Ray-space360: An extension of ray-space for omnidirectional free viewpoint

Jung, Hyunmin; Lee, Hyuk-Jae; Rhee, Chae Eun

doi:10.1109/iscas.2018.8351480

Cited by 4 publications

(7 citation statements)

References 6 publications

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“…The most basic forms are the 3D and 4D LFs. At the intermediate level, both circular [30], [31] and square-shaped structures [16], [32] are modified versions of the 3D LF. Due to the layout changes, light rays from four directions can be acquired, expanding the range of view rendering.…”

Section: B Light Field-based Free Viewpoint Systemsmentioning

confidence: 99%

“…Ray-space360 [32] always uses a physical connection scheme and requires a light ray with a horizontal incident angle of up to 90 • , corresponding to k = 90 • in Fig. 11 (a).…”

Section: B Hybrid 3d Lf Connectionmentioning

confidence: 99%

“…Fig. 14 compares the proposed Hybrid 3D LF connection with other connection-based methods, LFU [16] and Ray-space360 [32], for two sample spaces. Figs.…”

Section: Effects Of Hybrid 3d Lf Connectionmentioning

confidence: 99%

“…In the given range of d src (1.2N to 2.5N ), the optimal k starts at 87 • and converges to 72 • . Since d src is not fixed to a single value in the real world, the optimal value of k must be finetuned between 72 • and 87 • .Ray-space360[32] always uses a physical connection scheme and requires a light ray with a horizontal incident angle of up to 90 • , corresponding to k = 90 • in Fig.11 (a). On the other hand, LFU[16] uses light rays with θ = ±45 • as a shared light ray, corresponding to k = 45 • .…”

mentioning

confidence: 99%

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Enabling Five-Degree-of-Freedom From Low-Dimensional Light Fields With Extended Light Ray Acquisition Field-of-View

2023

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Conventional captured-image-based virtual reality (VR) systems hardly support free movement of the viewpoint, greatly reducing the user's sense of reality. A light field (LF), which generates a novel view at a free viewpoint through a combination of light rays, is a suitable approach for increasing the degree of freedom (DoF) in captured-image-based VR. Previous LF-based VR systems have increased LF dimensions or used various acquisition layouts to obtain as many light rays as possible and thereby expand the renderable view range. However, these attempts are costly and time-consuming. This paper enables 5-DoF outcomes from a low-dimensional LF by increasing the field-of-view during light ray acquisition. The method starts with the simple idea that if a three-dimensional (3D) LF is constructed with 360 • images that can capture all directions, the renderable range can be widened in a cost-efficient manner. However, using light rays with a large incident angle in a 3D LF can cause visual artifacts. To cope with this problem, this paper initially defines and analyzes the visual artifacts. While these errors were simply ignored in the past, they become particularly noticeable when using light rays with large incident angles. Thus, a careful analysis of the errors and their impacts is required. Additionally, this paper proposes two schemes to deal with visual artifacts based on the error analysis: a horizontal LF and vertical depth (HLF-VD) view generation scheme that complements the structural limitation of 3D LFs and can address all types of errors, and a hybrid 3D LF connection scheme that effectively reduces connection errors by controlling the connection position of neighboring 3D LFs. The proposed system is implemented and verified in various real-world scenarios, and the experimental results show that the user's movement is naturally reflected at a level similar to that of high-dimensional LF, with minimal visual artifacts. INDEX TERMSFree viewpoint, Image-based rendering, Light field, View navigation, Virtual reality I. INTRODUCTIONA few years ago, virtual reality (VR) technology gained significant attention. However, problems such as insufficient technical maturity, lack of VR content, and motion sickness drastically reduced interest in VR. Nevertheless, with the onset of the COVID-19 pandemic, VR technology is experiencing a resurgence. The pandemic has changed the way people interact, and to avoid direct contact, telecommut-ing, video conferencing, and video education have become increasingly popular. VR technology can provide an allencompassing solution in the COVID-19 era as it allows people to work, meet, and play in a virtual space separated from the real world. However, the level of VR technology is still not as advanced as people expect, and there are numerous challenges that need to be addressed.Computer graphic-based virtual reality (CG-based VR)

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Section: B Light Field-based Free Viewpoint Systemsmentioning

confidence: 99%

“…Ray-space360 [32] always uses a physical connection scheme and requires a light ray with a horizontal incident angle of up to 90 • , corresponding to k = 90 • in Fig. 11 (a).…”

Section: B Hybrid 3d Lf Connectionmentioning

confidence: 99%

“…Fig. 14 compares the proposed Hybrid 3D LF connection with other connection-based methods, LFU [16] and Ray-space360 [32], for two sample spaces. Figs.…”

Section: Effects Of Hybrid 3d Lf Connectionmentioning

confidence: 99%

mentioning

confidence: 99%

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Enabling Five-Degree-of-Freedom From Low-Dimensional Light Fields With Extended Light Ray Acquisition Field-of-View

2023

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“…The light field information of dense multi-view images is frequently used in such applications as post-refocusing [ 3 ], super-resolution [ 4 ], occlusion reconstruction [ 5 ] and depth estimation. Recently, light field-based virtual reality (VR) recognizes an interactive and immersive “walk-around space” by rendering an image of an arbitrary viewpoint through a combination of pixels [ 6 , 7 ]. During the image capturing step, noise can be generated for various reasons.…”

Section: Introductionmentioning

confidence: 99%

Improved Light Field Compression Efficiency through BM3D-Based Denoising Using Inter-View Correlation

Jin

Rhee

2021

Sensors

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Multi-view or light field images have recently gained much attraction from academic and commercial fields to create breakthroughs that go beyond simple video-watching experiences. Immersive virtual reality is an important example. High image quality is essential in systems with a near-eye display device. The compression efficiency is also critical because a large amount of multi-view data needs to be stored and transferred. However, noise can be easily generated during image capturing, and these noisy images severely deteriorate both the quality of experience and the compression efficiency. Therefore, denoising is a prerequisite to produce multi-view-based image contents. In this paper, the structural characteristics of linear multi-view images are fully utilized to increase the denoising speed and performance as well as to improve the compression efficiency. Assuming the sequential processes of denoising and compression, multi-view geometry-based denoising is performed keeping the temporal correlation among views. Experimental results show the proposed scheme significantly improves the compression efficiency of denoised views up to 76.05%, maintaining good denoising quality compared to the popular conventional denoise algorithms.

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Immersive Virtual Reality Content Supporting a Wide and Free Viewpoint Made With a Single 360° Camera

2023

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Light field (LF)-based virtual reality (VR) systems have been proposed to tackle the problem of 360 • panoramic image based VR not being able to support viewpoint movements. LF-based approaches still have shortcomings in that the user's movement range is narrow and an extensive setup and high cost are required for data acquisition. This paper proposes lawn mowing pattern LF (LMP-LF) structure and presents a wide and free VR system utilizing an LMP-LF. The contributions of this paper are as follows. First, this paper proposes an LMP-LF in which several three-dimensional LFs (3DLFs) are arranged at uniform intervals. This simplifies the data acquisition process and widens the range of viewpoint movements. Second, this paper defines a light ray pair between two adjacent 3DLFs of the LMP-LF. The relationship between two light rays forming a light ray pair is expressed only with one-dimensional (1D) disparity, which greatly reduces the amount of disparity and the estimation complexity. Third, a real-time VR system using the LMP-LF is implemented and demonstrated. The proposed VR system achieves a high rendering speed of 125 frames-per-second (fps). In the prototype system, wide and free rendering performance was verified by building an LMP-LF for an automobile showroom at a size of 50m 2 .INDEX TERMS Light field, free viewpoint, virtual reality, view navigation, view synthesis.

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Ray-space360: An extension of ray-space for omnidirectional free viewpoint

Cited by 4 publications

References 6 publications

Enabling Five-Degree-of-Freedom From Low-Dimensional Light Fields With Extended Light Ray Acquisition Field-of-View

Enabling Five-Degree-of-Freedom From Low-Dimensional Light Fields With Extended Light Ray Acquisition Field-of-View

Improved Light Field Compression Efficiency through BM3D-Based Denoising Using Inter-View Correlation

Immersive Virtual Reality Content Supporting a Wide and Free Viewpoint Made With a Single 360° Camera

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