Classification and retrieval of thoracic diseases using patch-based visual words: a study on chest x-rays.

This research work explores the Content-Based Medical Image Retrieval system (CBMIR) to categorization and retrieval of different types of common thoracic diseases such as Atelectasis, cardiomegaly, Effusion, Infiltration etc, based on local patch representation of 'Bag of Visual Words' approach, when performing patch-based image representation, the selected patch size has significant impact on image categorization and retrieval process. It is a challenging task in selecting the appropriate patch size to the current experimental dataset. Chest Xray8 medical image database is used, to analyze the impact of different patch size to categorize and retrieval of eight common thorax diseases. 1000 frontal view x-ray images is obtained (100 images from each category and 200 images combination of more than one disease) from the database. Different sizes of image patches (16 × 16 and 32 × 32) and different codebook sizes (500, 1000, 1500, 2000) created to identify best precision and recall values. From the excremental result, 32 × 32 patch size and 1500 codebook size gives the good precision and recall value using Radial Basis Function SVM kernel.