Profilometry of a gastrointestinal surface by an endoscope with laser beam projection.

An active triangulation method that uses an endoscope with laser beam projection is proposed for measuring the profile of a gastrointestinal surface. When a laser beam is projected onto an object surface in a given direction, the coordinates of the beam spot in an endoscope image are uniquely related to the distance from the endoscope to the surface. This relation is investigated experimentally, and the results are presented in a look-up table. By calibration of the image with this look-up table, a profile measurement with high precision is realized. Results of experiments with both a test object with known dimensions and a sample extracted from a real stomach are described.