This paper proposes the combination of histogram based methods in order to achieve an improved contrast enhancement technique. In the proposed method, at first the histogram is modified in a way that deals with the histogram spikes with less computational complexity. A method is then utilized to preserve the mean brightness of image. In addition, black and white stretching is applied to increase the quality of resulting image. A new method is also introduced so that the stretching parameters can be selected proportional to the intensity distribution of each image. The proposed method is fully automatic, robust against noise, and user-friendly. Experimental results indicate the efficiency of the new technique from both of the objective and subjective viewpoints.