METHOD OF DECIDING DEGREE OF PROXIMITY OF STRUCTURE BY RADIANT ENERGY

摘要

PURPOSE: To obtain a method for accurately deciding the approaching degree and dimensional shape of a nonconductive structure by using an eddy current probe. CONSTITUTION: A portable target medium 11 is moved to a predetermined position to a nonconductive structure. The medium 11 has a conductive material strongly coupling to a varying magnetic field. An eddy current probe for generating the field is moved to the position to generate a signal representing the magnitude of the mutual action of the field and the medium 11, and a distance between the probe from such a signal and the medium 11 is calculated. When such a method is used, the approaching degree of the structure made of plastic tube embedded under the ground can be decided, and the dimensional shape of the structure can be decided. The dimensional shape of the structure can not only be decided, but also the dimensional shape of the structure can also be measured when the medium contains strong magnetic material.