System and method for encoded spatio-spectral information processing

• US 6,859,275 B2
• Filed: 03/01/2001
• Issued: 02/22/2005
• Est. Priority Date: 04/09/1999
• Status: Expired due to Fees

• Current Assignee: Plain Sight Systems Incorporated (Water Intelligence Plc)
• Original Assignee: Plain Sight Systems Incorporated (Water Intelligence Plc)
• Inventors: Fateley, William G., Geshwind, Frank, Coifman, Ronald R., DeVerse, Richard A.
• Primary Examiner(s): Evans, F. L.
• Application Number:
  US09/798,860
• Publication Number:
  US 20020057431A1
• Time in Patent Office: 1,454 Days
• Field of Search: 356/310, 356/330
• US Class Current: 356/330
• CPC Class Codes: G01J 2003/2866 Markers; Calibrating of scan
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/021 using plane or convex mirrors, parallel phase plates, or particular reflectors
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/0229 using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 3/0232 using shutters
• CPC Class Codes: G01J 3/027 Control of working procedures of a spectrometer; Failure detection; Bandwidth calculation
• CPC Class Codes: G01J 3/06 Scanning arrangements arrangements for order-selection
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/18 using diffraction elements, e.g. grating gratings per se G02B
• CPC Class Codes: G01J 3/2823 Imaging spectrometer
• CPC Class Codes: G01J 3/2846 using modulation grid; Grid spectrometers
• CPC Class Codes: G01J 3/2889 Rapid scan spectrometers; Time resolved spectrometry
• CPC Class Codes: G01J 3/32 Investigating bands of a spectrum in sequence by a single detector
• CPC Class Codes: G01J 3/42 Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry beam switching arrangements G01J3/08
• CPC Class Codes: G01J 3/433 Modulation spectrometry; Derivative spectrometry
• CPC Class Codes: G01J 3/457 Correlation spectrometry, e.g. of the intensity G01J3/453 takes precedence
• CPC Class Codes: G01N 2021/393 and using a spectral variation of the interaction of the laser beam and the sample
• CPC Class Codes: G01N 2021/6463 Optics
• CPC Class Codes: G01N 21/39 using tunable lasers
• CPC Class Codes: G02B 26/0833 : the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 26/0841 : the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 27/1013 : for colour or multispectral image sensors, e.g. splitting an image into monochromatic image components on respective sensors spectral imaging systems G01J
• CPC Class Codes: G02B 27/1086 : operating by diffraction only
• CPC Class Codes: G02B 27/126 : The splitting element being a prism or prismatic array, including systems based on total internal reflection

Abstract

Encoded spatio-spectral information processing is performed using a system having a radiation source, wavelength dispersion device and two-dimensional switching array, such as digital micro-mirror array (DMA). In one aspect, spectral components from a sample are dispersed in space and modulated separately by the switching array, each element of which may operate according to a predetermined encoding pattern. The encoded spectral components can then be detected and analyzed. In a different aspect, the switching array can be used to provide a controllable radiation source for illuminating a sample with radiation patterns that have predetermined characteristics and separately encoded components. Various applications are disclosed.

Claims

1. A tunable source of radiation, comprising:

a broad-band radiation source providing a substantially continuous spectrum of radiation components within a predetermined portion of the spectrum;

a spatial light modulator (SLM) illuminated by the broad-band radiation source and spatially modulating the broad-band radiation; and

a wavelength dispersing device dispersing the broad-band radiation modulated by the SLM.

2. The tunable source of radiation of claim 1, wherein the SLM is an optical switch array.

3. The tunable source radiation of claim 2, wherein the SLM is a digital micro-mirror array (DMA).

4. The tunable source of radiation of claim 1, wherein the SLM encodes at least some of said series of radiation bands in a known manner.

5. The tunable source of radiation of claim 1, further comprising an exit aperture disposed to receive a selected subset of the dispersed radiation, wherein no integrating device (device for remixing the dispersed wavelengths) is interposed between the wavelength dispersing device and the exit aperture.

7. The tunable source of radiation of claim 1, wherein the SLM comprises a MEMS array.

8. The tunable source of radiation of claim 1, wherein the wavelength dispersing device comprises a diffracting grating.

9. The tunable source of radiation of claim 1, wherein the wavelength dispersing device comprises a prism.

6. The tunable source of radiation of claims, wherein the broad-band radiation source comprises a LED.

10. A device for measuring interaction of electromagnetic radiation with samples of material, comprising:

a radiation source for irradiating at least one sample of the material with electromagnetic radiation, said source having predetermined characteristics;

means for encoding arbitrary radiation bands from the sample with a unique code;

processing means for processing encoded radiation bands in the analog domain;

detector means receiving input from said processing means and providing on output an indication of the interaction between the electro-magnetic radiation from the source with the sample of material.

11. The device of claim 10, wherein the means for encoding apply an orthogonal basis of encoding functions.

12. The device of claim 10, wherein the processing means is configured to perform Hadamard processing.

13. The device of claim 10, wherein the processing means is configured to perform hyperspectral imaging.

14. The device of claim 10, wherein the detector means comprises a radiation transducer.