Digitization and Synchronization Method for Electrocardiogram Printouts

A method of digitization and synchronization of ECG signals for use in vectorcardiography is hereby presented. It is intended to allow the computerized use of the ECG printout used by most cardiologists. The problem is solved by digitizing the printout, which can then be used for vectorcardiography and other modern techniques, once it is synchronized using cross-correlation. Cross-correlation was found to be a superior technique for synchronization over other methods, like R-peak synchronization that can be erroneously used, due to time correspondence. The highest and lowest normalized rms error of the digitized and original signals was found to be 13.49% and 9.85% for recording V1 and Lead III, respectively. The error found was expected because of the comparison of an image with many points in a single instant of time, in comparison to only one point as it is in a digital signal. The result obtained from the work presented here is that the ECG printout needs no longer to remain only as a graphical report, but could also be used for computerized analyses.