A Fast Thinning Algorithm for Fingerprint Image

Thinning algorithms can be classified into two general types: serial and parallel algorithms. Several algorithms have been proposed, but they have limitations. A new thinning algorithm based on the centroid of the block is presented. The new algorithm checks the 9*9 local neighborhoods around the pixel to find out the centroid pixel of the block, and other pixels are removed. The process is performed iteratively until less than ten pixels are deleted in one loop. To ensure the ridge is one pixel wide, a post-processing loop is designed and the pixels are deleted from the image if they satisfy some conditions. Experimental results are used to compare this new algorithm to other algorithms and their relative performances are assessed. The new algorithm is fast than other algorithms and the ridges are one pixel wide after thinned.