Flicker Perception on Digital Videos at LIVE
Flicker perception on digital videos at LIVE is being conducted in collaboration with CPS (http://www.utexas.edu/cola/cps/).
- An important element of the design of video quality assessment (VQA) models that remains poorly understood is the effect of temporal visual masking on the visibility of temporal distortions. The visibility of temporal distortions like local flicker can be strongly reduced by motion. Based on a recently discovered visual change silencing illusion, we have developed a full reference VQA model that accounts for temporal visual masking of local flicker. The proposed model, called Flicker Sensitive – MOtion- based Video Integrity Evaluation (FS-MOVIE), augments the well-known MOVIE Index by combining motion tuned video integrity features with a new perceptual flicker visibility/masking index. FS-MOVIE captures the separated spectral signatures caused by local flicker distortions, by using a model of the responses of neurons in primary visual cortex to video flicker, an energy model of motion perception, and a divisive normalization stage. FS-MOVIE predicts the perceptual suppression of local flicker by the presence of motion and evaluates local flicker as it affects video quality. Experimental results show that FS-MOVIE significantly improves VQA performance against its predecessor and is highly competitive with top performing VQA algorithms when tested on the LIVE, IVP, EPFL, and VQEGHD5 VQA databases.
L. K. Choi and A. C. Bovik, "Video quality assessment accounting for temporal visual masking of local flicker," Signal Process. Image Commun.,
vol. 67, pp. 182-198, Jun. 2018. (PDF)
Motion silencing is a peripheral effect that does not occur near the point of fixation. To better understand the effect of eccentricity on motion silencing, we measured the amount of motion silencing as a function of eccentricity in human observers using
traditional psychophysics. Further, we modeled the response of a population of simulated V1 neurons to our stimuli. We suggest the plausible explanation that as eccentricity increases, the combined motion-flicker signal falls outside the narrow spatiotemporal frequency response
regions of the modeled receptive fields, thereby reducing flicker visibility.
L. K. Choi, A. C. Bovik, and L. K. Cormack, "The effect of eccentricity and spatiotemporal energy on motion silencing,"
Journal of Vision., vol. 16, no. 5, pp. 1-13, Mar. 2016. (PDF)
We have developed a new LIVE Flicker Video Database that studies the motion silencing effects on the visibility of flicker distortions in naturalistic videos. LIVE Flicker Video Database includes the human subjective scores on flicker visibility as a function of object motion, eccentricity, flicker frequency, and video quality with eye tracker data.
L. K. Choi, L. K. Cormack, and A. C. Bovik, "Motion silencing of flicker distortions on naturalistic videos,"
Signal Process. Image Commun., vol. 39, pp. 328-341, Mar. 2015. (PDF)
L. K. Choi, L. K. Cormack, and A. C. Bovik, "LIVE Flicker Video Database," Online: http://live.ece.utexas.edu/research/quality/live_flicker_video.html, 2015.
L. K. Choi, L. K. Cormack, and A. C. Bovik, "On the visibility of flicker distortions in naturalistic videos,"
Proc. IEEE Int. Workshop Qual. Multimedia Exper., Jul. 2013, pp. 164-169. (PDF)
L. K. Choi, L. K. Cormack, and A. C. Bovik, "Eccentricity effect of motion silencing on naturalistic videos,"
Proc. IEEE 3rd Global Conf. Sig. and Inf. Process., Dec. 2015. (PDF)
Motion can impair the perception of other visual changes. To understand why the visual system might be insensitive to changes in
object luminances (‘flicker’) in the presence of object motion, we conducted human psychophysical experiments to examine
motion silencing as a function of stimulus velocity, flicker frequency, and spacing; and we created a
simple filter-based model as a working hypothesis of motion silencing.
L. K. Choi, A. C. Bovik, and L. K. Cormack, "Spatiotemporal Flicker Detector Model of Motion Silencing,"
Perception, vol. 43, no. 12, pp. 1286-1302, Dec. 2014. (PDF)
L. K. Choi, A. C. Bovik, and L. K. Cormack, "A Flicker Detector Model of the Motion Silencing Illusion,"
Journal of Vision, vol. 12, no 777. pp. 777, Aug. 2012. (Abstract)