Infrared imaging system for simultaneous generation of temperature, emissivity and fluorescence images

• US 5,272,340 A
• Filed: 09/29/1992
• Issued: 12/21/1993
• Est. Priority Date: 09/29/1992
• Status: Expired due to Fees

• Current Assignee: Amara, Inc.
• Original Assignee: Amara, Inc.
• Inventors: Anbar, Michael
• Primary Examiner(s): FIELDS, CAROLYN
• Application Number:
  US07/953,990
• Time in Patent Office: 448 Days
• Field of Search: 250/339, 250/458.1, 250/332, 250/330, 364/557, 374/9, 374/121, 374/124
• US Class Current: 250/332
• CPC Class Codes: G01J 2005/0074 having separate detection of emissivity
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 3/32 Investigating bands of a spectrum in sequence by a single detector
• CPC Class Codes: G01J 5/0022 for sensing the radiation of moving bodies
• CPC Class Codes: G01J 5/0025 Living bodies ear thermometers G01J5/0011; detecting, measuring or recording for diagnostic purposes A61B5/00
• CPC Class Codes: G01J 5/53 Reference sources, e.g. standard lamps; Black bodies
• CPC Class Codes: G01J 5/601 using spectral scanning
• CPC Class Codes: G01J 5/602 using selective, monochromatic or bandpass filtering
• CPC Class Codes: G01N 21/6456 Spatial resolved fluorescence measurements; Imaging
• CPC Class Codes: G01N 25/72 Investigating presence of flaws

Abstract

The present invention comprises a method and apparatus for determining actual temperature, reflectivity and fluorescence of a surface and comprises in the preferred embodiment a two-dimensional focal plane array of rapidly tunable infrared detectors, 11, adapted to detect the emitted infrared flux from a surface of interest, 10, across pre-selected spectral segments in the 4-15 μm range. The invention further comprises a computer having deconvolution algorithms, 13, for isolating the effects of reflectivity, fluorescence and environmental factors affecting infrared emission for each pixel of the generated image at various spectral segments in the 4-15 μm range. The device further includes means for generating images of temperature, emissivity and fluorescence for diagnostic use. The preferred embodiment of the invention also contemplates the use of thermostated black body reference emitters, 12, at the edges of the field of view for enhancing and speeding deconvolution of the detected data across the 4-15 μm spectrum.

Claims

1. An apparatus for determining temperature, reflectivity (or emissivity) and fluorescence of an area of interest from the detection of emitted infrared flux, comprising:

infrared detection means adapted to measure emitted infrared flux of said area in the 4-15 μ

m spectrum, said detection means being further adapted to be modulated over a plurality of pre-selected narrower spectral segments and to measure said emitted infrared flux in said segments over said 4-15 μ

m spectrum for each unit of said area of interest, said detection means further comprising a plurality of detectors arranged in a pre-selected configuration for detecting said emitted infrared flux in parallel over said narrower spectral segments for each portion of said area;

computing means, operatively communicating with said detector means and adapted to deconvolute the measured detected infrared flux for each pixel of said area to numeric values for temperature, fluorescence and reflectivity, said computing means further adapted to generate images of the deconvoluted temperature, reflectivity and fluorescence for said area of interest;

whereby, detection of infrared flux across an area of interest through spectral segments enables deconvolution of the detected data to accurately measure temperature, fluorescence and reflectivity (or emissivity).

2. The apparatus according to claim 1 wherein said detector means is a 256×

256 focal plane array of tunable infrared flux detectors.

3. The apparatus according to claim 2 wherein said detectors are comprised of tunable Putley detectors.

4. The apparatus according to claim 1 wherein said detector means is adapted to detect emitted infrared flux in said preselected spectral segments of from 1 to 3 μ

m and wherein said preselected spectral segments number is at least 5.

5. The apparatus according to claim 1 wherein said computing means is a digital computer adapted to deconvolute said detected data using a series of algorithms describing temperature, reflectivity and fluorescence of the surface of interest as a function of the temperature of a black body emitter, the wavelength dependence of emissivity of the area, the temperature of the surrounding environment, the wavelength of light of the environment, the wavelength of exciting photons of fluorescence, and the wavelength of the fluorescent emission.

6. The device according to claim 1 wherein said detection means further comprises a plurality of black body reference emitters operatively arranged at the periphery of the field of view and means for maintaining said black body emitters at a constant, known temperature.

7. The apparatus according to claim 1 wherein said detection means comprises a 256×

256 focal plane array of wide-band infrared detectors modulated by and communicating with filter means for detecting emitted infrared flux in said pre-selected spectral segments.

8. The apparatus according to claim 7 wherein said filter means is a continuously tunable acousto-optical filter.

9. The device according to claim 7 wherein said filter means is a rotatable sector disk of fixed band width infrared filters and wherein said multi-sectors number is at least 5.

10. The method for determining temperature, fluorescence and reflectivity (or emissivity) of a surface of interest through detection and measurement of emitted infrared flux, comprising the steps of:

providing detecting means adapted to measure emitted infrared flux for each unit of said surface in the 4-15 μ

m wavelength band;

providing modulating means adapted to selectively modulate said detecting means over a plurality of pre-selected spectral segments across said 4-15 μ

m wavelength band and wherein said plurality of pre-selected spectral segments is at least 5 in number;

detecting through the use of said detecting means the value of emitted infrared flux of each pixel of said surface for each of said pre-selected spectral segments;

providing a series of algorithms as a function of temperature of an ideal black body emitter, wavelength of emissivity of said surface, temperature of the surrounding environment, wavelength of the light of the environment, wavelength of exciting photons of fluorescence, and wavelength fluorescent emission, the solution of which determines temperature, reflectivity (or emissivity) and fluorescence of said surface;

providing computing means adapted to communicate with said detecting means and to deconvolute said emitted infrared flux into temperature, fluorescence and reflectivity for each of said pixels of said surface through the use of the provided algorithms;

generating an image of the distribution of said deconvoluted values of temperature, reflectivity (or emissivity) and fluorescence for said surface of interest.

11. The method according to claim 10 wherein the provided computing means is a digital computer adapted to solve said algorithms and to generate said image of temperature, fluorescence and reflectivity (or emissivity) and the temporal values thereof.

12. The method according to claim 10 wherein the provided detection means is a 256×

256 focal plane array of tunable infrared flux detectors.

13. The method according to claim 10 wherein said detecting means comprises a two-dimensional focal plane array of tunable infrared detectors adapted to be modulated over at least 5 spectral segments.

14. Method according to claim 10 wherein said spectral segments are of between 1-3 μ

m.

15. The method according to claim 10 wherein the provided detecting means comprises a two-dimensional focal plane array of wide-band infrared detectors modulated by and communicating with a filter means for detecting emitted infrared flux in said pre-selected spectral segments.

16. The method according to claim 15 wherein said filter means is a continuously tunable acousto-optical filter.

17. The method according to claim 15 wherein said filter means is a rotatable multi-sector set of fixed band infrared filters.