Patent ID: 6511418
Filing Date: 2003-01-28
Classification: A61B

Abstract:
Apparatus for use in calibrating lens position and field of view in an endoscope having an elongate shaft and a distal-end lens, comprising:a plurality of tracking elements mounted at fixed positions on the endoscope's shaft, a holder having a guide in which the endoscope can be received to align the endoscope shaft in the holder and position the endoscope lens for viewing a three-dimensional object or pattern contained at a target area in the holder, positional elements mounted on the holder at known positions with respect to the guide and three-dimensional object or pattern, a sensing device for sensing the tracking and positional elements, a display device, and a processor operably connected to the sensing device and the display device for carrying out the following operations: (i) determining the positions of the tracking and positional elements, with the endoscope shaft received in the holder guide, (ii) using the determined positions of the tracking and positional elements to place the endoscope and the holder in a common frame of reference, (iii) projecting on the display device, a video image of the three-dimensional holder object or pattern as seen by the endoscope with the endoscope shaft received in the holder guide, (iv) projecting a model image of the three dimensional object or pattern on the display device, representing the three dimensional object as seen from a known lens position and field of view, and (v) using information about the relative sizes, positions, and orientations of the two images to calculate the coordinates of the endoscope lens with respect to the tracking elements, and the field of the view of the lens.