Device for determining the longitudinal and angular position of a rotationally symmetrical apparatus

摘要

A device for determining the longitudinal and angular position of a rotationally symmetrical apparatus (3) when guided inside a longitudinal element surrounding the same where a spherical object is held in motion-transmitting contact with said apparatus, and including an imaging optical navigation sensor that measures the motion of the underlying surface of said spherical object by comparing successive images. Additional features of the captured images are used to identify the insertion or withdrawal of the instrument, as they cause a displacement of the bead, therefore allowing the determination of the absolute position of the instrument. The device comprises a light source (31) and a light detector (32). Light emitted by said light source (31) is directed onto a surface (101) of a spherical object (100) being in motion-transmitting contact with said rotationally symmetrical apparatus (3). Reflected light from said surface (101) is detected by said light detector (32) to produce a position signal showing a locally varying distribution in the longitudinal direction (110) and in the peripheral direction (112) to enable said precise position and angular measurement.