| 摘要 |
Method and apparatus for automatically evaluating an indentation produced in a material according to the Vickers hardness testing method. A diaphragm apertured in two coordinate directions is guided over an image of the indentation, while a photoelectric receiver system produces an electrical signal representing the luminous flux passing through the diaphragm. The electrical signal is differentiated, and changes in the differentiated signal exceeding predetermined thresholds are used to indicate detection of edges of the indentation. The respective positions of the diaphragm when the indentation edges are detected, and a known dimension of the diaphragm, are used to calculate the length of a diagonal of the indentation.
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