A method and device for determining a breathing movement of an object under examination is provided for the method includes determining a breathing movement of an object under examination and includes receiving a mathematical breathing model, the mathematical breathing model including a displacement of a thoracic cage of the object under examination over time, using a projection means to project a structured image pattern onto a sagittal plane and onto a thoracic region of the object under examination, using a camera to record a sequence of at least two images of the thoracic region of the object under examination, and adapting the mathematical breathing model at least in dependence on the recorded sequence of images of the thoracic region of the object under examination. The invention also describes a corresponding device for determining a breathing movement of an object under examination.
