| 摘要 |
<p>The present invention relates to a method to accurately inspect the inner wall of a closed tank which is large like a liquefied natural gas (LNG) storage tank. A camera is put into a tank through an inlet arranged on the top of the tank to acquire a first image. After the time is passed in the state, the camera is put in the tank again to acquire a second image. The first and second images are compared to each other to extract a difference and to output an alarm through a screen or a speaker if the difference is greater than a predetermined criterion. If the rephotographing command of a user is applied, an image part which a user selects is rephotographed in a state where a height and a photographing direction of the camera is changed and then is displayed on the screen. The present invention can accurately and reliably find cracks, deteriorations, and other signs of damage to be generated on the inner wall of an LNG storage tank by comparing an inner wall image of the entire inner wall of the tank and an inner wall image obtained before when the inner wall of the closed tank which is large like the LNG storage tank.</p> |
