Respiratory motion tracking with a multi-camera vision system

During radiotherapy, tumors in thorax or abdomen may deviate from the beam because of the physiological or physical influence, such as breathing. Extracorporeal marker is an important substitution to locate the tumors affected by respiratory motion. In this paper, a multi-camera vision system is proposed to track the extracorporeal marker on the model which can simulate respiratory motion. By acquiring the video of the marker, the barycentric coordinates of the markers are obtained. Finally, the 3D coordinate are calculated through calibrating the internal and external parameters of the cameras.