Autostereoscopic 3D Display

Alioscopy developed a multiview 3D display that shows 3D content without glasses within 100-degree viewing angle and 30-degree viewing zone. The user can freely walk around the display within the 30-degree viewing zone undisturbed 3D content without jumping views; however, in 100-degree viewing angle the 3D content is visible but views are observed with jumping effect. The 3D display has its own 3D mixer player that requires 8 different perceptive views of the same scene in order to correctly display the content in 3D. Furthermore, the viewers are not required to wear any special glasses to experience 3d depth.

Chapter 6 – Integration and Object Segmentation Page 163 Now, taking it further to capture with 8 cameras will not only increase the cost widely, but also involve complicated calibration of 8 cameras. Furthermore, the multi-camera setup is not very mobile in comparison to stereoscopic production, which makes it very difficult for content producers. Therefore, holoscopic capturing is proposed in generating 8 views for such systems without having the need of complex and expensive multi camera calibration to produce content. This approach will show the capability of delivering content on motion pictures for multiview display. Also, this experiment will be the first of its kind in attempting to generate multi views from holoscopic camera on video. Fig 6. 15 shows the workflow from capturing to display.

Fig 6. 15 : The workflow graphically. (a) Scene capture with (b) holoscopic camera. (c) Frames are rendered in post-production and playing on 2D display (d).

The capturing process described earlier in section 6.1.1 is used in generating 2D as well as 3D stereoscopic views from holoscopic 3D capturing. Hence, the same holoscopic 3D content is chosen to produce content for multiview display, in

Chapter 6 – Integration and Object Segmentation Page 164 deliver content for multiple display technologies out in the market.

Note that the rendering process that takes the same steps in generating stereo view in section 6.2 but with more than two views are required in here. Therefore, different perception views from holoscopic 3D content are rendered using up-sampling, shift and integration approach and displayed on multiview screen using its player. Multiview 3D display used here does not necessarily requires the views to have large baseline; otherwise, it would have been difficult to produce content knowing that the baseline is limited at this stage. This is due to small image sensor size that limits the use of larger microlens with wide viewing angle. The rendering process is explained in example below where only 20 pixels are considered under each EIs for the sake of simplicity and also shown graphically in Fig 6.16.

Example: element images (EIs) are of resolution 20 by 20 pixels and 6 views

are extracted from each EI. Notice that the position of view one on x-axis (x1) and y-axis (y1) inside the element image are 3 and 10, respectively. On the other hand, the view two of y-axis (y2) stays constant as well as all that of the other views, which will avoid misalignment of views projection causing bad 3D effect when it is displayed. The x-axis position is different for each view, but have the same distance from each other as shown in Fig 6.16. The difference between view one pixel 1 to view two pixel 1 are two pixels, where it is the same with view two with view three and the others too. The positions of views are represented with different colors in Fig 6.16, each color presenting one view from different perceptive, using up-sampling, shift and integration process.

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Chapter 6 – Integration and Object Segmentation Page 166 Results of 8 views from holoscopic 3D image are shown in fig 6.17. Each view is kept at the same distance from each other during rendering. In pre-processing, each frame is processed with σ = 6, kernel = [10x10], then up-sampling, shift and integration process is carried out with SI=10 and 8x8 number of different views. Finally, post-processing is performed to remove any blur in the views and also noises with λ = 0.005. Also note here that parameters are set constant throughout as well as in the 8 extracted views from each frame. Differences between the views are 3 pixels as it is shown below in Fig 6. 17 with each views’ axis position under each EI.

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Fig 6. 17 : Illustration of 8 extracted views from single holoscopic frame no 3.

Finally, all the rendered frames of 8 views are replayed on the multiview 3D display from Alioscopy using their own players to process and display in 3D. The results are shown in Fig 6. 18 taking picture of the display from different viewing points to show motion parallax. Looking at the depth of the scene, it seems all the objects are inside the screen, feeling like looking outside through a window. This is because in the holoscopic camera the image plane of the main lens is in front of the micro-lens array, where each microlens is rotated by 180 degrees on this centre axis. Therefore, the depth is observed inside the screen. The depth can be outside the screen with the image plane of the main lens in the capturing stages. During capturing, the image plane of the main lens needs to be behind microlens array, creating virtual image plane behind the micro-lens array. This is also tested here with Canon camera images while results are played on the display to observe the difference in depth. Result in Fig 6. 19

Chapter 6 – Integration and Object Segmentation Page 168 objects in scene move closer to the observer.

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Fig 6. 19a : Results are demonstrated on the multiview display when focusing on the background