Absorbance measurements using portable electronic devices with built-in camera

• US 8,493,441 B2
• Filed: 09/11/2009
• Issued: 07/23/2013
• Est. Priority Date: 09/11/2009
• Status: Expired due to Fees

• Current Assignee: Thonhauser GMBH (Zep Inc.)
• Original Assignee: Thonhauser GMBH (Zep Inc.)
• Inventors: Thonhauser, Christian
• Primary Examiner(s): DINH, KHANH Q
• Application Number:
  US12/558,442
• Publication Number:
  US 20110063433A1
• Time in Patent Office: 1,411 Days
• Field of Search: 382/163, 348/135, 348/336
• US Class Current: 348/135
• CPC Class Codes: G01N 21/251 Colorimeters; Construction thereof
• CPC Class Codes: G01N 21/255 Details, e.g. use of specially adapted sources, lighting or optical systems
• CPC Class Codes: G01N 21/78 producing a change of colour
• CPC Class Codes: G01N 2201/0221 Portable; cableless; compact; hand-held
• CPC Class Codes: G01N 2201/08 Optical fibres; light guides
• CPC Class Codes: H04M 2250/12 including a sensor for measuring a physical value, e.g. temperature or motion telephones including GPS signal receivers H04M2250/10

Abstract

A method comprising obtaining a mobile electronic device comprising a color sensitive light sensor and outward facing optics, exposing a sample to light having a predetermined optical path-length between a light source and the color sensitive light-sensor, and measuring the amount of light transmitted though the sample with the color sensitive light sensor. Also a mobile electronic device comprising a color sensitive light sensor and outward facing optics, the mobile electronic device configured for quantitative analysis of absorbance in colored liquids. Additionally, a system comprising a mobile electronic device configured for quantitative analysis of absorbance in colored samples, the mobile electronic device comprising a color sensitive light sensor and outward facing optics and a light source.

Claims

1. A method comprising:

obtaining a mobile electronic device comprising a color sensitive light sensor and outward facing optics;

exposing a sample to light, wherein the sample comprises a colored liquid; and

measuring the amount of light transmitted though a predetermined optical path-length in the sample with the color sensitive light sensor, wherein the sample and the mobile electronic device are not enclosed within the same housing.

2. The method of claim 1, further comprising determining the light absorption of the sample by wavelength-extraction from red, green and blue colors.

3. The method of claim 2, further comprising calculating the mass or molar concentrations of a substance in the sample.

4. The method of claim 1 further comprising adding a color indicating reagent to the sample.

5. The method of claim 1, further comprising adding a reagent of unknown concentration to the sample, the sample comprising a color indicating agent.

6. The method of claim 4, wherein the color indicating reagent is selected from redox, acid-base and complexation.

7. The method of claim 5, wherein the color indicating reagent is selected from redox, acid-base and complexation.

8. The method of claim 1, wherein the color sensitive light sensor is part of a digital camera.

9. The method of claim 1, wherein the mobile electronic device comprises a backlit display and the backlit display is used as the light source.

10. The method of claim 9, wherein the backlit display is used discontinuously by selectively displaying discrete colors for a predetermined amount of time.

11. The method of claim 10, wherein the discrete colors are complementary to absorption maxima of a substance in the sample.

12. The method of claim 9, further comprising channeling light from the backlit display though the sample and to the outward facing optics with an optical fiber.

13. The method of claim 1, wherein the color sensitive light sensor is illuminated uniformly by the light source.

14. The method of claim 1, wherein the mobile electronic device uses 8-bit color processing.

15. The method of claim 1, wherein the light source comprises a source of white light and a source of ultraviolet light.

16. The method of claim 1, further comprising putting the sample in a container having parallel walls.

17. The method of claim 1, wherein the device comprises voice control.

18. The method of claim 1, further comprising measuring the amount of light transmitted though a reference.

19. The method of claim 18, wherein the reference has essentially 100% transmittance.

20. The method of claim 1, wherein if the mobile electronic device has automatic exposure, the automatic exposure is turned off.

21. The method of claim 1, wherein a captured image from the color sensitive light sensor is cropped in a predetermined configuration.

22. The method of claim 1, further comprising determining average values for red, green, and blue light levels.

23. The method of claim 1, wherein the device is configured to capture an image.

24. The method of claim 1, further comprising using a reference transmittance of 100% if no reference transmittance has been measured.

25. The method of claim 1, wherein the mobile electronic device and/or the light source are immersed in the sample.

26. The method of claim 1, wherein the light source is selected from fluorescent and light emitting diode.

27. A mobile electronic device comprising a color sensitive light sensor, a processor, and outward facing optics, the processor comprising computer executable instructions for quantitative analysis of absorbance in a colored liquid, wherein the mobile electronic device is configured to measure the amount of light transmitted though a predetermined optical path-length in the colored liquid with the color sensitive light sensor.

28. The device of claim 27, further comprising a visual or acoustic user interface.

29. The device of claim 27, wherein the device is configured for quantitative analysis of absorbance in the colored liquid with software.

30. The device of claim 27, wherein the device is configured for quantitative analysis of absorbance in the colored liquid with hardware.

31. The device of claim 27, wherein the light sensor is a digital camera.

32. The device of claim 27, wherein the device comprises hardware and firmware and/or software and wherein at least one of the hardware, firmware and software is user-programmable.

33. The device of claim 27, further comprising a user interface comprising a dot-matrix display.

34. The device of claim 27, further comprising a user interface comprising a touch-sensitive display.

35. The device of claim 27, wherein the device is configured to calculate the mean red, green and blue color levels from predetermined portions of the digital image.

36. The device of claim 27, wherein the device is configured to calculate liquid absorbances based on wavelength-extraction of red, green and blue color levels.

37. The device of claim 27, wherein the device is configured to calculate mass or molar concentrations of a substance external to the liquid, further.

38. The device of claim 37, wherein the liquid is reactive towards the substance and changes colors upon contact with the substance.

39. The device of claim 27, further comprising a backlit display configured for use as light source.

40. The device of claim 39, wherein the device is configure to display multiple colors in succession and respective light-sensor intensities are captured.

41. The device of claim 31, wherein the digital camera is configured to operate in video mode.

42. The device of claim 41, wherein the device is configured to monitor a change in color as a function of time.

43. A system comprising:

a mobile electronic device comprising a color sensitive light sensor, a processor, and outward facing optics, the processor comprising computer executable instructions for quantitative analysis of absorbance in a colored liquid; and

a light source,

wherein the mobile electronic device is configured to measure the amount of light transmitted though a predetermined optical path-length in the colored liquid with the color sensitive light sensor.

44. The system of claim 43, further comprising a fixed optical path length for the colored liquid.

45. A system of claim 43, further comprising a fluorescent lamp as light source.

46. The system of claim 43, further comprising a user interface physically built into the mobile device.

47. The system of claim 43, wherein the mobile electronic device comprises a backlit display configured for use as light source.

48. The system of claim 47, further comprising an optical fiber configured to transmit light from the backlit display to the colored liquid.

49. The system of claim 48, further comprising an optical fiber configured to transmit light from the colored liquid to the color sensitive light sensor.

50. The system of claim 43, wherein the mobile electronic device is configured to determine light absorption of the colored liquid based on wavelength-extraction from red, green and blue colors.

51. The system of claim 50, wherein the mobile electronic device is configured to calculate the mass or molar concentrations of a substance in the colored liquid.

52. The system of claim 43, wherein the color sensitive light sensor is part of a digital camera.

53. The system of claim 43, wherein the mobile electronic device is configured to use 8-bit color processing.

54. The system of claim 43, further comprising a sample and a blank.

55. The system of claim 54, wherein the sample is selected from liquids, gases, gels, and semi-transparent solids.