A tutorial on the segmentation of metallographic images: Taxonomy,new MetalDAM dataset,deep learning-based ensemble model,experimental analysis and challenges

Image segmentation is an important issue in many industrial processes, with high potential to enhance the manufacturing process derived from raw material imaging. For example, metal phases contained in microstructures yield information on the physical properties of the steel. Existing prior literature has been devoted to develop specific computer vision techniques able to tackle a single problem involving a particular type of metallographic image. However, the field lacks a comprehensive tutorial on the different types of techniques, methodologies, their generalizations and the algorithms that can be applied in each scenario. This paper aims to fill this gap. First, the typologies of computer vision techniques to perform the segmentation of metallographic images are reviewed and categorized in a taxonomy. Second, the potential utilization of pixel similarity is discussed by introducing novel deep learning-based ensemble techniques that exploit this information. Third, a thorough comparison of the reviewed techniques is carried out in two openly available real-world datasets, one of them being a newly published dataset directly provided by ArcelorMittal, which opens up the discussion on the strengths and weaknesses of each technique and the appropriate application framework for each one. Finally, the open challenges in the topic are discussed, aiming to provide guidance in future research to cover the existing gaps.     

BSE系列耐低温乳化型震源药柱

概述了作药震源在石油、天然气地震勘探中的重要作用与国内现状。阐述了ＢＳＥ系列耐低温乳化型震源药柱的组分选择、品种配方、生产工艺与主要性能，讨论了该系列震源药柱的使用技术与获得的结果，预测了该系列震源药柱对我国地霞勘探技术发展的影响．     

基于H.264的煤矿井下无线视频通信

煤是我国的第一能源。要振兴煤炭工业，最重要的一条是依靠现代科学技术和提高现代化管理水平。但是，从我国目前煤矿现有的硬件装备及软件等技术水平来看，还远远达不到煤矿现代化通讯、煤炭生产及安全管理手段的要求。煤炭开采主要以井下为主，巷道可达数千米。矿井生产工序多、作业地点分散，人员流动性大且工作环境恶劣，事故隐患极大。矿井生产的这些特点对于建立一个良好的无线通信系统有着迫切的要求，而无线视频通信的实现，将是系统中最重要也是最具挑战性的工作。     

影响线切割加工工件表面质量因素及改善措施

对在线切割加工中影响工件表面质量的机床结构、运丝机构、切割参数、工艺参数、电参数、工件材料、工作液等进行分析,并就相应的影响程度提出了相应措施和改善办法。     

利用阈值分割技术提取煤泥浮选泡沫图像的物理特征

探讨了煤泥浮选泡沫图像特征的提取方法，首先将RGB图像转化为灰度级图像，再采用直方图均衡化和局域中值滤波处理，以改善图像的对比度，利用阈值分割技术和二值化处理方法提取了气泡的个数，对亮点的面积，形状，周长进行了计算，求出了气泡的粒度分布，通过对51幅煤泥浮选泡沫图像的研究。发现该方法适用于亮点明显，气泡粒度大的图像，可以用来指导煤泥浮选的操作。     

嵌入式Web视频服务器的设计

嵌入式Web视频服务器监控系统以ARM芯片作微处理器,摄像机视频信号压缩采用MPEG-2编码格式并在嵌入式Linux中内置服务器应用程序.数据采集压缩模块实时采集视频数据,压缩后发给网络传输模块,媒体流经ARM芯片发到Internet.该服务器直接浏览Web视频,授权用户可控制摄像机或对系统配置操作,实现远端现场监控.     

Characterization of particulate emissions from occupant activities in offices

This paper characterizes the relationship between occupant activities and indoor air particulate levels in a non-smoking office building. Occupant activities were recorded on video. Particulate concentrations were monitored by three optical particle counters (OPCs) in five size ranges at three heights. Particulate mass concentrations were measured gravimetrically and bioaerosol concentrations were determined by impaction methods. Occupant activities and number concentrations were determined with 1-min resolution over a 1-week period. Occupant activities such as walking past or visiting the monitoring site explained 24-55% of the variation of 1- to 25-micron diameter particle number concentrations. Statistical models associating particulate concentrations with occupant activities depended on the size fraction and included an autocorrelative term. Occupant activities are estimated to contribute up to 10 micrograms m-3 in particulate concentrations per person. Number concentrations of particles smaller than 1 micron had little correlation with indoor activities other than cigarette smoking and were highly correlated with outdoor levels. The method can be used to characterize emissions from activities if rapid measurements can be made and if activities can be coded from the video record.     

Land cover mapping with patch-derived landscape indices

Automated-classification procedures of satellite imagery are mainly based on surface reflectance and generally ignore shape and size of landforms. On the other hand, quantitative landscape ecology has been focused on the patch concept as a landscape unit due to its relevance in the theory and practice of the conservation of species in human-modelled landscapes. The present paper explores how landscape metrics can introduce the component of spatial pattern of landscape elements to enhance land cover classification reliability. In particular, a method is proposed to extract patch-derived indices and to introduce them in a supervised classification of Landsat Thematic Mapper (TM) images as neo-channels. To extract patch-derived indices, an image segmentation method based on edge detection was used to define patches without an a priori knowledge of land cover classes. We calculated four patch indices: area, perimeter, shape index and fractal dimension. These indices were introduced in the classification to test the improvement of classification reliability. Well-known additional information (texture and topographic features) was also tested for comparison purposes. The method was tested for mapping land cover types in a mountainous region in the French Pyrenees, the Massif of Arize. The results of classification reliability allowed us to conclude that patch indices and topographic features significantly improved the discrimination of land cover classes. The combination of these additional information types by means of data fusion is useful for land cover classification purposes.     

石拱桥的有限弹簧法分析及其安全性评价

依据计算几何学的分割理论,开发了对石拱桥进行任意形状单元划分的计算机前处理系统,提出了用有限弹簧法模拟石拱桥力学性能的计算方法。其特点是能够把石拱桥的拱圈看成个别石材块体构成的不连续体,考虑拱圈随着偏心压缩而引起的石材块体间开口变形的同时,也考虑拱背填料和拱圈的相互作用及其它的荷载分散效果。数值模拟了多跨石拱桥在分布活荷载及其水平地震荷载作用下的力学性能,并进行了安全性评价。     

AutoCAD中圆弧折线化方法与实现

AutoCAD作为一种重要的地形图制图软件,图中存在大量的圆弧图元。由于圆弧只有端点或圆心坐标,弧线本身缺乏精确的坐标信息,因此导致一些数据检查时出错。Auto CAD软件本身不提供圆弧转折线的功能。本文尝试采用等角切分方法,利用VBA二次开发技术,在保持图形原有特征及精度要求的前提下,将圆弧、圆及多段线中的圆弧分别转换为纯折线的多段线,从而去除圆弧部分。满足基础地理信息数据库建库等特殊的数据需求。