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. Author manuscript; available in PMC: 2008 Dec 1.
Published in final edited form as: J Opt Soc Am A Opt Image Sci Vis. 2007 Dec;24(12):B174–B187. doi: 10.1364/josaa.24.00b174

Fig. 4.

Fig. 4

Illustration of the side-by-side video segments used to determine the just noticeable differences (JNDs) in levels of MPEG-enhancement in the third preliminary experiment. In this example the reference video is on the left, with k = 11.8. The level of enhancement of the stimulus video on the right alternated every 850ms between that of the reference video and a test level. The test level of enhancement was increased or decreased at every flicker cycle until the observer correctly reported the side that was flickering. The difference between the reference and test k at that time was the JND. The image shown on the right (k = 35.4) represents 4 JNDs, as a single JND is hard to appreciate in the print.