Testing Brinell indentation needs applying optical instrument to measure the size of indentation. The traditional testing method is to use the reading microscope shown as following. 

In recent years, an advanced indentation measurement began to be applied. The system is made of camera and image processing software. The camera is used as indentation testing head, while the image processing software is instored in the computer. While testing, place the testing head on indentation, then there is relevant indentation image on the computer display screen. Move the 4 lines with mouse and make them tangent with the circumference of the indentation. Or choose 3 points on the clear part of indentation circumference, and the display screen will appear the indentation diameter and hardness value(shown as following).

An indentation measurement system with better capacity is shown as Figure 3. This instrument researched and produced by Shenyang Tianxing has advanced image processing software, measuring various indentation on common pretreatment surface 100% automatically. As long as putting the test head on indentation, there would be image of the indentation and indentation diameter and Brinell hardness value on the display immediately. The pretreatment surface can be polished by angle grinder, grinding machine or abrasive paper, or processed by various machine tool, even some iron stained indentation could also be measured. This indentation measurement system with automatic testing ability could be applied in the hardness automatic test lines.