Exploring the Potential of 3D Visualization Techniques for Usage in Collaborative Design

Best practice for collaborative design demands good interaction between its collaborators. The capacity to share common knowledge about design models at hand is a basic requirement. With current advancing technologies gathering collective knowledge is more straightforward, as the dialog between experts can be supported better. The potential for 3D visualization techniques to become the right support tool for collaborative design is explored. Special attention is put on the possible usage for remote collaboration. The opportunities for current state-of-the-art visualization techniques from stereoscopic vision to holographic displays are researched. A classification of the various systems is explored with respect to their tangible usage for augmented reality. Appropriate interaction methods can be selected based on the usage scenario

A joint motion & disparity motion estimation technique for 3D integral video compression using evolutionary strategy

3D imaging techniques have the potential to establish a future mass-market in the fields of entertainment and communications. Integral imaging, which can capture true 3D color images with only one camera, has been seen as the right technology to offer stress-free viewing to audiences of more than one person. Just like any digital video, 3D video sequences must also be compressed in order to make it suitable for consumer domain applications. However, ordinary compression techniques found in state-of-the-art video coding standards such as H.264, MPEG-4 and MPEG-2 are not capable of producing enough compression while preserving the 3D clues. Fortunately, a huge amount of redundancies can be found in an integral video sequence in terms of motion and disparity. This paper discusses a novel approach to use both motion and disparity information to compress 3D integral video sequences. We propose to decompose the integral video sequence down to viewpoint video sequences and jointly exploit motion and disparity redundancies to maximize the compression. We further propose an optimization technique based on evolutionary strategies to minimize the computational complexity of the joint motion disparity estimation. Experimental results demonstrate that Joint Motion and Disparity Estimation can achieve over 1 dB objective quality gain over normal motion estimation. Once combined with Evolutionary strategy, this can achieve up to 94% computational cost saving

Neural \'{E}tendue Expander for Ultra-Wide-Angle High-Fidelity Holographic Display

Holographic displays can generate light fields by dynamically modulating the wavefront of a coherent beam of light using a spatial light modulator, promising rich virtual and augmented reality applications. However, the limited spatial resolution of existing dynamic spatial light modulators imposes a tight bound on the diffraction angle. As a result, modern holographic displays possess low \'{e}tendue, which is the product of the display area and the maximum solid angle of diffracted light. The low \'{e}tendue forces a sacrifice of either the field-of-view (FOV) or the display size. In this work, we lift this limitation by presenting neural \'{e}tendue expanders. This new breed of optical elements, which is learned from a natural image dataset, enables higher diffraction angles for ultra-wide FOV while maintaining both a compact form factor and the fidelity of displayed contents to human viewers. With neural \'{e}tendue expanders, we experimentally achieve 64$\times$ \'{e}tendue expansion of natural images in full color, expanding the FOV by an order of magnitude horizontally and vertically, with high-fidelity reconstruction quality (measured in PSNR) over 29 dB on retinal-resolution images

일상용 근안 디스플레이에 대한 연구: 폼 팩터, 시야각, 아이박스, 투명 및 3차원 홀로그래픽 디스플레이

학위논문(박사) -- 서울대학교대학원 : 공과대학 전기·정보공학부, 2021.8. 이병호.The purpose of the display technology is to deliver visual information through light. When the information becomes larger in its amount and more similar to the natural 3D scene, the user will get a more immersive experience. In this point of view, among many 3D display technologies, the near-eye display (NED) can provide the most immersive experience since it utilizes the information in the most efficient way. Nevertheless, the NED devices are still struggling to penetrate the public market because of the bottlenecks of performance in their optical systems. Especially, among the major required performances, the form factor of the NED optical system is the most urgent problem to solve for NED's daily use in public. In this dissertation, three different methods are presented to reduce the form factor of the NEDs while considering the trade-off with the other performances. In Chapter 2, a method to make a glasses-sized virtual reality (VR) NED is presented. While having a thin form factor, other performances are still comparable such as field of view (FOV), eye-box, and resolution. In Chapter 3, a method to reduce the form factor of the holographic NED is presented, which can offer accommodation 3D focus cue. Conventional holographic projection part which required tens of centimeters of path length can be substituted by a 2 mm thick Bragg grating filter. In Chapter 4, a method to reduce the form factor of a holographic optical see-through NED is presented. When the holographic NED is combined with the waveguide image combiner, both the thin and transparent glass-like form factor of waveguide and the capability of 3D holographic display can be acquired. Moreover, this method also can enlarge the narrow eye-box of the holographic NED. The NED technology just started to run. The goal of the daily-use NED seems far but surely it is in a visible future. The author believes the daily-use NED will revolutionize peoples' lifestyles like smartphones have done. Hopefully, these works' effort toward the daily-use NED will contribute to the upcoming future.디스플레이 기술의 목적은 빛을 통해 시각정보를 전달하는 것이다. 디스플레이가 더 많은 양의 정보를 전달하고, 자연스러운 3D 환경과 더 비슷한 정보를 제공할 수 있을 때, 사용자는 몰입감을 경험할 수 있다. 이러한 정보 전달의 관점에서, 근안 디스플레이는 가장 효율적인 방법으로 많은 자유도를 가지면서 정보를 전달할 수 있는 기술이기 때문에, 가장 몰입감 있는 디스플레이 기술이라고 말할 수 있다. 그럼에도 불구하고 근안 디스플레이는 여전히 시장에 침투하기 위해서 고군분투하고 있다. 여기서 광학계 성능이 병목현상이 되고 있다. 특히 여러 성능들 중에서도 폼 팩터는 일상용 근안 디스플레이를 위해서 가장 시급하게 해결해야하는 문제이다. 이 학위논문에서는 근안 디스플레이의 폼팩터를 줄이면서도 다른 성능을 크게 해치지 않을 수 있는 세 가지 방법을 소개한다. 제 2장에서는 안경 크기의 가상현실용 근안 디스플레이를 만드는 방법을 소개한다. 이 시스템은 얇은 폼팩터를 가졌음에도 시야각, 아이박스, 해상도 등의 다른 성능도 크게 훼손되지 않는다. 제 3장에서는 3차원 초점조절반응을 제공할 수 있는 홀로그래픽 근안 디스플레이에서 폼팩터를 줄일 수 있는 방법을 소개한다. 기존 홀로그래픽 투사 광학계는 수십 센티미터의 광경로가 필요했지만, 이 시스템을 2 mm 두께의 Bragg 격자만으로 대체할 수 있다. 제 4장에서는 홀로그래픽 투명 근안 디스플레이에서의 폼팩터를 줄일 수 있는 방법을 소개한다. 홀로그래픽 근안 디스플레이가 광도파로 영상결합기와 결합되면 두 가지 장점을 모두 가질 수 있다. 따라서 광도파로의 투명하고 얇은 폼팩터와 홀로그래픽 디스플레이의 3차원 초점조절반응 제공가능한 특성을 모두 가질 수 있다. 게다가, 이 방법은 홀로그래픽 근안 디스플레이에서 문제가 되었던 좁은 아이박스에 대한 문제도 해결할 수 있다. 근안 디스플레이 기술은 이제 달리기 시작했다. 일상용 근안 디스플레이에 대한 꿈은 멀어보이지만 분명히 보일만한 거리에 있다. 저자는 일상용 근안 디스플레이가 마치 스마트폰이 그랬듯이 사람들의 삶의 방식을 개혁할 것이라고 믿는다. 이 학위논문연구에서의 노력이 다가오는 미래에 기여할 수 있기를 바란다.1 Introduction 1 1.1 Near-eye display (NED) 1 1.1.1 Display and information 1 1.1.2 3D displays and NED 4 1.2 Daily-use NED 9 1.2.1 VR, AR, and daily-use NED 9 1.2.2 Performance of NED optics 11 1.2.3 Priority of performance for daily-use NED 15 1.3 Dissertation overview 17 2 Compact VR NED using optimized lens array 19 2.1 Introduction 19 2.2 Related works 23 2.2.1 Conventional VR optics 23 2.2.2 Pancake VR optics 23 2.2.3 Lenslet array and light field near-eye display 24 2.2.4 Waveguide near-eye displays 24 2.3 Design approach 25 2.3.1 Why conventional VR is bulky 25 2.3.2 Lenslet array and collecting lens 27 2.3.3 Fresnel lens 29 2.3.4 Polarization-based optical folding (pancake lens) 31 2.4 Design space 33 2.4.1 Light field analysis 33 2.4.2 Design parameter selection 36 2.5 Aberration analysis 38 2.5.1 Fresnel lens selection 38 2.5.2 Image distortion 41 2.6 Implementation 43 2.6.1 Benchtop prototype 43 2.6.2 VR glasses prototype 44 2.7 Display result 46 2.7.1 Camera used in experiments 46 2.7.2 FOV and image distortion 47 2.7.3 Eye-box and pupil swim distortion 49 2.7.4 Resolution and chromatic aberration 50 2.7.5 VR glasses prototype 52 2.8 Discussion and future works 53 2.8.1 System thickness 53 2.8.2 Leakage noise 53 2.8.3 Fresnel lens optimization 54 2.8.4 Pupil tracker synchronization 55 2.8.5 See-through display 55 2.9 Conclusion 55 3 Compact holographic projection using Bragg grating noise filter 57 3.1 Introduction 57 3.2 Related works 58 3.3 Principles 59 3.3.1 Angular stop filter (ASF) 59 3.3.2 Noise in a holographic display 60 3.4 Filter design 61 3.4.1 Design of DC angular stop filter (ASF) 61 3.4.2 Design of high-order angular stop filter (ASF) 64 3.5 Experiments 64 3.6 Discussion 69 3.6.1 Effect of ring-shaped filtered region 69 3.6.2 Application to full color holographic display 69 3.7 Conclusion 70 4 Compact holographic AR NED using waveguide image combiner 73 4.1 Introduction 73 4.1.1 Terminology 74 4.2 Trade-offs in conventional holographic see-through NED 75 4.2.1 Optical see-through property and form factor 75 4.2.2 Holographic NED and narrow eye-box 76 4.3 Limitation of conventional waveguide image combiner 78 4.3.1 Basic principle of waveguide image combiner 78 4.3.2 Limitation in providing accommodation 3D focus cue 80 4.4 Principle of holographic waveguide NED 82 4.4.1 Capability of accommodation 3D focus cue 82 4.4.2 Capability of the eye-box shifting 85 4.5 Algorithm 86 4.5.1 Algorithm for input hologram calculation 86 4.5.2 Algorithm for waveguide system measurement 94 4.6 Experimental results 98 4.6.1 Holographic waveguide NED setup 98 4.6.2 Waveguide system model estimation 101 4.6.3 3D waveguide display results 103 4.7 Discussion 104 4.8 Conclusion 106 5 Conclusion 109 Appendix 124 초록 125박

Interferometers as Probes of Planckian Quantum Geometry

A theory of position of massive bodies is proposed that results in an observable quantum behavior of geometry at the Planck scale, $t_P$. Departures from classical world lines in flat spacetime are described by Planckian noncommuting operators for position in different directions, as defined by interactions with null waves. The resulting evolution of position wavefunctions in two dimensions displays a new kind of directionally-coherent quantum noise of transverse position. The amplitude of the effect in physical units is predicted with no parameters, by equating the number of degrees of freedom of position wavefunctions on a 2D spacelike surface with the entropy density of a black hole event horizon of the same area. In a region of size $L$, the effect resembles spatially and directionally coherent random transverse shear deformations on timescale $\approx L/c$ with typical amplitude $\approx \sqrt{ct_PL}$. This quantum-geometrical "holographic noise" in position is not describable as fluctuations of a quantized metric, or as any kind of fluctuation, dispersion or propagation effect in quantum fields. In a Michelson interferometer the effect appears as noise that resembles a random Planckian walk of the beamsplitter for durations up to the light crossing time. Signal spectra and correlation functions in interferometers are derived, and predicted to be comparable with the sensitivities of current and planned experiments. It is proposed that nearly co-located Michelson interferometers of laboratory scale, cross-correlated at high frequency, can test the Planckian noise prediction with current technology.Comment: 23 pages, 6 figures, Latex. To appear in Physical Review

비등방성 광학 소자를 이용한 광 시야각 근안 디스플레이

학위논문 (박사)-- 서울대학교 대학원 : 공과대학 전기·컴퓨터공학부, 2019. 2. 이병호.Near-eye display is considered as a promising display technique to realize augmented reality by virtue of its high sense of immersion and user-friendly interface. Among the important performances of near-eye display, a field of view is the most crucial factor for providing a seamless and immersive experience for augmented reality. In this dissertation, a transmissive eyepiece is devised instead of a conventional reflective eyepiece and it is discussed how to widen the field of view without loss of additional system performance. In order to realize the transmissive eyepiece, the eyepiece should operate lens to virtual information and glass to real-world scene. Polarization multiplexing technique is used to implement the multi-functional optical element, and anisotropic optical elements are used as material for multi-functional optical element. To demonstrate the proposed idea, an index-matched anisotropic crystal lens has been presented that reacts differently depending on polarization. With the combination of isotropic material and anisotropic crystal, the index-matched anisotropic crystal lens can be the transmissive eyepiece and achieve the large field of view. Despite the large field of view by the index-matched anisotropic crystal lens, many problems including form factor still remain to be solved. In order to overcome the limitations of conventional optics, a metasurface is adopted to the augmented reality application. With a stunning optical performance of the metasurface, a see-through metasurface lens is proposed and designed for implementing wide field of view near-eye display. The proposed novel eyepieces are expected to be an initiative study not only improving the specification of the existing near-eye display but opening the way for a next generation near-eye display.근안 디스플레이는 높은 몰입감과 사용자 친화적인 인터페이스로 인해 증강 현실을 구현하는 가장 효과적인 기술로 최근 활발한 연구가 계속되고 있다. 이러한 근안 디스플레이의 중요한 성능 중 시야각은 매끄럽고 몰입감 있는 경험을 사용자에게 전해줌으로써 가장 중요한 광학적 평가지표 중에 하나이다. 본 논문에서는 기존의 반사형 아이피스 (eyepiece) 를 대신하는 투과형 아이피스를 제안한다. 이러한 투과형 아이피스를 구현하기 위해서는 외부 정보에 대해서는 투명한 유리와 같이 투과시키며, 동시에 가상 정보는 렌즈로 작동하여 먼 거리에 띄울 수 있는 광학소자를 개발하여야 한다. 이러한 투과형 아이피스를 구현하기 위해서 편광에 따라 다르게 반응하는 굴절률 정합 이방성 결정 렌즈 (index-matched anisotropic crystal lens) 를 제안하였다. 이방성 결정 구조 (anisotropic crystal)로 이루어진 렌즈와 이를 둘러싼 등방성 물질 (isotropic crytal) 로 이루어진 굴절률 정합 이방성 결정 렌즈는 편광에 따라 다르게 작동한다. 이러한 투과형 아이피스는 기존의 근안 디스플레이에 비해 넓은 시야각을 제공할 수 있지만 이방성 결정 구조의 낮은 굴절률 차이로 인해 시스템의 크기가 커지는 단점을 가지고 있다. 본 논문에서는 이러한 단점을 개선하기 위해 메타 표면을 증강 현실 디스플레이 분야에 적용하였다. 메타 표면의 기존 광학 소자를 능가하는 놀라운 광학 성능을 이용하여 넓은 시야각을 가지는 근안 디스플레이를 구현하기 위해 투명 메타 렌즈를 제안하였다. 편광에 따라 다르게 반응하는 투명 메타렌즈는 넓은 시야각과 경량화 시스템 구현이 가능하며 이를 입증하기 위해 투명 메타렌즈의 설계 방법 뿐 아니라 실제 구현을 통한 가능성을 입증하였다. 이러한 새로운 아이피스에 대한 개념은 기존의 근안 디스플레이의 사양 개선에 유용하게 사용될 뿐 아니라 차세대 근안 디스플레이를 위한 선도적인 역할을 할 것으로 기대된다.Abstract Contents List of Tables List of Figures Near-eye displays with wide field of view using anisotropic optical elements Chapter 1 Introduction 1.1 Near-eye displays for augmented reality 1.2 Optical performances of near-eye display 1.3 State-of-the-arts of near-eye display 1.4 Motivation and contribution of this dissertation Chapter 2 Transmissive eyepiece for wide field of view near-eye display 2.1 Transmissive eyepiece for near-eye display Chapter 3 Near-eye display using index-matched anisotropic crystal lens 3.1 Introduction 3.2 Index-matched anisotropic crystal lens 3.2.1 Principle of the index-matched anisotropic crystal lens 3.2.2 Aberration analysis of index-matched anisotropic crystal lens 3.2.3 Implementation 3.3 Near-eye displays using index-matched anisotropic crystal lens 3.3.1 Near-eye display using index-matched anisotropic crystal lens 3.3.2 Flat panel type near-eye display using IMACL 3.3.3 Polarization property of transparent screen 3.4 Conclusion Chapter 4 Near-eye display using metasurface lens 4.1 Introduction 4.2 See-through metasurface lens 4.2.1 Metasurface lens 4.3 Full-color near-eye display using metasurface lens 4.3.1 Full-color near-eye display using metasurface lens 4.3.2 Holographic near-eye display using metasurface lens for aberration compensation 4.4 Conclusion Chapter 5 Conclusion Bibliography AppendixDocto

Optimization of Computer generated holography rendering and optical design for a compact and large eyebox Augmented Reality glass

Thesis (Master of Science in Informatics)--University of Tsukuba, no. 41288, 2019.3.2