Digital film grain

• US 7,015,479 B2
• Filed: 07/31/2003
• Issued: 03/21/2006
• Est. Priority Date: 07/31/2003
• Status: Active Grant

• Current Assignee: CareStream Health Incorporated
• Original Assignee: Eastman Kodak Company
• Inventors: Tredwell, Timothy J., Haas, Daniel D., Moore, William E.
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): VU, MINDY D
• Application Number:
  US10/631,092
• Publication Number:
  US 20050023476A1
• Time in Patent Office: 964 Days
• Field of Search: 250/370.11, 250/370.09, 235/492
• US Class Current: 250/370.11
• CPC Class Codes: G01T 1/2928 using solid state detectors
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof

Abstract

A digital film grain (20) comprises a phototransistor (40) which produces an electrical signal having a strength which is related to an input radiation flux. A transponder receives commands and power from a base station (80) and transmits information quantifying the radiation observed by that digital film grain. An image accumulator (84) connected to the base station (80) assembles an image from the profile of radiation reported by a distribution of digital film grains correlated to the locations of those grains.

Claims

1. A digital film grain for detection of x-rays which comprises:

a photodetector which produces an electrical signal having a strength which is related to an input x-ray flux;

a transponder which receives said electrical signal and transmits information quantifying said electrical signal; and

wherein said digital film grain is disposed in a container and said container contains a material producing a light emission in response to an input radiation flux.

2. A digital film grain as in claim 1 wherein said photodetector is direct radiation detector.

3. A digital film grain as in claim 2 wherein said direct radiation detector is comprised of a layer selected from a group comprised of cadmium telluride, cadmium zinc telluride, lead iodide, mercuric iodide, and amorphous selenium.

4. A digital film grain as in claim 1 wherein said photodetector is an indirect radiation detector.

5. A digital film grain as in claim 1 wherein a luminophor is in proximity to said photodetector.

6. A digital film grain as in claim 1 wherein said transponder comprises a radio frequency generator.

7. A digital film grain as in claim 1 wherein said transponder comprises an antenna.

8. A digital film grain as in claim 1 wherein said transponder comprises a modulator.

9. A digital film grain as in claim 1 wherein said transponder extracts electrical energy from a radiated field to provide electrical power for said digital film grain.

10. A digital film grain as in claim 1 wherein electrical power for said photodetector and said transponder is stored in a capacitor.

11. A digital film grain as in claim 10 wherein said capacitor is located on said digital film grain.

12. A digital film grain as in claim 1 wherein said container is a capillary.

13. A digital film grain as in claim 1 wherein said digital film grain has an individual identifier.

14. A digital film grain as in claim 1 wherein said photodetector is selected from a group comprised of photodiode, charged coupled device (CCD), complementary metal oxide semiconductor (CMOS), phototransistor, and avalanche photodiode.

15. An imaging system comprising:

a distribution of two or more digital film grains wherein each of said digital film grains comprise a photodetector and transponder;

a base station containing a transponder capable of sending information to and receiving information from to each of said digital film grain transponder; and

an image accumulator which assembles signals related to an light flux received at said digital film grains and arranging said signals in an order dependent upon a location of each of said digital grains.

16. A method of acquiring an image by:

detecting an irradiance profile with a distribution of digital film grains;

sending a signal and an identification number from each of said digital film grains to an image accumulator;

determining a location of each of said digital film grains in said distribution;

assembling said signals from said digital film grains in an order according to said location of each of said digital film grain.

17. A method for determining locations of digital film grains in a distribution by:

directing a spot of irradiation to which said distribution is sensitive toward said distribution, wherein at least one dimension of said spot of irradiation is smaller than a smallest distance between said digital film grains;

recording said location of each of said spots of irradiation;

recording signals from said digital film grains in said distribution; and

correlating said location of said spot of irradiation to each of said digital film grains sending a signal exceeding a predetermined threshold.

18. A method as in claim 17 comprising:

moving said spot of irradiation to another location and correlating digital film grain signals with location until a set of locations for a substantial fraction of the film grains in said distribution have sent a signal indicating detection of irradiation.

19. A digital film grain for detection of visible light, ultraviolet, or infrared radiation which comprises:

a photodetector which produces an electrical signal having a strength which is related to an input radiation;

a transponder which receives said electrical signal and transmits information quantifying said electrical signal;

wherein components of said digital film grain are fabricated on a single substrate; and

wherein spatial dimensions in said substrate are approximately equal with a pixel size of an image produced by an array of said digital film grains.

20. A digital film grain for detection of visible light, ultraviolet, or infrared radiation which comprises:

a photodetector which produces an electrical signal having a strength which is related to an input radiation;

a transponder which receives said electrical signal and transmits information quantifying said electrical signal;

wherein components of said digital film grain are fabricated on a single substrate; and

wherein said substrate spatial dimension is 200 μ

m or smaller.