帧间差值的DCT压缩ECG数据的方法

A Compression Method for ECG Based on DCT of Difference between Two Adjacent Frames

心电图 ( ECG)信号具有准周期性 ,各个心动周期 (称其为帧 )的 ECG波形极为相似 ,将相邻两帧的 ECG波形数据相减 ,得到差值数据的波形比原始 ECG波形平坦、数据值小 ,差值数据的DCT有效分量更为集中在低频段 ,且这些分量的幅度较低 ,由此 ,可以得到更高的数据压缩比。因此本文提出了一种利用 ECG帧间差值代替原始 ECG信号进行 DCT变换 ,并用双码长编码方法对 DCT分量进行编码的数据压缩方法。用该方法得到的重构 ECG波形具有良好的保真度。

Since most of the DCT coefficients of an initial ECG signal are spread in low frequency,so is the energy of the signal, we can get a higher compression ratio(CR) by distributing DCT coefficients in a smaller region of low frequency and by degrading the amplitude of main DCT coefficients. ECG is a quasi periodic signal with strong correlation between adjacent frames, so the difference sequence between them is more smooth and has lower amplitudes. Based on this property, a method of ECG data compression via DCT is presented in this paper, and it replaces the DCT coefficients of the original signal with the DCT coefficients of difference between two adjacent frames of the original signal and the DCT coefficients are encoded into two kinds of codes with different lengths. The quality of the reconstructed signal got by this way is high.