This paper proposes a modified structure of Retinex algorithm for the image enhancement method. The proposed algorithm performs robustly and stably on various environments, particularly in bad weather and night vision. Especially, Retinex algorithm tends to show outstanding results as compared with other approaches, and also shows advantages at night vision. However, the Retinex algorithm has problems such as the halo effect and the color distortion. In this paper, the proposed algorithm has a simple idea to remove above problems that combines a reflectance and a luminance image with some constant factors respectively. Since the result includes the luminance component, it works on diverse environment such as not only foggy image but also night vision image. Furthermore, this algorithm has proper structure for real time processing. Results on a variety of images show the effectiveness of this approach.