A lot of current 3D displays suffer from the fact that their spatial resolution is lower compared to their 2D
counterparts. One reason for this is that the multiple views needed to generate 3D are often spatially multiplexed.
Besides this, imperfect separation of the left- and right-eye view leads to blurring or ghosting, and therefore to
a decrease in perceived sharpness. However, people watching stereoscopic videos have reported that the 3D
scene contained more details, compared to the 2D scene with identical spatial resolution. This is an interesting
notion, that has never been tested in a systematic and quantitative way. To investigate this effect, we had people
compare the amount of detail ("detailedness") in pairs of 2D and 3D images. A blur filter was applied to one
of the two images, and the blur level was varied using an adaptive staircase procedure. In this way, the blur
threshold for which the 2D and 3D image contained perceptually the same amount of detail could be found.
Our results show that the 3D image needed to be blurred more than the 2D image. This confirms the earlier
qualitative findings that 3D images contain perceptually more details than 2D images with the same spatial
The image quality circle is a commonly accepted framework to model the relation between the technology variables of a display and the resulting image quality. 3D-TV systems, however, go beyond the concept of image quality. Research has shown that, although 3D scenes are clearly more appreciated by subjects, the concept 'image quality' does not take this added value of depth into account. Concepts as 'naturalness' and 'viewing experience' have turned out to be more useful when assessing the overall performance of 3D displays. In this paper, experiments are described that test 'perceived depth', 'perceived image quality' and 'perceived naturalness' in images with different levels of blur and different depth levels. Results show that naturalness incorporates both blur level as well as depth level, while image quality does not include depth level. These results confirm that image quality is not a good measure to assess the overall performance of 3D displays. Naturalness is a more promising concept.