1. A method comprising: splitting an image composed of pixels into two semi-images; initializing local parameters based on values of pixels that lie in an area adjacent to both sides of a boundary separating said semi-images; calculating an adaptive threshold for each of said semi-images proceeding from said initialized local parameters; and performing a binarization separately for each of said semi-images using said adaptive threshold, wherein said binarization of said semi-images results in a binarized image of said image.