There is provided detecting modification of optically active cellulose-based film. A method comprises split refracting or split reflecting (302) light received by a surface pattern of an optically active cellulose-based film into a plurality of output light patterns, wherein an output light pattern is determined from the plurality of output light patterns on the basis of a modification applied to the optically active cellulose-based film.
Patent family as of 17.6.2022:
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|IPC||G06T 7/ 00 A I|
|Publication status||Published - 6 May 2021|
|MoE publication type||H1 Granted patent|