PURPOSE: To judge the width and the depth of a defect and to enhance the detecting accuracy by estimating the actual width and the depth of the object surface of the defect in the same direction based on the temperature distribution in the direction of the object surface which is obtained with the temperature signal from an infrared- ray radiometer.
CONSTITUTION: A running truck 3 is provided on the roof of a building 1 in order to heat an outer wall 1A. A gondola 7 is suspended through a winch 5 and a piece of wire 6 which are provided at the tip of an arm 4 extending from the truck 3. A hot-gas blowing means 8 is provided at the gondola 7. In this constitution, the suspending position of the gondola 7 and the position of the running truck 3 are adjusted. The height and the position of the horizontal direction of the gondola 7 are set. The surface of the outer wall 1A is heated with the hot-gas blowing means 8. The observing direction of an infrared-ray radiometer 2 is made to agree with the part of the outer wall 1A. The infrared-ray radiant energy from the part is detected. The detected signal is analyzed with an image analyzing device 20. The presence or absence of the defective part or its place in the region of the outer wall 1A is judged. The width and the depth of the defect can be also estimated.
ITO TOMOHISA
OWA IKU
