ELECTROCARDIOGRAM SIGNAL COMPRESSION AND DE-COMPRESSION SYSTEM
First Claim
1. An electrocardiogram signal compression system includes:
- a normalization device for receiving N electrocardiogram signals and performing normalization operation on the N electrocardiogram signals to generate N normalized signals, where N is a positive integer;
a discrete cosine transform device connected to the normalization device for receiving the N normalized signals and performing discrete cosine operation to generate N discrete cosine signals;
an absolute vale and quantization device connected to the discrete cosine transform device for receiving N discrete cosine signals and performing absolute value operation and quantization operation to generate N quantized amplitude signals;
a difference coding device connected to the absolute vale and quantization device for receiving the N quantized amplitude signals and performing differential pulse code modulation (DPCM) on the N quantized amplitude signals to generate N difference signals;
a first variable length coding device connected to the difference coding device for performing variable length coding operation on the N difference signals to generate a first data stream;
a sign and difference device connected to the discrete cosine transform device for receiving the N discrete cosine signals and recoding signs of the N discrete cosine signals, so as to generate three sign signals;
a second variable length coding device connected to the sign and difference device for performing variable length coding operation on the three sign signals to generate a second data stream; and
a mixer connected to the first variable length coding device and the second variable length coding device for mixing the first data stream and the second data stream to generate a compressed electrocardiogram data stream.
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Accused Products
Abstract
The invention provides an electrocardiogram signal compression and de-compression system. The invention uses the sign characteristics of the coefficients of the discrete cosine transform type IV and the characteristics of quantization of spectrum to perform the differential pulse code modulation of the spectrum for preserving the high frequency characteristics of the spectrum of the discrete Fourier transform. The invention also uses the Huffman coding to increase the compression ratio. Different from the conventional compression technology, the invention uses the fact that the quantization values of the spectrum in the high frequency are almost the same to increase the compression ratio and preserve the characteristics of high frequency components of the spectrum.
112 Citations
16 Claims
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1. An electrocardiogram signal compression system includes:
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a normalization device for receiving N electrocardiogram signals and performing normalization operation on the N electrocardiogram signals to generate N normalized signals, where N is a positive integer; a discrete cosine transform device connected to the normalization device for receiving the N normalized signals and performing discrete cosine operation to generate N discrete cosine signals; an absolute vale and quantization device connected to the discrete cosine transform device for receiving N discrete cosine signals and performing absolute value operation and quantization operation to generate N quantized amplitude signals; a difference coding device connected to the absolute vale and quantization device for receiving the N quantized amplitude signals and performing differential pulse code modulation (DPCM) on the N quantized amplitude signals to generate N difference signals; a first variable length coding device connected to the difference coding device for performing variable length coding operation on the N difference signals to generate a first data stream; a sign and difference device connected to the discrete cosine transform device for receiving the N discrete cosine signals and recoding signs of the N discrete cosine signals, so as to generate three sign signals; a second variable length coding device connected to the sign and difference device for performing variable length coding operation on the three sign signals to generate a second data stream; and a mixer connected to the first variable length coding device and the second variable length coding device for mixing the first data stream and the second data stream to generate a compressed electrocardiogram data stream. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An electrocardiogram signal de-compression system includes:
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a parser device for receiving a compressed electrocardiogram data stream and analyzing the compressed electrocardiogram data stream, so as to generate a first data stream and a second data stream; a first variable length decoding device connected to the parser device for performing variable length decoding operation on the first data stream to generate N difference signals, where N is a positive integer; a difference decoding device connected to the first variable length decoding device for receiving the N difference signals and performing differential pulse code modulation (DPCM) operation on the N difference signals to generate N quantized amplitude signals; an inverse quantization device connected to the difference decoding device for receiving the N quantized amplitude signals and performing inverse quantization operation to generate inverse quantization signals of N discrete cosine signals; a second variable length decoding device connected to the parser device for performing variable length decoding operation on the second data stream to generate three sign and difference signals; a restored difference and sign prediction device connected to the second variable length decoding device for receiving the three sign and difference signals and performing restored difference and sign prediction operation to generate signs of the N discrete cosine signals; an inverse discrete cosine transform device connected to the inverse quantization device and the restored difference and sign prediction device for receiving the inverse quantization signals of the N discrete cosine signals and the signs of the N discrete cosine signals to generate the N discrete cosine signals, and performing inverse discrete cosine operation on the N discrete cosine signals so as to generate N normalized signals; and an inverse normalization device connected to the inverse discrete cosine transform device for receiving the N normalized signals and performing inverse normalization operation on the N normalized signals to generate N electrocardiogram signals. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification