Degraded color document image enhancement based on NRCIR

An automatic algorithm of degraded color document image enhancement is proposed based on our previous work on Natural Rendering of Color Image using Retinex (NRCIR) with respects to document image characteristics. In the proposed work, an adaptive workflow is designed to enhance both luminance and chrominance contrast of document image while maintaining degradations within tolerance and hue-shift minimized. Tests with degraded document image databases are effectuated, and the results show an encouraging performance of the proposed method.