Abhijit Mitra,  Restoration of Noisy Document Images with an Efficient Bi-Level Adaptive Thresholding.   journal   = {International Journal of Computer and Information Engineering}, [online]. World Academy of Science, Engineering and Technology.
    June 2008, vol. 18(6). 2226 - 2231
    [viewed 11 May 2024]. Available from: https://publications.waset.org/pdf/15663.