To provide a method and an apparatus for detecting the position of the seam of a seam welded pipe, by which method and apparatus, the position of the seam can be robustly (stably) detected without the erroneous detection due to the change of color of the surface of the pipe caused by heat, rust, etc. in welding and illuminating conditions, etc. (disturbances) in detection.
An image arithmetic processing circuit 4 calculates an autocorrelation function for the groups of pixels of the image of the outer circumference of a seam welded pipe 11, the image having been picked up by a CCD camera 2, and obtains the lines of the pixels having periodicity in the calculated results, and detects the position of the lines of the pixels as the position of the seam. The detection of the position of the seam by calculating the autocorrelation function can provide the detection of the position of the seam, which detection is robust and resistible against disturbances.
Toshio Nakamura
Miyazaki Yoshio
Kaoru Onozuka
Akio Tagami
High Masahiro