25 research outputs found
Sample4Geo: Hard Negative Sampling For Cross-View Geo-Localisation
Cross-View Geo-Localisation is still a challenging task where additional
modules, specific pre-processing or zooming strategies are necessary to
determine accurate positions of images. Since different views have different
geometries, pre-processing like polar transformation helps to merge them.
However, this results in distorted images which then have to be rectified.
Adding hard negatives to the training batch could improve the overall
performance but with the default loss functions in geo-localisation it is
difficult to include them. In this article, we present a simplified but
effective architecture based on contrastive learning with symmetric InfoNCE
loss that outperforms current state-of-the-art results. Our framework consists
of a narrow training pipeline that eliminates the need of using aggregation
modules, avoids further pre-processing steps and even increases the
generalisation capability of the model to unknown regions. We introduce two
types of sampling strategies for hard negatives. The first explicitly exploits
geographically neighboring locations to provide a good starting point. The
second leverages the visual similarity between the image embeddings in order to
mine hard negative samples. Our work shows excellent performance on common
cross-view datasets like CVUSA, CVACT, University-1652 and VIGOR. A comparison
between cross-area and same-area settings demonstrate the good generalisation
capability of our model
Orientation-Guided Contrastive Learning for UAV-View Geo-Localisation
Retrieving relevant multimedia content is one of the main problems in a world
that is increasingly data-driven. With the proliferation of drones, high
quality aerial footage is now available to a wide audience for the first time.
Integrating this footage into applications can enable GPS-less geo-localisation
or location correction.
In this paper, we present an orientation-guided training framework for
UAV-view geo-localisation. Through hierarchical localisation orientations of
the UAV images are estimated in relation to the satellite imagery. We propose a
lightweight prediction module for these pseudo labels which predicts the
orientation between the different views based on the contrastive learned
embeddings. We experimentally demonstrate that this prediction supports the
training and outperforms previous approaches. The extracted pseudo-labels also
enable aligned rotation of the satellite image as augmentation to further
strengthen the generalisation. During inference, we no longer need this
orientation module, which means that no additional computations are required.
We achieve state-of-the-art results on both the University-1652 and
University-160k datasets
SoccerNet 2023 Challenges Results
peer reviewedThe SoccerNet 2023 challenges were the third annual video understanding
challenges organized by the SoccerNet team. For this third edition, the
challenges were composed of seven vision-based tasks split into three main
themes. The first theme, broadcast video understanding, is composed of three
high-level tasks related to describing events occurring in the video
broadcasts: (1) action spotting, focusing on retrieving all timestamps related
to global actions in soccer, (2) ball action spotting, focusing on retrieving
all timestamps related to the soccer ball change of state, and (3) dense video
captioning, focusing on describing the broadcast with natural language and
anchored timestamps. The second theme, field understanding, relates to the
single task of (4) camera calibration, focusing on retrieving the intrinsic and
extrinsic camera parameters from images. The third and last theme, player
understanding, is composed of three low-level tasks related to extracting
information about the players: (5) re-identification, focusing on retrieving
the same players across multiple views, (6) multiple object tracking, focusing
on tracking players and the ball through unedited video streams, and (7) jersey
number recognition, focusing on recognizing the jersey number of players from
tracklets. Compared to the previous editions of the SoccerNet challenges, tasks
(2-3-7) are novel, including new annotations and data, task (4) was enhanced
with more data and annotations, and task (6) now focuses on end-to-end
approaches. More information on the tasks, challenges, and leaderboards are
available on https://www.soccer-net.org. Baselines and development kits can be
found on https://github.com/SoccerNet
Less Is More: Linear Layers on CLIP Features as Powerful VizWiz Model
Current architectures for multi-modality tasks such as visual question
answering suffer from their high complexity. As a result, these architectures
are difficult to train and require high computational resources. To address
these problems we present a CLIP-based architecture that does not require any
fine-tuning of the feature extractors. A simple linear classifier is used on
the concatenated features of the image and text encoder. During training an
auxiliary loss is added which operates on the answer types. The resulting
classification is then used as an attention gate on the answer class selection.
On the VizWiz 2022 Visual Question Answering Challenge we achieve 60.15 %
accuracy on Task 1: Predict Answer to a Visual Question and AP score of 83.78 %
on Task 2: Predict Answerability of a Visual Question.Comment: VizWiz Grand Challenge: Describing Images and Videos Taken by Blind
People (CVPR Workshop 2022
A Bayesian Modeling Approach to Examine the Role of Testosterone Administration on the Endowment Effect and Risk-Taking
Financial risk-taking and loss aversion are multifaceted phenomena that are the focus of neuroscience, psychology, and economics research. A growing number of studies highlighted the role of hormones (particularly of testosterone) on socio-economic decision-making. However, the effects of testosterone on risk-taking under framing and consumer-based choices and preferences are inconclusive. We investigated the effects of 100 mg testosterone administration on aspects of decision-making within the Prospect Theory framework which is the most used descriptive model of decision-making under risk. We assessed risk-taking under framing and the endowment effect (effect of possession) using Bayesian modeling. Forty men participated in this double-blind placebo-controlled fully-randomized cross-over experiment and performed two tasks. One was a risk-taking task with binary choices under positive and negative framing associated with different probabilities. In the second task participants had to bid money for hedonic and utilitarian items. We observed a significant increase in serum testosterone concentrations after transdermal application. Compared to placebo, testosterone administration increased risk-taking under the positive framing (very large effect size) and decreased under the negative framing (moderate to small). The sensitivity to gain was positive in each framing. Our model showed that decision-making is jointly influenced by testosterone and the trade-off between gains and losses. However, while the endowment effect was more pronounced for hedonic than for utilitarian items, the effect was independent of testosterone. The findings provide novel information on the complex modulatory role of testosterone on risk-taking within the framework of prospect theory and shed light on mechanisms of behavioral economic biases. The proposed models of effects of individual differences in testosterone on risk-taking could be used as predictive models for reference-depended behavior under positive and negative framing with low and high probabilities
Interference in simultaneously perceiving and producing facial expressions - Evidence from Electromyography
Risk taking and loss aversion under testosterone
Data from the project where we investigated testosterone administration on risk-taking under framing (positive and negative) and Endowment Effect.
Manuscript: https://doi.org/10.3389/fnins.2022.85816
Serum Testosterone and Cortisol Concentrations After Single-Dose Administration of 100-Mg Transdermal Testosterone in Healthy Men
The growing interest in testosterone's effects on men's social behaviors, in particular aggressive, risk-taking, or status maintenance behaviors, is accompanied by a paucity of dose-dependent pharmacokinetic data. Examining the neurophysiological effects of transdermal testosterone typically includes a 4h delay before further brain-behavior measurements. Nevertheless, high heterogeneity regarding the timing of follow-up measurements and dosage remains. In a double-blind placebo-controlled design, we examined the short-term pharmacokinetic profile of 100-mg transdermal testosterone (Testotop ®) to determine the optimal time for detecting testosterone-mediated effects. Across two studies, 35 healthy men received a single dose of testosterone and placebo in two separate sessions. In study one (n = 16), serum testosterone and cortisol were assessed serially every 30 min up to 2 h posttreatment. In study two (n = 19), we assessed serum testosterone and cortisol at baseline, 2 h, and 4.15 h (255 min) posttreatment. Relative to baseline and placebo, transdermal testosterone significantly increased total serum testosterone concentrations 90 min posttreatment, reaching maximum concentration between 2 h and 3 h posttreatment. Albeit elevated, serum testosterone levels gradually decreased between 2 h and 4 h following treatment. Transdermal testosterone did not suppress cortisol release. Instead, cortisol concentrations decreased according to cortisol's known circadian rhythm. Unlike previous findings showing significant testosterone concentration increases as soon as 60 min and as late as 3 h post 150-mg testosterone treatment, our 100-mg testosterone manipulation significantly increased testosterone concentrations 90 min following treatment. These pharmacokinetic data are important in facilitating the optimization of timing parameters for future testosterone challenge studies
Serum Testosterone and Cortisol Concentrations After Single-Dose Administration of 100-Mg Transdermal Testosterone in Healthy Men
The growing interest in testosterone's effects on men's social behaviors, in particular aggressive, risk-taking, or status maintenance behaviors, is accompanied by a paucity of dose-dependent pharmacokinetic data. Examining the neurophysiological effects of transdermal testosterone typically includes a 4h delay before further brain-behavior measurements. Nevertheless, high heterogeneity regarding the timing of follow-up measurements and dosage remains. In a double-blind placebo-controlled design, we examined the short-term pharmacokinetic profile of 100-mg transdermal testosterone (Testotop ®) to determine the optimal time for detecting testosterone-mediated effects. Across two studies, 35 healthy men received a single dose of testosterone and placebo in two separate sessions. In study one (n = 16), serum testosterone and cortisol were assessed serially every 30 min up to 2 h posttreatment. In study two (n = 19), we assessed serum testosterone and cortisol at baseline, 2 h, and 4.15 h (255 min) posttreatment. Relative to baseline and placebo, transdermal testosterone significantly increased total serum testosterone concentrations 90 min posttreatment, reaching maximum concentration between 2 h and 3 h posttreatment. Albeit elevated, serum testosterone levels gradually decreased between 2 h and 4 h following treatment. Transdermal testosterone did not suppress cortisol release. Instead, cortisol concentrations decreased according to cortisol's known circadian rhythm. Unlike previous findings showing significant testosterone concentration increases as soon as 60 min and as late as 3 h post 150-mg testosterone treatment, our 100-mg testosterone manipulation significantly increased testosterone concentrations 90 min following treatment. These pharmacokinetic data are important in facilitating the optimization of timing parameters for future testosterone challenge studies
Influence of acute tryptophan depletion on verbal declarative episodic memory in young adult females
Diminished synthesis of the neurotransmitter serotonin (5-HT) in the brain has been linked to disturbed memory processes. The present study investigated the effects of diminished central nervous 5-HT synthesis as achieved by an acute dietary tryptophan depletion (ATD) on verbal declarative episodic memory in young women while controlling for the effects of female sex hormones. Eighteen healthy females (aged 20–31 years) participated in a within-subject repeated measures study, with two separate days of assessment spaced at least one individual menstrual cycle apart. On one day, participants were subjected to ATD, thus lowering central nervous 5-HT synthesis. The other day participants received a tryptophan-balanced amino acid load (BAL = control condition). The study was randomized, counterbalanced and double blind in terms of ATD/BAL administration. Measurements took place in the early follicular phase of the participants’ menstrual cycle. Estrogen, FSH and LH levels were assessed at baseline. Verbal declarative episodic memory was assessed using a structured word-learning task. Short-term memory, as indexed by immediate recall, was reduced after ATD intake, whereas delayed recall and recognition after a 25-min delay did not show any differences after intake of ATD or BAL. In young women, verbal short-term memory function was more vulnerable to ATD than consolidation processes. In light of the possible interplay between female sex hormones and 5-HT, further studies comparing different menstrual cycle phases are needed