Programmable spectral imaging system

• US 7,342,658 B2
• Filed: 12/28/2005
• Issued: 03/11/2008
• Est. Priority Date: 12/28/2005
• Status: Expired due to Fees

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Patton, David L., Kowarz, Marek W., Spoonhower, John P.
• Primary Examiner(s): Lauchman; Layla G.
• Assistant Examiner(s): Nur; Abdullahi
• Application Number:
  US11/319,933
• Publication Number:
  US 20070146700A1
• Time in Patent Office: 804 Days
• Field of Search: 356/328, 356/326, 356/310, 356/320, 356/330, 356/300, 250/461.2, 359/298, 359/308, 359/297
• US Class Current: 356/328
• CPC Class Codes: G01J 2003/1282 Spectrum tailoring
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0208 using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
• CPC Class Codes: G01J 3/021 using plane or convex mirrors, parallel phase plates, or particular reflectors
• CPC Class Codes: G01J 3/0229 using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 3/0256 Compact construction
• CPC Class Codes: G01J 3/0262 Constructional arrangements for removing stray light
• CPC Class Codes: G01J 3/0291 Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
• CPC Class Codes: G01J 3/1838 Holographic gratings
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G01J 3/2823 Imaging spectrometer

Abstract

An imaging apparatus for obtaining spectral image data from an object that includes: a) a light source; b) an input optics section; c) a programmable spectral filter that conditions the multispectral image bearing light according to a predetermined spectral transmission function; d) a detector array in the path of the conditioned multispectral image bearing light and providing a corresponding output signal; and, e) a control logic processor in communication with the spatial light modulator for modulating addressable areas of the spatial light modulator to provide the spectral transmission function thereby.

Claims

1. An imaging apparatus for obtaining spectral image data from an object comprising:

a) a light source for directing light toward the object;

b) an input optics section for gathering light to obtain a multispectral image bearing light;

c) a programmable spectral filter that conditions the multispectral image bearing light according to a predetermined spectral transmission function, wherein the programmable spectral filter comprises;

i) a wavelength distributing element for distributing spectral components of the multispectral image bearing light to provide an input spatially distributed image bearing light;

ii) at least one spatial light modulator in the path of the input spatially distributed image-bearing light, the at least one spatial light modulator comprising a plurality of addressable areas, at least one addressable area modulating a corresponding spectral band of the spatially distributed image bearing light according to the spectral transmission function to provide one or more output modulated spectral bands of image-bearing light such that the input spatially distributed image-bearing light and the output modulated spectral bands are substantially parallel to each other and travel in opposite directions when in close proximity to the spatial light modulator, and wherein the spectral transmission function provides a continuously variable transmission;

iii) a wavelength recombining element in the path of the output modulated spectral bands of image-bearing light, wherein the wavelength recombining element recombines the one or more modulated spectral bands of image-bearing light to form a conditioned multispectral image bearing light;

d) a detector array in the path of the conditioned multispectral image bearing light and providing a corresponding output signal; and

,

e) a control logic processor in communication with the spatial light modulator for modulating addressable areas of the spatial light modulator to provide the spectral transmission function thereby.

2. An imaging apparatus for obtaining spectral image data from an object comprising:

a) a light source for directing light toward the object;

b) an input optics section for gathering light to obtain a multispectral image bearing light;

c) a programmable spectral filter that conditions the multispectral image bearing light according to a predetermined spectral transmission function, wherein the programmable spectral filter comprises;

i) a wavelength distributing element for distributing spectral components of the multispectral image bearing light to provide an input spatially distributed image bearing light;

ii) at least one spatial light modulator in the path of the input spatially distributed image-bearing light, the at least one spatial light modulator comprising a plurality of addressable areas, at least one addressable area modulating a corresponding spectral band of the spatially distributed image bearing light according to the spectral transmission function to provide one or more output modulated spectral bands of image-bearing light such that the input spatially distributed image-bearing light and the output modulated spectral bands are substantially parallel to each other and travel in substantially one direction when in close proximity to the spatial light modulator;

iii) a wavelength recombining element in the path of the output modulated spectral bands of image-bearing light, wherein the wavelength recombining element recombines the one or more modulated spectral bands of image-bearing light to form a conditioned multispectral image bearing light;

d) a detector array in the path of the conditioned multispectral image bearing light and providing a corresponding output signal; and

,

e) a control logic processor in communication with the spatial light modulator for modulating addressable areas of the spatial light modulator to provide the spectral transmission function thereby.

3. An imaging apparatus for obtaining spectral image data from an object comprising:

a) a light source for directing light toward the object;

b) an input optics section for gathering light to obtain a multispectral image bearing light;

c) a programmable spectral filter that conditions the multispectral image bearing light according to a predetermined spectral transmission function, wherein the programmable spectral filter comprises;

i) a wavelength distributing element for distributing spectral components of the multispectral image bearing light to provide an input spatially distributed image bearing light;

ii) at least one spatial light modulator in the path of the input spatially distributed image-bearing light, the at least one spatial light modulator comprising a plurality of addressable areas, at least one addressable area modulating a corresponding spectral band of the spatially distributed image bearing light according to the spectral transmission function to provide one or more output modulated spectral bands of image-bearing light such that the input spatially distributed image-bearing light and the output modulated spectral bands are substantially parallel to each other when in close proximity to the spatial light modulator;

iii) a wavelength recombining element in the path of the output modulated spectral bands of image-bearing light, wherein the wavelength recombining element recombines the one or more modulated spectral bands of image-bearing light to form a conditioned multispectral image bearing light;

d) a detector array in the path of the conditioned multispectral image bearing light and providing a corresponding output signal; and

,

e) a control logic processor in communication with the spatial light modulator for modulating addressable areas of the spatial light modulator to provide the spectral transmission function such that the spectral transmission function is characterized by a programmable center wavelength and bandwidth.

4. A method for obtaining spectral image data from an object comprising:

a) gathering light to obtain a multispectral image bearing light;

b) conditioning the multispectral image bearing light according to a spectral transmission function that provides a continuously variable transmission by;

i) distributing spectral components of the multispectral image bearing light to provide an input spatially distributed image bearing light;

ii) modulating a plurality of spectral bands of the input spatially distributed image bearing light at a spatial light modulator according to the spectral transmission function such that the input spatially distributed image-bearing light and a output modulated spectral bands are substantially parallel to each other when in close proximity to the spatial light modulator;

iii) recombining the one or more modulated spectral bands of image-bearing light to form the conditioned multispectral image bearing light;

c) directing the conditioned multispectral image bearing light to a detector array for forming the spectral image data.

5. A method for obtaining spectral image data from an object comprising:

a) gathering light to obtain a multispectral image bearing light;

b) conditioning the multispectral image bearing light in an iterative manner according to a spectral transmission function by;

i) distributing spectral components of the multispectral image bearing light to provide an input spatially distributed image bearing light;

ii) modulating a plurality of spectral bands of the input spatially distributed image bearing light at a spatial light modulator according to the spectral transmission function such that the input spatially distributed image-bearing light and a output modulated spectral bands are substantially parallel to each other when in close proximity to the spatial light modulator, and wherein the spectral transmission function is iteratively conditioned;

iii) recombining the one or more modulated spectral bands of image-bearing light to form the conditioned multispectral image bearing light;

c) directing the conditioned multispectral image bearing light to a detector array for forming the spectral image data.

6. A method for obtaining spectral image data from an object comprising:

a) gathering light to obtain a multispectral image bearing light;

b) conditioning the multispectral image bearing light according to a programmable spectral transmission function by;

i) distributing spectral components of the multispectral image bearing light to provide an input spatially distributed image bearing light;

ii) modulating a plurality of spectral bands of the input spatially distributed image bearing light at a spatial light modulator according to the spectral transmission function such that the input spatially distributed image-bearing light and a output modulated spectral bands are substantially parallel to each other when in close proximity to the spatial light modulator, and wherein the spectral transmission function is characterized by a programmable center wavelength and bandwidth;

iii) recombining the one or more modulated spectral bands of image-bearing light to form the conditioned multispectral image bearing light;

c) directing the conditioned multispectral image bearing light to a detector array for forming the spectral image data.