Abstract: The metal magnetic memory technique was used to develop a detection system for the borehole casing pipe.The system collects the magnetic memory signals liberated from the stress concentration zone of the inuse borehole casing pipe,judges fast and correctly the state of the zone.Based on the energy operator Teager of the wavelet coefficients,the energy of the decomposed magnetic memory signals was increased.Using the signal singularity detection theory of the wavelet transform,combining the observation on the multidimensional transform results and the in Russia patented(gradient) technique,the selfadaptive wavelet noise suppression of the signal was realized and the characteristic gradient of the magnetic memory was extracted.The experiment results proved the validity and feasibility of the proposed technique.

Key words: information processing, metal magnetic memory, casing pipe, stress concentration, wavelet analysis