A review on computer-aided diagnostic system to classify the disorders of the gastrointestinal tract

Various diseases, such as colon cancer, gastric cancer, celiac, and bleeding, pose a significant risk to the gastrointestinal (GI) tract, which serves as a fundamental component of the human body. It is less invasive to observe the inner part for disease recognition by using endoscopy and colonoscopy devices. Gastroenterologists consider the increased frame rate in video endoscopy to be challenging when it comes to identifying pathological findings. The detailed examination requires an experienced gastroenterologist. The ordinary procedure takes much time in disease classification. A machine-learning-based computer-aided diagnostic system (CADx) is in high demand for helping Gastroenterologists diagnose GI tract diseases with high accuracy (Acc). CADx takes very little time in diagnosing diseases and supports the training of clinicians. With the assistance of a gastroenterologist, CADx has an impact on reducing the mortality rate by finding diseases in their early stages. In an extensive examination of CADx, the focus is placed on ailments affecting the GI tract, various imaging methods, as well as diverse forms of CADx and techniques. These encompass preprocessing, feature extraction (both handcrafted and deep learning features), feature selection, and classification. In addition, future research directions in the area of automatic disease identification and categorization employing endoscopic frames are being looked into based on the existing literature.