Digital film grain
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.
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 μm or smaller.