Patent ID: 6310643
Filing Date: 2001-10-30
Classification: B31B,G01N

Abstract:
A method of detecting adhesive material (2) applied to a blank (3) from which to form a container for tobacco articles, said blank (3) having prescored lines along which the blank may be folded, the adhesive material (2) forming a number of distinct masses (18) of adhesive material (2) on one face (27) of the blank (3); the method comprising the steps of:reproducing an image (IMD) of at least one part of said face (27) comprising a number of first image portions (IMD1) corresponding to a face (27) portion covered by said masses (18), and a second image portion (IMD2) corresponding to a face (27) portion free of said masses (18);said image (IMD) is generated by a video camera (35) and is defined by a number of pixels (36), each of which is assigned a digital value (VD) and two coordinates (X, Y) depending on the location of the pixels (36) with respect to the image (IMD); the image (IMD) is a digital image obtained from an analog image (IMA) defined by a number of analog values (VA) assigned to the pixels (36); said analog values (VA) being emitted by said video camera (35) as a function of a characteristic brightness of each point on the face (27) of the blank (3);electronically defining a number of given application regions (28) equal to the number of said given masses (18) in said image (IMD); said given application regions (28) corresponding to regions (28) of said blank (3) and each of said application regions (28) being determined according to a respective acceptability criteria, according to which the location of each of said masses (18) is acceptable when inside a respective region (28) and unacceptable when outside said respective region (28) and said acceptability criteria for given masses (18) within the region (28) being defined by a given acceptable range of coverage values (I) extending from a minimum quantity of masses (18) in said region (28) sufficient to join parts of the blank to one another to a maximum quantity of masses (18) to prevent said masses (18) from oozing out of the blank when the parts are joined;converting each analog value (VA) assigned to each pixel (36) in a given application region (28) into a digital value (VD) of 1 or 0, depending on whether said analog value (VA) is respectively above or below a given threshold value (VS);determining within each of said application regions (28) the sum of the number of pixels (36) assigned a digital value (VD) of 1; said sum representing the value of a cover signal (SR) for said given application region (28);emitting said cover signal (SR) for each region 28, the cover signal (SR) corresponding to the portion of said application region (28) occupied by a respective first image portion (IMD1) and thereby defining the quantity of each of said masses (18) inside the respective region (28);comparing the cover signal (SR) of each respective region (28) with the given acceptable range of coverage values (I) for the respective regions (28); andemitting an error signal (SE) when at least one cover signal (SR) associated with a respective region (28 is outside said maximum quantity of said given acceptable range of coverage values (I).