57,719 research outputs found
Novel Image Mosaic Algorithm for Concrete Pavement Surface Image Reconstruction
AbstractIn this paper, a novel image mosaic method for concrete pavement surface image sequences reconstruction has been proposed. Harris corner points are extracted uniformly from the overlapped areas of concrete pavement surface images, which are considered feature points. The commonly used circular projection method is applied for coarse matching step and an improved point matching method is proposed for invariance of image rotation and distortion. The image fusion strategy of fading in and fading out is employed for the smooth and seamless of mosaic image. For the practical pavement surface images, which exists rotation and distortion, the corresponding experimental results show that the proposed image matching method has higher precision and stronger robustness
Recovering refined surface normals for relighting clothing in dynamic scenes
In this paper we present a method to relight captured 3D video sequences of non-rigid, dynamic scenes, such as clothing of real actors, reconstructed from multiple view video. A view-dependent approach is introduced to refine an initial coarse surface reconstruction using shape-from-shading to estimate detailed surface normals. The prior surface approximation is used to constrain the simultaneous estimation of surface normals and scene illumination, under the assumption of Lambertian surface reflectance. This approach enables detailed surface normals of a moving non-rigid object to be estimated from a single image frame. Refined normal estimates from multiple views are integrated into a single surface normal map. This approach allows highly non-rigid surfaces, such as creases in clothing, to be relit whilst preserving the detailed dynamics observed in video
Meshed Up: Learnt Error Correction in 3D Reconstructions
Dense reconstructions often contain errors that prior work has so far
minimised using high quality sensors and regularising the output. Nevertheless,
errors still persist. This paper proposes a machine learning technique to
identify errors in three dimensional (3D) meshes. Beyond simply identifying
errors, our method quantifies both the magnitude and the direction of depth
estimate errors when viewing the scene. This enables us to improve the
reconstruction accuracy.
We train a suitably deep network architecture with two 3D meshes: a
high-quality laser reconstruction, and a lower quality stereo image
reconstruction. The network predicts the amount of error in the lower quality
reconstruction with respect to the high-quality one, having only view the
former through its input. We evaluate our approach by correcting
two-dimensional (2D) inverse-depth images extracted from the 3D model, and show
that our method improves the quality of these depth reconstructions by up to a
relative 10% RMSE.Comment: Accepted for the International Conference on Robotics and Automation
(ICRA) 201
CVRecon: Rethinking 3D Geometric Feature Learning For Neural Reconstruction
Recent advances in neural reconstruction using posed image sequences have
made remarkable progress. However, due to the lack of depth information,
existing volumetric-based techniques simply duplicate 2D image features of the
object surface along the entire camera ray. We contend this duplication
introduces noise in empty and occluded spaces, posing challenges for producing
high-quality 3D geometry. Drawing inspiration from traditional multi-view
stereo methods, we propose an end-to-end 3D neural reconstruction framework
CVRecon, designed to exploit the rich geometric embedding in the cost volumes
to facilitate 3D geometric feature learning. Furthermore, we present
Ray-contextual Compensated Cost Volume (RCCV), a novel 3D geometric feature
representation that encodes view-dependent information with improved integrity
and robustness. Through comprehensive experiments, we demonstrate that our
approach significantly improves the reconstruction quality in various metrics
and recovers clear fine details of the 3D geometries. Our extensive ablation
studies provide insights into the development of effective 3D geometric feature
learning schemes. Project page: https://cvrecon.ziyue.cool
A bayesian approach to simultaneously recover camera pose and non-rigid shape from monocular images
© . This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/In this paper we bring the tools of the Simultaneous Localization and Map Building (SLAM) problem from a rigid to a deformable domain and use them to simultaneously recover the 3D shape of non-rigid surfaces and the sequence of poses of a moving camera. Under the assumption that the surface shape may be represented as a weighted sum of deformation modes, we show that the problem of estimating the modal weights along with the camera poses, can be probabilistically formulated as a maximum a posteriori estimate and solved using an iterative least squares optimization. In addition, the probabilistic formulation we propose is very general and allows introducing different constraints without requiring any extra complexity. As a proof of concept, we show that local inextensibility constraints that prevent the surface from stretching can be easily integrated.
An extensive evaluation on synthetic and real data, demonstrates that our method has several advantages over current non-rigid shape from motion approaches. In particular, we show that our solution is robust to large amounts of noise and outliers and that it does not need to track points over the whole sequence nor to use an initialization close from the ground truth.Peer ReviewedPostprint (author's final draft
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