Measurement of ringing artifacts in JPEG images

Ringing artifacts refer to the noisy-looking vicinity of edges that are supposed to belong to a smooth object. In this paper, we propose a no-reference method to measure the visual impact of ringing artifacts for JPEG images. Unlike previous work, we perform a global analysis on the smooth regions in a JPEG image and classify them into different objects according to their colors and texture characteristics. We study the region activity for each type of the object in the image and assign an appropriate proxy object to each potential ringing region adjacent to an edge. The contrast between the noise levels of the ringing regions and their proxies are used to determine the visual impact of the ringing artifact. Finally, a ringing feature is computed for each edge pixel based on the feature values of the ringing artifacts in a local window. We thus obtain a ringing map to indicate the visibility of local ringing artifacts. Our preliminary results show a consistency between our model and the visual impact of the ringing artifacts.