US Patent 7517314 Endoscopic imaging with indication of gravity direction

A method for presenting an indicator of the upright orientation of an endoscopic image. An electronic rotation pick-up means is fixed to the housing of an endoscope. The electronic rotation pick-up means produces signals indicating rotations of the endoscope. A microprocessor uses these signals to calculate the difference between the upright image orientation and the actual image orientation. The calculation includes factors to account for endoscope roll, endoscope pitch, and endoscope viewing direction. The upright indicator is displayed on a video display device along with the endoscopic image.