Fig. 6From: Respiratory level tracking with visual biofeedback for consistent breath-hold level with potential application in image-guided interventionsProne position. Superimposed graphs of mean depth, measured by the Kinect (blue, left axis) and volume, measured with spirometry (red, right axis) of a volunteer in prone position. Periods of breath-hold are indicated with grey boxes. FRC functional residual capacity, VT tidal volumeBack to article page