US Patent 10268853 Optical information reading device

[Object] To enhance a reading accuracy of a code even when a light amount, which can be received by an imaging element, varies greatly. [Means to solve the problems] A plurality of second images in response to a plurality of different conversion characteristics is generated by using the first image obtained at the time of setting of an optical information reading device. The results, in which codes included in the generated second images are respectively decoded by a decoding part, are analyzed, and one of the conversion characteristics is selected. The second image in response to the selected conversion characteristic is generated by using the first image at the time of operation of the optical information reading device.