John B Oehrle

US Patent:

49454900, Jul 31, 1990

Filed:

Apr 11, 1988

Appl. No.:

7/179598

Inventors:

Ernest L. Biddle - Bryn Mawr PA
John D. Laessig - Newtown Square PA
John B. Oehrle - Villanova PA

International Classification:

G06K 900
G01N 342

US Classification:

364506

Abstract:

Methods and apparatus for performing Brinell hardness test measurements produce hardness numbers and average Brinell indentation diameter readings automatically and minimize operator intervention and hence, operator error. The apparatus uses a light source, a video camera, a video image digitizer and a computer having a display device. In the method of the invention, electromagnetic radiation is applied to the indentation at an acute angle to the surface of the test specimen in which the indentation has been made. The electromagnetic radiation reflected from the indentation and the surrounding area is sensed. Differences in intensity, such as between light and dark, are digitized and the resulting digital field is numerically analyzed to produce a diameter, preferably major and minor diameters, of the Brinell hardness impression. The diameter or major and minor diameters are used to compute a Brinell hardness number which is displayed by the computer.