Study on Measuring Medium and Heavy Plate Flatness and Spot Center Extraction Algorithm

摘要

Oblique incidence laser triangulation was used to detect medium and heavy plate flatness in this paper. The article mainly focused on point laser spot center extraction algorithm. In field detection of medium and heavy plate flatness, according to the problem of the point laser spot center extraction difficulty in interference condition, and for enhancing lightness of spot center filed, an extraction algorithm of point laser spot center is put forward in this paper which combines threshold method and square-weighted gray level based on floor board effect and traditional centroid method. Under no interference condition, point laser spot center extraction using traditional centroid method has high accuracy. In the field detection with dusts, oil drops, water drops or other interferences, measurement precision has since fallen sharply. On this background, according to a kind of point laser spot center with the interference of water drops or oil drops, classification extraction algorithm of point laser spot center was put forward in this paper. At the first level, the spot and the drop contour was extracted with Sobel Operators. At the second level, the spot area was extracted. And then, this spot area center was extracted by a point laser spot center extraction algorithm which combines threshold method and square-weighted gray level. And the center we get is point laser spot center. The validation results show that with the water drop interference, the accuracy with a point laser spot center extraction algorithm which combines threshold method and square-weighted gray level is obviously improved by 94.17% than the traditional centroid method.