Measurement device, portable electronic instrument, and measurement method

• US 6,023,662 A
• Filed: 08/25/1997
• Issued: 02/08/2000
• Est. Priority Date: 10/18/1995
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group), Seiko Instruments Incorporated (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group), Seiko Instruments Incorporated (Seiko Group)
• Inventors: Hayakawa, Motomu, Nakamura, Chiaki
• Primary Examiner(s): Assouad, Patrick
• Assistant Examiner(s): VO, HIEN XUAN
• Application Number:
  US08/849,877
• Time in Patent Office: 897 Days
• Field of Search: 702/75, 600/500, 600/587, 600/503, 600/483
• US Class Current: 702/75
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6831 Straps, bands or harnesses

Abstract

In a measurement device and a measurement method for determining output values by analyzing the frequency of cyclically changing detection data, such as pulse count, the output value indicating a peak in the analysis result is corrected using side lobe values that appear on both sides of said peak, and an output value having higher precision than the output value indicating the peak value is derived, such that a value closer to the original output value of the detection data can be obtained. Because the measurement device and measurement method according to the invention can improve the precision of the output value without increasing the sampling count, highly precise output values such as pulse counts can be obtained at high speeds without extending the data fetch time.

Claims

1. A measurement device comprising:

analysis means for analyzing a frequency of cyclically changing detection data obtained from a sensor and for producing an analysis result as digital data having a first resolution; and

derivation means for deriving one of a cycle and a frequency as an output value based on the analysis result from said analysis means,

wherein said derivation means corrects the output value indicating a peak value in the analysis result using a side lobe value that appears adjacent to and on at least one side of said peak, and derives the output value of the detection data at a second resolution that is higher than the first resolution.

2. A measurement device according to claim 1, wherein said derivation means comprises:

correction direction determination means for selecting one of a first and second side lobe values used for correction by said derivation means by comparing magnitudes of the first lobe value, the second lobe value, and the peak value; and

correction magnitude calculation means for determining a correction magnitude by comparing the magnitude of the peak value with the magnitude of the selected one of the first and second side lobe values selected by said correction direction determination means and for correcting the output value indicating the peak value.

3. A measurement device according to claim 2, wherein said correction magnitude calculation means uses a digital value approximate a mesial magnitude of the first resolution as a maximum of the correction magnitude, and wherein said correction magnitude calculation means then calculates the correction magnitude using a predetermined function to convert a ratio of the magnitude of the selected one of the first and second lobes selected by said correction direction determination means.

4. A portable electronic instrument having a sensor that can detect cyclically changing data, said portable electronic instrument comprising:

a control device for processing signals from the sensor, said control device comprising an analyzer for analyzing a frequency of the cyclically changing data detected by said sensor and for producing an analysis result as digital data having a first resolution, and a deriving device for deriving one of a cycle and a frequency as an output value from the analysis result, wherein said deriving device corrects the output value indicating a peak value in the analysis result using a side lobe value that appears adjacent to and on at least one side of said peak, and wherein said deriving device derives the output value of the detection data having a second resolution that is higher than the first resolution; and

a display device that can display the output from said control device.

5. A method for measuring of cyclically changing detection data comprising the steps of:

(a) analyzing a frequency of the cyclically changing detection data and producing an analysis result as digital data having a first resolution; and

(b) deriving one of a cycle and frequency as an output value based on the analysis result from step (a) and correcting the output value indicating a peak value in the analysis result, using a side lobe value that appears adjacent to and on at least one side of said peak, and deriving the output value of the detection data at a second resolution that is higher than the first resolution.

6. A method according to claim 5, wherein step (b) further comprises the steps of:

(c) selecting one of a first and second side lobe values used for correction by comparing magnitudes of the first lobe value, the second lobe value, and the peak value; and

(d) determining a correction magnitude by comparing the magnitude of the peak value with the magnitude of the selected one of the first and second side lobe values selected and for correcting the output value indicating the peak value.

7. A method according to claim 6, wherein step (c) further comprises the steps of:

using a digital value approximate a mesial magnitude of the first resolution as a maximum of the correction magnitude; and

then calculating the correction magnitude using a predetermined function to convert a ratio of the magnitude of the selected one of the first and second lobes.

8. An apparatus for measuring cyclically changing detection data comprising:

frequency analyzer for performing a frequency analysis of the cyclically changing detection data to obtain frequency analysis data having a first resolution;

peak detector for detecting a peak value of the frequency analysis data obtained by said frequency analyzer;

correction direction determination means for determining whether a correction direction is one of (1) less than the peak value, and (2) at least the peak value; and

correction magnitude calculation means for determining a correction magnitude by comparing the intensity of said peak with that of the correction direction in accordance with said correction direction determination means and then corrects said output value indicating said peak to obtain a corrected peak value having a second resolution greater than the first resolution.

9. An article of manufacture, comprising:

a computer readable medium having computer readable code storage means embodied therein for measuring cyclically changing detection data, the computer readable code storage means comprising;

computer readable program code for performing a frequency analysis of the cyclically changing detection data to obtain frequency analysis data having a first resolution;

computer readable program code for determining a peak of the frequency analysis data;

computer readable program code for determining whether a correction direction is one of (1) less than the peak, and (2) at least the peak; and

computer readable program code for determining a correction magnitude by comparing the intensity of said peak with that of the correction direction and then corrects said output value indicating said peak to obtain a corrected peak value having a second resolution greater than the first resolution.