BUILDING ACCURACY MEASURING METHOD FOR STEEL COLUMN USING LASER VERTICAL GAUGE AND APPARATUS THEREFOR

摘要

PURPOSE:To improve reading-out accuracy of a laser spot position, by providing a cross-sectional shape of an irradiated beam with anisotropy and detecting electrically a direction oriented on the beam-receiving side by beam-receiving position of the laser beam and cross-sectional shape. CONSTITUTION:An image processing apparatus 3 introduces a signal from a IV camera 22 for image processing and detects a center of an elliptic shape in a laser spot developed on the beam-receiving plate 21 and the direction of the major axis. In this case, the image is represented as an assembly of a number of picture elements in the image processing apparatus 3. Namely, if an elliptic shape is assumed to be composed of (n) image elements of DELTAAi an areas of the ellipse is expressed by equation I, the primary moment SX relative to the X-axis (OX) by II, and the primary moment SY relative to the Y-axis (OY) by III. And, co-ordinates -X, -Y of the center of the ellipse can be defined as an equation IV and by reducing the size of one picture element to a sufficiently small one, the co-ordinates of the center of the ellipse can be obtained accurately.