INFORMATION INPUT ASSISTANCE SHEET, DOT CODE OPTICAL READING DEVICE USING INFORMATION INPUT ASSISTANCE SHEET, DOT CODE INFORMATION PROCESSING SYSTEM, AND CALIBRATION METHOD

摘要

The present invention addresses the technical problem of providing an information input assistance sheet capable of reading a dot pattern even if an optical reading device is inclined relative to the information input assistance sheet, and capable of absorbing or attenuating unnecessary reflected infrared light, excluding infrared ray reflection patterns, or capable of changing a wavelength region. The optical reading device comprises: an infrared irradiation means that irradiates infrared rays of a prescribed wavelength region; a filter that causes at least infrared rays of the prescribed wavelength region to be transmitted therethrough and blocks visible light; an imaging means that captures images of at least infrared rays of the prescribed wavelength region; and a decoding means that decodes dot pattern images captured by the imaging means, into dot code. Dots in the dot pattern are characterized by being printed onto a transparent sheet by using an ink having: infrared ray expansion properties in at least the prescribed wavelength region; or infrared ray expansion and reflection properties and visible light transmittance properties.