A perceptual metric for blind measurement of blocking artifacts with applications in transform-block-based image and video coding
In this paper, we analyze the formation of blocking artifacts as a result of quantization of the discrete cosine transform (DCT) coefficients. These artifacts are known to be the dominant distortion of lossy block-based hybrid image and video coding schemes when operating at very low data rates. Our analysis is carried out based on the theory of edge detection and by means of a mathematical framework to model the properties of receptive fields, which are known to be the main mechanism for sensing intensity contrasts and edges. Based on our analysis we propose a metric to quantify the blocking artifact distortion. The proposed distortion metric considers the susceptibility of a region in a reconstructed (decoded) image to the formation of blocking artifacts via a probabilistic model, which quantifies the possibility of a detected edge to be a distortion.