The apparatus and method of the present invention provide a quick, simple and
accurate manner in which to measure the dimensions or characteristics of a hole
without contacting the hole. The apparatus and method of the present invention
also automatically detect different materials defining the hole and, therefore,
the location of the interface where the materials meet. To measure the characteristics
of the hole, the apparatus and method measure the intensities of the light reflected
off the hole wall. In addition, the light directed toward the hole wall by the
optical fiber may be of the type, such as collimated or focused, to provide distinct
reflections that are received and measured by the optical receiver to supply accurate
measurements of the hole characteristics.