Multichannel ECG Compression Using Cross-Channel Predictive Coding

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Solution Overview

Problem

Current methods for compressing multichannel electrocardiogram (ECG) signals face challenges in achieving high compression ratios while maintaining losslessness, due to power consumption constraints in portable devices and the need for compliance with medical norms that restrict distortion.

Innovation Solution

A method for lossless compression of multichannel ECG signals using a combination of delta encoding, in-channel and cross-channel predictive encoding, and entropy coding, which reduces statistical redundancy and allows for efficient data representation with low computational complexity, suitable for portable devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If lossless compression methods are used to maintain data quality for medical diagnosis, then the compression ratio is limited and computational complexity increases, but if simple compression methods are used, then computational complexity decreases but compression efficiency is insufficient

Engineering Contradiction:
Improvedata qualityVSAvoidcomputational complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The compression method segments the ECG signal processing into distinct stages: delta encoding to remove baseline drift, linear predictive coding to exploit temporal redundancy, and entropy coding to achieve final compression. This segmentation allows each stage to be optimized independently, maintaining lossless compression while managing computational complexity through modular processing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The method applies preliminary delta encoding and linear predictive coding before final entropy coding. By performing preliminary compression stages that remove obvious redundancies first, the subsequent entropy coding operates on already simplified data, reducing the overall computational burden while maintaining lossless compression ratios.

Inventive Principle:
Principle #10Preliminary action

2Loss of information

If advanced compression algorithms are used to achieve high compression ratios, then compression efficiency improves, but power consumption increases which is unacceptable for portable devices

Engineering Contradiction:
Improvecompression ratioVSAvoidpower consumption
Core Design Contradiction:
Loss of informationVSUse of energy by moving object

Solution Approach 1:

The patent replaces complex mechanical signal processing with efficient digital algorithms. Specifically, it substitutes heavy computational methods with lightweight linear predictive coding and entropy coding techniques that achieve high compression ratios with minimal power consumption, suitable for battery-powered portable ECG devices.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The method changes the parameter representation of ECG signals by transforming time-domain signals into prediction residuals and entropy-coded bitstreams. This parameter transformation enables compact representation with fewer bits while maintaining diagnostic quality, reducing the energy required for data transmission and storage in portable devices.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If multiple ECG channels are processed simultaneously to provide redundancy for reliable diagnosis, then reliability improves, but the data volume and processing complexity increase

Engineering Contradiction:
Improvediagnostic reliabilityVSAvoidprocessing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the processing of multiple ECG channels by applying the same compression algorithm suite (delta encoding, linear predictive coding, entropy coding) to each channel simultaneously. This unified approach processes multiple channels through a single standardized pipeline, reducing overall system complexity while maintaining the diagnostic reliability benefits of multichannel redundancy.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3764548B1Method, computer program, and computer system for lossless compression of a multichannel electrocardiogram signal
Publication Date: 2023.08.23 COMARCH HEALTHCARE SPOKA AKCYJNA
  • EP3764548B1 patent drawingFigure 1
  • EP3764548B1 patent drawingFigure 2
  • EP3764548B1 patent drawingFigure 3

AI summary

The object of the invention is a method for lossless compression of a multichannel electrocardiogram signal carried out by a computer system. The method comprises encoding (1), predictors training (2), decoding (3). Encoding (1) comprises: delta encoding (10) and overflow prevention (11) of an electrocardiogram signal from each channel, detecting heartbeats, entropy coding (14) with the use of a variance of a prediction error, multiplexing (15) encoded signals from multiple channels into sequence of symbols. The invention is characterized in: in-channel predictive encoding (12) using the provided in-channel predictor coefficients, separate for heartbeats and background components of the electrocardiogram signal, cross-channel predictive decoding (13) using the provided tree of dependencies and cross-channel predictor coefficients. Parameters of prediction and entropy coding are obtained during predictors training (2) for blocks with predefined length of electrocardiogram signal from at least one channel