Markless Registration System For Labels In Labelling Machines

A method for controlling labelling in labelling machines comprising the sequential steps of:

• in a first step, determining which part of the printed matter of a test label in a label film has a maximum measure of signal-to-noise ratio or contrast to constitute a reference region;
• in a second step, identifying a processing region of a subsequent processing label of the label film;
• in a third step, comparing corresponding points of said processing region with said reference region and computing the length of the processing label;
• in a fourth step, reading each processing region of each subsequent processing label, comparing it with said reference region, and computing the length of the processing label, and
• in a fifth step, controlling an operation of the labelling machine as a function of the label length computed in the previous step.

A method for controlling labelling in labelling machines, comprising the steps of:

• reading one or more test labels in the label film, or a heading of one or more labels of said label film;
• selecting part of or the whole region of the printed matter of said one or more test label as a reference region that functions as a virtual mark of the label, wherein said selection is made on the basis of the maximization of the signal-to-noise ratio or of a contrast measure;
• reading a subsequent processing label of the label film and identifying a processing region in said label under examination by comparing it with the reference region previously selected in the one or more test labels;
• computing the length of the processing label under examination as the distance between corresponding points of said processing region and of the reference region of the one or more test labels;
• reading each of the subsequent processing labels in an iterative manner, identifying a processing region in said label under examination by comparing it with the reference region previously selected in the one or more test labels and computing the length of the processing label under examination as the distance between said processing region and the processing region of the immediately preceding processing label;
• and
• controlling an operation of the labelling machine as a function of the label length computed in a previous step.

A method for controlling labelling in labelling machines comprising the steps of:

• 1A) Feeding a label film causing it to pass through an optical sensor and inputting a first signal of label start and a second signal of label end to the computing and control system, said first and second signals being associated with a first and second spatial coordinate values, respectively, the interval between said first and second spatial coordinate values defining the test label length;
• 2A) Reading the printed matter associated to a test label on the label film by passing said test label along a reading path for the optical sensor and acquiring a set of signals associated to said test label, to each signal being associated a given signal-to-noise ratio or a given contrast measure and a spatial coordinate value, so that to create a set of spatial coordinate values;
• 3A) Repeating step 2A) on at least one subsequent test label of the label film;
• 4A) Comparing the signals acquired according to steps 1A) to 3A) and selecting a reference region of the acquired set of signals, said reference region being the region wherein the signal-to-noise ratio (SNR) or the contrast measure is maximised, a subset of spatial coordinate values being associated to said reference region, said subset comprising a first and second spatial coordinate values that identify, with respect to said reading path, the start point and the end point, respectively, of said reference region of the test label;
• 5A) Computing an offset reference value between said start point or said end point of the reference region of the test label and the label start point or alternatively between said start point or said end point of the reference region of the test label and the label end point, said offset reference value being associated with an interval of spatial coordinate values.