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2022 Journal article Open Access OPEN
Comparing the performance of Hebbian against backpropagation learning using convolutional neural networks
Lagani G., Falchi F., Gennaro C., Amato G.
In this paper, we investigate Hebbian learning strategies applied to Convolutional Neural Network (CNN) training. We consider two unsupervised learning approaches, Hebbian Winner-Takes-All (HWTA), and Hebbian Principal Component Analysis (HPCA). The Hebbian learning rules are used to train the layers of a CNN in order to extract features that are then used for classification, without requiring backpropagation (backprop). Experimental comparisons are made with state-of-the-art unsupervised (but backprop-based) Variational Auto-Encoder (VAE) training. For completeness,we consider two supervised Hebbian learning variants (Supervised Hebbian Classifiers--SHC, and Contrastive Hebbian Learning--CHL), for training the final classification layer, which are compared to Stochastic Gradient Descent training. We also investigate hybrid learning methodologies, where some network layers are trained following the Hebbian approach, and others are trained by backprop. We tested our approaches on MNIST, CIFAR10, and CIFAR100 datasets. Our results suggest that Hebbian learning is generally suitable for training early feature extraction layers, or to retrain higher network layers in fewer training epochs than backprop. Moreover, our experiments show that Hebbian learning outperforms VAE training, with HPCA performing generally better than HWTA.Source: Neural computing & applications (Print) (2022). doi:10.1007/s00521-021-06701-4
DOI: 10.1007/s00521-021-06701-4
Project(s): AI4EU via OpenAIRE, AI4Media via OpenAIRE
Metrics:


See at: ISTI Repository Open Access | link.springer.com Restricted | CNR ExploRA Restricted


2022 Conference article Open Access OPEN
AIMH Lab for Trustworthy AI
Messina N., Carrara F., Coccomini D., Falchi F., Gennaro C., Amato G.
In this short paper, we report the activities of the Artificial Intelligence for Media and Humanities (AIMH) laboratory of the ISTI-CNR related to Trustworthy AI. Artificial Intelligence is becoming more and more pervasive in our society, controlling recommendation systems in social platforms as well as safety-critical systems like autonomous vehicles. In order to be safe and trustworthy, these systems require to be easily interpretable and transparent. On the other hand, it is important to spot fake examples forged by malicious AI generative models to fool humans (through fake news or deep-fakes) or other AI systems (through adversarial examples). This is required to enforce an ethical use of these powerful new technologies. Driven by these concerns, this paper presents three crucial research directions contributing to the study and the development of techniques for reliable, resilient, and explainable deep learning methods. Namely, we report the laboratory activities on the detection of adversarial examples, the use of attentive models as a way towards explainable deep learning, and the detection of deepfakes in social platforms.Source: Ital-IA 2020 - Workshop su AI Responsabile ed Affidabile, Online conference, 10/02/2022

See at: ISTI Repository Open Access | CNR ExploRA Open Access | www.ital-ia2022.it Open Access


2022 Conference article Open Access OPEN
AIMH Lab for Cybersecurity
Vairo C., Coccomini D. A., Falchi F., Gennaro C., Massoli F. V., Messina N., Amato G.
In this short paper, we report the activities of the Artificial Intelligence for Media and Humanities (AIMH) laboratory of the ISTI-CNR related to Cy-bersecurity. We discuss about our active research fields, their applications and challenges. We focus on face recognition and detection of adversarial examples and deep fakes. We also present our activities on the detection of persuasion techniques combining image and text analysis.Source: Ital-IA 2022 - Workshop su AI per Cybersecurity, 10/02/2022

See at: ISTI Repository Open Access | CNR ExploRA Open Access | www.ital-ia2022.it Open Access


2022 Conference article Open Access OPEN
AIMH Lab for Healthcare and Wellbeing
Di Benedetto M., Carrara F., Ciampi L., Falchi F., Gennaro C., Amato G.
In this work we report the activities of the Artificial Intelligence for Media and Humanities (AIMH) laboratory of the ISTI-CNR related to Healthcare and Wellbeing. By exploiting the advances of recent machine learning methods and the compute power of desktop and mobile platforms, we will show how artificial intelligence tools can be used to improve healthcare systems in various parts of disease treatment. In particular we will see how deep neural networks can assist doctors from diagnosis (e.g., cell counting, pupil and brain analysis) to communication to patients with Augmented Reality .Source: Ital-IA 2022 - Workshop AI per la Medicina e la Salute, Online conference, 10/02/2022

See at: ISTI Repository Open Access | CNR ExploRA Open Access | www.ital-ia2022.it Open Access


2022 Conference article Open Access OPEN
AIMH Lab for the Industry
Carrara F., Ciampi L., Di Benedetto M., Falchi F., Gennaro C., Massoli F. V., Amato G.
In this short paper, we report the activities of the Artificial Intelligence for Media and Humanities (AIMH) laboratory of the ISTI-CNR related to Industry. The massive digitalization affecting all the stages of product design, production, and control calls for data-driven algorithms helping in the coordination of humans, machines, and digital resources in Industry 4.0. In this context, we developed AI-based Computer-Vision technologies of general interest in the emergent digital paradigm of the fourth industrial revolution, fo-cusing on anomaly detection and object counting for computer-assisted testing and quality control. Moreover, in the automotive sector, we explore the use of virtual worlds to develop AI systems in otherwise practically unfeasible scenarios, showing an application for accident avoidance in self-driving car AI agents.Source: Ital-IA 2022 - Workshop su AI per l'Industria, Online conference, 10/02/2022

See at: CNR ExploRA Open Access | www.ital-ia2022.it Open Access


2022 Conference article Open Access OPEN
AIMH Lab: Smart Cameras for Public Administration
Ciampi L., Cafarelli D., Carrara F., Di Benedetto M., Falchi F., Gennaro C., Massoli F. V., Messina N., Amato G.
In this short paper, we report the activities of the Artificial Intelligence for Media and Humanities (AIMH) laboratory of the ISTI-CNR related to Public Administration. In particular, we present some AI-based public services serving the citizens that help achieve common goals beneficial to the society, putting humans at the epicenter. Through the automatic analysis of images gathered from city cameras, we provide AI applications ranging from smart parking and smart mobility to human activity monitoring.Source: Ital-IA 2022 - Workshop su AI per la Pubblica Amministrazione, Online conference, 10/02/2022

See at: ISTI Repository Open Access | CNR ExploRA Open Access | www.ital-ia2022.it Open Access


2022 Contribution to book Open Access OPEN
Training convolutional neural networks with competitive hebbian learning approaches
Lagani G., Falchi F., Gennaro C., Amato G.
We explore competitive Hebbian learning strategies to train feature detectors in Convolutional Neural Networks (CNNs), without supervision. We consider variants of the Winner-Takes-All (WTA) strategy explored in previous works, i.e. k-WTA, e-soft-WTA and p-soft-WTA, performing experiments on different object recognition datasets. Results suggest that the Hebbian approaches are effective to train early feature extraction layers, or to re-train higher layers of a pre-trained network, with soft competition generally performing better than other Hebbian approaches explored in this work. Our findings encourage a path of cooperation between neuroscience and computer science towards a deeper investigation of biologically inspired learning principles.Source: Machine Learning, Optimization, and Data Science, edited by Nicosia G., Ojha V., La Malfa E., La Malfa G., Jansen G., Pardalos P.M., Giuffrida G., Umeton R., pp. 25–40, 2022
DOI: 10.1007/978-3-030-95467-3_2
Project(s): AI4EU via OpenAIRE, AI4Media via OpenAIRE
Metrics:


See at: ISTI Repository Open Access | ZENODO Open Access | link.springer.com Restricted | CNR ExploRA Restricted


2022 Contribution to book Open Access OPEN
Evaluating hebbian learning in a semi-supervised setting
Lagani G., Falchi F., Gennaro C., Amato G.
We propose a semi-supervised learning strategy for deep Convolutional Neural Networks (CNNs) in which an unsupervised pre-training stage, performed using biologically inspired Hebbian learning algorithms, is followed by supervised end-to-end backprop fine-tuning. We explored two Hebbian learning rules for the unsupervised pre-training stage: soft-Winner-Takes-All (soft-WTA) and nonlinear Hebbian Principal Component Analysis (HPCA). Our approach was applied in sample efficiency scenarios, where the amount of available labeled training samples is very limited, and unsupervised pre-training is therefore beneficial. We performed experiments on CIFAR10, CIFAR100, and Tiny ImageNet datasets. Our results show that Hebbian outperforms Variational Auto-Encoder (VAE) pre-training in almost all the cases, with HPCA generally performing better than soft-WTA.Source: Machine Learning, Optimization, and Data Science, edited by Nicosia G.; Ojha V.; La Malfa E.; La Malfa G.; Jansen G.; Pardalos P.M.; Giuffrida G.; Umeton R., pp. 365–379, 2022
DOI: 10.1007/978-3-030-95470-3_28
Project(s): AI4EU via OpenAIRE, AI4Media via OpenAIRE
Metrics:


See at: ISTI Repository Open Access | ZENODO Open Access | link.springer.com Restricted | CNR ExploRA Restricted


2022 Journal article Open Access OPEN
An embedded toolset for human activity monitoring in critical environments
Di Benedetto M., Carrara F., Ciampi L., Falchi F., Gennaro C., Amato G.
In many working and recreational activities, there are scenarios where both individual and collective safety have to be constantly checked and properly signaled, as occurring in dangerous workplaces or during pandemic events like the recent COVID-19 disease. From wearing personal protective equipment to filling physical spaces with an adequate number of people, it is clear that a possibly automatic solution would help to check compliance with the established rules. Based on an off-the-shelf compact and low-cost hardware, we present a deployed real use-case embedded system capable of perceiving people's behavior and aggregations and supervising the appliance of a set of rules relying on a configurable plug-in framework. Working on indoor and outdoor environments, we show that our implementation of counting people aggregations, measuring their reciprocal physical distances, and checking the proper usage of protective equipment is an effective yet open framework for monitoring human activities in critical conditions.Source: Expert systems with applications 199 (2022). doi:10.1016/j.eswa.2022.117125
DOI: 10.1016/j.eswa.2022.117125
Project(s): AI4EU via OpenAIRE, AI4Media via OpenAIRE
Metrics:


See at: ISTI Repository Open Access | CNR ExploRA Restricted


2022 Doctoral thesis Open Access OPEN
Relational Learning in computer vision
Messina N.
The increasing interest in social networks, smart cities, and Industry 4.0 is encouraging the development of techniques for processing, understanding, and organizing vast amounts of data. Recent important advances in Artificial Intelligence brought to life a subfield of Machine Learning called Deep Learning, which can automatically learn common patterns from raw data directly, without relying on manual feature selection. This framework overturned many computer science fields, like Computer Vision and Natural Language Processing, obtaining astonishing results. Nevertheless, many challenges are still open. Although deep neural networks obtained impressive results on many tasks, they cannot perform non-local processing by explicitly relating potentially interconnected visual or textual entities. This relational aspect is fundamental for capturing high-level semantic interconnections in multimedia data or understanding the relationships between spatially distant objects in an image. This thesis tackles the relational understanding problem in Deep Neural Networks, considering three different yet related tasks: Relational Content-based Image Retrieval (R-CBIR), Visual-Textual Retrieval, and the Same-Different tasks. We use state-of-the-art deep learning methods for relational learning, such as the Relation Networks and the Transformer Networks for relating the different entities in an image or in a text.

See at: etd.adm.unipi.it Open Access | ISTI Repository Open Access | CNR ExploRA Open Access


2022 Conference article Open Access OPEN
MOBDrone: a drone video dataset for Man OverBoard Rescue
Cafarelli D., Ciampi L., Vadicamo L., Gennaro C., Berton A., Paterni M., Benvenuti C., Passera M., Falchi F.
Modern Unmanned Aerial Vehicles (UAV) equipped with cameras can play an essential role in speeding up the identification and rescue of people who have fallen overboard, i.e., man overboard (MOB). To this end, Artificial Intelligence techniques can be leveraged for the automatic understanding of visual data acquired from drones. However, detecting people at sea in aerial imagery is challenging primarily due to the lack of specialized annotated datasets for training and testing detectors for this task. To fill this gap, we introduce and publicly release the MOBDrone benchmark, a collection of more than 125K drone-view images in a marine environment under several conditions, such as different altitudes, camera shooting angles, and illumination. We manually annotated more than 180K objects, of which about 113K man overboard, precisely localizing them with bounding boxes. Moreover, we conduct a thorough performance analysis of several state-of-the-art object detectors on the MOBDrone data, serving as baselines for further research.Source: ICIAP 2022 - 21st International Conference on Image Analysis and Processing, pp. 633–644, Lecce, Italia, 23-27/05/2022
DOI: 10.1007/978-3-031-06430-2_53
Metrics:


See at: ISTI Repository Open Access | link.springer.com Restricted | CNR ExploRA Restricted


2022 Dataset Open Access OPEN
MOBDrone: a large-scale drone-view dataset for man overboard detection
Cafarelli D., Ciampi L., Vadicamo L., Gennaro C., Berton A., Paterni M., Benvenuti C., Passera M., Falchi F.
The Man OverBoard Drone (MOBDrone) dataset is a large-scale collection of aerial footage images. It contains 126,170 frames extracted from 66 video clips gathered from one UAV flying at an altitude of 10 to 60 meters above the mean sea level. Images are manually annotated with more than 180K bounding boxes localizing objects belonging to 5 categories --- person, boat, lifebuoy, surfboard, wood. More than 113K of these bounding boxes belong to the person category and localize people in the water simulating the need to be rescued.

See at: ISTI Repository Open Access | CNR ExploRA | zenodo.org


2022 Conference article Open Access OPEN
Combining EfficientNet and vision transformers for video deepfake detection
Coccomini D. A., Messina N., Gennaro C., Falchi F.
Deepfakes are the result of digital manipulation to forge realistic yet fake imagery. With the astonishing advances in deep generative models, fake images or videos are nowadays obtained using variational autoencoders (VAEs) or Generative Adversarial Networks (GANs). These technologies are becoming more accessible and accurate, resulting in fake videos that are very difficult to be detected. Traditionally, Convolutional Neural Networks (CNNs) have been used to perform video deepfake detection, with the best results obtained using methods based on EfficientNet B7. In this study, we focus on video deep fake detection on faces, given that most methods are becoming extremely accurate in the generation of realistic human faces. Specifically, we combine various types of Vision Transformers with a convolutional EfficientNet B0 used as a feature extractor, obtaining comparable results with some very recent methods that use Vision Transformers. Differently from the state-of-the-art approaches, we use neither distillation nor ensemble methods. Furthermore, we present a straightforward inference procedure based on a simple voting scheme for handling multiple faces in the same video shot. The best model achieved an AUC of 0.951 and an F1 score of 88.0%, very close to the state-of-the-art on the DeepFake Detection Challenge (DFDC). The code for reproducing our results is publicly available here: https://tinyurl.com/cnn-vit-dfd.Source: ICIAP 2022 - 21st International Conference on Image Analysis and Processing, pp. 219–229, Lecce, Italy, 23-27/05/2022
DOI: 10.1007/978-3-031-06433-3_19
Metrics:


See at: ISTI Repository Open Access | doi.org Restricted | link.springer.com Restricted | CNR ExploRA Restricted


2022 Journal article Open Access OPEN
Multi-camera vehicle counting using edge-AI
Ciampi L., Gennaro C., Carrara F., Falchi F., Vairo C., Amato G.
This paper presents a novel solution to automatically count vehicles in a parking lot using images captured by smart cameras. Unlike most of the literature on this task, which focuses on the analysis of single images, this paper proposes the use of multiple visual sources to monitor a wider parking area from different perspectives. The proposed multi-camera system is capable of automatically estimating the number of cars present in the entire parking lot directly on board the edge devices. It comprises an on-device deep learning-based detector that locates and counts the vehicles from the captured images and a decentralized geometric-based approach that can analyze the inter-camera shared areas and merge the data acquired by all the devices. We conducted the experimental evaluation on an extended version of the CNRPark-EXT dataset, a collection of images taken from the parking lot on the campus of the National Research Council (CNR) in Pisa, Italy. We show that our system is robust and takes advantage of the redundant information deriving from the different cameras, improving the overall performance without requiring any extra geometrical information of the monitored scene.Source: Expert systems with applications (2022). doi:10.1016/j.eswa.2022.117929
DOI: 10.1016/j.eswa.2022.117929
Project(s): AI4EU via OpenAIRE, AI4Media via OpenAIRE
Metrics:


See at: ISTI Repository Open Access | CNR ExploRA Restricted | www.sciencedirect.com Restricted


2022 Conference article Open Access OPEN
Recurrent vision transformer for solving visual reasoning problems
Messina N., Amato G., Carrara F., Gennaro C., Falchi F.
Although convolutional neural networks (CNNs) showed remarkable results in many vision tasks, they are still strained by simple yet challenging visual reasoning problems. Inspired by the recent success of the Transformer network in computer vision, in this paper, we introduce the Recurrent Vision Transformer (RViT) model. Thanks to the impact of recurrent connections and spatial attention in reasoning tasks, this network achieves competitive results on the same-different visual reasoning problems from the SVRT dataset. The weight-sharing both in spatial and depth dimensions regularizes the model, allowing it to learn using far fewer free parameters, using only 28k training samples. A comprehensive ablation study confirms the importance of a hybrid CNN + Transformer architecture and the role of the feedback connections, which iteratively refine the internal representation until a stable prediction is obtained. In the end, this study can lay the basis for a deeper understanding of the role of attention and recurrent connections for solving visual abstract reasoning tasks. The code for reproducing our results is publicly available here: https://tinyurl.com/recvitSource: ICIAP 2022 - 21st International Conference on Image Analysis and Processing, pp. 50–61, Lecce, Italy, 23-27/05/2022
DOI: 10.1007/978-3-031-06433-3_5
Project(s): AI4EU via OpenAIRE, AI4Media via OpenAIRE
Metrics:


See at: ISTI Repository Open Access | link.springer.com Restricted | CNR ExploRA Restricted


2022 Conference article Open Access OPEN
Towards unsupervised machine learning approaches for knowledge graphs
Minutella F., Falchi F., Manghi P., De Bonis M., Messina N.
Nowadays, a lot of data is in the form of Knowledge Graphs aiming at representing information as a set of nodes and relationships between them. This paper proposes an efficient framework to create informative embeddings for node classification on large knowledge graphs. Such embeddings capture how a particular node of the graph interacts with his neighborhood and indicate if it is either isolated or part of a bigger clique. Since a homogeneous graph is necessary to perform this kind of analysis, the framework exploits the metapath approach to split the heterogeneous graph into multiple homogeneous graphs. The proposed pipeline includes an unsupervised attentive neural network to merge different metapaths and produce node embeddings suitable for classification. Preliminary experiments on the IMDb dataset demonstrate the validity of the proposed approach, which can defeat current state-of-the-art unsupervised methods.Source: IRCDL 2022 - 18th Italian Research Conference on Digital Libraries, Padua, Italy, 24-25/02/2022
Project(s): OpenAIRE Nexus via OpenAIRE

See at: ceur-ws.org Open Access | ISTI Repository Open Access | CNR ExploRA Open Access


2022 Conference article Open Access OPEN
A spatio-temporal attentive network for video-based crowd counting
Avvenuti M., Bongiovanni M., Ciampi L., Falchi F., Gennaro C., Messina N.
Automatic people counting from images has recently drawn attention for urban monitoring in modern Smart Cities due to the ubiquity of surveillance camera networks. Current computer vision techniques rely on deep learning-based algorithms that estimate pedestrian densities in still, individual images. Only a bunch of works take advantage of temporal consistency in video sequences. In this work, we propose a spatio-temporal attentive neural network to estimate the number of pedestrians from surveillance videos. By taking advantage of the temporal correlation between consecutive frames, we lowered state-of-the-art count error by 5% and localization error by 7.5% on the widely-used FDST benchmark.Source: ISCC 2022 - 27th IEEE Symposium on Computers and Communications, Rhodes Island, Greece, 30/06/2022-03/07/2022
DOI: 10.1109/iscc55528.2022.9913019
Project(s): AI4Media via OpenAIRE
Metrics:


See at: ISTI Repository Open Access | ieeexplore.ieee.org Restricted | CNR ExploRA Restricted


2022 Dataset Unknown
Bus Violence: a large-scale benchmark for video violence detection in public transport
Foszner P., Staniszewski M., Szczesna A., Cogiel M., Golba D., Ciampi L., Messina N., Gennaro C., Falchi F., Amato G., Serao G.
The Bus Violence dataset is a large-scale collection of videos depicting violent and non-violent situations in public transport environments. This benchmark was gathered from multiple cameras located inside a moving bus where several people simulated violent actions, such as stealing an object from another person, fighting between passengers, etc. It contains 1,400 video clips manually annotated as having or not violent scenes, making it one of the biggest benchmarks for video violence detection in the literature.Project(s): AI4Media via OpenAIRE

See at: CNR ExploRA | zenodo.org


2022 Contribution to conference Open Access OPEN
AI and computer vision for smart cities
Amato G., Carrara F., Ciampi L., Di Benedetto M., Gennaro C., Falchi F., Messina N., Vairo C.
Artificial Intelligence (AI) is increasingly employed to develop public services that make life easier for citizens. In this abstract, we present some research topics and applications carried out by the Artificial Intelligence for Media and Humanities (AIMH) laboratory of the ISTI-CNR of Pisa about the study and development of AI-based services for Smart Cities dedicated to the interaction with the physical world through the analysis of images gathered from city cameras. Like no other sensing mechanism, networks of city cameras can 'observe' the world and simultaneously provide visual data to AI systems to extract relevant information and make/suggest decisions helping to solve many real-world problems. Specifically, we discuss some solutions in the context of smart mobility, parking monitoring, infrastructure management, and surveillance systems.Source: I-CiTies 2022 - 8th Italian Conference on ICT for Smart Cities And Communities, Ascoli Piceno, Italy, 14-16/09/2022
Project(s): AI4Media via OpenAIRE

See at: icities2022.unicam.it Open Access | ISTI Repository Open Access | ISTI Repository Open Access | CNR ExploRA Open Access


2022 Contribution to conference Open Access OPEN
CrowdVisor: an embedded toolset for human activity monitoring in critical environments
Di Benedetto M., Carrara F., Ciampi L., Falchi F., Gennaro C., Amato G.
As evidenced during the recent COVID-19 pandemic, there are scenarios in which ensuring compliance to a set of guidelines (such as wearing medical masks and keeping a certain physical distance among people) becomes crucial to secure a safe living environment. However, human supervision could not always guarantee this task, especially in crowded scenes. This abstract presents CrowdVisor, an embedded modular Computer Vision-based and AI-assisted system that can carry out several tasks to help monitor individual and collective human safety rules. We strive for a real-time but low-cost system, thus complying with the compute- and storage-limited resources availability typical of off-the-shelves embedded devices, where images are captured and processed directly onboard. Our solution consists of multiple modules relying on well-researched neural network components, each responsible for specific functionalities that the user can easily enable and configure. In particular, by exploiting one of these modules or combining some of them, our framework makes available many capabilities. They range from the ability to estimate the so-called social distance to the estimation of the number of people present in the monitored scene, as well as the possibility to localize and classify Personal Protective Equipment (PPE) worn by people (such as helmets and face masks). To validate our solution, we test all the functionalities that our framework makes available over two novel datasets that we collected and annotated on purpose. Experiments show that our system provides a valuable asset to monitor compliance with safety rules automatically.Source: I-CiTies 2022 - 8th Italian Conference on ICT for Smart Cities And Communities, Ascoli Piceno, Italy, 14-16/09/2022
Project(s): AI4EU via OpenAIRE, AI4Media via OpenAIRE

See at: icities2022.unicam.it Open Access | ISTI Repository Open Access | ISTI Repository Open Access | CNR ExploRA Open Access