System and method for annotating and compressing waveform data
First Claim
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1. A method of storing data for an implantable medical device (IMD), the method comprising:
- digitizing values of a physiologic waveform to obtain data points, wherein the sampled data points make up a sampled data set;
providing a truncated entropy encoding codeword set in the device for probable data values and including a prefix codeword indicating that a predetermined amount of data following the prefix codeword is unencoded;
assigning a data point value to an exit code, wherein the exit code indicates that a predetermined amount of data following the exit code is annotation data;
employing the device to parse the sampled data set of the waveform to select ones of the data points and replace the selected ones of the data points with codewords;
employing the device to analyze the waveform to identify an occurrence of one or more predetermined events;
storing the codewords and those ones of the data points which were not replaced with codewords in the device;
employing the device to annotate the stored data if one or more of the predetermined events occurs, wherein the annotation includes storing the prefix codeword, followed by the exit code, followed by the annotation data at a point in time of the occurrence if a codeword is expected and storing the exit code followed by the annotation data at the point of time of the occurrence if a codeword is not expected; and
employing a transceiver to telemeter the stored data out of the implanted medical device.
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Abstract
Waveforms are digitally sampled and compressed for storage in memory. The compression of the data includes generating a truncated entropy encoding map and using the values within the map to obtain good compression. An encoder further sub-selects values to be encoded and values to remain unencoded to provide an overall compression of the data.
30 Citations
16 Claims
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1. A method of storing data for an implantable medical device (IMD), the method comprising:
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digitizing values of a physiologic waveform to obtain data points, wherein the sampled data points make up a sampled data set; providing a truncated entropy encoding codeword set in the device for probable data values and including a prefix codeword indicating that a predetermined amount of data following the prefix codeword is unencoded; assigning a data point value to an exit code, wherein the exit code indicates that a predetermined amount of data following the exit code is annotation data; employing the device to parse the sampled data set of the waveform to select ones of the data points and replace the selected ones of the data points with codewords; employing the device to analyze the waveform to identify an occurrence of one or more predetermined events; storing the codewords and those ones of the data points which were not replaced with codewords in the device; employing the device to annotate the stored data if one or more of the predetermined events occurs, wherein the annotation includes storing the prefix codeword, followed by the exit code, followed by the annotation data at a point in time of the occurrence if a codeword is expected and storing the exit code followed by the annotation data at the point of time of the occurrence if a codeword is not expected; and employing a transceiver to telemeter the stored data out of the implanted medical device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An implantable medical device (IMD) comprising:
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means for digitizing values of a physiologic waveform to obtain data points wherein the data points make up a sampled data set; means for truncated entropy encoding comprising a codeword set for probable values of the data points and for including a prefix codeword indicating that a predetermined amount of data following the prefix codeword is unencoded, and for including an exit code assigned to a data point value, wherein the exit code indicates that a predetermined amount of data following the exit code is annotation data; means for parsing a sampled data set of the waveform and selecting ones of the data points and for replacing the selected ones of the data points with codewords and for storing the codewords and un-selected ones of the data points as stored data; means for analyzing the waveform to identify an occurrence of one or more predetermined events; means for annotating the stored data if one or more of the predetermined events occurs, wherein the annotation includes storing in the storing means the prefix codeword, followed by the exit code, followed by the annotation data at a point in time of the occurrence if a codeword is expected and storing the exit code followed by the annotation data at the point of time of the occurrence if a codeword is not expected; and transceiver means for telemetering the stored data out of the implanted medical device. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification