Few papers present quality-stationary motion estimation algorithms for video sequences with mixed fast-motion, moderate-motion, and slow-motion content.
However, a real video sequence may have different types of content, such as slow-motion, moderate-motion, and fast-motion, and little quality degradation in average does not imply the quality is acceptable all the time.
Figure2 shows an example of this effect in two different sequences, one with low motion activity like Container and other with moderate motion activity like Foreman.
The model is able to accommodate moderate motion of S, as long as the relationship between S and ( overrightarrow{f} ) is maintained.
The quality of structural MRI scans was rated according to a five-point rating scale by an experienced radiologist (MPW) as 1: no motion artifacts, excellent quality, 2: little motion artifacts, good quality, 3: moderate motion artifacts, acceptable quality, 4: excessive motion artifacts, poor quality, and 5: incomplete scan (Fig. 2).
From Figure 3, although the video sequence "table" is, in the literature, regarded as a moderate motion, there exists the high interframe variation between the third GOP and the seventh GOP.
We simulated the moderate motion video sequence "table" in H.264 JM10.2 software, where the length of GOP is fifteen frames, the frame rate is 30 frames/s, the bit rate is 450 k bits/s, and initial is 34.
Subjective image quality in terms of motion artefacts will be evaluated using a 5-point Likert scale (5 = excellent, no motion artefacts; 4 = good, minor motion artefacts; 3 = sufficient, moderate motion artefacts; 2 = moderate, significant motion artefacts but diagnostic; 1 = non-diagnostic due to motion artefacts).
At heart rates ≥70 bpm, minor to moderate motion artifacts accounted for 68.2% (73/107) of image quality impairment, while in patients with an Agatston score ≥400, severe arterial wall calcifications were mainly responsible for decreased image quality [76.4% (94/123)].
