tailieunhanh - Contourlet transform and histogram equalization for brightness enhancement of color image

The S component is enhanced by histogram equalization while the H component does not change to avoid degradation color balance between the HSI components. Finally the enhanced S and I together with H are converted back to its original color system. The new approach gives Brightness enhancement more than 20% when was applied on different type of images and tested the performance. | International Journal of Computer Networks and Communications Security C VOL. 1, NO. 4, SEPTEMBER 2013, 140–143 Available online at: ISSN 2308-9830 N C S Contourlet Transform and Histogram Equalization for Brightness Enhancement of Color Image Khalil Ibraheem AlSaif 1 and Ahmed S. Abdullah2 12 Dept. of Computer Science College of Computer & Mathematic Science-Mosul Univ./ IRAQ E-mail: 1khalil_alsaif@, 2ahmedsaadi84@ ABSTRACT For decades, several image enhancement techniques have been proposed. Although most techniques require profuse amount of advance and critical steps, the result for the perceive image are not as satisfied, In this paper a new approach for enhancing brightness of color image based on contourlet transform and histogram equalization proposes. The color image is converted to HSI (hue, saturation, intensity) values. The i, which represent the luminance value of color image, decomposed to its coefficients by non-sampling contourlet transform, then applying grey-level contrast enhancement technique on some of the coefficients. Then, inverse contourlet transform is performed to reconstruct the enhanced S compoment. The S component is enhanced by histogram equalization while the H component does not change to avoid degradation color balance between the HSI components. Finally the enhanced S and I together with H are converted back to its original color system. The new approach gives Brightness enhancement more than 20% when was applied on different type of images and tested the performance. Keywords: Image Processing, Image Enhancement, Brightness Enhancement, Contourlet Transform , HSI Color Space. 1 INTRODUCTION Image enhancement is a technology to improve the quality of an image in terms of visual perception of human beings [1]. With the growing quality in image acquisition, image enhancement technologies are more and more needed for many applications [2]. Images are categorized into greylevel images and .