Signal processing method and apparatus

• US 5,379,238 A
• Filed: 07/30/1992
• Issued: 01/03/1995
• Est. Priority Date: 03/03/1989
• Status: Expired

• Current Assignee: Edward W. Stark
• Original Assignee: Edward W. Stark
• Inventors: Stark, Edward W.
• Primary Examiner(s): Voeltz, Emanuel T.
• Assistant Examiner(s): Pipala, Edward J.
• Application Number:
  US07/923,029
• Time in Patent Office: 887 Days
• Field of Search: 364/573, 364/574, 364/498, 364/578, 364/413.07, 364/413.08, 364/413.09, 324/312, 324/322, 356/39, 356/40, 128/633
• US Class Current: 703/11
• CPC Class Codes: G01J 2003/2843 Processing for eliminating interfering spectra
• CPC Class Codes: G01N 21/359 using near infrared light
• CPC Class Codes: G01N 2201/1215 for interfering gases
• CPC Class Codes: G06F 17/10 Complex mathematical operations function generation by table look-up G06F1/03; evaluation of elementary functions by calculation G06F7/544

Abstract

A method and apparatus for the determination of spectral samples is disclosed wherein spectral measurements are taken, normalization of the spectral measurements takes place, and a bilinear modeling is performed to extract spectral data. Once this data is derived, the interference quantitization levels are determined using multiple linear regression analysis, and are then removed from the sample readings in order to determine a more precise level of analyte spectra, such as analyte levels of glucose in serum or whole blood.

Claims

1. In a method for determining analyte levels for displaying glucose levels in blood using near infrared techniques including the steps of:

measuring glucose levels of a parameter related to blood using near infra-red optical techniques to provide a set of signals representing spectral data, said spectral data including spectral components resulting from physical properties of an environment in which measurement takes place which components interfere with the measured data; and

processing said spectra-representing signals having said interfering spectral components by;

removing the effect of constant analyte contribution by subtracting signals representing average spectra of replicate groups of said spectral data to form signals representing modified spectra representing variable interference information;

determining signals representing component spectra of said modified spectral signals by bilinear model analysis;

determining signals representing the magnitude of each said component spectra contained in each original spectrum and applying these signals representing magnitudes to signals representing component spectra to develop signals representing interference spectra; and

removing said signals representing the resulting interference spectra from said signals representing said original spectra for producing corrected spectral signals representing said spectral data of glucose blood levels with said interference components removed.

2. Apparatus for processing signals representing measured spectral data for removing effects of spectral components which interfere with said measured data in determining analyte levels and in displaying glucose levels in blood using near infrared techniques comprising:

means for measuring glucose levels of a parameter related to blood using near infrared optical techniques to provide a set of signals representing spectral data, said spectral data including spectral components resulting from physical properties of an environment in which measurement takes place which components interfere with the measured data;

means for processing said spectra-representing signals having said interfering spectral components including;

a subtractor for removing the effect of constant analyte contribution by subtracting signals representing the average spectra of replicate groups of said spectral data to form signals representing modified spectra representing variable interference information;

a components analyzer for determining representative signals of component spectra of said modified spectra by bilinear model analysis;

an analyzer for determining signals representing the magnitude of each said component spectra contained in each original spectrum and means for applying these magnitude-representing signals to the component spectra to develop signals representing interference spectra; and

a combiner for removing said signals representing the resulting interference spectra from said signals representing said original spectra for producing corrected spectral signals representing said spectral data of glucose blood levels with said interference components removed.