Determining a viewpoint for navigating a virtual camera through a biological object with a lumen

Abstract

A method of orienting a virtual camera for rendering a virtual endoscopy image of a lumen in a biological structure represented by a medical image data set, e.g., a colon. The method comprises selecting a location from which to render an image, determining an initial orientation for the virtual camera relative to the data set for the selected location based on the geometry of the lumen, determining an offset angle between the initial orientation and a bias direction; and orienting the virtual camera in accordance with a rotation from the initial orientation towards the bias direction by a fractional amount of the offset angle which varies according to the initial orientation. The fractional amount may vary according to the offset angle and/or a separation between a predetermined direction in the data set and a view direction of the virtual camera for the initial orientation. Thus the camera orientation can be configured to tend towards a preferred direction in the data set, while maintaining a good view of the lumen and avoiding barrel rolling effects.