Method and system for determining a pattern deviation value of a visible surface of a panel

A method for determining a pattern deviation value of a top surface of a floor panel or wall panel, comprising the steps of:

• a) providing at least one panel having a top surface;
• b) providing at least one database comprising a plurality of standard pattern values of the panel;
• c) selecting at least one standard pattern value from the database;
• d) capturing at least one image of at least part of the panel,
• e) determining at least one pattern value of at least part of the image, wherein the top surface of the panel is illuminated with blue light, red light, or a combination thereof, and
• f) calculating a pattern deviation value based upon the at least one pattern value determined during step e) and the at least one standard pattern value selected during step c)
• wherein after step d), at least one dominant colour region of the at least one image captured is determined, wherein the at least one pattern value in step e) comprises at least one colour value of the dominant colour region, wherein the pattern deviation value is a geometric mean difference value, and wherein a threshold value for the pattern deviation value is 1 or lower.