Title:
METHOD FOR DETECTING PRINT DEFECT ON METAL CAN
Document Type and Number:
Japanese Patent JP3405085
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To detect a print defecte.g. a flaw, on the surface of a metal can accurately in a short time.
SOLUTION: While turning a metal can having printed surface, image of the surface print is picked up and then the Xaxis and Y-axis distributions of the print image are calculated and compared with those of a reference print image. Both print images are then matched each other to eliminate the shift of Xaxis and Y-axis distributions before being divided into a plurality of blocks of small region. Furthermore, an arbitrary block of at least one print image is fixed and the block of the other print image corresponding to the arbitrary block is moved while being superposed partially in a predetermined peripheral region. The blocks of both print images are compared each other every time when the block is moved and absolute value of the difference of gray scale value is determined for each pixel in both blocks. A comparison block having the smallest difference of gray scale value is then specified and compared with a fixed block for all print images thus detecting a print defect.
Inventors:
Junichi Takada
Application Number:
JP24155396A
Publication Date:
May 12, 2003
Filing Date:
September 12, 1996
Export Citation:
Assignee:
Toyo Seikan Co., Ltd.
International Classes:
G01N21/89; G01N21/88; G01N21/93; G01N21/952; (IPC1-7): G01N21/89; G01N21/952
Domestic Patent References:
| JP5126762A | ||||
| JP63168788A | ||||
| JP7192132A | ||||
| JP60159972A | ||||
| JP8152413A |
Attorney, Agent or Firm:
Kenji Yoshida (1 person outside)
Previous Patent: CONTROLLER OF SERIES HYBRID ELECTRIC VEHICLE
Next Patent: THREAD JOINT FOR OIL WELL PIPE
Next Patent: THREAD JOINT FOR OIL WELL PIPE