150 research outputs found
Chapter International Standardization of FTV
FTV (Free-viewpoint Television) is visual media that transmits all ray information of a 3D space and enables immersive 3D viewing. The international standardization of FTV has been conducted in MPEG. The first phase of FTV is multiview video coding (MVC), and the second phase is 3D video (3DV). The third phase of FTV is MPEG-FTV, which targets revolutionized viewing of 3D scenes via super multiview, free navigation, and 360-degree 3D. After the success of exploration experiments and Call for Evidence, MPEG-FTV moved MPEG Immersive project (MPEG-I), where it is in charge of video part as MPEG-I Visual. MPEG-I will create standards for immersive audio-visual services
Automatic Labeled LiDAR Data Generation based on Precise Human Model
Following improvements in deep neural networks, state-of-the-art networks
have been proposed for human recognition using point clouds captured by LiDAR.
However, the performance of these networks strongly depends on the training
data. An issue with collecting training data is labeling. Labeling by humans is
necessary to obtain the ground truth label; however, labeling requires huge
costs. Therefore, we propose an automatic labeled data generation pipeline, for
which we can change any parameters or data generation environments. Our
approach uses a human model named Dhaiba and a background of Miraikan and
consequently generated realistic artificial data. We present 500k+ data
generated by the proposed pipeline. This paper also describes the specification
of the pipeline and data details with evaluations of various approaches.Comment: Accepted at ICRA201
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Quantized Census for Stereoscopic Image Matching
Current depth capturing devices show serious drawbacks in certain applications, for example ego-centric depth recovery: they are cumbersome, have a high power requirement, and do not portray high resolution at near distance. Stereo-matching techniques are a suitable alternative, but whilst the idea behind these techniques is simple it is well known that recovery of an accurate disparity map by stereo-matching requires overcoming three main problems: occluded regions causing absence of corresponding pixels; existence of noise in the image capturing sensor and inconsistent color and brightness in the captured images. We propose a modified version of the Census-Hamming cost function which allows more robust matching with an emphasis on improving performance under radiometric variations of the input images
MADGAN: unsupervised medical anomaly detection GAN using multiple adjacent brain MRI slice reconstruction.
BACKGROUND: Unsupervised learning can discover various unseen abnormalities, relying on large-scale unannotated medical images of healthy subjects. Towards this, unsupervised methods reconstruct a 2D/3D single medical image to detect outliers either in the learned feature space or from high reconstruction loss. However, without considering continuity between multiple adjacent slices, they cannot directly discriminate diseases composed of the accumulation of subtle anatomical anomalies, such as Alzheimer's disease (AD). Moreover, no study has shown how unsupervised anomaly detection is associated with either disease stages, various (i.e., more than two types of) diseases, or multi-sequence magnetic resonance imaging (MRI) scans. RESULTS: We propose unsupervised medical anomaly detection generative adversarial network (MADGAN), a novel two-step method using GAN-based multiple adjacent brain MRI slice reconstruction to detect brain anomalies at different stages on multi-sequence structural MRI: (Reconstruction) Wasserstein loss with Gradient Penalty + 100 [Formula: see text] loss-trained on 3 healthy brain axial MRI slices to reconstruct the next 3 ones-reconstructs unseen healthy/abnormal scans; (Diagnosis) Average [Formula: see text] loss per scan discriminates them, comparing the ground truth/reconstructed slices. For training, we use two different datasets composed of 1133 healthy T1-weighted (T1) and 135 healthy contrast-enhanced T1 (T1c) brain MRI scans for detecting AD and brain metastases/various diseases, respectively. Our self-attention MADGAN can detect AD on T1 scans at a very early stage, mild cognitive impairment (MCI), with area under the curve (AUC) 0.727, and AD at a late stage with AUC 0.894, while detecting brain metastases on T1c scans with AUC 0.921. CONCLUSIONS: Similar to physicians' way of performing a diagnosis, using massive healthy training data, our first multiple MRI slice reconstruction approach, MADGAN, can reliably predict the next 3 slices from the previous 3 ones only for unseen healthy images. As the first unsupervised various disease diagnosis, MADGAN can reliably detect the accumulation of subtle anatomical anomalies and hyper-intense enhancing lesions, such as (especially late-stage) AD and brain metastases on multi-sequence MRI scans
Hypertriton Production in p-Pb Collisions at √sNN = 5.02 TeV
The study of nuclei and antinuclei production has proven to be a powerful
tool to investigate the formation mechanism of loosely bound states in
high-energy hadronic collisions. The first measurement of the production of
in p-Pb collisions at = 5.02
TeV is presented in this Letter. Its production yield measured in the rapidity
interval -1 < y < 0 for the 40% highest multiplicity p-Pb collisions is . The measurement is compared with the expectations of statistical
hadronisation and coalescence models, which describe the nucleosynthesis in
hadronic collisions. These two models predict very different yields of the
hypertriton in small collision systems such as p-Pb and therefore the
measurement of is crucial to distinguish between them.
The precision of this measurement leads to the exclusion with a significance
larger than 6 of some configurations of the statistical hadronisation,
thus constraining the production mechanism of loosely bound states
Adversarial Patch Attacks on Monocular Depth Estimation Networks
Thanks to the excellent learning capability of deep convolutional neural
networks (CNN), monocular depth estimation using CNNs has achieved great
success in recent years. However, depth estimation from a monocular image alone
is essentially an ill-posed problem, and thus, it seems that this approach
would have inherent vulnerabilities. To reveal this limitation, we propose a
method of adversarial patch attack on monocular depth estimation. More
specifically, we generate artificial patterns (adversarial patches) that can
fool the target methods into estimating an incorrect depth for the regions
where the patterns are placed. Our method can be implemented in the real world
by physically placing the printed patterns in real scenes. We also analyze the
behavior of monocular depth estimation under attacks by visualizing the
activation levels of the intermediate layers and the regions potentially
affected by the adversarial attack.Comment: Publisher's Open Access PDF with the CC-BY copyright. Associated
video, data and programs are available at
https://www.fujii.nuee.nagoya-u.ac.jp/Research/MonoDepth
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