Roberta Hlavatá

Dr. Roberta Hlavatá

Department of multimedia and ICT, University of Žilina, Žilina, Žilinský, Slovakia
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Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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17 January 2022 in Applied Sciences
Verified
Journal Article
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Roberta HlavatáRoberta Hlavatá
Roberta Hlavatá
Robert HudecRobert Hudec
Robert Hudec
Patrik KamencayPatrik Kamencay
Patrik Kamencay
Peter SykoraPeter Sykora
Peter Sykora
Interest in utilizing neural networks in a variety of scientific and academic studies and in industrial applications is increasing. In addition to the growing interest in neural networks, there is also a rising interest in video classification. Object detection from an image is used as a tool for various applications and is the basis for video classification. Identifying objects in videos is more difficult than for single images, as the information in videos has a time continuity constraint. Common neural networks such as ConvLSTM (Convolutional Long Short-Term Memory) and 3DCNN (3D Convolutional Neural Network), as well as many others, have been used to detect objects from video. Here, we propose a 3DCNN for the detection of human activity from video data. The experimental results show that the optimized proposed 3DCNN provides better results than neural network architectures for motion, static and hybrid features. The proposed 3DCNN obtains the highest recognition precision of the methods considered, 87.4%. In contrast, the neural network architectures for motion, static and hybrid features achieve precisions of 65.4%, 63.1% and 71.2%, respectively. We also compare results with previous research. Previous 3DCNN architecture on database UCF Youtube Action worked worse than the architecture we proposed in this article, where the achieved result was 29%. The experimental results on the UCF YouTube Action dataset demonstrate the effectiveness of the proposed 3DCNN for recognition of human activity. For a more complex comparison of the proposed neural network, the modified UCF101 dataset, full UCF50 dataset and full UCF101 dataset were compared. An overall precision of 82.7% using modified UCF101 dataset was obtained. On the other hand, the precision using full UCF50 dataset and full UCF101 dataset was 80.6% and 78.5%, respectively.

4 March 2023 in Sensors
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Journal Article
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Roberta HlavatáRoberta Hlavatá
Roberta Hlavatá
Patrik KamencayPatrik Kamencay
Patrik Kamencay
Robert HudecRobert Hudec
Robert Hudec
Peter SykoraPeter Sykora
Peter Sykora
Currently, three-dimensional convolutional neural networks (3DCNNs) are a popular approach in the field of human activity recognition. However, due to the variety of methods used for human activity recognition, we propose a new deep-learning model in this paper. The main objective of our work is to optimize the traditional 3DCNN and propose a new model that combines 3DCNN with Convolutional Long Short-Term Memory (ConvLSTM) layers. Our experimental results, which were obtained using the LoDVP Abnormal Activities dataset, UCF50 dataset, and MOD20 dataset, demonstrate the superiority of the 3DCNN + ConvLSTM combination for recognizing human activities. Furthermore, our proposed model is well-suited for real-time human activity recognition applications and can be further enhanced by incorporating additional sensor data. To provide a comprehensive comparison of our proposed 3DCNN + ConvLSTM architecture, we compared our experimental results on these datasets. We achieved a precision of 89.12% when using the LoDVP Abnormal Activities dataset. Meanwhile, the precision we obtained using the modified UCF50 dataset (UCF50mini) and MOD20 dataset was 83.89% and 87.76%, respectively. Overall, our work demonstrates that the combination of 3DCNN and ConvLSTM layers can improve the accuracy of human activity recognition tasks, and our proposed model shows promise for real-time applications.

12 April 2022 in Sensors
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Journal Article
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Roberta HlavatáRoberta Hlavatá
Roberta Hlavatá
Robert HudecRobert Hudec
Robert Hudec
Patrik KamencayPatrik Kamencay
Patrik Kamencay
Peter SykoraPeter Sykora
Peter Sykora
Recognizing various abnormal human activities from video is very challenging. This problem is also greatly influenced by the lack of datasets containing various abnormal human activities. The available datasets contain various human activities, but only a few of them contain non-standard human behavior such as theft, harassment, etc. There are datasets such as KTH that focus on abnormal activities such as sudden behavioral changes, as well as on various changes in interpersonal interactions. The UCF-crime dataset contains categories such as fighting, abuse, explosions, robberies, etc. However, this dataset is very time consuming. The events in the videos occur in a few seconds. This may affect the overall results of the neural networks that are used to detect the incident. In this article, we create a dataset that deals with abnormal activities, containing categories such as Begging, Drunkenness, Fight, Harassment, Hijack, Knife Hazard, Normal Videos, Pollution, Property Damage, Robbery, and Terrorism. We use the created dataset for the training and testing of the ConvLSTM (convolutional long short-term memory) neural network, which we designed. However, we also test the created dataset using other architectures. We use ConvLSTM architectures and 3D Resnet50, 3D Resnet101, and 3D Resnet152. With the created dataset and the architecture we designed, we obtained an accuracy of classification of 96.19% and a precision of 96.50%.

26 July 2021
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Conference Paper
Closed access
Roberta HlavatáRoberta Hlavatá
Roberta Hlavatá
PSPeter Sykora
Peter Sykora
PKPatrik Kamencay
Patrik Kamencay
Robert HudecRobert Hudec
Robert Hudec
RRRoman Radil
Roman Radil
Deep learning algorithms have achieved amazing performance in computer vision area. However, a biggest problem deep learning has, is the high dependency on hyper-parameters. The algorithm results may be different, depending on hyper-parameters. This paper presents an effective method for hyper-parameter tuning using deep learning. The deep neural network structure for video classification using Convolutional Long Short-Term Memory (ConvLSTM) was used. The proposed method for hyper-parameter tuning using ConvLSTM was described. This proposed method with hyper-parameter tuning methods (Grid search, Bayesian optimization and Genetic algorithm) was compared. The experiment results show that proposed approach using ConvLSTM can be compared with the results obtained from the methods analogs to the proposed approach. However, we are looking for other hyper-parameters, for example number of filters, filter size, number of epochs, batch size and training optimization algorithm. The proposed approach can be used for correct or incorrect use of face mask during COVID-19 pandemic.

1 February 2025 in AI
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Journal Article
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JSJana Sturekova
Jana Sturekova
Patrik KamencayPatrik Kamencay
Patrik Kamencay
Peter SykoraPeter Sykora
Peter Sykora
Roberta HlavatáRoberta Hlavatá
Roberta Hlavatá
This study explores the extraction of remote Photoplethysmography (rPPG) signals from images using various neural network architectures, addressing the challenge of accurate signal estimation in biomedical contexts. The objective is to evaluate the effectiveness of different models in capturing rPPG signals from dataset snapshots. Two training strategies were investigated: pre-training models with only the fully connected layer being fine-tuned and training the entire network from scratch. The analysis reveals that models trained from scratch consistently outperform their pre-trained counterparts in extracting rPPG signals. Among the architectures assessed, DenseNet121 demonstrated superior performance, offering the most reliable results in this context. These findings underscore the potential of neural networks in advancing rPPG signal extraction, which has promising applications in fields such as clinical monitoring and personalized medical care. This study contributes to the integration of advanced imaging techniques and neural network-based analysis in biomedical engineering, paving the way for more robust and efficient methodologies.

14 October 2020
Verified
Conference Paper
Closed access
Roberta HlavatáRoberta Hlavatá
Roberta Hlavatá
Robert HudecRobert Hudec
Robert Hudec
Peter SykoraPeter Sykora
Peter Sykora
PKPatrik Kamencay
Patrik Kamencay
MBMiroslav Benco
Miroslav Benco
Detection of video information is a great help in classifying non-standard / abnormal human behavior. It is more difficult to detect objects from videos when information in videos are time bound to each other. In this paper we discuss the need to detect and classify this data. Also, we try to improve classification process by various methods. A specially modified convolution neural network architecture was used along with Long Short-Term Memory (LSTM) and time distribution in experiment. Convolution neural layers for 2D data, in architecture were used.