Moire Method to Measure Surface Depth Profiles on Unevenly Corroded Metals

本文介绍了一种由微机、电视摄像机和图象输入处理单元组成的用于测量不均匀腐蚀金属表面三维形貌的自动化系统。当样品向下移动时，照明光和光栅在样品上产生由明暗条纹组成的莫尔条纹。每个点的深度是通过分析亮度变化来确定的，亮度变化是到达暗条纹中心所需的步数。该系统的校准与维氏压痕和钻孔深度范围从50至360<micro>米。该系统测量的深度与光学显微镜测量的深度在10 m的误差范围内一致<micro>。这些应用是用暴露在流动海水中的黄铜试样和低合金钢进行的。

An automated system is presented which consists of a microcomuter, a TV camera and an image input processing unit to measure three dimensional profiles for unevenly corroded metal surfaces. When a specimen is moved downward, an illumination light and a grating present moire patterns projected onto the specimen which consist of bright and dark fringes. Depth of each point is determined by the analysis of the brightness variation as the number of steps required to reach the dark fringe center. Calibrations of the system were made with Vickers indentations and drilling holes with depths ranging from 50 to 360 <micro> m. The depths measured by this system coincided with the ones done by an optical microscope within error of 10 <micro> m. The applications were made with a brass specimen and a low alloyed steel which had been exposed in flowing sea water.