Vignetting refers to a position dependent loss of light in the output of an optical system causing gradual fading out of an image near the periphery. In this paper, we propose a method for correcting vignetting distortion by introducing nonlinear model fitting of a proposed vignetting distortion function. The proposed method aims for embedded digital imaging applications as well as conventional image enhancement. We could obtain a light intensity profile distribution without precisely controlled illumination and considerably reduce memory requirement for vignetting correction compared with the traditional lookup table (LUT) methods. We show the effectiveness of the proposed method by presenting the experimental results obtained from commercial digital cameras.