Projection type transparent 3D display using active screen

There is often confusion among the general public between holograms and the type of contemporary 3D images seen in movie theaters, in which viewers from each side of the theater see the same image on the screen. As astonishing as these 3D effects are, the technologies used are typically based on either polarization stereoscopy (the technique currently used in cinemas and 3D television), digital image fusion, or 2D semitransparent screens. These techniques have little to do with holography, which is based on the reproduction of not only the amplitude but also the phase of light by diffraction. These 3D images can have depth but are typically filmed from a single perspective. On the other hand, for a viewer moving around a hologram, the appearance of the object changes continuously and smoothly as the viewer’s perspective changes, as if the object is real. A standard 3D movie camera (which actually uses two cameras) captures light scattered from an object at two different angles, one for each eye, from a single perspective. However, in the real world, light reflects from objects at an infinite number of angles. For a 3D television viewing experience to be maximally realistic, it must be autostereoscopic (requiring no glasses), present continuous parallax (rather than just stereopsis), and realistically represent other perceptual depth cues, such as proper visual accommodation (focusing) and vergence. The display technology most likely able to offer these features is holographic television. Some recent 3D display technologies, though not necessarily holographic, have been commercialized due to the increasing demand from the public for autostereoscopic 3D TVs, 3D games, and mobile devices equipped with 3D displays. This chapter systematically reviews various 3D display technologies. Byoungho Lee et.al. and Jason Geng have recently published excellent review articles concerning many state-of-the-art 3D display technologies, which will be summarized in this chapter.

This paper proposes the interactive lecture system based on mixed reality using a transparent display that enables interaction with the users watching the display. This system unlike existing remote video lectures, will allow students to participate progressively in the lectures by enabling the interaction between the instructor and students. Furthermore, this system also improves the reality in such a way that, during the visualization of the real-time video lectures on the transparent display, it seems that the instructor is in the same place with the students. This paper experiments and implements the proposed system based on the transparent display, 2D camera, and 3D sensors.

Although a significant research effort has been carried out for investigating 3 Dimensional (3D) video display, transmission, coding, etc, the same is not applicable for 3D video adaptation. In addition, ambient illumination, spatial resolution and 3D video content related contexts have not been particularly considered in a hybrid manner for the 3D video adaptation purpose in literature to date. In this paper, an adaptation decision taking technique is designed to predict the bit rate of 3D video sequences to be adapted by a proposed adaptation model. The ambient illumination condition of the viewing environment is considered in these proposed technique and model together with spatial resolution, video quality, and depth perception related contexts of the 3D video. Experimental results derived by the assistance of subjective experiments prove that the proposed model is quite efficient to adapt the 3D video sequences without compromising the 3D video perception of the users.

We used body sway to evaluate a viewer's sense of presence with three kinds of 3D displays as follows: a head mounted display (HMD), a 70 inch 3D display and a consumer 3D television. This expedient used images with a fixed foreground and a rolling background as the visual stimuli to induce body sway. The images were taken from a boat rolling at five different frequencies (approx. 0.125, 0.20, 0.25, 0.33, 0.50 Hz). We examined eight healthy adults viewing each of the five images for three minutes on each display. We evaluated body sway using a motion analyzing system to measure the displacement of a marker placed on the head of the subjects. It was found that at all rolling frequencies of the image background, the HMD induced the greatest amount of body sway followed by the large 3D display and then the consumer 3D television. The amount of body sway was the greatest when the rolling frequency was 0.33 Hz. The results showed the amount of body sway depended on the type of display and the rolling frequency.

A holographic three-dimensional (3D) display is a recognized and ideal 3D display technology. In the field of holographic research, cylindrical holography with the merit of 360° field of view (FOV) has recently become a hot issue, as it naturally solves the problem of limited FOV in planar holography. The recently proposed approximate phase compensation (APC) method successfully obtains larger FOV and fast generation of segment cylindrical hologram (SCH) in the visible light band. However, the FOV of SCH remains limited due to its intrinsic limitations, and, to our best knowledge, the issue has not been effectively addressed. In this paper, the restricted conditions are first analyzed for the generation of SCH by the APC method. Then, an FOV expansion method is proposed for realizing a large FOV holographic display by gapless splicing of multi-SCH. The proposed method can successfully obtain larger FOV cylindrical holograms and effectively eliminate the splicing gaps; its effectiveness is verified by the results of numerical simulation and optical experiments. Therefore, the proposed method can effectively solve the FOV limitation problem of the APC method for the generation of SCH in the visible band, realize a large FOV 3D display, and provide a useful reference for holographic 3D display.

A high‐resolution autostereoscopic three‐dimensional (3D) display is proposed. It comprises two light source arrays (LSAs), a transparent liquid crystal display (LCD) panel, a scattering layer, and a lenticular lens. Light emitted from the LSAs is directed onto the transparent LCD panel, which projects the opening units corresponding to different parallax image pixels into distinct spatial locations, thereby creating new pixels. These new pixels are modulated and reconstructed by the scattering layer, incorporating both the original parallax image pixel information and the information from adjacent pixels post‐differentiation. Consequently, when the new pixels are projected through the lenticular lens to the viewpoint, a high‐resolution 3D image is displayed. The experimental results demonstrate the validity of our proposed autostereoscopic 3D display.

ABSTRACTThe aim of this paper is to image particularly buried archaeological remains with a new technique for 3D display in the Temple of Augustus (Monumentum Ancyranum) relating to the Roman time, around and in Agora in the Ulus district of Ankara, Turkey. 2D ground‐penetrating radar (GPR) data were acquired on constant spaced parallel profiles in the study area. After data processing, a 3D data volume was built using a parallel 2D data set. The full data block was divided into sub‐data blocks in time. A weak amplitude range was made invisible with zero opaque by applying zero opacity to these values in the visualization. The arranged visible maximum amplitude range was enlarged or the amplitude scale was weighted with a constant coefficient, which was greater than one and smaller than two and had a decimal number, according to the time range. In this way, a transparent 3D image was obtained for determining buried remains according to the depth range. Interactive visualization was carried out by constructing sub‐blocks of the transparent 3D volume.The interactive transparent 3D visualization was provided to identify the archaeological remains on native locations with depth in a 3D volume. Very complex and deep wall structures were visualized with any depth range inside (cella) of the Temple of Augustus and a few very narrow cubic anomalies exceeding 4 m deep were determined at the East side of the temple. An excavation could not be carried out in the cella because of the sensitivity problem of the cella walls. However, excavations in front of the East wall of the temple encouraged the new 3D image results. In addition, a lot of iron clamps connecting wall marble stones were determined on a profile gathered on the East wall.

Between July 2000 and December 2003, a total number of 3,472 fetuses was evaluated by two-dimensional (2D) and three-dimensional (3D) ultrasonography. All examinations were carried out as part of a detailed level III ultrasound examination for fetal anomalies. The gestational age was between 11 and 35 weeks. A 3D endovaginal probe (5 - 7 MHz) was used for examinations between 11 and 13 weeks, and an abdominal 3D probe (5 MHz) after 13 weeks. Four different 3D image display modes were employed in visualizing fetal malformations: triplanar orthogonal display; surface display; transparent display; and the combined transparent and color display (= glass body-rendering). In 906 of the 3,472 high-risk pregnancies, fetuses with one to five fetal defects were found (mean 1.17). The total number of detected defects was 1,012, exclusive of 48 fetal heart defects. Fetal heart defects were excluded from this study since a reliable demonstration of these defects was not possible by 3D ultrasound. Comparing the 2D and 3D techniques, 3D sonography proved advantageous in 60.8 % of the defects, with the benefit derived from the exact tomographic survey using the multiplanar view in 69.9 % of these cases, from a more precise demonstration of the defect in the surface view in 25.2 %, from a distinct demonstration in the transparent view in 3.9 %, and from a precise demonstration in the combined transparent and color view in 1.0 %. In 42 of the 1,012 malformations (4.2 %), a defect was accurately identified or verified with 3D ultrasound only. 3D ultrasound proves not only a useful tool in appreciating the severity of a fetal defect, but also provides more convincing evidence of a normal fetus than conventional two-dimensional sonograms in cases with increased risk of a recurrent surface malformation.

General design method for three-dimensional displays with horizontally asymmetric pixel structures

Medical image diagnosis processes with stereoscopic depth by 3D display have not been developed widely yet and remain understudied Many stereoscopic displays require glasses that are inappropriate for use in clinical diagnosis/explanation/operating processes in hospitals. An eye-tracking based glasses-free three-dimensional autostereoscopic display monitor system has been developed, and its feasibility for medical 3D images was investigated, as a cardiac CT 3D navigator. Our autostereoscopic system uses slit-barrier with BLU, and it is combined with our vision-based eye tracking system to display 3D images. Dynamic light field rendering technique is applied with the 3D coordinates calculated by the eye-tracker, in order to provide a single viewer the best 3D images with less x-talk. To investigate the feasibility of our autostereoscopic system, 3D volume was rendered from 3D coronary CTA images (512 by 512 by 400). One expert reader identified the three main artery structures (LAD, LCX and RCA) in shorter time than existing 2D display. The reader did not report any eye fatigue or discomfort. In conclusion, we proposed a 3D cardiac CT navigator system with a new glasses-free 3D autostereoscopy, which may improve diagnosis accuracy and fasten diagnosis process.

With the arrival of auto-stereoscopic 3D displays for mobile devices, and emergence of more 3D content, there is much anticipation for 3D mobile multimedia experiences, including 3D display gaming. Simultaneously, with the emergence of cloud computing, more mobile applications are being developed to take advantage of the elastic cloud resources. In this paper, we explore the possibility of developing Cloud-based 3D Mobile Gaming, where the 3D video rendering and encoding is performed on cloud servers, with the resulting 3D video streamed over wireless networks to mobile devices with 3D displays for a true 3D mobile gaming experience. However, with the significantly higher bit rate requirement for 3D video, ensuring user experience may be a challenge, both in terms of 3D video quality and network delay (response time), considering the bandwidth constraints and fluctuations of wireless networks. In this paper, we propose a new asymmetric graphics rendering approach which can significantly reduce the video encoding bit rate needed for a certain video quality, thereby making it easier to transmit the video over wireless network. However, since asymmetric rendering may also impair the graphics quality, we need to be able to understand and measure its impact. We conduct subjective tests to study and model the impairments due to asymmetric rendering and network delay, thereby developing a user experience model for cloud based mobile 3D display gaming. By conducting subsequent subjective tests, we prove the correctness of the impairment functions and the resulting user experience model. We also conduct experiments using real 4G-LTE network profile. Experimental results show that by making use of the user experience model, it is possible to set appropriate graphics rendering parameters according to network constraints, such that the user experience can be maintained to a high level.

Two types of transparent three-dimensional display systems applicable for the augmented reality are demonstrated. One of them is a head-mounted-display-type implementation which utilizes the principle of the system adopting the concave floating lens to the virtual mode integral imaging. Such configuration has an advantage in that the threedimensional image can be displayed at sufficiently far distance resolving the accommodation conflict with the real world scene. Incorporating the convex half mirror, which shows a partial transparency, instead of the concave floating lens, makes it possible to implement the transparent three-dimensional display system. The other type is the projection-type implementation, which is more appropriate for the general use than the head-mounted-display-type implementation. Its imaging principle is based on the well-known reflection-type integral imaging. We realize the feature of transparent display by imposing the partial transparency to the array of concave mirror which is used for the screen of reflection-type integral imaging. Two types of configurations, relying on incoherent and coherent light sources, are both possible. For the incoherent configuration, we introduce the concave half mirror array, whereas the coherent one adopts the holographic optical element which replicates the functionality of the lenslet array. Though the projection-type implementation is beneficial than the head-mounted-display in principle, the present status of the technical advance of the spatial light modulator still does not provide the satisfactory visual quality of the displayed three-dimensional image. Hence we expect that the head-mounted-display-type and projection-type implementations will come up in the market in sequence.

Three-dimensional (3D) Image quality assessment (IQA) is becoming one of hot research area recently. 3D image refers to a technique for enhancing the illusion of depth and protrusion in an image by presenting two offset images separately to the left and right eye of the viewer. These two-dimensional images are combined in the brain to give the perception of 3D depth and protrusion. With the advent of visual revolution, 3D visual becoming more and more important to us, but how could we enjoy an excellent effect 3D image or video? This is the question that we would like to solve in this paper, and the answer is an assessment of 3D image system based on objective and subjective method was built and in this paper we discussed the result comprehensively.

Numerous research studies in recent years have been done on analyzing gestures and sounds from video, and using them for man-machine interfaces. Human posture estimation by conventional techniques uses only 2D (2D) images or 3D data. However, estimation at fine angles is difficult using the 2D images, while use of special photography equipment is necessary to gather 3D data. In this paper, a technique for performing facial posture estimation from 2D video using a 3D reference picture is proposed. By this technique, the features of a human face are extracted using a 3D form of the human face obtained beforehand with a range finder. The 3D reference picture after the feature extraction is accumulated as a database. The human facial posture in an animation is presumed in analyzing the 2D facial domain extracted from the accumulated 3D reference picture and the animation. In posture estimation processing, in order to make the size and inclination of a human face, calibration is performed on the human face domain extracted from the 2D input image using a circular mask. Furthermore, a movement vector is computed from the relation with the previous and subsequent processing frames, and human face operation in the processing frame is predicted based on the calculated result. From the prediction results, posture estimation processing is accelerated by thinning out the rotation angle of the 3D reference. The key feature of this technique is in its ability to perform posture estimation with robust sufficient accuracy to the size or inclination of a human face.

We have developed a real-time color autostereoscopic display system using a reconstruction method of parallax rays. The notable point is to be able to display a volumetric image such as holography. Moreover, the data of this system can reduce much than that of hologram. Also, this system is visible to multiple viewers at the same time without special glasses. Well-known integral photography (IP) is similar to our system. Pseudoscopic images for IP are the most important problem that has to be solved. Using the method of ray-space representation on our display, it is not probability to appear pseudoscopic image. This paper describes the three-dimensional (3D) image input system based on ray-space representation for a color 3D display using a method of the reconstruction of parallax rays. The ray-space representation is one of image-based rendering techniques. It uses images of real objects to recreate photo realistic images of complex shaped objects without any explicit geometric model. Using similarities between a reference plane in ray-space representation and the screen of this 3D display, parallax rays for a 3D image, which we can observe at arbitrary viewing point, compose of amount of some parallax images. As an experimental result, the 3D image of origami bird (crane) is reconstructed.