Automatic view classification of echocardiograms using Histogram of Oriented Gradients

When imaging the heart, using a 2D ultrasound probe, different views can manifest depending on the location and angulations of the probe. Some of these views have been labeled as standard views, due to the presentation and ease of assessment of key cardiac structures in them. We present an approach for automatic recognition and classification of these standard views - namely the Parasternal Long Axis (PLAX) and the Short Axis (SAX) B-mode echocardiograms. The Histogram of Oriented Gradients (HOG) used as the discriminating feature encodes the spatial arrangement of edges/gradients in the images. The HOG feature is computed on the pre-scan converted image data in the ultrasound beam space. On a fairly large database of 703 images, with a Support Vector Machine classifier we obtained an accuracy of about 98%.