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Updated: Sep 23, 2025

Lung CT Segmentation to Identify Consolidations and Ground Glass Areas for Quantitative Assesment of SARS-CoV Pneumonia
Published on: December 19, 2020
Computer-aided diagnosis of COVID-19 from chest X-ray images using histogram-oriented gradient features and Random
Malathy Jawahar1, J Prassanna2, Vinayakumar Ravi3
1Leather Process Technology Division, CSIR-Central Leather Research Institute, Adyar, Chennai, 600020 India.
This study introduces an optimized Random Forest (RF) classifier with Histogram Oriented Gradient (HOG) features for accurate COVID-19 diagnosis from X-ray images. The method achieved 99.73% accuracy, aiding radiologists in faster detection.
Area of Science:
- Medical Imaging
- Computer-Aided Diagnosis
- Machine Learning in Healthcare
Background:
- Accurate and rapid diagnosis of COVID-19 is critical for pandemic control.
- Manual interpretation of chest X-rays for COVID-19 is challenging due to image similarities with other respiratory diseases.
- Automated diagnostic tools are needed to assist healthcare professionals.
Purpose of the Study:
- To develop an automated system for COVID-19 detection using X-ray images.
- To evaluate the effectiveness of Histogram Oriented Gradient (HOG) features combined with an optimized Random Forest (RF) classifier.
- To compare HOG with other feature extraction techniques and RF with various classification algorithms.
Main Methods:
- Feature extraction using Histogram Oriented Gradient (HOG), Gray-Level Co-Occurrence Matrix (GLCM), and Hu moments.
- Training and optimization of a Random Forest (RF) classifier.
- Comparative analysis of RF against Linear Regression (LR), Linear Discriminant Analysis (LDA), K-nearest neighbor (kNN), Classification and Regression Trees (CART), Support Vector Machine (SVM), and Multi-layer perceptron neural network (MLP).
Main Results:
- HOG features effectively capture local edge descriptions and structural information for discriminating COVID-19.
- The optimized RF classifier trained with HOG features achieved a highest classification accuracy of 99.73%.
- HOG outperformed GLCM and Hu moments in feature extraction for COVID-19 diagnosis.
Conclusions:
- The proposed HOG feature extraction with RF classifier offers a highly accurate and efficient method for automated COVID-19 diagnosis from X-ray images.
- This approach can significantly assist radiologists and physicians in clinical decision-making.
- The study highlights the potential of machine learning in improving diagnostic speed and accuracy for infectious diseases.
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