To improve the quality of scanned image captured by cameras, we propose a novel and efficient method for image processing by using color-correction and gradient minimization. Our method is divided into two steps. To derive a colorimetric mapping between digital RGB signals and real image values, we use a polynomial model by considering the interrelations among the standard color spaces. A L0 gradient minimization is used to remove the image noises. Based on the half-quadratic splitting method, an iterative algorithm for our proposed method is developed. The iterative algorithm is easy to implement with the optimal complexity O(NlogN). Our method is particularly beneficial to correct image color and remove image noises. Various tests are presented to demonstrate the robustness and efficiency of our method.