VECTORIZATION AND LINE DETECTION FOR AUTOMATIC IMAGE RECOGNITION

We propose an algorithm for creating line graphs from binary images. The algorithm consists of a vectorizer followed by a line detector that can handle a large variety of binary images and is tolerant to noise. The proposed algorithm can accurately extract higher-level geometry from the images lending itself well to automatic image recognition tasks. Our algorithm revisits the technique of image polygonization proposing a very robust variant based on subpixel resolution and the construction of directed paths along the center of the border pixels where each pixel can correspond to multiple nodes along one path. The algorithm has been used in the areas of chemical structure and musical score recognition and is available for testing at www.docnition.com. Extensive testing of the algorithm against commercial and noncommercial methods has been conducted with favorable results.