Etude, conception et validation d'une technique efficace d'elimination en temps-reel des ECG dans les EMGdi

EMG are electrical signals characterizing the neuromuscular activity of a given muscle. These signals are used for various medical applications such as abnormal muscle function diagnostic and myoelectric prosthesis control.;The main difficulty for EMG using is ECG cancellation. Indeed, the EMG obtained using an electrode is the sum of all motor unit action potentials of a given muscle in the detection area of this electrode. However, the cardiac signal is so powerful that it can be detected by these electrodes. Thus, detected EMG is always contaminated by cardiac artefacts implying a RMS error and making the electrical information obtained from a given muscle less accurate. A simple filter can not eliminate this contamination because the spectra of EMG and ECG overlap. Thus, there is a need for a complex filter to obtain easily exploitable results. However, two more difficulties appear when the EMG signal is used for prosthesis control or for mechanical ventilation. The first difficulty is obtaining EMG signals which can be used directly in real-time because, in this case, ECG cancellation should be done in real-time. The second difficulty is automatic detection of muscular activity using these signals because this operation needs the use of an complex algorithm to detect EMG activation and deactivation.;In order to find efficient solutions for the previous difficulties, this project present a new solution that was developed in three steps.;The first step is a comparison of techniques for ECG cancellation in EMG signals already proposed. This comparison is made to choose the most powerful and suitable technique for real-time applications. The existing techniques will be compared to identify the technique that can operate in real-time and automatically. Thereafter, the identified techniques will be adapted for EMGdi and compared using a LabView software to choose the most efficient method. A comparison of muscular activity detection methods will also be made in order to present the advantages and disadvantages of each method.;Recently, the diaphragmatic electromyogram signals (EMGdi) were used increasingly and several research dealt with the use of EMGdi in classical medical applications such as diagnostic of respiratory diseases or innovative applications such as control of mechanical ventilation.;In a second part, the method that was chosen in the previous step will be validated in a hardware system. This validation will be done using a system based on two microcontrollers. Thereafter, an architecture implementing the chosen method will be proposed and implemented in VHDL.;Finally, a new method based on the chosen technique will be proposed and its performance will be evaluated compared to current methods. A global method combining ECG cancellation and muscular activity detection will also be proposed.;The LabView software, the system based on microcontrollers, the VHDL implementation and the global method are working correctly.