Patent ID: 7170645

Claim:
A method of enhancing digital image quality wherein original brightness data Xij of a concerned pixel is compared with brightness levels X 1 and X 2 to obtain new brightness data Yij with enhanced contrast, the method comprising: setting initial values of the brightness level X 1 , the brightness level X 2 , a parameter Vb for calculating the brightness level X 1 and a parameter Vp for calculating the brightness level X 2 ; generating enhanced RGB color data for the concerned pixel by: transforming RGB color data for the concerned pixel into the brightness data Xij and chrominance data; comparing the brightness data Xij with the parameters Vb and Vp and resetting the parameters Vb and Vp according to results of the comparison; identifying whether the concerned pixel belongs to a background area requiring contrast enhancement according to results of a comparison between the brightness data Xij and at least one of parameter X 1 and X 2 ; performing contrast enhancement on pixels belonging to the background area requiring contrast enhancement to obtain the brightness data Yij with enhanced contrast; inversely transforming the enhanced contrast brightness data Yij and the transformed chrominance data into enhanced RGB color data; determining whether the concerned pixel is a last pixel in the concerned line; generating the enhanced RGB color data for a next concerned pixel in the concerned line, if the concerned pixel is not the last pixel in the concerned line; updating the brightness levels X 1 and X 2 using the parameters Vb and Vp, respectively, if the concerned pixel is the last pixel in the concerned line; and generating the RGB color data for a next concerned pixel in a next concerned line, if the concerned pixel is not the last pixel to be subjected to the image quality enhancement processing.