Local entropy difference-fast marching method for leak diagnosis and localization

In this paper, an effective technique for leak diagnosis and localization which couples the local entropy difference method (LEDM) to the fast marching method (FMM) is proposed. A computer-based system is described to combine a specific pneumatic circuit with an on-line infrared camera which is used to test the air-tightness of a test vessel. The test object is charged with cryogenic compressed air and its temperature field is acquired by infrared thermography in this system. Then, both the leakage point and its edge can be identified by means of the designed LED-FM method. An experiment is conducted that confirms that the leak diagnosis and localization method presented in this paper is effective in diagnosing leakage points and in extracting accurate leakage edges, in spite of the presence of surface defects.