US Patent 11593578 Data encoding in printed material using varying IR reflective materials

Disclosed herein are methods and systems for encoding data in composite patterns such that the encoded data is perceptible in one or more infrared spectral ranges while significantly imperceptible in visible light spectral range by encoding the data in one or more first partial patterns and/or in one or more second partial patterns of the composite pattern where the first partial pattern(s) is painted using a first print material and the second partial pattern(s) is painted using a second. The first and second paint materials are characterized by reflecting substantially similar light in the visible light spectral range and significantly different light in the infrared spectral range(s) such that the first and second patterns are indistinguishable in the visible light spectral range while highly distinguishable in the infrared spectral range(s). further disclosed are methods and systems for decoding the composite patterns to decode and extract the encoded data.