Patent ID: 7015447

Claim:
An illuminance calibrating method of an illuminator having a light source capable of changing illuminance thereof according to an applied current value, the illuminator irradiating an illumination light of an illuminance in accordance with a command value inputted from the outside for commanding the illuminance of the illumination light, the method comprising: a light-receiving intensity measuring step for taking an image of the illumination light from the illuminator by an image pickup device capable of changing an exposure time thereof to measure the relationship between the applied current value and a light-receiving intensity of the image pickup device while changing the exposure time; a characteristic curve calculating step for calculating a characteristic curve of an intensity of the illumination light of the illuminator and the applied current value based on the result of the light-receiving intensity measuring step; and a command-value/current-value table generating step for generating a table storing the command value and the applied current value based on the calculated characteristic curve.