69 research outputs found
Exploiting Low-confidence Pseudo-labels for Source-free Object Detection
Source-free object detection (SFOD) aims to adapt a source-trained detector
to an unlabeled target domain without access to the labeled source data.
Current SFOD methods utilize a threshold-based pseudo-label approach in the
adaptation phase, which is typically limited to high-confidence pseudo-labels
and results in a loss of information. To address this issue, we propose a new
approach to take full advantage of pseudo-labels by introducing high and low
confidence thresholds. Specifically, the pseudo-labels with confidence scores
above the high threshold are used conventionally, while those between the low
and high thresholds are exploited using the Low-confidence Pseudo-labels
Utilization (LPU) module. The LPU module consists of Proposal Soft Training
(PST) and Local Spatial Contrastive Learning (LSCL). PST generates soft labels
of proposals for soft training, which can mitigate the label mismatch problem.
LSCL exploits the local spatial relationship of proposals to improve the
model's ability to differentiate between spatially adjacent proposals, thereby
optimizing representational features further. Combining the two components
overcomes the challenges faced by traditional methods in utilizing
low-confidence pseudo-labels. Extensive experiments on five cross-domain object
detection benchmarks demonstrate that our proposed method outperforms the
previous SFOD methods, achieving state-of-the-art performance
SimpleNet: A Simple Network for Image Anomaly Detection and Localization
We propose a simple and application-friendly network (called SimpleNet) for
detecting and localizing anomalies. SimpleNet consists of four components: (1)
a pre-trained Feature Extractor that generates local features, (2) a shallow
Feature Adapter that transfers local features towards target domain, (3) a
simple Anomaly Feature Generator that counterfeits anomaly features by adding
Gaussian noise to normal features, and (4) a binary Anomaly Discriminator that
distinguishes anomaly features from normal features. During inference, the
Anomaly Feature Generator would be discarded. Our approach is based on three
intuitions. First, transforming pre-trained features to target-oriented
features helps avoid domain bias. Second, generating synthetic anomalies in
feature space is more effective, as defects may not have much commonality in
the image space. Third, a simple discriminator is much efficient and practical.
In spite of simplicity, SimpleNet outperforms previous methods quantitatively
and qualitatively. On the MVTec AD benchmark, SimpleNet achieves an anomaly
detection AUROC of 99.6%, reducing the error by 55.5% compared to the next best
performing model. Furthermore, SimpleNet is faster than existing methods, with
a high frame rate of 77 FPS on a 3080ti GPU. Additionally, SimpleNet
demonstrates significant improvements in performance on the One-Class Novelty
Detection task. Code: https://github.com/DonaldRR/SimpleNet.Comment: Accepted to CVPR 202
AdaptGuard: Defending Against Universal Attacks for Model Adaptation
Model adaptation aims at solving the domain transfer problem under the
constraint of only accessing the pretrained source models. With the increasing
considerations of data privacy and transmission efficiency, this paradigm has
been gaining recent popularity. This paper studies the vulnerability to
universal attacks transferred from the source domain during model adaptation
algorithms due to the existence of malicious providers. We explore both
universal adversarial perturbations and backdoor attacks as loopholes on the
source side and discover that they still survive in the target models after
adaptation. To address this issue, we propose a model preprocessing framework,
named AdaptGuard, to improve the security of model adaptation algorithms.
AdaptGuard avoids direct use of the risky source parameters through knowledge
distillation and utilizes the pseudo adversarial samples under adjusted radius
to enhance the robustness. AdaptGuard is a plug-and-play module that requires
neither robust pretrained models nor any changes for the following model
adaptation algorithms. Extensive results on three commonly used datasets and
two popular adaptation methods validate that AdaptGuard can effectively defend
against universal attacks and maintain clean accuracy in the target domain
simultaneously. We hope this research will shed light on the safety and
robustness of transfer learning. Code is available at
https://github.com/TomSheng21/AdaptGuard.Comment: ICCV202
Improving Zero-Shot Generalization for CLIP with Synthesized Prompts
With the growing interest in pretrained vision-language models like CLIP,
recent research has focused on adapting these models to downstream tasks.
Despite achieving promising results, most existing methods require labeled data
for all classes, which may not hold in real-world applications due to the long
tail and Zipf's law. For example, some classes may lack labeled data entirely,
such as emerging concepts. To address this problem, we propose a plug-and-play
generative approach called \textbf{S}ynt\textbf{H}es\textbf{I}zed
\textbf{P}rompts~(\textbf{SHIP}) to improve existing fine-tuning methods.
Specifically, we follow variational autoencoders to introduce a generator that
reconstructs the visual features by inputting the synthesized prompts and the
corresponding class names to the textual encoder of CLIP. In this manner, we
easily obtain the synthesized features for the remaining label-only classes.
Thereafter, we fine-tune CLIP with off-the-shelf methods by combining labeled
and synthesized features. Extensive experiments on base-to-new generalization,
cross-dataset transfer learning, and generalized zero-shot learning demonstrate
the superiority of our approach. The code is available at
\url{https://github.com/mrflogs/SHIP}.Comment: Accepted by ICCV 202
Efficient Characterizations of Multiphoton States with Ultra-thin Integrated Photonics
Metasurface enables the generation and manipulation of multiphoton
entanglement with flat optics, providing a more efficient platform for
large-scale photonic quantum information processing. Here, we show that a
single metasurface optical chip would allow more efficient characterizations of
multiphoton entangled states, such as shadow tomography, which generally
requires fast and complicated control of optical setups to perform projective
measurements in different bases, a demanding task using conventional optics.
The compact and stable device here allows implementations of general positive
observable value measures with a reduced sample complexity and significantly
alleviates the experimental complexity to implement shadow tomography.
Integrating self-learning and calibration algorithms, we observe notable
advantages in the reconstruction of multiphoton entanglement, including using
fewer measurements, having higher accuracy, and being robust against optical
loss. Our work unveils the feasibility of metasurface as a favorable integrated
optical device for efficient characterization of multiphoton entanglement, and
sheds light on scalable photonic quantum technologies with ultra-thin
integrated optics.Comment: 15 pages, 9 figure
First Look at z > 1 Bars in the Rest-Frame Near-Infrared with JWST Early CEERS Imaging
Stellar bars are key drivers of secular evolution in galaxies and can be
effectively studied using rest-frame near-infrared (NIR) images, which trace
the underlying stellar mass and are less impacted by dust and star formation
than rest-frame UV or optical images. We leverage the power of {\it{JWST}}
CEERS NIRCam images to present the first quantitative identification and
characterization of stellar bars at based on rest-frame NIR F444W images
of high resolution (~1.3 kpc at z ~ 1-3). We identify stellar bars in these
images using quantitative criteria based on ellipse fits. For this pilot study,
we present six examples of robustly identified bars at with spectroscopic
redshifts, including the two highest redshift bars at ~2.136 and 2.312
quantitatively identified and characterized to date. The stellar bars at ~
1.1-2.3 presented in our study have projected semi-major axes of ~2.9-4.3 kpc
and projected ellipticities of ~0.41-0.53 in the rest-frame NIR. The barred
host galaxies have stellar masses ~ to
, star formation rates of ~ 21-295 yr, and
several have potential nearby companions. Our finding of bars at ~1.1-2.3
demonstrates the early onset of such instabilities and supports simulations
where bars form early in massive dynamically cold disks. It also suggests that
if these bars at lookback times of 8-10 Gyr survive out to present epochs,
bar-driven secular processes may operate over a long time and have a
significant impact on some galaxies by z ~ 0.Comment: 16 pages, 5 figures. Accepted for Publication in Astrophysical
Journal Letter
First Look at z > 1 Bars in the Rest-frame Near-infrared with JWST Early CEERS Imaging
Stellar bars are key drivers of secular evolution in galaxies and can be effectively studied using rest-frame near-infrared (NIR) images, which trace the underlying stellar mass and are less impacted by dust and star formation than rest-frame UV or optical images. We leverage the power of JWST CEERS NIRCam images to present the first quantitative identification and characterization of stellar bars at z > 1 based on rest-frame NIR F444W images of high resolution (∼1.3 kpc at z ∼ 1-3). We identify stellar bars in these images using quantitative criteria based on ellipse fits. For this pilot study, we present six examples of robustly identified bars at z > 1 with spectroscopic redshifts, including the two highest-redshift bars at z ∼ 2.136 and 2.312 quantitatively identified and characterized to date. The stellar bars at z ∼ 1.1-2.3 presented in our study have projected semimajor axes of ∼2.9-4.3 kpc and projected ellipticities of ∼0.41-0.53 in the rest-frame NIR. The barred host galaxies have stellar masses ∼1 × 10 10 to 2 × 10 11 M ⊙ and star formation rates of ∼21-295 M ⊙ yr −1, and several have potential nearby companions. Our finding of bars at z ∼ 1.1-2.3 demonstrates the early onset of such instabilities and supports simulations where bars form early in massive dynamically cold disks. It also suggests that if these bars at lookback times of 8-11 Gyr survive out to present epochs, bar-driven secular processes may operate over a long time and have a significant impact on some galaxies by z ∼ 0.</p
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