Author : P.Gangadhara Reddy 1
Date of Publication :7th March 2017
Abstract: Due to many environmental factors, improper handling and the poor quality of the materials used in the creation of old document images cause them to suffer a high degree of degradation which includes faded ink, bleed-through, show-through, uneven illumination, variations in image contrast and deterioration of the cellulose structure. In proposed algorithm a robust phase-based binarization technique is used for the binarization and enhancement of historical documents and manuscripts. The main object of proposed method consists of preprocessing, main binarization, and post-processing. The preprocessing step mainly involves image denoising with phase preservation, followed by some morphological operations to denoise the image and detection of edge information by using canny edge detector. Then, the phase congruency features used for the main binarization step. The foreground of ancient documents can be modeled by phase congruency. After completing the three binarization steps on the input images using phase congruency features and a denoised image, the enhancement processes are applied. A median filter and a phase congruency feature are used to construct an object exclusion map image. This map is then used to remove unwanted lines and interfering patterns. while in the post processing step, specialized adaptive Gaussian and median filters are considered. One of the outputs of the binarization step, which shows high recall performance, is used in a proposed post processing method to improve the performance of other binarization methodologies.
Reference :
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