Niblack algorithm for Document binarization

image-processing, matlab, signal-processing

Solution

i tried sauvola algorithm in this paper Adaptive document image binarization J. Sauvola*, M. PietikaKinen section 3.3

it's a modified version of niblack algorithm which uses a modified equation of niblack

which returned a pretty good answers :

as well as i tried another modification of Niblack which is implemented in this paper in the 5.5 Algorithm No. 9a: Université de Lyon, INSA, France (C. Wolf, J-M Jolion)

which returned a good results as well :

Problem

i've this photo : and i'm trying to make Document binarization using niblack algorithm i've implemented the simple Niblack algorithm T = mean + K* standardDiviation and that was it's result: the problem is there's some parts of the image in which the window doesn't contain any objects so it detects the noise as objects and elaborates them . i tried to apply blurring filter then global thresholding that was the result : which wont be solved by any other filter i guess the only solution is preventing the algorithm from detecting global noise if the window i free from object i'm interested to do this using niblack algorithm not using other algorithm so any suggestions ?

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