Patent ID: 8581162
Filing Date: 2013-11-12
Classification: G01B,G02B,G06T

Abstract:
1. A method for operating a precision machine vision inspection system to determine Z-height quality meta-data associated with focus-based Z-height measurements on a workpiece, the precision machine vision inspection system comprising an imaging portion, a focusing portion, and a control portion comprising an image processor, the method comprising: (a) defining at least one focus region of interest on the workpiece for which Z heights and Z-height quality meta-data are to be determined; (b) acquiring an image stack set of images of the at least one focus region of interest, the image stack set comprising member images acquired at corresponding known Z heights throughout a focus range; (c) determining a focus peak determining data set for the at least one focus region of interest based on the image stack set, wherein the focus peak determining data set comprises focus metrics based on the at least one focus region of interest in the member images; (d) determining a best focus Z height for the at least one focus region of interest, based on the focus peak determining data set for the at least one focus region of interest; (e) determining Z-height quality meta-data corresponding to the best focus Z height for the at least one focus region of interest, wherein the Z-height quality meta-data is based on data used to determine the best focus Z height for the at least one focus region of interest, and the Z-height quality meta-data is indicative of at least one of the reliability and the uncertainty of the corresponding best focus Z height for the at least one focus region of interest; and (f) associating the Z-height quality meta-data for the at least one focus region of interest with the corresponding best focus Z height for the at least one focus region of interest, such that the Z-height quality meta-data for the at least one focus region of interest are usable to establish Z-height quality weighting factors that are used in association with the corresponding best focus Z height for the at least one focus region of interest in subsequent operations that fit a workpiece surface representation to a plurality of the best focus Z heights.