Illumination setting method, apparatus and computer-readable medium for a brightness tool of an image measuring apparatus

摘要

A value of a current corresponding to a relationship between an illumination intensity instruction value and illumination intensity is calculated based on a previously obtained relationship between a current flowing through a light emitting device and the illumination intensity. A calibration table including the illumination intensity instruction value, the calculated value of the current, and the illumination intensity is created. A required illumination intensity is calculated based on exposure time per frame during autofocusing. An illumination intensity instruction value corresponding to the required illumination intensity is calculated using the calibration table. The calculated illumination intensity instruction value is set using the calibration table such that brightness of a measured image remains consistent even when a frame rate is changed.

主权项

1. A method of setting illumination of an image measuring apparatus, the method comprising:
calculating a value of a current corresponding to a relationship between an illumination intensity instruction value and illumination intensity based on a previously-obtained relationship between a current flowing through a light emitting device and the illumination intensity; creating a calibration table including the illumination intensity instruction value, the calculated value of the current, and the illumination intensity; storing, in a memory, the calibration table; emitting light, by the light emitting device, at a work piece; performing autofocusing of the image measuring apparatus; determining exposure time per frame during the autofocusing; calculating a required illumination intensity based on the determined exposure time per frame; calculating an illumination intensity instruction value corresponding to the required illumination intensity using the calibration table; and setting the calculated illumination intensity instruction value for measuring the work piece.