公开(公告)号：US5047851A

公开(公告)日：1991-09-10

申请号：US485133

申请日：1990-02-26

申请人： Kurt Sauerwein ,  Hans P. Busse ,  Rainer Link ,  Helmut Wiacker ,  Christian Stapf ,  Rudiger Schulz ,  Ekhard Stolzenberg ,  Kurt Disselhorst ,  Herbert Burghoff ,  Karl Kirchesch ,  James D. Lean ,  Laurence F. Topping ,  Wolfgang Zindler

发明人： Kurt Sauerwein ,  Hans P. Busse ,  Rainer Link ,  Helmut Wiacker ,  Christian Stapf ,  Rudiger Schulz ,  Ekhard Stolzenberg ,  Kurt Disselhorst ,  Herbert Burghoff ,  Karl Kirchesch ,  James D. Lean ,  Laurence F. Topping ,  Wolfgang Zindler

IPC分类号： G01N21/88 ,  G01N21/91 ,  G01N21/93 ,  G01N27/84

CPC分类号： G01N21/91 ,  G01N21/93 ,  G01N27/84 ,  G01N2021/8887 ,  G01N2021/8896 ,  G01N2021/936 ,  G01N2201/102

摘要： A process and device for detecting and evaluating surface cracks in workpieces wherein a picture is produced of the surface of the workpiece by means of a video camera and said picture is digitized and is processed by means of a computer to produce a binary picture of any cracks present and a sorting report is triggered when a preselected threshold level is exceeded. In order to obtain a sorting signal that is independent of the absolute brightness of the original picture a blurred background picture is derived from the original picture levels that have been converted to digitized grey shade levels and subtracted from the original picture, the difference picture formed in this way giving the crack representation. A dynamic threshold level for the sorting signal is determined by comparing the grey shade distribution of the original or the difference picture with at least one previously evaluated or difference picture and a binary picture is produced from the original or the difference picture and the grey shade threshold, and picture elements with their gray shades exceeding the set threshold are indicated as defects. The surface of the workpiece may be pre-treated by the magnetic powder or dye penetration process and/or contrast intensifying means.

摘要翻译： 一种用于检测和评估工件中的表面裂纹的工艺和装置，其中通过摄像机产生工件表面的图像，并且所述图像被数字化，并且通过计算机进行处理以产生任何裂缝的二进制图像 当超过预先选择的阈值水平时触发排序报告。 为了获得独立于原始图像的绝对亮度的分类信号，从已被转换成数字化灰度级并从原始图像中减去的原始图像级别导出模糊背景图像，形成在 这样给出裂纹表示。 通过将原始或差分图像的灰度分布与至少一个先前评估的或差分图像进行比较来确定分类信号的动态阈值水平，并且从原始图像或差分图像和灰度阈值产生二值图像 ，其灰度超过设定阈值的图像元素被表示为缺陷。 可以通过磁粉或染料渗透过程和/或对比增强装置对工件的表面进行预处理。