12 research outputs found
HashSDF: Accurate Implicit Surfaces with Fast Local Features on Permutohedral Lattices
Neural radiance-density field methods have become increasingly popular for
the task of novel-view rendering. Their recent extension to hash-based
positional encoding ensures fast training and inference with state-of-the-art
results. However, density-based methods struggle with recovering accurate
surface geometry. Hybrid methods alleviate this issue by optimizing the density
based on an underlying SDF. However, current SDF methods are overly smooth and
miss fine geometric details. In this work, we combine the strengths of these
two lines of work in a novel hash-based implicit surface representation. We
propose improvements to the two areas by replacing the voxel hash encoding with
a permutohedral lattice which optimizes faster in three and higher dimensions.
We additionally propose a regularization scheme which is crucial for recovering
high-frequency geometric detail. We evaluate our method on multiple datasets
and show that we can recover geometric detail at the level of pores and
wrinkles while using only RGB images for supervision. Furthermore, using sphere
tracing we can render novel views at 30 fps on an RTX 3090
Cardiac rehabilitation after catheter ablation of atrial fibrilation
Atrial fibrillation is the most common arrhythmia worldwide. Besides antiarrhythmic drugs and electrical cardioversion, atrial
fibrillation can be treated with a newer technique called catheter ablation. Patients suffering a catheter ablation can benefit from an
integrated rehabilitation programme like all other patients suffering a cardiac surgery. Physical training and psycho-educative
consultations are specific after catheter ablation and integrated rehabilitation can improve mental health, physical capacity and
permits return to sports activities
NeuralMVS: Bridging Multi-View Stereo and Novel View Synthesis
Multi-View Stereo (MVS) is a core task in 3D computer vision. With the surge
of novel deep learning methods, learned MVS has surpassed the accuracy of
classical approaches, but still relies on building a memory intensive dense
cost volume. Novel View Synthesis (NVS) is a parallel line of research and has
recently seen an increase in popularity with Neural Radiance Field (NeRF)
models, which optimize a per scene radiance field. However, NeRF methods do not
generalize to novel scenes and are slow to train and test. We propose to bridge
the gap between these two methodologies with a novel network that can recover
3D scene geometry as a distance function, together with high-resolution color
images. Our method uses only a sparse set of images as input and can generalize
well to novel scenes. Additionally, we propose a coarse-to-fine sphere tracing
approach in order to significantly increase speed. We show on various datasets
that our method reaches comparable accuracy to per-scene optimized methods
while being able to generalize and running significantly faster. We provide the
source code at https://github.com/AIS-Bonn/neural_mvsComment: Accepted for International Joint Conference on Neural Networks
(IJCNN) 2022. Code available at https://github.com/AIS-Bonn/neural_mv
PROPERTIES OF TITANIUM NITRIDE LAYERS DEPOSITED BY PLASMA THERMAL SPRAYING AND HVOF METHOD
Accuracy of Three-Dimensional Printed Dental Models Based on Ethylene Di-Methacrylate-Stereolithography (SLA) vs. Digital Light Processing (DLP)
Additive manufacturing is a technology that has many uses across a variety of fields. Its usage spans many fields, including the fields of art, design, architecture, engineering and medicine, including dentistry. The study aims to evaluate and compare the accuracy of three-dimensional printed dental models based on ethylene di-methacrylate using the SLA and DLP techniques. For evaluation, a reference model containing 16 maxillary permanent molars was chosen. An ATOS Capsule 3D scanner was used to scan the reference model. Using a photo-cured liquid resin, eight three-dimensional printed models were obtained using the reference model as benchmark. Four of the models (A1–A4) were obtained using SLA printing technology and four models (B1–B4) were manufactured using DLP printing technology. A standard best fit method was used to pre-align the reference and the printed model surfaces. The height of the teeth, and the mesial–distal and buccal–lingual distances were analyzed. The assessment of the two manufacturing methods was achieved by using non-parametric tests to compare the mean ranks for the assessed features. The results show that models obtained through DLP had a higher precision but also a higher bias. Both methods still are within the required accuracy range for dental models