This document provides an overview of the 31st Stereoscopic Displays and Applications conference and an introduction to the conference proceedings.

Compared with the 2-view 3D display, the multiview 3D display provides more views to the observers, which allows a stereoscopic perception relatively closer to real viewing condition. Depth sensitivity (DS) on multi-view 3D display has not been investigated with respect to view number and stimulus contents. A lenticular glasses-free 3D display with alternative view numbers (2 views and 28 views) was used as the test platform. Two types of stimulus were implemented for DS investigation, including random dot stereogram (RDS) and contour stereogram (CS). 20 adults (22.8 ±2.1 years old) with normal vision participated in the experiment. Experimental results showed that the DS on 2-view display mode was consistent with that measured with the conventional DS test (t-ratio = 0.2560, P=0.8569). Besides, the DS was significantly better for 28-view display mode, compared with 2- view display mode (t-ratio = 4.326, P<0.0001). For the influence of stimulus type, subjects were able to perceive more precise depth information with the RDS (t-ratio=2.023, P=0.0422), compared with the CS. The proposed investigation indicates that depth perception is closely related to view numbers and stimulus content, the proposed investigation provides essential cues for the choice of view numbers and contents to achieve the desired perception effect.

We introduce the Morpholo library which is able to convert a stereoscopic snapshot into a native multi-view image through morphing and takes into account display calibration data for specific slanted lenticular monitors. Holograms are generated fast by creating Lookup Tables to replace runtime computation. The implementation of Morpholo for glasses-free streaming of live 3D video is considered.

In this paper we propose an application of high-resolution autostereoscopic display for medical purposes. To realize high resolution autostereoscopy for medical applications, we use timedivision multiplexing parallax barrier technology. Moreover, we evaluate the merit of using the autostereoscopic display we propose based on subjective experiments. From the results of the subjective experiments, we find out that 3D image is perceived to have a higher resolution compared with the 2D image.

The objective of this paper is to research a dynamic computation of Zero-Parallax-Setting (ZPS) for multi-view autostereoscopic displays in order to effectively alleviate blurry 3D vision for images with large disparity. Saliency detection techniques can yield saliency map which is a topographic representation of saliency which refers to visually dominant locations. By using saliency map, we can predict what attracts the attention, or region of interest, to viewers. Recently, deep learning techniques have been applied in saliency detection. Deep learning-based salient object detection methods have the advantage of highlighting most of the salient objects. With the help of depth map, the spatial distribution of salient objects can be computed. In this paper, we will compare two dynamic ZPS techniques based on visual attention. They are 1) maximum saliency computation by Graphic-Based Visual Saliency (GBVS) algorithm and 2) spatial distribution of salient objects by a convolutional neural networks (CNN)-based model. Experiments prove that both methods can help improve the 3D effect of autostereoscopic displays. Moreover, the spatial distribution of salient objects-based dynamic ZPS technique can achieve better 3D performance than maximum saliency-based method.

We propose 3D display that scans light rays from projector and enables stereoscopic display by arranging a number of long and thin mirror scanners with a gap and spinning each mirror scanner. This proposal aims at large-screen 3D display that allows multiple people to observe simultaneously with the naked eye. In previous study, multi-projection type 3D display was proposed as largescreen 3D display. However, many projectors make installation and adjustment complicated. Therefore, we have proposed 3D display that can display large screen with single projector in the past. However, there is a problem that the screen vibrates due to the screen swing mechanism, the scanning speed cannot be increased, and the displayed image appears to flicker. Our new proposed method can reduce the screen vibration by the spin mechanism, increase the scanning speed, and prevent the displayed image from flickering. Computer simulation was performed to confirm the principle of the proposed method, and it was confirmed that appropriate parallax could be presented. The necessary conditions and problems when manufacturing the actual machine were considered, and the prototype was designed.

We enhanced the resolution characteristics of a threedimensional (3D) image using time-division multiplexing methods in a full-parallax multi-view 3D display. A time-division light-ray shifting (TDLS) method is proposed that uses two polarization gratings (PGs). As PG changes the diffraction direction of light rays according to the polarization state of the incident light, this method can shift light rays approximately 7 mm in a diagonal direction by switching the polarization state of incident light and adjusting the distance between the PGs. We verified the effect on the characteristics of 3D images based on the extent of the shift. As a result, the resolution of a 3D image with depth is improved by shifting half a pitch of a multi-view image using the TDLS method, and the resolution of the image displayed near the screen is improved by shifting half a pixel of each viewpoint image with a wobbling method. These methods can easily enhance 3D characteristics with a small number of projectors.

We propose a large screen 3D display which enables multiple viewers to see simultaneously without special glasses. In prior researches, methods of using a projector array or a swinging screen were proposed. However, the former has difficulty in installing and adjusting a large number of projectors and the latter cases occurrence of vibration and noise because of the mechanical motion of the screen. Our proposed display consists of a wavelength modulation projector and a spectroscopic screen. The screen shows images of which color depends on viewing points. The projector projects binary images to the screen in time-division according to wavelength of projection light. The wavelength of the light changes at high-speed with time. Therefore, the system can show 3D images to multiple viewers simultaneously by projecting proper images according to each viewing points. The installation of the display is easy and vibration or noise are not occurred because only one projector is used and the screen has no mechanical motion. We conducted simulation and confirmed that the proposed display can show 3D images to multiple viewers simultaneously.

In recent years, 3D reconstruction systems comprising multiple depth sensors have received increasing interest for dynamic scene reconstruction and related applications. Publicly available ground truth data are of limited usefulness when dealing with quality assessment of self-recorded data delivered by customized stereo configurations. In this paper, we propose a framework that incorporates versatile strategies for quantitative and qualitative evaluation of a multi-stereo reconstruction system and its intermediate products. Besides the design of suitable calibration objects for quantitative measurements, the framework exploits multiview data redundancy and generated novel views for objective quality assessment and to obtain subjective ratings from users. We demonstrate the applicability of our evaluation system in experiments with several stereo matching algorithms and view fusion approaches along with a pair-comparison based user study. We believe that our proposed evaluation framework is beneficial for the assessment of 3D products derived from self-recorded dynamic data of comparable set-ups, for example, in the context of subsequent augmented reality applications.