| 摘要 |
PROBLEM TO BE SOLVED: To detect front and tail end positions with high accuracy even when a self-emission light brightness is uneven in a length direction of a measured object so as to measure a length of the measured object with high accuracy.SOLUTION: A method of measuring a long body, includes: when a length of a measured object, which is a long body having a temperature at which self-emission light of visible light is emitted, is measured in a non-contact manner, imaging a whole body of the measured object from a direction substantially perpendicular to an axial direction thereof; detecting edges of both side faces of a self-emission image of the imaged measured object; detecting, as a thickness of the measured object, a width in a direction perpendicular to an axial direction of a long body, which is interposed between the edges of both side faces thus detected; detecting, as front and tail ends of the measured object, positions in an axial direction of the long body which causes the thickness to be zero or a value smaller than a preset threshold value; and calculating, on the basis of an interval between the front and tail ends thus detected, a length of the measured object from a relationship between a visual field and an absolute size, which is separately determined. |
