312 research outputs found
Learning Light Field Angular Super-Resolution via a Geometry-Aware Network
The acquisition of light field images with high angular resolution is costly.
Although many methods have been proposed to improve the angular resolution of a
sparsely-sampled light field, they always focus on the light field with a small
baseline, which is captured by a consumer light field camera. By making full
use of the intrinsic \textit{geometry} information of light fields, in this
paper we propose an end-to-end learning-based approach aiming at angularly
super-resolving a sparsely-sampled light field with a large baseline. Our model
consists of two learnable modules and a physically-based module. Specifically,
it includes a depth estimation module for explicitly modeling the scene
geometry, a physically-based warping for novel views synthesis, and a light
field blending module specifically designed for light field reconstruction.
Moreover, we introduce a novel loss function to promote the preservation of the
light field parallax structure. Experimental results over various light field
datasets including large baseline light field images demonstrate the
significant superiority of our method when compared with state-of-the-art ones,
i.e., our method improves the PSNR of the second best method up to 2 dB in
average, while saves the execution time 48. In addition, our method
preserves the light field parallax structure better.Comment: This paper was accepted by AAAI 202
Large-Scale Light Field Capture and Reconstruction
This thesis discusses approaches and techniques to convert Sparsely-Sampled Light Fields (SSLFs) into Densely-Sampled Light Fields (DSLFs), which can be used for visualization on 3DTV and Virtual Reality (VR) devices. Exemplarily, a movable 1D large-scale light field acquisition system for capturing SSLFs in real-world environments is evaluated. This system consists of 24 sparsely placed RGB cameras and two Kinect V2 sensors. The real-world SSLF data captured with this setup can be leveraged to reconstruct real-world DSLFs. To this end, three challenging problems require to be solved for this system: (i) how to estimate the rigid transformation from the coordinate system of a Kinect V2 to the coordinate system of an RGB camera; (ii) how to register the two Kinect V2 sensors with a large displacement; (iii) how to reconstruct a DSLF from a SSLF with moderate and large disparity ranges. To overcome these three challenges, we propose: (i) a novel self-calibration method, which takes advantage of the geometric constraints from the scene and the cameras, for estimating the rigid transformations from the camera coordinate frame of one Kinect V2 to the camera coordinate frames of 12-nearest RGB cameras; (ii) a novel coarse-to-fine approach for recovering the rigid transformation from the coordinate system of one Kinect to the coordinate system of the other by means of local color and geometry information; (iii) several novel algorithms that can be categorized into two groups for reconstructing a DSLF from an input SSLF, including novel view synthesis methods, which are inspired by the state-of-the-art video frame interpolation algorithms, and Epipolar-Plane Image (EPI) inpainting methods, which are inspired by the Shearlet Transform (ST)-based DSLF reconstruction approaches
Light Field Depth Estimation Based on Stitched-EPI
Depth estimation is one of the most essential problems for light field
applications. In EPI-based methods, the slope computation usually suffers low
accuracy due to the discretization error and low angular resolution. In
addition, recent methods work well in most regions but often struggle with
blurry edges over occluded regions and ambiguity over texture-less regions. To
address these challenging issues, we first propose the stitched-EPI and
half-stitched-EPI algorithms for non-occluded and occluded regions,
respectively. The algorithms improve slope computation by shifting and
concatenating lines in different EPIs but related to the same point in 3D
scene, while the half-stitched-EPI only uses non-occluded part of lines.
Combined with the joint photo-consistency cost proposed by us, the more
accurate and robust depth map can be obtained in both occluded and non-occluded
regions. Furthermore, to improve the depth estimation in texture-less regions,
we propose a depth propagation strategy that determines their depth from the
edge to interior, from accurate regions to coarse regions. Experimental and
ablation results demonstrate that the proposed method achieves accurate and
robust depth maps in all regions effectively.Comment: 15 page
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