Exploiting Spatio-temporal Information for View Recognition in Cardiac Echo Videos

2D Echocardiography is all important diagnostic aid for morphological and functional assessment of the heart. The transducer position is varied during an echo exam to elicit important information about the heart function and its anatomy. The knowledge of the transducer viewpoint is important in automatic cardiac echo interpretation to understand the regions being depicted as well as in the quantification of their attributes. In this paper we address the problem of inferring the transducer viewpoint from the spatiotemporal information in cardiac echo videos. Unlike previous approaches, we exploit motion of the heart within a cardiac cycle in addition to spatial information to discriminate between viewpoints. Specifically, we use an active shape model (ASM) to model shape and texture information in an echo frame. The motion information derived by tracking ASMs through a heart cycle is then projected into the eigen-motion feature space of the viewpoint class for matching. We report comparison with a re-implementation of state-of-the-art view recognition methods in echos on a large database of patients with various cardiac diseases.