Abstract
It is now possible to economically film and present movies at much higher frame rates (HFR) than the traditional 24 frames per second (fps). The higher fidelity enabled by HFR should allow viewers to see more detail. In this experiment we asked viewers (N = 31) to assess the impact of motion on their ability to discern detail in fabrics and costume ornamentation. Stimuli were four garments hung on a hanger. These were filmed at all combinations of two resolutions (2k and 4k), three frame rates (24, 48 and 60 fps), and two shutter angles (180° and 358°). On each trial, participants viewed two clips of the same garment on a 4k monitor. The first clip showed the garment while stationary. The second showed the same outfit while the hanger was either moved up or down in the frame. Observers rated the quality of the moving clip relative to the stationary clip in terms of degradation of sharpness. As expected, we found that the fabric detail became noticeably less distinct when in motion. Increasing the frame rate significantly increased perceived detail. However, shutter angle had a small effect except at the lowest frame rate where increased shutter angle was associated with more impairment. The effect of frame rate was expected because, as frame rate is increased, temporal resolution is enhanced and motion blur and aliasing are avoided. Given the relatively weak effects of shutter angle, we conclude that aliasing and judder were stronger determinants of perceived detail than motion blur. Our results suggest that naïve observers perceive enhanced detail in fabrics and costumes in HFR film. Improved perception of detail could underlie both the positive and negative reactions to HFR film, depending on the nature of the content and whether it lends itself to such high fidelity.
Meeting abstract presented at VSS 2017