Method for measuring Z height values of a workpiece surface with a machine vision inspection system

摘要

A method for measuring Z height values of a workpiece surface with a machine vision inspection system comprises illuminating a workpiece surface with structured light, collecting at least two stacks of images of the workpiece, each stack including a different X-Y position between the structured light and the workpiece surface at a corresponding Z height in each of the stacks, and determining Z values based on sets of intensity values of a pixel corresponding to the same workpiece position in the X-Y plane which are at the same Z heights. The X-Y position is changed at a slower rate than the Z height in each stack of images, and is changed either continuously during each of the at least two stacks at a slower rate than the Z shift, or fixed to a different value during each of the at least two stacks.