Chemistry Strip Reader And Method

• US 20110096160A1
• Filed: 01/07/2011
• Published: 04/28/2011
• Est. Priority Date: 04/18/2007
• Status: Abandoned Application

• Current Assignee: Dale Capewell
• Original Assignee: Dale Capewell
• Inventors: Capewell, Dale
• Application Number:
  US12/987,010
• Publication Number:
  US 20110096160A1
• Time in Patent Office: Days
• US Class Current: 348/135
• CPC Class Codes: G01N 2035/00108 Test strips, e.g. paper
• CPC Class Codes: G01N 35/021 having a flexible chain, e.g. "cartridge belt", conveyor for reaction cells or cuvettes
• CPC Class Codes: Y10T 436/110833 Utilizing a moving indicator strip or tape

Abstract

A chemistry strip reader and method for analyzing chemistry strips. A conveyor moves chemical strips through different imaging positions at discrete points in time across the field of view of a camera, which captures images of each chemistry strip at different discrete times. A processor determines reflectance values for each of the chemical strips from the captured images at the discrete points in time. Calibration targets adjacent the chemistry strips can be used to adjust the determined reflectance values. The light source can sequentially illuminate each chemistry strip with three different wavelengths of light, where the processor calculates a concentration determination associated with the chemistry strip by calculating different chromaticity coordinates for the different wavelengths of light, and comparing them to known chromaticity coordinates for known analyte concentrations.

Claims

1. A chemistry strip reader for analyzing chemistry strips, comprising:

a light source for sequentially illuminating a chemistry strip with first, second and third wavelengths of light;

a camera for capturing first, second and third images of the chemistry strip while illuminated with the first, second and third wavelengths of light, respectively; and

a processor for calculating a concentration determination associated with the chemistry strip by;

determining reflectance values A, B and C for the chemical strip from the captured first, second and third images, respectively;

calculating a first chromaticity coordinate equal to A/(A+B+C)

calculating a second chromaticity coordinate equal to B/(A+B+C); and

determining a concentration associated with the chemistry strip by comparing the first and second chromaticity coordinates to chromaticity coordinates for known analyte concentrations.

2. The chemistry strip reader of claim 2, wherein the comparing of the first and second chromaticity coordinates includes comparing a ratio of the first and second chromaticity coordinates to that for known analyte concentrations.

3. The chemistry strip reader of claim 2, wherein the comparing of the first and second chromaticity coordinates includes plotting the first and second chromaticity coordinates against each other, and comparing the plotted location to that of a spine that runs through plotted values of chromaticity coordinates for known analyte concentrations.

4. The chemistry strip reader of claim 2, wherein the three wavelengths are red, blue and green.

5. A method of analyzing chemistry strips, comprising:

sequentially illuminating a chemistry strip with first, second and third wavelengths of light;

capturing first, second and third images of the chemistry strip while illuminated with the first, second and third wavelengths of light, respectively;

calculating a concentration determination associated with the chemistry strip by;

determining reflectance values A, B and C for the chemical strip from the captured first, second and third images, respectively,

calculating a first chromaticity coordinate equal to A/(A+B+C),

calculating a second chromaticity coordinate equal to B/(A+B+C), and

determining a concentration associated with the chemistry strip by comparing the first and second chromaticity coordinates to chromaticity coordinates for known analyte concentrations.

6. The method of claim 5, wherein the comparing of the first and second chromaticity coordinates includes comparing a ratio of the first and second chromaticity coordinates to that for known analyte concentrations.

7. The method of claim 5, wherein the comparing of the first and second chromaticity coordinates includes plotting the first and second chromaticity coordinates against each other, and comparing the plotted location to that of a spine that runs through plotted values of chromaticity coordinates for known analyte concentrations.

8. The method of claim 5, wherein the three wavelengths are red, blue and green.