Patent ID: 6888635

Claim:
A method for detecting fiducial marking in a tufted carpet material, comprising the steps of a. providing tufted carpet material with at least one fiducial marking, the fiducial marking being in a configuration designed to be related to the pattern of the tufted carpet and characterized by the ability to absorb light in a first wavelength range and to fluoresce in a second wavelength range that is at least partially outside the first wavelength range, b. directing light at the tufted carpet material in the first wavelength range, to cause the fiducial marking material to absorb the light in the first wavelength range and to fluoresce in the second wavelength range, and c. optically examining the tufted carpet material at a predetermined detection site relative to the tufted carpet material, to determine whether fluorescence from the fiducial marking which is in the second wavelength range is detected at the predetermined detection site and to provide output related to the configuration of the fiducial marking.