Ringing effect modeling

The behavior of ringing effect produced by different image processing algortihms can be different. Understanding the characteristics of ringing effect of different types can help us to develop efficient algortihms for ringing detection and suppression.

The necessary step for the development of ringing detection and suppression algorithms is creating the ringing database with ringing effect introduced by various image processing algorithms. The ringing database contains high quality reference images and the results of image processing algorithms which produce ringing effect. We aim to cover the majority of ringing effect types by modeling ringing effect by different algorithms.

We use the following image processing algorithms and methods that produce synthetic ringing effect:

• high-frequency cut-off after Fourier and Hermite transforms;
• image upsampling;
• image deblurring and sharpening;
• image compression.

We also take images with real ringing effect:

• MRI images;
• Television frames received from analog broadcast.

Additionally we consider a special case of radially symmetric image processed by denoising method based on Laguerre polinomials.