Sensing device and sensing method

• US 9,995,779 B2
• Filed: 04/28/2015
• Issued: 06/12/2018
• Est. Priority Date: 11/01/2012
• Status: Active Grant

• Current Assignee: Terumo Kabushiki Kaisha
• Original Assignee: Terumo Kabushiki Kaisha
• Inventors: Fukai, Toshio, Matsumoto, Atsushi
• Primary Examiner(s): Dejong, Eric S
• Application Number:
  US14/698,607
• Publication Number:
  US 20150247887A1
• Time in Patent Office: 1,141 Days
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence
• CPC Class Codes: G01N 33/66 involving blood sugars, e.g. galactose
• CPC Class Codes: G01R 29/26 Measuring noise figure; Measuring signal-to-noise ratio

Abstract

The present invention relates to a sensing device and a sensing method for continuously or intermittently quantifying a concentration of analyte. A measurement signal correlated with a concentration of analyte is sequentially acquired by use of a sensor (12). A filter processing is performed on a time sequence of the measurement signal acquired by the sensor (12) in a frequency domain via one type of filter among a plurality of types of filters (48, 49, 84). One type of filter used in the filter processing is switched depending on the amount of temporal change of the measurement signal.

Claims

1. A sensing device for continuously or intermittently quantifying a concentration of an analyte, comprising:

a sensor sequentially acquiring a measurement signal correlated with the concentration of the analyte;

a plurality of filters that perform filter processing on a time sequence of the measurement signal acquired by sensor in a frequency domain, the plurality of filters to eliminate noise components from the measurement signal, the plurality of filters at least comprising;

a first filter;

a second filter;

a filter processing unit, wherein the filter processing unit receives a switch variable from a switch variable computation unit, the filter processing unit comprising;

a switch, electrically coupled between the sensor and the plurality of filters;

wherein the filter processing unit compares the switch variable to a predetermined threshold;

wherein, if the switch variable is greater than the predetermined threshold, the filter processing unit signals the switch to route the measurement signal to the first filter;

wherein, if the switch variable is less than the predetermined threshold, the filter processing unit signals the switch to route the measurement signal to the second filter.

2. The sensing device according to claim 1, wherein the first filter comprises an identity transformation filter for performing identity transformation on a time sequence of the measurement signal, and wherein the switch switches to the identity transformation filter when the switch variable is greater than the predetermined threshold.

3. The sensing device according to claim 1, wherein the first filter has a low average value of an amount of phase delay in a band at a cutoff frequency or less, wherein the second filter has a high average value of an amount of phase delay in a band at a cutoff frequency or less;

wherein the switch switches to the first filter when the switch variable is large; and

wherein the switch switches to the second filter with a high average value of the amount of phase delay when the switch variable is small.

4. The sensing device according to claim 1, wherein the analyte is glucose.

5. The sensing device according to claim 1, wherein the first filter and/or second filter comprises one or more of a low-pass filter, a high-pass filter, a band-pass filter, a band-rejection filter, and an all-pass filter.

6. The sensing device according to claim 1, wherein the first filter and/or second filter comprises a finite impulse response (FIR) filter or an infinite impulse response (IIR) filter.

7. The sensing device according to claim 6, wherein the FR filter comprises five taps.

8. The sensing device according to claim 1, further comprising the switch variable computation unit to compute a switch variable that indicates an amount of temporal change of the measurement signal, wherein the switch variable is a variation trend of the measurement signal based on two or more measurement samples.

9. The sensing device according to claim 1, wherein the threshold is 0.3 [l/min].

10. The sensing device according to claim 1, wherein the first filter and/or second filter applies one of a Butterworth property, a Chebyshev property, an inverse Chebyshev property, and/or an alliance Chebyshev property to a shape of an amplitude property.

11. A sensing method for continuously or intermittently quantifying a concentration of an analyte, comprising:

sequentially acquiring, by a sensor, a measurement signal correlated with the concentration of the analyte;

determining a switch variable that indicates an amount of temporal change of the measurement signal;

comparing the switch variable to a predetermined threshold;

if the switch variable is greater than the predetermined threshold, switching, by a switch, the measurement signal to a first filter to perform filtering on a time sequence of the measurement signal acquired by the sensor in a frequency domain, wherein the first filter removes noise components from the measurement signal; and

if the switch variable is less than the predetermined threshold, switching, by the switch;

the measurement signal to a second filter to perform filtering on a time sequence of the measurement signal acquired by the sensor in a frequency domain, wherein the first filter removes noise components from the measurement signal, wherein the first and second filters are different.

12. The sensing method according to claim 11, wherein the first filter comprises an identity transformation filter for performing identity transformation on a time sequence of the measurement signal, and wherein the switch switches to the identity transformation filter when the switch variable is greater than the predetermined threshold.

13. The sensing method according to claim 12, wherein the first filter has a low average value of an amount of phase delay in a band at a cutoff frequency or less, wherein the second filter has a high average value of an amount of phase delay in a band at a cutoff frequency or less;

wherein the switch switches to the first filter when the switch variable is large; and

wherein the switch switches to the second filter with a high average value of the amount of phase delay when the switch variable is small.

14. The sensing method according to claim 11, wherein the first filter and/or second filter comprises one or more of a low-pass filter, a high-pass filter;

a band-pass filter, a band-rejection filter, and an all-pass filter.

15. The sensing method according to claim 11, wherein the threshold is 0.3 [l/min].

16. The sensing method according to claim 11, wherein the analyte is glucose.

17. The sensing method according to claim 11, wherein any of the plurality of filters may apply one of a Butterworth property, a Chebyshev property, an inverse Chebyshev property, and an alliance Chebyshev property to a shape of an amplitude property.

18. A non-transitory computer readable medium having instructions for performing a method for continuously or intermittently quantifying a concentration of an analyte, the instructions comprising:

instructions for sequentially acquiring, by a sensor, a measurement signal correlated with the concentration of the analyte;

instructions for determining a switch variable that indicates an amount of temporal change of the measurement signal;

instructions for comparing the switch variable to a predetermined threshold;

if the switch variable is greater than the predetermined threshold, instructions for switching, by a switch, the measurement signal to a first filter to perform filtering on a time sequence of the measurement signal acquired by the sensor in a frequency domain, wherein the first filter removes noise components from the measurement signal; and

if the switch variable is less than the predetermined threshold, instructions for switching, by the switch, the measurement signal to a second filter to perform filtering on a time sequence of the measurement signal acquired by the sensor in a frequency domain, wherein the first filter removes noise components from the measurement signal, wherein the first and second filters are different.

19. The computer readable medium according to claim 18, wherein the first filter and/or second filter comprises one or more of a low-pass filter, a high-pass filter, a band-pass filter, a band-rejection filter, an all-pass filter, a finite impulse response filter, an infinite impulse response filter, and/or an identity transformation filter.

20. The computer readable medium according to claim 19, further comprising instructions for computing the switch variable that indicates the amount of temporal change of the measurement signal, wherein the switch variable is a variation trend of the measurement signal based on two or more measurement samples.