| 摘要 |
A method and a device for optical monitoring of at least one string, especially glue string (2, 3), continuously transported on an underlayer (1) in a first plane in one first direction (4), substantially coinciding with the longitudinal direction of the glue string, is disclosed. The device comprises a light source (5, 6) for directing light towards the glue's string and a camera (7) with a detector (8) in the focal plane in the form of a CCD line array, for continuous imaging of one part of the glue string. The camera is provided to emit one corresponding digital video signal, which is fed to a signal processing unit (9). The light source is provided to direct light substantially perpendicularly, alpha DEG , towards said first direction (4), in an angle beta DEG between 0 DEG and 90 DEG relative to said first plane (1), the camera being directed substantially perpendicularly straight above the glue string, with the CCD-line array substantially at right angle relative to the first direction. The device is characterized primarily in that the signal processing unit (9) is provided to store in a first memory, one video signal coming from the camera (7), continuously intermittenly forming a gradient, combined with information, coming from a position determining means (8, 10, 11) about the position of a glue string (2, 3), to a first table as a reference, and that the signal processing unit (9) is provided to store, correspondingly, in at least one second memory, video signal and position for at least one individual glue string so that there is obtained for this an individual table, the signal processing unit (9) being provided to continuously compare the second table with the first table, and at a difference, above a certain, previously determined level, give an indicating signal.
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