Computer-aided diagnosis of COVID-19 from chest X-ray images using histogram-oriented gradient features and Random Forest classifier

Abstract

The decision-making process is very crucial in healthcare, which includes quick diagnostic methods to monitor and prevent the COVID-19 pandemic disease from spreading. Computed tomography (CT) is a diagnostic tool used by radiologists to treat COVID patients. COVID x-ray images have inherent texture variations and similarity to other diseases like pneumonia. Manually diagnosing COVID X-ray images is a tedious and challenging process. Extracting the discriminant features and fine-tuning the classifiers using low-resolution images with a limited COVID x-ray dataset is a major challenge in computer aided diagnosis. The present work addresses this issue by proposing and implementing Histogram Oriented Gradient (HOG) features trained with an optimized Random Forest (RF) classifier. The proposed HOG feature extraction method is evaluated with Gray-Level Co-Occurrence Matrix (GLCM) and Hu moments. Results confirm that HOG is found to reflect the local description of edges effectively and provide excellent structural features to discriminate COVID and non-COVID when compared to the other feature extraction techniques. The performance of the RF is compared with other classifiers such as Linear Regression (LR), Linear Discriminant Analysis (LDA), K-nearest neighbor (kNN), Classification and Regression Trees (CART), Random Forest (RF), Support Vector Machine (SVM), and Multi-layer perceptron neural network (MLP). Experimental results show that the highest classification accuracy (99. 73%) is achieved using HOG trained by using the Random Forest (RF) classifier. The proposed work has provided promising results to assist radiologists/physicians in automatic COVID diagnosis using X-ray images.

A Novel Lightweight Approach to COVID-19 Diagnostics Based on Chest X-ray Images

“…First of all, they are tree-based algorithms, and they perform very well in binary classification problems. Secondly, they have been already used in similar applications, as presented in [ 29 , 30 , 31 ], providing promising results.…”

Advances of AI in Image-Based Computer-Aided Diagnosis: A Review

“…The inferred model, which can help with diagnosis, is also known as "the new knowledge discovered from the data." Supervised learning algorithms such as Decision Tree [16], K-Nearest Neighbor (KNN) [55], Linear classifiers (LR), Random Forest (RF) [56], Support Vector Machine (SVM) [57] play a vital role in diagnosing or early-stage prediction of cancer and many other diseases, while unsupervised learning algorithms such as K-means clustering [16] used in a sporadic case. Table 2 provides a concise overview of notable recent research on machine learning algorithms designed to analyze medical images in CAD systems.…”