DIFF Subgroup
G01N 21/8983 Full Title
Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light (G01N3/00 - G01N19/00 take precedence) > Systems specially adapted for particular applications > Investigating the presence of flaws or contamination > in moving material, e.g. running paper or textiles (G01N21/90, G01N21/91, G01N21/94 take precedence) > characterised by the flaw, defect or object feature examined > Irregularities in textured or patterned surfaces, e.g. textiles, wood