System and method for smoothing sampled digital signals
First Claim
Patent Images
1. An implantable medical device (IMD) comprising:
- a memory;
an analog to digital converter (ADC) configured to receive an analog waveform and sample the waveform into digitized data;
a smoothing filter configured to process the sampled signal and classify each data point into a first type or a second type and to apply a smoothing function to the first type of classified data and to retain a sampled valued for the second type of classified data;
a predictive encoding module operatively coupled with the ADC to generate an encoded waveform data point for each of an equivalent data point from a subset of the digitized data; and
an entropy encoding module operatively coupled with the predictive encoder and configured to selectively replace an encoded waveform data point with a codeword for that data point; and
wherein the smoothing filter is configured to determine variability between sampled data points adjacent to a given data point being classified and classifying the given data point into the first type if the variability is less than a predetermined variability value and into the second group if the variability is equal to or greater than the predetermined variability value.
1 Assignment
0 Petitions
Accused Products
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.
-
Citations
6 Claims
-
1. An implantable medical device (IMD) comprising:
-
a memory; an analog to digital converter (ADC) configured to receive an analog waveform and sample the waveform into digitized data; a smoothing filter configured to process the sampled signal and classify each data point into a first type or a second type and to apply a smoothing function to the first type of classified data and to retain a sampled valued for the second type of classified data; a predictive encoding module operatively coupled with the ADC to generate an encoded waveform data point for each of an equivalent data point from a subset of the digitized data; and an entropy encoding module operatively coupled with the predictive encoder and configured to selectively replace an encoded waveform data point with a codeword for that data point; and
wherein the smoothing filter is configured to determine variability between sampled data points adjacent to a given data point being classified and classifying the given data point into the first type if the variability is less than a predetermined variability value and into the second group if the variability is equal to or greater than the predetermined variability value.
-
-
2. A method comprising:
-
obtaining sampled data; defining an adjustment set of data points for each given data point; determining a value for variability in the adjustment set; and smoothing the given data point relative to the adjustment set responsive to the determined variability being below a predetermined maximum; wherein the adjustment set includes the given data point, a first data point immediately preceding the given data point and a second data point immediately subsequent to the given data point; wherein determining variability includes measuring a difference in a value between each data point within the adjustment set; and wherein determining variability includes adding a first absolute value of a difference between the first data point and the given data point and a second absolute value of a difference between the second data point and the given data point.
-
-
3. A method comprising:
-
obtaining sampled data; defining an adjustment set of data points for each given data point; determining a value for variability in the adjustment set; and smoothing the given data point relative to the adjustment set if the determined variability is below a predetermined maximum, wherein smoothing the given data point includes averaging the adjustment set and setting a value of the given data point for subsequent encoding equal to the average value; and further comprising predicatively encoding the sampled data subsequent to selectively smoothing the data; and further comprising selectively providing entropy encoded codewords for the predicatively encoded data based upon a truncated entropy codeword set. - View Dependent Claims (4, 5, 6)
-
Specification