Elimination of adaptive mono-frequency interference based on cosine function
基于余弦函数的自适应单频干扰消除

There is a strong mono-frequency interference around 50Hz in seismic records when a high-tension line crosses over a seismic line in the process of field seismic data acquisition. This interference has strong energy over whole time period of seismic records, and its frequency, phase and amplitude can be different from the shallow layer to the deep one. But their variations are not much too great, so they can be basically considered to maintain invariable. Adopting suppression method in frequency domain interference and signal have been only suppressed at certain amount simultaneously and the interference has hardly been removed, that is to say, signal-to-noise ratio has not been yet improved in the vicinity of mono-frequency component. So, a technique of the elimination of adaptive mono-frequency interference based on cosine function ( EAMFI ) is proposed to eliminate this interference in the seismic data. The mono-frequency interference is first expressed as a cosine function about frequency, time-lag, and amplitude in time domain, then we estimate the frequency and time-lag of the mono-frequency interference using an adaptive method, and directly compute the amplitude of the mono-frequency interference using the formula of the amplitude computation, as well as the mono-frequency interference wave, finally subtract it from seismic record for the purpose of eliminating the interference wave. The most major advantage of this method is that only interference wave with mono-frequency component has been quickly and effectively eliminated, and useful signal has not been harmed, so the signal-to-noise ratio has been improved in the vicinity of mono-frequency component. We show that this method is feasible and effective through real data examples.