| Abstract: | It is common for libraries to provide public access
to historical and ancient document image collections.
It is common for such document images to require
specialized processing in order to remove background
noise and become more legible. In this paper, we
propose a hybrid binarizatin approach for improving
the quality of old documents using a combination of
global and local thresholding. First, a global
thresholding technique specifically designed for old
document images is applied to the entire image. Then,
the image areas that still contain background noise are
detected and the same technique is re-applied to each
area separately. Hence, we achieve better adaptability
of the algorithm in cases where various kinds of noise
coexist in different areas of the same image while
avoiding the computational and time cost of applying a
local thresholding in the entire image. Evaluation
results based on a collection of historical document
images indicate that the proposed approach is effective
in removing background noise and improving the
quality of degraded documents while documents
already in good condition are not affected. |
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Greek