Application of Discrete Cosine Transform for Pre-Filtering Signals in Electrogastrography

Electrogastrography (EGG) is the technique of the cutaneous recording of the myoelectrical activity of the stomach. Due to its noninvasiveness and correlation with the gastric motility it is the attractive complement for imaging stomach’s diagnostic methods. As the EGG signal is the mixture of the electrical activity of the stomach and surrounding organs so the raw EGG also contains the noise, the electrocardiographic (ECG), and the respiration (RESP) signals. The aim of this paper is to present the effective tool for pre-filtering EGG signal. The filtering in the Cosine Discrete Transform (DCT) domain has been proposed as an efficient tool for denoising EGG signal. The obtained results are compared with the outcomes determined by means of the traditional digital (Butterworth, in this case) filtering method.