A device (10) for processing data (3), which were obtained from a medical device suitable for imaging the lungs or the thorax, particularly an electrical impedance tomography device (30), provides improved visualization of a three-dimensional thoracic dimension (350) of the lungs. A characteristic contour (34, 350) is determined continuously by continuous reference to a previously determined outer contour (905) of the lungs as a comparison variable and is outputted, provided and visualized as an output signal (35).
