Color Image Enhancement Based on Contourlet Transform Coefficients

In this study, new method for enhancing color image based on contourlet transform and human visual system proposes. The color image is converted to HSV (Hue , Saturation, Value) values. The V, which represents the luminance value of color image, decomposed to its coefficients by nonsubsampling contourlet transform, then applying grey-level contrast enhancement technique on some of the coefficients. Then, inverse contourlet transform is performed to reconstruct the enhanced V values. The S component is treated by histogram equalization while the H component does not change to avoid degradation color balance between the HSV components. Finally, the enhanced S and V together with H are converted back to its original color system. The new approach gives color enhancement more than 50% in the Contrast and more than 25%in the Luminance.