A NOVEL REGION FILLING ALGORITHM FOR DISCONTINUOUS CONTOURS

Arshad Javeed

Abstract: This is a new algorithm which can be applied to contours having discontinuous boundaries in order to obtain its1-pixel thickness equivalent and complete the shape of the contour which can be followed by region filling operation. The conventional thinning algorithm often modifies the shape of the contour and the obtained skeleton will not resemble the original image and hence the thinning operation is not used in the proposed algorithm. After reducing the thickness of the boundary to 1 pixel, the shape is completed by traversing along the boundary and joining each black pixel (if there is no black pixel in N8 (p)) to its nearest black pixel. The completion of the shape is necessary because if region filling algorithm is applied directly it will result in blackening of the entire image or may have no effect depending on the algorithm being used. Hence after linking the discontinuities an existing region filling algorithm such as Boundary Fill is employed to fill the region.

Keywords: region filling; 1-pixel thickness; boundary traversing; shape completion; discontinuous contours; linking pixels; distance transform;

DOI: https://doi.org/10.15623/ijret.2017.0612004