The preprocessing step uses otsu, which is pretty inaccurate, because it uses only one single threshold value for the whole image. An adaptive thresholding algo

The preprocessing step uses otsu, which is pretty inaccurate, because it uses only one single threshold value for the whole image. An adaptive thresholding algorithm (like Sauvola or Wolf binarization) could improve the whole preprocessing A LOT on many images, that are not only black and white. See https://github.com/chriswolfvision/local_adaptive_binarization https://github.com/chriswolfvision/local_adaptive_binarizati... for details. Other nice resources: - https://www.researchgate.net/publication/306352164_Watershed_algorithm_based_segmentation_for_handwritten_text_identification https://www.researchgate.net/publication/306352164_Watershed... - https://isi.edu/integration/papers/chiang11-icdar.pdf https://isi.edu/integration/papers/chiang11-icdar.pdf