THZ MEASUREMENT METHOD AND THZ MEASUREMENT DEVICE FOR SURVEYING A MEASUREMENT OBJECT, IN PARTICULAR A PIPE

摘要

The invention relates to a THz measurement method for surveying a measurement object (6), for example a pipe made of plastic or rubber, comprising - a calibration step of measuring an unbroken time of flight of at least one THz emission beam through an empty run length between a first measurement position (MP1) and a second measurement position (MP2) of a measurement area (4) without the measurement object (6) and ascertaining the empty run length (sO), - positioning a measurement object (6) in the measurement area (4) between measurement positions (MP1, MP2), - performing a first THz measurement from the first measurement position (MP1) with a THz emission beam (20-1) along a first optical axis (A) while measuring a first external time of flight (tL1) to an outer surface (6a) of the measurement object (6), a first wall time of flight (tR1) through a first wall area of the measurement object (6) and an internal time of flight (tL2, tL2_1) through an interior (6c) of the measurement object, - performing a second THz measurement from the second measurement position (MP1) along a second optical axis (A) while measuring a second external time of flight (tL3) between the second measurement position (MP2) and the outer surface (6a) of the measurement object (6) and a second wall time of flight (tR2) through a second wall area of the measurement object (6) - ascertaining an overall time of flight (tges_R) through the measurement area (4) containing the measurement object, and - ascertaining a first wall thickness (sR1) of the first wall area and a second wall thickness (sR2) of the second wall area from the measured times of flight (St7).