Fig. 1

Steps of the proposed CV estimation algorithm. a 150-ms segment of a 7-channel synthetic S-EMG signal (without IZ). The horizontal axis represents time, and the vertical axis represents both channel number (i.e., spatial position along the electrode array) and signal amplitudes (scaled to the \([-1,+1]\) range). b Image representation of the multichannel S-EMG signal shown in (a). Bi-cubic interpolation was applied along the temporal (two-fold) and spatial (100-fold) axes. The aspect ratio was changed for display purposes only. c Hermite-filtered image. Note that the conduction lines are softer and have been highlighted from the background. d Segmented (and cropped) image. The slope of each of the segmented lines provides the CV of one MUAP. The mean CV may then be calculated for the segment