electrical engineering, sirjan university of technology
The contourlet transform has the benefit of efficiently capturing the oriented geometrical structures of images. In this paper, by incorporating the ideas of Stein’s Unbiased Risk Estimator (SURE) approach in Nonsubsampled Contourlet Transform (NSCT) domain, a new image denoising technique is devised. We utilize the characteristics of NSCT coefficients in high and low subbands and apply SURE shrinkage and bilateral filter respectively. Moreover, SURE-LET strategy is modified to minimize the estimation of the Mean Square Error (MSE) between the clean image and the denoised one in the NSCT domain. The simulation testing has been carried on under the different noise level, and the denoising effect has been evaluated by using the Peak Signal to Noise Ratio (PSNR). The obtained results for different kinds of sample image show that the proposed method in this paper can preserve most important information of images, remove Gaussian white noise more effectively, and get a higher PSNR value, which also has a better visual effect.