| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and device for measuring the diameter of a reinforcing bar suited for automating the inspection of reinforcing bar arrangement of steel. SOLUTION: An image pick-up device 10 where a light source 5 of a plane slit beam 4 and a camera 7 with a filter 6 are mounted on a mounting stand 9 which can be freely rotated by a rotary shaft r1 is provided facing to a reinforcing bar 1. Then, while changing an angle positionθr1 of the rotary shaft r1 , slit beams 4 are crossed at a cross position which is different from that of the bar 1 and the images of a group of cross points are picked up by the camera 7 and the three-dimensional coordinates of a group of corresponding cross points RP1 -RPn and a corresponding gravity point RP0 are calculated by the slit light projection method from the two-dimensional coordinates of images P1 -Pn of a group of cross points on a camera image Id of each cross position and the gravity point P0 . A gravity axisχfor connecting the corresponding gravity point RP0 at different cross positions is determined, a projection image IS is created by a group of projection points S1 -Sn where a group of corresponding cross points RP1 -RPn at each cross position are regularly projected on a projection surfaceσwhich is vertical to the gravity axisχ, the curvature of each point on a connection curve for connecting a group of projection points S1 -Sn is calculated, and the diameter of the reinforcing bar section at each cross position is obtained from the curvature radius of a part with a fixed curvature out of the connection curve.
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