Sheet recognition unit, sheet handling device, sheet recognition method, and non-transitory computer-readable storage medium

A sheet recognition method comprising:

• a step of irradiating a sheet on which a photoluminescent ink to be recognized is printed, with at least excitation light from a light source;
• a step of receiving, with a light sensor, photoluminescence emitted from the sheet irradiated with the excitation light and outputting a photoluminescence detection signal;
• and
• a step of recognizing the sheet based on a photoluminescent image of the photoluminescent ink to be recognized and a learned model, the photoluminescent image being generated from the photoluminescence detection signal output from the light sensor.

A non-transitory computer-readable storage medium storing a sheet recognition program,

• the sheet recognition program causing a sheet recognition unit to execute:
• a processing of irradiating a sheet on which a photoluminescent ink to be recognized is printed with at least excitation light from a light source;
• a processing of receiving, with a light sensor, photoluminescence emitted from the sheet irradiated with the excitation light and outputting a photoluminescence detection signal;
• and
• a processing of recognizing the sheet based on a photoluminescent image of the photoluminescent ink to be recognized and a learned model, the photoluminescent image being generated from the photoluminescence detection signal output from the light sensor.