In many image processing applications, labeling objects and computing their features for recognition are crucial steps for further analysis. In general these two steps are done separately. This paper proposes a new approach to label all objects and computer their features (such as moments, best fit ellipse, major and minor axis) in one pass. The basic idea of the algorithm is to detect interval overlaps among the line segments as the image is scanned from left to right, top to bottom. Ambiguity about an object's connectivity can also be resolved with the proposed algorithm. It is a fast algorithm and can be implemented on either serial or parallel processors.
Tan Q. Thai, Tan Q. Thai,
"Fast one-pass algorithm to label objects and compute their features", Proc. SPIE 1567, Applications of Digital Image Processing XIV, (1 December 1991); doi: 10.1117/12.50866; https://doi.org/10.1117/12.50866