AColDSS: Robust Unsupervised Automatic Color Segmentation System for Noisy Heterogeneous Document Images
Résumé
We present the first fully automatic color analysis system suited for
noisy heterogeneous documents. We developed a robust color segmentation
system adapted for business documents and old handwritten document with
significant color complexity and dithered background. We have developed the
first fully data-driven pixel-based approach that does not need a priori information,
training or manual assistance. The system achieves several operations
to segment automatically color images, separate text from noise and graphics
and provides color information about text color. The contribution of our work
is four-fold: Firstly, it does not require any connected component analysis and
simplifies the extraction of the layout and the recognition step undertaken by
the OCR. Secondly, it is the usage of color morphology to simultaneously segment
both text and inverted text using conditional color dilation and erosion
even in cases where there are overlaps between the two. Thirdly, our system
removes efficiently noise and speckles from dithered background and automatically
suppresses graphical elements using geodesic measurements. Fourthly, we
develop a method to splits overlapped characters and separates characters from
graphics if they have different colors. The proposed Automatic Color Document
Processing System has archived 99 % of correctly segmented document
and has the potential to be adapted into different document images. The system
outperformed the classical approach that uses binarization of the grayscale image.