A framework for enhancing Bangla document images printed on newsprint papers

The process of modifying images to achieve improved resultant images is called image enhancement. Though there are some researches done on image enhancement of Bangla document images but research on enhancement of newsprint Bangla document images is almost an untouched field of research. So for enhancing Bangla newsprint document images we have divided our whole working procedure into three phases. At the first phase, we have tried to explore the main reason behind the failure of well known image enhancement techniques on newsprint papers by running out analytic experimentation. In second phase we proposed a tentative framework by applying commonly used mathematical morphology method in a modified way. But due to huge diversity of Bangla letters this approach also did not provide the expected output. Finally, in the third phase we have proposed a framework addressing the issues of the second phase, where we have used bitmap color substitution method along with the well known Sauvola's algorithm. To enhance the result more we have then modified Sauvola's algorithm to fill missing edges along the horizontal and vertical lines.