The Fast Automatic Color Equalization Algorithm in Logarithm Domain

Images containing constant color areas or low contrast areas usually suffer from Gray-out phenomenon after correction.By using the whole region of image as the computational subset,Automatic Color Equalization(ACE) can reduce Gray-out phenomenon.However,it increases computational cost greatly.Aim at this problem,a fast algorithm which fuses local and global characteristic in logarithm domain is proposed.First,the coupling between illumination and reflectance coefficient is decoupled by logarithm transformation.Then,the local characteristic and lateral inhibition of the transformed image are computed and adjusted.The global characteristic is then computed.Finally,the fused image of the last two steps is mapped to a suitable domain using canonical gain/offset method so that the final image can display correctly with improved contrast.Experimental results show that this improved algorithm not only can reduce the computational cost and reduce the gray-out phenomenon effectively,but also can provide better color correction performance.