Optical information reading method, optical information reading device, and storage medium

An optical information reading device comprising:

• an imager;
• an imaging controller configured to cause the imager to periodically capture an image;
• a reading part configured to analyze the image captured by the imager to read optical information contained in the image;
• and
• an adjusting part configured to adjust an imaging condition of the imager so that a brightness index value of an image to be obtained in subsequent capturing reaches a predetermined target level, the brightness index value of the image captured by the imager being calculated based on pixel values of pixels in the image, the brightness index value being determined based on a threshold obtained by classifying pixels sampled from the image captured by the imager into a first class of dark pixels and a second class of bright pixels based on variance of pixel values of the pixels within each class.

A non-transitory machine-readable storage medium containing program instructions executable by a computer, and when executed, causing one computer or a plurality of computers in cooperation to execute an optical information reading method, the method comprising:

• periodically capturing an image by an imager;
• analyzing the image captured by the imager to read optical information contained in the image;
• and
• adjusting an imaging condition of the imager so that a brightness index value of an image to be obtained in subsequent capturing reaches a predetermined target level, the brightness index value of the image captured by the imager being calculated based on pixel values of pixels in the image, the brightness index value being determined based on a threshold obtained by classifying pixels sampled from the image captured by the imager into a first class of dark pixels and a second class of bright pixels based on variance of pixel values of the pixels within each class.