1 research outputs found
Multistage Curvilinear Coordinate Transform Based Document Image Dewarping using a Novel Quality Estimator
The present work demonstrates a fast and improved technique for dewarping
nonlinearly warped document images. The images are first dewarped at the
page-level by estimating optimum inverse projections using curvilinear
homography. The quality of the process is then estimated by evaluating a set of
metrics related to the characteristics of the text lines and rectilinear
objects for measuring parallelism, orthogonality, etc. These are designed
specifically to estimate the quality of the dewarping process without the need
of any ground truth. If the quality is estimated to be unsatisfactory, the
page-level dewarping process is repeated with finer approximations. This is
followed by a line-level dewarping process that makes granular corrections to
the warps in individual text-lines. The methodology has been tested on the
CBDAR 2007 / IUPR 2011 document image dewarping dataset and is seen to yield
the best OCR accuracy in the shortest amount of time, till date. The usefulness
of the methodology has also been evaluated on the DocUNet 2018 dataset with
some minor tweaks, and is seen to produce comparable results