Signal compression based on curvature parameters
First Claim
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1. A system comprising:
- an input circuit adapted to receive a sampled signal;
a controller coupled to the input circuit and programmed to;
generate a curvature series as a function of the sampled signal, the curvature series corresponding to a curvature signal;
identify lobes in the curvature series, the lobes each corresponding to a portion of the curvature signal starting when the curvature signal crosses a first threshold in one direction and ending when the curvature signal crosses a second threshold in an opposite direction;
calculate an area for each lobe of the identified lobes between the portion of the curvature signal corresponding to the each lobe and a baseline;
identify a parameter of the each lobe if the area of the each lobe is greater than a predetermined value; and
generate a characteristic point including a time of the parameter and an amplitude corresponding to the time of the parameter; and
a memory coupled to the curvature series generator and adapted to store the characteristic points generated by the controller.
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Abstract
For a sampled signal, storing characteristic points generated based on parameters corresponding to curvature of the signal. The characteristic points include a time of occurrence of a lobe in a curvature series based on the signal and a corresponding amplitude of the signal. The characteristic points provide a compressed version of the sampled signal. The signal is reconstructed by establishing a function between a chronological sequence of characteristic points. For a repetitive signal, the stored data includes a code to indicate a time of reoccurrence of a previous cycle or data corresponding to differences between a previous cycle and a current cycle.
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Citations
21 Claims
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1. A system comprising:
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an input circuit adapted to receive a sampled signal; a controller coupled to the input circuit and programmed to; generate a curvature series as a function of the sampled signal, the curvature series corresponding to a curvature signal; identify lobes in the curvature series, the lobes each corresponding to a portion of the curvature signal starting when the curvature signal crosses a first threshold in one direction and ending when the curvature signal crosses a second threshold in an opposite direction; calculate an area for each lobe of the identified lobes between the portion of the curvature signal corresponding to the each lobe and a baseline; identify a parameter of the each lobe if the area of the each lobe is greater than a predetermined value; and generate a characteristic point including a time of the parameter and an amplitude corresponding to the time of the parameter; and a memory coupled to the curvature series generator and adapted to store the characteristic points generated by the controller. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An implantable medical device, comprising:
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an input circuit to receive a sampled cardiac signal; a controller coupled to the input circuit wherein the controller is programmed to; generate a curvature series as a function of the sampled signal, the curvature series corresponding to a curvature signal; identify lobes in the curvature series, the lobes each corresponding to a portion of the curvature signal starting when the curvature signal crosses a first threshold in one direction and ending when the curvature signal crosses a second threshold in an opposite direction; calculate an area for each lobe of the identified lobes between the portion of the curvature signal corresponding to the each lobe and a baseline; and generate a plurality of characteristic points as a function of the curvature series, each characteristic point of the plurality of characteristic points associated with a lobe of the identified lobes that has an area greater than a predetermined value and including a time component corresponding to a time of occurrence of the lobe and an amplitude component of the sampled cardiac signal at the time of the occurrence; and a memory coupled to the controller and adapted to store each characteristic point of the plurality of characteristic points. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification