319 research outputs found
Seamless Multimodal Biometrics for Continuous Personalised Wellbeing Monitoring
Artificially intelligent perception is increasingly present in the lives of
every one of us. Vehicles are no exception, (...) In the near future, pattern
recognition will have an even stronger role in vehicles, as self-driving cars
will require automated ways to understand what is happening around (and within)
them and act accordingly. (...) This doctoral work focused on advancing
in-vehicle sensing through the research of novel computer vision and pattern
recognition methodologies for both biometrics and wellbeing monitoring. The
main focus has been on electrocardiogram (ECG) biometrics, a trait well-known
for its potential for seamless driver monitoring. Major efforts were devoted to
achieving improved performance in identification and identity verification in
off-the-person scenarios, well-known for increased noise and variability. Here,
end-to-end deep learning ECG biometric solutions were proposed and important
topics were addressed such as cross-database and long-term performance,
waveform relevance through explainability, and interlead conversion. Face
biometrics, a natural complement to the ECG in seamless unconstrained
scenarios, was also studied in this work. The open challenges of masked face
recognition and interpretability in biometrics were tackled in an effort to
evolve towards algorithms that are more transparent, trustworthy, and robust to
significant occlusions. Within the topic of wellbeing monitoring, improved
solutions to multimodal emotion recognition in groups of people and
activity/violence recognition in in-vehicle scenarios were proposed. At last,
we also proposed a novel way to learn template security within end-to-end
models, dismissing additional separate encryption processes, and a
self-supervised learning approach tailored to sequential data, in order to
ensure data security and optimal performance. (...)Comment: Doctoral thesis presented and approved on the 21st of December 2022
to the University of Port
Deep Face Morph Detection Based on Wavelet Decomposition
Morphed face images are maliciously used by criminals to circumvent the official process for receiving a passport where a look-alike accomplice embarks on requesting a passport. Morphed images are either synthesized by alpha-blending or generative networks such as Generative Adversarial Networks (GAN). Detecting morphed images is one of the fundamental problems associated with border control scenarios. Deep Neural Networks (DNN) have emerged as a promising solution for a myriad of applications such as face recognition, face verification, fake image detection, and so forth. The Biometrics communities have leveraged DNN to tackle fundamental problems such as morphed face detection. In this dissertation, we delve into data-driven morph detection which is of great significance in terms of national security.
We propose several wavelet-based face morph detection schemes which employ some of the computer vision algorithms such as image wavelet analysis, group sparsity, feature selection, and the visual attention mechanisms. Wavelet decomposition enables us to leverage the fine-grained frequency content of an image to boost localizing manipulated areas in an image. Our methodologies are as follows: (1) entropy-based single morph detection, (2) entropy-based differential morph detection, (3) morph detection using group sparsity, and (4) Attention aware morph detection. In the first methodology, we harness mismatches between the entropy distribution of wavelet subbands corresponding to a pair of real and morph images to find a subset of most discriminative wavelet subbands which leads to an increase of morph detection accuracy. As the second methodology, we adopt entropy-based subband selection to tackle differential morph detection. In the third methodology, group sparsity is leveraged for subband selection. In other words, adding a group sparsity constraint to the loss function of our DNN leads to an implicit subband selection. Our fourth methodology consists of different types of visual attention mechanisms such as convolutional block attention modules and self-attention resulting in boosting morph detection accuracy.
We demonstrate efficiency of our proposed algorithms through several morph datasets via extensive evaluations as well as visualization methodologies
Improving Classification in Single and Multi-View Images
Image classification is a sub-field of computer vision that focuses on identifying objects within digital images. In order to improve image classification we must address the following areas of improvement: 1) Single and Multi-View data quality using data pre-processing techniques. 2) Enhancing deep feature learning to extract alternative representation of the data. 3) Improving decision or prediction of labels. This dissertation presents a series of four published papers that explore different improvements of image classification. In our first paper, we explore the Siamese network architecture to create a Convolution Neural Network based similarity metric. We learn the priority features that differentiate two given input images. The metric proposed achieves state-of-the-art Fβ measure. In our second paper, we explore multi-view data classification. We investigate the application of Generative Adversarial Networks GANs on Multi-view data image classification and few-shot learning. Experimental results show that our method outperforms state-of-the-art research. In our third paper, we take on the challenge of improving ResNet backbone model. For this task, we focus on improving channel attention mechanisms. We utilize Discrete Wavelet Transform compression to address the channel representation problem. Experimental results on ImageNet shows that our method outperforms baseline SENet-34 and SOTA FcaNet-34 at no extra computational cost. In our fourth paper, we investigate further the potential of orthogonalization of filters for extraction of diverse information for channel attention. We prove that using only random constant orthogonal filters is sufficient enough to achieve good channel attention. We test our proposed method using ImageNet, Places365, and Birds datasets for image classification, MS-COCO for object detection, and instance segmentation tasks. Our method outperforms FcaNet, and WaveNet and achieves the state-of-the-art results
How to Boost Face Recognition with StyleGAN?
State-of-the-art face recognition systems require vast amounts of labeled
training data. Given the priority of privacy in face recognition applications,
the data is limited to celebrity web crawls, which have issues such as limited
numbers of identities. On the other hand, self-supervised revolution in the
industry motivates research on the adaptation of related techniques to facial
recognition. One of the most popular practical tricks is to augment the dataset
by the samples drawn from generative models while preserving the identity. We
show that a simple approach based on fine-tuning pSp encoder for StyleGAN
allows us to improve upon the state-of-the-art facial recognition and performs
better compared to training on synthetic face identities. We also collect
large-scale unlabeled datasets with controllable ethnic constitution --
AfricanFaceSet-5M (5 million images of different people) and AsianFaceSet-3M (3
million images of different people) -- and we show that pretraining on each of
them improves recognition of the respective ethnicities (as well as others),
while combining all unlabeled datasets results in the biggest performance
increase. Our self-supervised strategy is the most useful with limited amounts
of labeled training data, which can be beneficial for more tailored face
recognition tasks and when facing privacy concerns. Evaluation is based on a
standard RFW dataset and a new large-scale RB-WebFace benchmark. The code and
data are made publicly available at
https://github.com/seva100/stylegan-for-facerec.Comment: 16 pages, 9 figures, 11 tables; accepted to ICCV 202
Detecting and Grounding Important Characters in Visual Stories
Characters are essential to the plot of any story. Establishing the
characters before writing a story can improve the clarity of the plot and the
overall flow of the narrative. However, previous work on visual storytelling
tends to focus on detecting objects in images and discovering relationships
between them. In this approach, characters are not distinguished from other
objects when they are fed into the generation pipeline. The result is a
coherent sequence of events rather than a character-centric story. In order to
address this limitation, we introduce the VIST-Character dataset, which
provides rich character-centric annotations, including visual and textual
co-reference chains and importance ratings for characters. Based on this
dataset, we propose two new tasks: important character detection and character
grounding in visual stories. For both tasks, we develop simple, unsupervised
models based on distributional similarity and pre-trained vision-and-language
models. Our new dataset, together with these models, can serve as the
foundation for subsequent work on analysing and generating stories from a
character-centric perspective.Comment: AAAI 202
Learning from Audio, Vision and Language Modalities for Affect Recognition Tasks
The world around us as well as our responses to worldly events are multimodal in nature. For intelligent machines to integrate seamlessly into our world, it is imperative that they can process and derive useful information from multimodal signals. Such capabilities can be provided to machines by employing multimodal learning algorithms that consider both the individual characteristics of unimodal signals as well as the complementariness provided by multimodal signals. Based on the number of modalities available during the training and testing phases, learning algorithms can be of three categories: unimodal trained and unimodal tested, multimodal trained and multimodal tested, and multimodal trained and unimodal tested algorithms. This thesis provides three contributions, one for each category and focuses on three modalities that are important for human-human and human-machine communication, namely, audio (paralinguistic speech), vision (facial expressions) and language (linguistic speech) signals. For several applications, either due to hardware limitations or deployment specifications, unimodal trained and tested systems suffice. Our first contribution, for the unimodal trained and unimodal tested category, is an end-to-end deep neural network that uses raw speech signals as input for a computational paralinguistic task, namely, verbal conflict intensity estimation. Our model, which uses a convolutional recurrent architecture equipped with attention mechanism to focus on task-relevant instances of the input speech signal, eliminates the need for task-specific meta data or domain knowledge based manual refinement of hand-crafted generic features. The second contribution, for the multimodal trained and multimodal tested category, is a multimodal fusion framework that exploits both cross (inter) and intra-modal interactions for categorical emotion recognition from audiovisual clips. We explore the effectiveness of two types of attention mechanisms, namely, intra and cross-modal attention by creating two versions of our fusion framework. In many applications, multimodal signals might be available during model training phase, yet we cannot expect the availability of all modality signals during testing phase. Our third contribution addresses this situation wherein we propose a framework for cross-modal learning where paired audio-visual instances are used during training to develop test-time stand-alone unimodal models
MFR-Net: Multi-faceted Responsive Listening Head Generation via Denoising Diffusion Model
Face-to-face communication is a common scenario including roles of speakers
and listeners. Most existing research methods focus on producing speaker
videos, while the generation of listener heads remains largely overlooked.
Responsive listening head generation is an important task that aims to model
face-to-face communication scenarios by generating a listener head video given
a speaker video and a listener head image. An ideal generated responsive
listening video should respond to the speaker with attitude or viewpoint
expressing while maintaining diversity in interaction patterns and accuracy in
listener identity information. To achieve this goal, we propose the
\textbf{M}ulti-\textbf{F}aceted \textbf{R}esponsive Listening Head Generation
Network (MFR-Net). Specifically, MFR-Net employs the probabilistic denoising
diffusion model to predict diverse head pose and expression features. In order
to perform multi-faceted response to the speaker video, while maintaining
accurate listener identity preservation, we design the Feature Aggregation
Module to boost listener identity features and fuse them with other
speaker-related features. Finally, a renderer finetuned with identity
consistency loss produces the final listening head videos. Our extensive
experiments demonstrate that MFR-Net not only achieves multi-faceted responses
in diversity and speaker identity information but also in attitude and
viewpoint expression.Comment: Accepted by ACM MM 202
Leveraging TCN and Transformer for effective visual-audio fusion in continuous emotion recognition
Human emotion recognition plays an important role in human-computer
interaction. In this paper, we present our approach to the Valence-Arousal (VA)
Estimation Challenge, Expression (Expr) Classification Challenge, and Action
Unit (AU) Detection Challenge of the 5th Workshop and Competition on Affective
Behavior Analysis in-the-wild (ABAW). Specifically, we propose a novel
multi-modal fusion model that leverages Temporal Convolutional Networks (TCN)
and Transformer to enhance the performance of continuous emotion recognition.
Our model aims to effectively integrate visual and audio information for
improved accuracy in recognizing emotions. Our model outperforms the baseline
and ranks 3 in the Expression Classification challenge.Comment: 2023 IEEE/CVF Conference on Computer Vision and Pattern Recognition
Workshops (CVPRW
Deep Learning for Head Pose Estimation: A Survey
Head pose estimation (HPE) is an active and popular area of research. Over the years, many approaches have constantly been developed, leading to a progressive improvement in accuracy; nevertheless, head pose estimation remains an open research topic, especially in unconstrained environments. In this paper, we will review the increasing amount of available datasets and the modern methodologies used to estimate orientation, with a special attention to deep learning techniques. We will discuss the evolution of the feld by proposing a classifcation of head pose estimation methods, explaining their advantages and disadvantages, and highlighting the diferent ways deep learning techniques have been used in the context of HPE. An
in-depth performance comparison and discussion is presented at the end of the work. We also highlight the most promising research directions for future investigations on the topic
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