土木工程专业外文翻译1.doc

中国地质大学长城学院本科毕业论文外文资料翻译外文资料翻译译文对土木工程的发展起关键作用的，首先是作为工程物质基础的土木建筑材料，其次是随之发展起来的设计理论和施工技术。每当出现新的优良的建筑材料时，土木工程就 会有飞跃式的发展。土木工程是具有很强的实践性的学科。在早期，土木工程是通过工程实践，总结成功的经验，尤其是吸取失败的教训发展起来的。从17世纪开始，以伽利略和牛顿为先导的近代力学同土木工程实践结合起来，逐渐形成材料力学、结构力学、流体力学、岩体力学，作为土木工程的基础理论的学科。这样土木工程才逐渐从经验发展成为科学。 工程图纸矢量化是把扫描所得到的光栅图像加以处理、分析、识别并最终转换成矢量图形格式的过程。矢量化研究是图纸复用、自动理解等应用的基础，是目前cad领域的一个研究热点。本文在研究了目前有代表性的扫描图纸识别输入系统和矢量化算法的基础上，利用可视化编程语言visual c+初步完成了一个矢量化软件。它包括图像预处理、自动矢量化、图形格式转换以及人工交互方式的光栅图像和矢量图形编辑等功能。 图像预处理是矢量化技术的前期准备阶段，有图像去噪、图像分割、图像细化等步骤。 直线是工程图中最基本的并且占绝对多数的图形元素，许多更高层次的图元如圆、圆弧等都是以直线为基础的，因此直线矢量化的质量成为评价矢量化性能的重要指标。本文在大量统计各种直线像素构成特点的基础上，分析了直线链码所出现的概率性规律，使直线链码的特征在freeman约束条件中显得具体化，提出了基于概率模型的直线矢量化方法，概率特点体现在两个方面：直线后续跟踪点的选择和第一次直线合并过程中。实践证明这种方法可以满足直线的最大延伸原则，从而减少直线分段现象。以直线为基础运用曲线拟合的方法实现二次曲线的矢量化；在自动矢量化过程中解决了基于细化的方法无法提取线宽信息的难题。 为了进一步提高图像处理的效果和矢量化的准确度，本文在图像处理阶段和自动矢量化后阶段均提供了简单的编辑功能，既可以对图像进行像素级操作，也可以对矢量化过程中产生的失真现象进行修正；同时给出矢量化数据到cad软件的图形格式转换接口，从而有利于和cad环境的无缝联接。 本文在工程图纸矢量化方面只是进行了简单的尝试，还存在许多问题，有待于进一步完善。外文原文civil engineering for the development of a key role, first as a material foundation for the civil engineering construction materials, followed by the subsequent development of the design theory and construction technology. every time a new quality of building materials, civil engineering will be a leap-style development. civil engineering is a very practical subjects. in the early days, through the civil engineering practice, summing up successful experience, in particular, to draw lessons from the failure of developed. from the beginning of the 17th century, with galileo and newton as a pilot with the mechanics of the modern civil engineering practice, gradually formed the mechanical, structural mechanics, fluid mechanics, rock mechanics, civil engineering as the basis of theoretical subjects. this experience in civil engineering from the gradually developed into a science. engineering drawing vectorization, i.e, raster-to-vector conversion, is the process of analyzing the scanned image of an engineering drawing in paper form and recognizing the graphic objects in the drawing, and finally, generating the vector format. vectorization is the foundation of the activities of reusing old drawings and the automatic interpretation of engineering drawings. it has been and still is a well-focused topic in cad research field. in this paper, on the bases of analyzing typical engineering drawing inputting and vectorization algorithm, this dissertation realizes this vectorization software using the technology of oop. it includes image preprocessing, graphics auto-recognition, graphics format conversion and human-computer interactive method, such as raster image edition and vector graphics edition.image preprocessing includes image filtering, image segment, image thinning, etc. this dissertation explains the thought and implementation technology of these algorithms;line is basic and the most graphic element in engineering drawing.line forms many high level graphic elements, for example circel, arc. so the quality of line vectorization is a very important mark in vectorization performance analyzing.on the bases of analyzing all kinds of lines pixel distribution characteristic, freeman restriction condition of line chains becomes clear. line vectorization is the foundation of other graphic vectorization. this dissertation analyses the feature of lines freeman chain code, then brings forward a new line vectorization method based on probability property model including selecting the next line tracking pixel and the first line mergence procedure. this method can satisfy maximum line extending principle , and can reduce line segmentphenomenon.the paper realizes the vectorization of conic , circle and arc using curve fitting method. this line vectorization method can recognise line width information.in order to improve the effect of image and the exactitude of vectorization, this dissertation supplies raster image edition and vector graphics edition, which can make pixel operation and amend image vectorization results. at the same time it supplies the image transform to the form of cad and can be edited and modified in the condition of cad.this d