Left to right channel differences of the transmission factors in a 3-D TV system result in asymmetric multiplicative luminance deviations, which can impair picture quality and/or can reduce the visual comfort. Twenty non-expert observers assessed the impairment of overall as well as localized asymmetric deviations (as it may happen, e.g., with lenticular screen displays) in terms of the CCIR impairment scale. The luminance asymmetries were produced by processing the digitized stereo image pair of two natural scenes, according to a reduction of the transfer function of only one channel. Results show that (1) overall and localized luminance asymmetries are perceptible if the transmission factors differ by 3...6 dB, depending on the spatial extension and gradient of the deviation; and (2) if a pattern of a sharply localized luminance deviation is moving (as it may happen, e.g., when an observer moves his head in front of a lenticular screen display), it is perceptible if the transmission factor differs by only 0.2 dB.
Ion Paul Beldie,
"Luminance asymmetry in stereo TV images", Proc. SPIE 1457, Stereoscopic Displays and Applications II, (1 August 1991); doi: 10.1117/12.46312; https://doi.org/10.1117/12.46312