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

A sheet recognition method for recognizing a sheet on which a photoluminescent ink is printed, the sheet recognition method comprising:

• a first step of emitting at least excitation light to a sheet to be recognized from a light source;
• a second step of receiving, with a light sensor including a plurality of light receiving elements, light emitted from the sheet to be recognized, the sheet being irradiated with the excitation light;
• and
• a third step of calculating an estimated value of a feature amount in the sheet to be recognized, using detection data acquired in the second step and a coefficient based on reference data and the feature amount,
• the reference data being data acquired by emitting the excitation light to a reference medium,
• the feature amount relating to the photoluminescent ink associated with the reference data,
• the coefficient being calculated as a least squares solution with which an error is minimum.

A non-transitory computer-readable storage medium storing a sheet recognition program for recognizing a sheet on which a photoluminescent ink is printed, the sheet recognition program causing a sheet recognition unit to execute:

• a first processing of emitting at least excitation light to a sheet to be recognized from a light source;
• a second processing of receiving, with a light sensor including a plurality of light receiving elements, light emitted from the sheet to be recognized, the sheet being irradiated with the excitation light;
• and
• a third processing of calculating an estimated value of a feature amount in the sheet to be recognized, using detection data acquired in the second processing and a coefficient based on reference data and the feature amount, the reference data being data acquired by emitting the excitation light to a reference medium,
• the feature amount relating to the photoluminescent ink associated with the reference data,
• the coefficient being calculated as a least squares solution with which an error is minimum.