Analyzing Cough Sounds for the Evidence of Covid-19 using Deep Learning Models

Early detection of infectious disease is the must to prevent/avoid multiple infections, and Covid-19 is an example. When dealing with Covid-19 pandemic, Cough is still ubiquitously presented as one of the key symptoms in both severe and non-severe Covid-19 infections, even though symptoms appear differently in different sociodemographic categories. By realizing the importance of clinical studies, analyzing cough sounds using AI-driven tools could help add more values when it comes to decision-making. Moreover, for mass screening and to serve resource constrained regions, AI-driven tools are the must. In this thesis, Convolutional Neural Network (CNN) tailored deep learning models are studied to analyze cough sounds to detect the possible evidence of Covid-19. In addition to custom CNN, pre-trained deep learning models (e.g., Vgg-16, Resnet-50, MobileNetV1, and DenseNet121) are employed on a publicly available dataset. In our findings, custom CNN performed comparatively better than pre-trained deep learning models

Analysis and Development of an End-to-End Convolutional Neural Network for Sounds Classification Through Deep Learning Techniques

El presente trabajo estudia el análisis y desarrollo continuo de un modelo de inteligencia artificial orientado a la clasificación de audio. El capítulo 1 presenta antecedentes sobre las diferentes tareas relacionadas a audio que la comunidad de investigación ha seguido a lo largo de los últimos años, también establece la hipótesis central de este trabajo y define objetivos generales y específicos para contribuir a la mejora del rendimiento sobre un generador de embeddings de audio de tipo end-to-end. El capítulo 2 presenta los métodos de vanguardia y trabajos publicados que se enfocan principalmente al desarrollo de la clasificación de audio y el aprendizaje profundo como disciplinas que aún tienen un gran potencial. El capítulo 3 presenta el marco conceptual en el que se basa esta tesis, dividido en dos secciones principales: preprocesamiento de audio y técnicas de aprendizaje profundo. Cada una de estas secciones se divide en varias subsecciones para representar el proceso de clasificación de audio a través de redes neuronales profundas. El capítulo 4 brinda una explicación profunda del generador de embeddings de audio llamado AemNet y sus componentes, utilizado como objeto de estudio, donde se detalla en las siguientes subsecciones. Se realizó una experimentación inicial sobre este enfoque y se presentaron resultados experimentales que sugirieron un mejor rendimiento mediante la modificación de las etapas de arquitectura de la red neuronal. El capítulo 5 es la primera aplicación objetivo de nuestra adaptación de AemNet que se presentó al desafío DCASE 2021. Los detalles sobre el desafío y los resultados se describen en las secciones de este capítulo, así como la metodología seguida para presentar nuestra propuesta. El capítulo 6 es la segunda aplicación objetivo y el primero en apuntar a los sonidos respiratorios. El desafío de ICBHI se explica en las secciones de este capítulo, así como la metodología y los experimentos realizados para llegar a un clasificador robusto que distingue cuatro anomalías de tos diferentes. Se creó un artículo a partir de la solución propuesta y se presentó en el IEEE LA-CCI 2021. El capítulo 7 aprovecha los diversos resultados anteriores para cumplir con un enfoque moderno como lo es la detección de COVID-19, cuya recopilación y experimentación de fuentes de datos se describen profundamente y los resultados experimentales sugieren que una adaptación de red residual denominada AemResNet, puede cumplir la función de distinguir a los pacientes con COVID-19 a partir de tos y sonidos respiratorios. Finalmente, las conclusiones de toda esta investigación y los resultados evaluados en cada una de las aplicaciones objetivo se discuten en el capítulo 8.ITESO, A. C

Распознавание голоса с использованием свёрточной нейронной сети

The article presents an approach, methodology, the software system based on a machine learning technologies for convolutional neural network and its use for voice (cough) recognition. Tasks of article are receiving evaluating a voice detection system with deep learning, the use of a convolutional neural network and Python language for patients with cough. The convolutional neural network has been developed, trained and tested using various datasets and Python libraries. Unlike the existing modern works related to this area, proposed system was evaluated using a real set of environmental sound data, and not only on filtered or separated voice audio tracks. The final compiled model showed a relatively high average accuracy of 85.37 %. Thus, the system is able to detect the sound of a voice in a crowded public place, and there is no need for a sound separation phase for pre-processing, as other modern systems require. Several volunteers recorded their voice sounds using microphones of their smartphones, and it was guaranteed that they would test their voices in public places to make noise, in addition to some audio files that were uploaded online. The results showed an average recognition accuracy – of 85.37 %, a minimum accuracy – of 78.8 % and a record – of 91.9 %. Представлены подход, методология, программная система, основанные на свёрточной нейронной сети, для распознавания голоса (кашля) в условиях зашумленности с использованием технологий машинного обучения. Разработана и оценена система распознавания кашля на основе машинного обучения, использования свёрточной нейронной сети и библиотек языка Python. Свёрточная нейронная сеть протестирована с помощью различных наборов данных и библиотек. В отличие от существующих современных работ в этой области предложенная система оценивалась с применением реального набора звуковых данных окружающей среды, а не только отфильтрованных или разделенных звуковых параметров голоса. Окончательная скомпилированная модель показала относительно высокую среднюю точность – 85,37 %. Предлагаемая система способна распознавать звук голоса в многолюдном общественном месте, и нет необходимости в фазе разделения звука для предварительной обработки, как в других системах. Несколько добровольцев записали звуки своего голоса с помощью смартфонов. Затем они протестировали свои голоса в общественных местах на предмет шума в дополнение к некоторым аудиофайлам, которые были загружены онлайн. Результаты показали среднюю точность распознавания – 85,37 %, минимальную – 78,8 % и рекордную – 91,9 %.

Automatic Recognition, Segmentation, and Sex Assignment of Nocturnal Asthmatic Coughs and Cough Epochs in Smartphone Audio Recordings: Observational Field Study

Background: Asthma is one of the most prevalent chronic respiratory diseases. Despite increased investment in treatment, little progress has been made in the early recognition and treatment of asthma exacerbations over the last decade. Nocturnal cough monitoring may provide an opportunity to identify patients at risk for imminent exacerbations. Recently developed approaches enable smartphone-based cough monitoring. These approaches, however, have not undergone longitudinal overnight testing nor have they been specifically evaluated in the context of asthma. Also, the problem of distinguishing partner coughs from patient coughs when two or more people are sleeping in the same room using contact-free audio recordings remains unsolved. Objective: The objective of this study was to evaluate the automatic recognition and segmentation of nocturnal asthmatic coughs and cough epochs in smartphone-based audio recordings that were collected in the field. We also aimed to distinguish partner coughs from patient coughs in contact-free audio recordings by classifying coughs based on sex. Methods: We used a convolutional neural network model that we had developed in previous work for automated cough recognition. We further used techniques (such as ensemble learning, minibatch balancing, and thresholding) to address the imbalance in the data set. We evaluated the classifier in a classification task and a segmentation task. The cough-recognition classifier served as the basis for the cough-segmentation classifier from continuous audio recordings. We compared automated cough and cough-epoch counts to human-annotated cough and cough-epoch counts. We employed Gaussian mixture models to build a classifier for cough and cough-epoch signals based on sex. Results: We recorded audio data from 94 adults with asthma (overall: mean 43 years; SD 16 years; female: 54/94, 57%; male 40/94, 43%). Audio data were recorded by each participant in their everyday environment using a smartphone placed next to their bed; recordings were made over a period of 28 nights. Out of 704,697 sounds, we identified 30,304 sounds as coughs. A total of 26,166 coughs occurred without a 2-second pause between coughs, yielding 8238 cough epochs. The ensemble classifier performed well with a Matthews correlation coefficient of 92% in a pure classification task and achieved comparable cough counts to that of human annotators in the segmentation of coughing. The count difference between automated and human-annotated coughs was a mean –0.1 (95% CI –12.11, 11.91) coughs. The count difference between automated and human-annotated cough epochs was a mean 0.24 (95% CI –3.67, 4.15) cough epochs. The Gaussian mixture model cough epoch–based sex classification performed best yielding an accuracy of 83%. Conclusions: Our study showed longitudinal nocturnal cough and cough-epoch recognition from nightly recorded smartphone-based audio from adults with asthma. The model distinguishes partner cough from patient cough in contact-free recordings by identifying cough and cough-epoch signals that correspond to the sex of the patient. This research represents a step towards enabling passive and scalable cough monitoring for adults with asthma

COVID-19 Cough Classification using Machine Learning and Global Smartphone Recordings

We present a machine learning based COVID-19 cough classifier which can discriminate COVID-19 positive coughs from both COVID-19 negative and healthy coughs recorded on a smartphone. This type of screening is non-contact, easy to apply, and can reduce the workload in testing centres as well as limit transmission by recommending early self-isolation to those who have a cough suggestive of COVID-19. The datasets used in this study include subjects from all six continents and contain both forced and natural coughs, indicating that the approach is widely applicable. The publicly available Coswara dataset contains 92 COVID-19 positive and 1079 healthy subjects, while the second smaller dataset was collected mostly in South Africa and contains 18 COVID-19 positive and 26 COVID-19 negative subjects who have undergone a SARS-CoV laboratory test. Both datasets indicate that COVID-19 positive coughs are 15\%-20\% shorter than non-COVID coughs. Dataset skew was addressed by applying the synthetic minority oversampling technique (SMOTE). A leave-$p$-out cross-validation scheme was used to train and evaluate seven machine learning classifiers: LR, KNN, SVM, MLP, CNN, LSTM and Resnet50. Our results show that although all classifiers were able to identify COVID-19 coughs, the best performance was exhibited by the Resnet50 classifier, which was best able to discriminate between the COVID-19 positive and the healthy coughs with an area under the ROC curve (AUC) of 0.98. An LSTM classifier was best able to discriminate between the COVID-19 positive and COVID-19 negative coughs, with an AUC of 0.94 after selecting the best 13 features from a sequential forward selection (SFS). Since this type of cough audio classification is cost-effective and easy to deploy, it is potentially a useful and viable means of non-contact COVID-19 screening.Comment: This paper has been accepted in "Computers in Medicine and Biology" and currently under productio