I. Introduction
With the rapid increase in the demand for high-quality video services, quality of service (QoS) has become an important issue; thus, intensive study of accurate quality assessment methods on video is essential. The Video Quality Expert Group (VQEG) has specified several guidelines to measure video quality [1], [2]. Traditionally, quality assessment methods are classified into three kinds, depending on the availability of original reference data: 1) full-reference (FR) methods measure the quality by referencing the original data [3], [4]; 2) reduced-reference (RR) methods [5] are similar to the full-reference except that the original data are limitedly transmitted or partially used at receiver sides; and 3) no-reference (NR) methods make visual quality assessment (VQA) without the original data, which can be very practical in many applications [6].