How to eliminate noise as well as preserve the effective information of signal is always a hotspot in nondestructive detection signal processing research. The single channel ultrasonic detection signal is attempted to expand to array signals by constructing a virtual observation signal, and then wave atoms method is used to realize noise reduction. The non-local means algorithm for smoothing is introduced to suppress Gibbs-like phenomena, which may be caused by the wave atoms hard threshold filtering. This algorithm is used on the simulation signal and the ultrasonic detection signal of a calcium carbonate fouling layer, and is compared with the wavelet threshold denoising. Results show that the method used in this paper has better effect on increasing the signal noise ratio, maintaining effective characteristics and weak signal.