| 摘要 |
PROBLEM TO BE SOLVED: To enable a contactless and highly accurate circularity measurement without making pipes still, and thus, enable the circularity measurement right after a process of pipe expansion in a pipe production line.SOLUTION: When measuring circularity of a pipe P in large diameter different in an outer diameter, an axial direction end surface of the pipe P is photographed by a camera 4, and a position of the axial direction end surface of the pipe P to be photographed by the camera 4, that is, diagonal four points L1 to L4 is illuminated by an illumination device 5. A center position O in a radial direction is different in the pipe P different in the outer diameter, and thereby an imaging device movement device 11 moves the camera 4 to the center position O in the radial direction of each pipe P. Similarly, in the pipe P different in the outer diameter, the diagonal four points L1 to L4 of the axial direction end surface of each pipe P are different, and thereby an illumination device movement device 8 moves the illumination device 5 to the diagonal four points L1 to L4 of the axial direction end surface of each pipe P. Then, an outer peripheral contour of the pipe P is obtained from a photographed image to calculate circularity from a maximum value of the outer diameter and a minimum value thereof. |
