金属疲劳条带显微图像的曲线拟合分析

A Curve Fitting Analysis of the Micro-Image for Fatigue Streaks in Metals

金属的疲劳试验是在交变应力(即变动负荷)下反复地长时间对金属机件进行的.由此金属内部发生组织结构上的变化,而产生不同的疲劳条带.分析这些条带的产生、走向及间距,对研究金属的性能是至关重要的.怎样确定这些条带及其产生的时间,通常是用人工对其显微放大图片进行条带寻找、定位、量取、计算来完成,工作量之大、之复杂是显而易见的.随着科学技术不断发展,用计算机图像处理技术替代人工对金属材料进行分析,有显著优越性.本文利用图像处理系统对金属条带进行分析,得到了一些初步结果.1 图象处理系统分析金属疲劳条带的设计原理用计算机图像处理系统分析金属疲劳条带,必须将金属疲劳条带的图片用摄像机输入到图像处理系统,并用曲线拟合的方法对图像中的条带进行曲线拟合.

The application of an image processing system in investigating the curve fitting of the micro-image for fatigue streaks in metals is described. For steel and aluminum alloys, the fatigue streaks exhibit a certain regularity in that they look like quadratic curves. For this reason, an ellipse curve has been used for the curve fitting of the streaks. Both the immediate and iterative ellipse fitting methods have been tried. The height parameters of the fatigue streaks are calculated. It has been found that the calculating accuracy by computer is better than that by hand as can be seen from the test results.