Stereoscopic 3D TVs convey depth perception to the viewer by delivering separately-filtered images to each eye that represent two slightly different perspectives. Currently two primary technologies are used in 3D televisions: active shutter systems and passive polarized systems. Active shutter systems use alternate frame sequencing to deliver a full-frame image to one eye at a time at a fast refresh rate. Passive polarized systems superimpose two half-frame left-eye and right-eye images at the same time through different polarizing filters. In this study, sixty subjects were recruited to compare their visual performance and subjective rating of two 3D televisions representing the two technologies.
Image quality for both 2D and 3D images were investigated by objectively measuring participant’s visual acuity and contrast sensitivity on each television. The 3D image was investigated further by objectively measuring stereoacuity, perceived versus intended depth perception, effect of viewing angles and a step-vergence task that measured the participant’s ability to swiftly diverge or converge to a new stimulus. A discomfort questionnaire was used to assess participant’s pre and post movie-viewing comfort. Subjective questionnaires were used to gather participant’s opinions on various image quality components, glasses preference, and overall television preference.
Objectively, the subjects had a lower measured contrast and acuity threshold in 2D on the active television, but they had a lower contrast threshold in 3D, as well as faster vergence reaction times on the passive television. With a single subject investigation, no difference between TVs was found for varying off-axis viewing angles, both horizontally and vertically, when comparing VA thresholds, contrast thresholds and stereoacuity at each angle. The passive television was subjectively preferred in all of the following ways: perceived image clarity, color, motion smoothness, overall immersion, perceived ghosting, less disruption from head tilting and viewing angles, longer predicted viewing time before discomfort, overall glasses preference and overall final television preference.
In conclusion, in this study, passive TV technology was a solid winner when it came to subject’s personal ratings, but only outperformed the active TV objectively with contrast and speed of vergence responses. When considering image quality, viewing comfort and room dimensions, subjects felt the passive TV outperformed the active TV in all three categories. With objective measures, passive statistically excelled at two traits in 3D mode and active statistically excelled at two traits in 2D mode for image quality, while no difference was found between televisions for viewing comfort. In addition, no variables were statistically different between TVs that would change the dimensions of a movie-viewing zone. It should be emphasized that the results are based on a relatively small sample size (57 subjects, most young female adults) and tested on specific display models. Investigation with a larger sample size and reaching to broader populations is required before reaching expansive conclusions. In addition, active and passive projector systems, could be a good option for classrooms that are able to afford the system. Future studies should compare the difference between 3D projector systems as well as any future glasses-free systems developed with a broader viewing range than the current available televisions.
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