A fast and adaptive algorithm for image enhancement is proposed. The algorithm first filters the image with Gaussian smoothing filter, and then offsets the image pixel values on the basis of global and local information. Finally, the offset pixel values and non-linear function is used to transform the image, thus enhancing the details of the image. By transforming the RGB image to HSV space, the method is extended to the color image enhancement. Experimental results demonstrate that the proposed method can efficiently improve image quality, and can also self-adaptively adjust the enhancement according to the environment.