Bio-Potential Signal Extraction from Multi-Channel Paper Recorded Charts

Problem statement: Almost all of the modern biomedical equipments that record the biopotential actions have digital output but the paper chart records are a must. The volume of these records is significant and increasing rapidly. Keeping a bio-signal chart of a patient make it easy for quick assessment but still create problems in the essence of data storage, archiving , data interchange and communications. Approach: As a solution to all these problems is to convert these paper records to digital form. In this study, a method for bio-potential signal extraction from single or multi-channel paper recorded charts using image processing techniques is developed. Results: After scanning the paper charts and converting them into images using a commercial scanner, the developed algorithm is applied to eliminate the background of the scanned paper chart from any recording device single channel or multi-channel using binary neighborhood morphological operations then converting the extracted waveform image into quantized values representing the waveform recorded paper chart. The extracted signal is then filtered to remove the high frequency effects that result from the morphological operations. A correlation and frequency analysis procedure is then conducted to verify the result against known sampled waveform. Conclusion: A chart paper conversion to digital values that represent only the values for the biopotential waveform and eliminating the other irrelevant information has been achieved. These resulted in a less space occupation of patient records and make it easy for data further processing and manipulations.