A lossless ECG data compression technique using ASCII character encoding

A software based lossless ECG compression algorithm is developed here. The algorithm is written in the C-platform. The algorithm has applied to various ECG data of all the 12 leads taken from PTB diagnostic ECG database (PTB-DB). Here, a difference array has been generated from the corresponding input ECG data and this is multiplied by a large number to convert the number of arrays into integers. Then those integers are grouped in both forward and reverse direction, out of which few are treated differently. Grouping has been done in such a way that every grouped number resides under valid ASCII value. Then all the grouped numbers along with sign bit and other necessary information are converted into their corresponding ASCII characters. The reconstruction algorithm has also been developed in using the reversed logic and it has been observed that data is reconstructed with almost negligible difference as compared with the original (PRD 0.023%).

Figure optionsDownload as PowerPoint slideHighlights
► Only ECG ‘Voltage’ values are taken.
► Associated information like sign-bit, position of critical numbers are generated.
► ‘Voltage’ values are amplified, grouped and printed in ASCII character.
► Reconstruction process follows the reverse algorithm and regenerates the signal with PRD 0.023%.
► Some standard ASCII compression algorithm can further compress the data and the file may be transmitted over GSM network.