Real-time, full web image processing method and system for web manufacturing supervision

Abstract

A method for detection of distinctive features in a web being transported in a moving direction during a web manufacturing process including the steps of: a) acquiring an image of the web, including a plurality of pixels P i with iϵ{1; . . . ; p}, b) identifying a plurality of regions of interest each corresponding to a distinctive feature by processing the plurality of pixels P i by: c) selecting a local pixel unit including a subset P j with jϵS⊂{1; . . . ; p} of the plurality of pixels, the subset i) being representative of a subregion of the digital image, and ii) different from previously selected local pixel units, d) deciding whether the local pixel unit is of interest or not, i) if the local pixel unit is of interest, 1) identifying whether the local pixel unit is located within an impact area A k of a previously identified region of interest R k with kϵA⊆{1; . . . ; n}, 2) if the local pixel unit is not located within any impact area A k of any previously identified region of interest R k with kϵA⊆{1; . . . ; n}, or no regions of interest have previously been identified, (a) identifying the local pixel unit as a new region R n+1 of interest; (b) initializing an impact area A n+1 for the new region R n+1 of interest; (c) incrementing a counter n representative of the number of previously identified regions of interest; if the local pixel unit is located within an impact area A k 0 of a previously identified region of interest R k 0, (a) merging, depending on a merging condition, the local pixel unit with the previously identified region of interest R k 0, (b) if the merging condition is fulfilled, updating the impact area A k 0 of the region of interest R k 0; ii) preferably, if the local pixel unit is not of interest, identifying whether the local pixel unit is located within an impact area A k of a previously identified region of interest R k with kϵ{1; . . . ; n},if the local pixel unit is located within an impact area A k 0 of a previously identified region of interest R k 0, updating the impact area A k 0; e) repeating steps b) through d) until at least essentially all pixels of the image have been processed.