Browsing by Author "Dufourq, Emmanuel"

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    Counting animals in ecological images
    (2022) Pillay, Nakkita; Durbach, Ian; Dufourq, Emmanuel
    In the field of ecology, counting of animals to estimate population size and prey abundance is important for the conservation of wildlife. This involves analyzing large volumes of image, video or audio data and manual counting. Automating the process of counting animals would be invaluable to researchers as it will eliminate the tedious time-consuming task of counting. The purpose of this dissertation is to address manual counting in images by implementing an automated solution using computer vision. This research applies a blob detection algorithm primarily based on the determinant of the Hessian matrix to estimate counts of animals in aerial images of colonies in a user-friendly web application and trains an object detection model using deep convolutional neural networks to automatically identify and count penguin prey in 2053 images extracted from animal-borne videos. The blob detection algorithm reports an average relative bias of less than 6% and the YOLOv3 object detection model automatically detects jellyfish, school of fish and fish with a mean average precision of 82,53% and counts with an average relative bias of -17,66% over all classes. The results show that applying traditional computer vision methods and deep learning on data-scarce and data-rich situations respectively, can save ecologists an immense amount of time used on manual tedious methods of analysis and counting. Additionally, these automated counting methods can contribute towards improving wildlife conservation and future studies.
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    Detection and Isolation of Prey Capture Events in Animal-Borne Images
    (2021) Chirwa, Temweka S; Durbach, Ian; Dufourq, Emmanuel
    Understanding the foraging habits and prey availability for a species is crucial. Prey availability is crucial to a species' survival and sustainability of the food pyramid. Identifying the type of prey consumed also allows ecologists to determine the energy received, while the duration and extent of foraging bouts provide information about the energy expended. With recent advancements in technology, data collection has become more accessible, and animal-borne video cameras are an increasingly popular mechanism for collecting information about foraging and other behaviour. Video recorders collect large volumes of data but create a bottleneck as data processing is still predominantly done manually. This process is time-consuming and costly, even with the assistance of crowdsourced tasks. Advancements in deep learning, and its applications to computer vision, provide opportunities to apply these tools to ecological problems, such as the processing of data from animal-borne video recorders. Speeding up the annotation process allows more time to be spent focused on the ecological research questions. This dissertation aims to develop detection and isolation models that will assist in the processing of visual data, namely images from animal-borne videos. The first model used for detection will perform an image classification determining whether prey is present or not. Images found to have prey present will then be presented to the second model for isolation that identifies exactly where within the image the prey is and labels the type of prey. The models were trained on video data of little penguins (Eudyptula minor ), whose main prey in this investigation are small fish, predominantly anchovies, and jellyfish. The image classification model based on the ResNet architecture achieved 85% accuracy with precision and recall values of 0.85 and 0.85 respectively on its test set. The object detection model based on the You Only Look Once (YOLO) framework achieved a mean average precision of 60% on its test set. However, the models did not perform well enough on unseen full length videos to be used without human supervision or to serve as alternatives to manual labelling. Rather, the models can be used to guide researchers to areas that may contain prey events.
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    Evolutionary deep learning
    (2019) Dufourq, Emmanuel; Bassett, Bruce A.
    The primary objective of this thesis is to investigate whether evolutionary concepts can improve the performance, speed and convenience of algorithms in various active areas of machine learning research. Deep neural networks are exhibiting an explosion in the number of parameters that need to be trained, as well as the number of permutations of possible network architectures and hyper-parameters. There is little guidance on how to choose these and brute-force experimentation is prohibitively time consuming. We show that evolutionary algorithms can help tame this explosion of freedom, by developing an algorithm that robustly evolves near optimal deep neural network architectures and hyper-parameters across a wide range of image and sentiment classification problems. We further develop an algorithm that automatically determines whether a given data science problem is of classification or regression type, successfully choosing the correct problem type with more than 95% accuracy. Together these algorithms show that a great deal of the current "art" in the design of deep learning networks - and in the job of the data scientist - can be automated. Having discussed the general problem of optimising deep learning networks the thesis moves on to a specific application: the automated extraction of human sentiment from text and images of human faces. Our results reveal that our approach is able to outperform several public and/or commercial text sentiment analysis algorithms using an evolutionary algorithm that learned to encode and extend sentiment lexicons. A second analysis looked at using evolutionary algorithms to estimate text sentiment while simultaneously compressing text data. An extensive analysis of twelve sentiment datasets reveal that accurate compression is possible with 3.3% loss in classification accuracy even with 75% compression of text size, which is useful in environments where data volumes are a problem. Finally, the thesis presents improvements to automated sentiment analysis of human faces to identify emotion, an area where there has been a tremendous amount of progress using convolutional neural networks. We provide a comprehensive critique of past work, highlight recommendations and list some open, unanswered questions in facial expression recognition using convolutional neural networks. One serious challenge when implementing such networks for facial expression recognition is the large number of trainable parameters which results in long training times. We propose a novel method based on evolutionary algorithms, to reduce the number of trainable parameters whilst simultaneously retaining classification performance, and in some cases achieving superior performance. We are robustly able to reduce the number of parameters on average by 95% with no loss in classification accuracy. Overall our analyses show that evolutionary algorithms are a valuable addition to machine learning in the deep learning era: automating, compressing and/or improving results significantly, depending on the desired goal.
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    Investigating automated bird detection from webcams using machine learning
    (2022) Mirugwe, Alex; Nyirenda, Juwa; Dufourq, Emmanuel
    One of the most challenging problems faced by ecologists and other biological researchers today is to analyze the massive amounts of data being collected by advanced monitoring systems such as camera traps, wireless sensor networks, high-frequency radio trackers, global positioning systems, and satellite tracking systems being used today. It has become expensive, laborious, and time-consuming to analyze the large datasets using manual and traditional statistical techniques. Recent developments in the field of deep learning are showing promising results towards automating the analysis of these extremely large datasets. The primary objective of this study is to test the capabilities of the state-of-the-art deep learning architectures to detect birds in the webcam captured images. A total of 10592 images were collected for this study from the Cornell Lab of Ornithology live stream feeds situated in six unique locations in United States, Ecuador, New Zealand, and Panama. To achieve the main objective of the study, two convolutional neural network object detection meta-architectures, single-shot detector (SSD) and Faster R-CNN in combination with MobileNet-V2, ResNet50, ResNet101, ResNet152, and Inception ResNet-V2 feature extractors were studied and evaluated. Through the use of transfer learning, all the models were initialized using weights pre-trained on the MS COCO (Microsoft Common Objects in Context) dataset provided by the TensorFlow 2 object detection API. The Faster R-CNN model coupled with ResNet152 outperformed all other models with a mean average precision of 92.3%. However, the SSD model with the MobileNet-V2 feature extraction network achieved the lowest inference time (110ms) and the smallest memory capacity (30.5MB) compared to its counterparts. The outstanding results achieved in this study confirm that deep learning-based algorithms are capable of detecting birds of different sizes in different environments and the best model could potentially help ecologists in monitoring and identifying birds from other species present in the environment.
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    Word Sense Disambiguation in the domain of Sentiment Analysis through Deep Learning
    (2022) Baiju, Vedanth; Er, Sebnem; Dufourq, Emmanuel
    Sentiment analysis forms part of a major component of Natural Language Processing (NLP), even though continuous improvements in NLP are being made, word disambiguation remains a complex problem within the domain of sentiment analysis (Navigli, 2009). Word Sense Disambiguation (WSD) is a problem that deals with identifying the correct sense of ambiguous words in a sentence. As such, various words can have multiple meanings depending on the context in which they are used. Although advances in deep learning continue to rise within the NLP domain, WSD is still a task in which deep learning is yet to be fully explored. Whilst there does exist research within WSD as a whole, there is limited research for WSD conducted within the domain of sentiment analysis (Seifollahi and Shajari, 2019). The proposed research explores the task of WSD in the domain of sentiment analysis through recent advances in deep neural networks with a specific focus on 1D Convolutional Neural Networks (CNN) and Long Short Term Memory (LSTM) algorithms. Sentiments expressed in text sourced from the Amazon product reviews data were analysed using 1D CNN and LSTM deep learning algorithms. The Amazon product reviews data is segmented according to the type of product category which is essentially a context category. The effectiveness of each algorithm was evaluated from a statistical performance and efficiency perspective. It was found that the inclusion of context as a model input, improves the model out of sample performance as compared to a model without context as an input. In addition to this, it was observed that including more context categories as an input had improved the out of sample performance for both 1D CNN and LSTM algorithms. Furthermore, the 1D CNN exhibited superior performance over the LSTM model from a statistical and efficiency stand-point. Given that there has not been a considerable amount of research which explores the application of deep learning to solving the problem of WSD within sentiment analysis, the findings of this research will aid in providing a base-level of knowledge on future potential exploration and applications for WSD relating to sentiment analysis.