An automatic algorithm for text skew estimation in document images using recursive morphological transforms

The text skew estimation algorithm utilizes recursive morphological transforms. With hand tuned parameters the algorithm produces estimated text skew angles which are within 0.1° of the true text skew angles 99% of the time. We also developed methodology to allow the algorithm to determine the optimal algorithm parameter settings on the fly without any human interaction. Under this automatic mode, our experimental results indicate that the algorithm generates estimated text skew angles which are within 0.5° of the true text skew angles 99% of the time. To process a 3300×2550 document image, the algorithm takes about 10 seconds on SUN Sparc 10 machines if discounting the document image file reading time