A method capable of digitising every type of biosignal paper recordings as a tool for database improvement

Most medical systems allow the printing of biomedical signals onto grid paper. This is used routinely in patient examination, diagnosis and medical history documentation. There are some commercial programs that are able to digitise these biosignals into electronic records, although they are usually restricted to work with only one commercial format. We propose an alternative program capable of recognising and digitising any kind of biosignal paper records, grids, large strips and different speeds by means of an easy procedure. This system is very useful for clinical applications and mainly for improving biosignal databases that allow us to face future studies which would be impossible without this method. The method consists of scanning the biosignals plotted on the paper as an image (BMP files). These records are later processed with proper software, which allows to eliminate the grid lines and all the possible noise present on the paper leaving only the plotted signal. This signal is then converted into numerical values according to a sample rate. The results of this process are ECG or EGM signals ready to be included in a database. We have mainly worked on electrocardiograms, electrograms and blood pressure signals, in collaboration with the Hospital Clinico de Valencia whose doctors have validated the results of this method.