resolution conditions is proposed. In practice, the beam diameter is measured from the STEM image of a crystalline hole in a gold thin film, utilizing an on-line computer system equipped with newly developed digital processing programs linked to a SEM in the transmission mode. The functions of the programs include statistical processing, matching, noise removal, interpolation, selection, and rotation. By combining these functions, the scanning beam diameter is accurately measured, in spite of difficulties, under most electron microscope operating conditions. The user simply appoints the edge included in the STEM image.     

基于最小生成树的显著性自适应形态学结构元素构造方法

经典数学形态学运算采用固定大小和形状的结构元素处理整幅图像,由于图像内容的多样性以及目标结构的复杂性,容易导致处理后的图像形状发生改变且丢失部分信息.为此,提出了一种基于最小生成树(Minimum spanning tree,MST)的显著性自适应形态学结构元素构造方法.首先,计算图像梯度,通过非极大值抑制(Non-maximum suppression,NMS)得到边缘图像,对边缘图像进行倒角距离变换,得到显著性图(Salience map,SM).然后,通过计算SM的极大极小值确定结构元素半径,并在SM上计算MST.最后,利用计算得到的半径构造出一种形状和大小随输入图像局部特征自适应变化的结构元素.利用该自适应结构元素对腐蚀、膨胀、开和闭等基本形态学算子进行了重新定义,并且与经典形态学算子做了仿真对比.结果表明,该方法能够充分利用图像的局部特征,在图像结构保持以及图像滤波等方面都具有较好的处理结果.     

基于最小生成树的显著性自适应形态学结构元素构造方法

经典数学形态学运算采用固定大小和形状的结构元素处理整幅图像,由于图像内容的多样性以及目标结构的复杂性,容易导致处理后的图像形状发生改变且丢失部分信息.为此,提出了一种基于最小生成树(Minimum spanning tree,MST)的显著性自适应形态学结构元素构造方法.首先,计算图像梯度,通过非极大值抑制(Non-maximum suppression,NMS)得到边缘图像,对边缘图像进行倒角距离变换,得到显著性图(Salience map,SM).然后,通过计算SM的极大极小值确定结构元素半径,并在SM上计算MST.最后,利用计算得到的半径构造出一种形状和大小随输入图像局部特征自适应变化的结构元素.利用该自适应结构元素对腐蚀、膨胀、开和闭等基本形态学算子进行了重新定义,并且与经典形态学算子做了仿真对比.结果表明,该方法能够充分利用图像的局部特征,在图像结构保持以及图像滤波等方面都具有较好的处理结果.     

An automatic optical inspection of drill point defects for micro-drilling

This study develops an automated visual inspection system for detecting and classifying defects in a micro-drill with 0.35 mm diameter using image processing techniques. The orientation of the micro-drill is first determined through image projection. Next, the digital image captured by the CCD is then segmented into regions of interest (ROI). The randomized line detection algorithm and the geometric relationship of the edge points in the ROI are then employed to identify the defects detected. Experimental results show that the developed automatic visual inspection system is as efficient as manual inspection, and can provide additional information concerning the defects for parameters tuning and quality control.     

阿克苏、连云港和淮安城市居民头发中氢、氧稳定同位素比值差异研究

人类头发中氢、氧稳定同位素比值（δ²H、δ¹⁸O）与其生活的地理位置具有相关性。为考察不同城市常住居民头发中δ²H、δ¹⁸O的差异性,本研究选择了西部的阿克苏和东部沿海的连云港、淮安3个城市常住居民的头发样本为研究对象,利用元素分析仪-稳定同位素比质谱仪（EA-IRMS）进行氢、氧稳定同位素比值检验,采用Bayes算法对检验结果进行判别分析。同时,采用波长扫描光腔衰荡光谱仪对3个城市的居民饮用水进行氢、氧稳定同位素比值检验,分析居民头发与其饮用水中氢、氧稳定同位素比值的相关性。结果表明：阿克苏与连云港、淮安的常住居民头发中氢、氧稳定同位素比值差异显著（P<0.05）;连云港与淮安的差异不显著（P>0.05）。Bayes判别分析结果表明：阿克苏与连云港、淮安的检测结果能够实现较好的区分,而连云港与淮安的区分效果较差;利用δ²H和δ¹⁸O共同作为判别因子的判别准确率高于单独使用δ¹⁸O或δ²H。3个城市常住居民头发与其饮用水中氢、氧稳定同位素比值具有相关性（δ²H：r=0.933;δ¹⁸O：r=0.998）。     

气凝胶隔热材料耐温性研究进展

气凝胶具有极低的热导率,是目前已知热导率最低的固体材料,是一种理想的轻质隔热材料。主要介绍了SiO2气凝胶、Al2O3气凝胶、ZrO2气凝胶耐高温性能的研究进展,同时对耐高温气凝胶隔热材料的发展方向进行了探讨。