Enhanced just noticeable difference model with visual regularity consideration
Just noticeable difference (JND) reveals the visibility of our human visual system (HVS), below which changes cannot be perceived by the human. Though dozens of JND estimation models have been introduced during the past decade, how to accurately estimate the JND thresholds for different content regions (e.g., edge and texture region) is still an open problem. Research on cognitive science indicates that the HVS is adaptive to extract the visual regularities from an input scene for content perception and understanding. Thus, we analyze the effect of content regularity on visual sensitivity, and suggest that the visual regularity is another important factor that determines the JND threshold. According to the orientation distributions of local regions, the content regularities are firstly calculated. Then, by considering the effect from content regularity, luminance adaptation, and contrast masking, a novel JND model is proposed. Experimental results demonstrate that the proposed model can effectively estimate the JND thresholds of regions with different visual contents.