An Improved Method of Adaptive Histogram Equilibrium for Document Image Enhancement
Xiao Li · 2007
Histogram equilibrium(HE) of image can extend the image's grey range.It's a classic and efficient method of image enhancement.But this method can blur image also,because of the algorithm is constructed by the basis of combination of similar grey pixels.Detail emphasized adaptive histogram equilibrium(DEAHE) has not only holding the advantage of HE-extend the grey range,but also amplifying image detail.Due to some noises were added to the images in the document digitalization procedure,so DEAHE amplified the noises simultaneously while it amplified the image detail.Therefore,we proposed an improved DEAHE method,called IDEAHE,to suppress noise,to amplify the image detail,and to adjust the grey range of the image.The experiments show that the IDEAHE method could improve the document image visually.It's an alternative method of image enhancement in digital document image producing.