An ensemble-based data fusion approach for characterizing ultrasonic liver tissue

This study investigates the feasibility of an ensemble of classifiers in characterizing ultrasonic liver tissue. Texture analysis generally requires feature representation and classification algorithm. From a variety of feature representations and classification algorithms, obtaining optimal ensembles composed of any feature-classifier pairs is difficult. This paper proposes an ensemble creation algorithm that can form an ensemble with high generalization performance. The pattern recognition process comprises four main stages. The first stage utilized multiresolution analysis to extract intrinsic features of ultrasonic liver images. By utilizing spatial-frequency decomposition, a feature vector was obtained by collecting the feature representation for each subimage. In the second stage of the study, various classification algorithms with diverse feature vectors were trained. Based on the trained classifiers, an ensemble was created by using the proposed algorithm in the third stage. The last stage was concerned with the aggregation of individual classifiers. The proposed approach was applied to discriminate ultrasonic liver images from three liver states: normal liver, cirrhosis, and hepatoma. Based on the six well-known fusion schemes, the experimental results showed that the ensemble proposed in this study yields more discrimination. The results indicate that the combining multiple classifiers with different features is an effective approach for characterizing ultrasonic live r tissue. Furthermore, a clinician can use the quantitative index of the classification results when deciding whether to conduct an advanced medical examination, thus improving the quality of medical care.