Image measurement can be roughly divided into three methods: contour measurement, surface measurement, and Z – axis measurement.
Contour measurement
This involves measuring the edge contour of the workpiece. Generally, bottom light is used to measure the contour. If necessary, surface light can also be added as auxiliary lighting to make the measured edge line clearer. This is beneficial for measurement and can reduce the error of the measurement result.
Surface measurement
Surface measurement is the main function of image measurement. Almost all the surface shapes of visible objects can be measured by the image measuring instrument under the illumination of surface light. For example, the dimensions of mechanical parts, circuit copper foils on PCB boards, IC circuits, and even plastic and rubber products can be easily measured.
Z – axis measurement
When equipped with a high – power objective lens and with sufficient aiming and positioning accuracy, and using surface light for illumination, the image measuring instrument can perform Z – axis measurement. For instance, it can measure the step height of workpieces, the depth of blind holes, etc.