Estimating Depth Range Required for 3-D Displays to Show Depth-Compressed Scenes Without Inducing Sense of Unnaturalness

It is often difficult to show deep 3-D scenes with sufficient quality on 3-D displays with light-ray reconstruction, such as light-field and integral 3-D displays, because their depth-reconstruction range is restricted. Scenes with substantial depth cannot be shown properly because the reconstructed images outside the range inevitably blur. Although promising methods for providing better quality 3-D visualization by contracting the scene depth to fit within the restricted depth range have been proposed, the size of the depth range required for showing deep 3-D scenes with perceptually appealing quality is not yet known. To reveal the required depth, we conducted evaluation experiments under practical viewing conditions using a 3-D-display simulator that provides binocular and motion disparities. Even with deep 3-D scenes (originally with a depth of 250 m), we found that a depth range of at least 1 m was necessary to show these scenes with sufficient quality in terms of naturalness using a nonlinear depth compression method. These results provide a design goal for future 3-D-television development, suggesting that 3-D displays can naturally show a variety of scenes that originally had substantial depths if they can reproduce a depth of 1 m.