Photofinishing utilizing modulated light source array

• US 6,163,363 A
• Filed: 12/29/1998
• Issued: 12/19/2000
• Est. Priority Date: 12/31/1997
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Gretag Imaging AG, Texas Instruments, Inc.
• Inventors: Nelson, William E., Frick, Beat
• Primary Examiner(s): Adams, Russell
• Assistant Examiner(s): FULLER, RODNEY EVAN
• Application Number:
  US09/221,517
• Time in Patent Office: 721 Days
• Field of Search: 355/18, 355/35, 355/40, 355/43, 355/54, 355/67, 355/71, 355/77, 347/224, 347/225, 347/232, 347/234, 347/237, 347/238, 347/239, 347/241, 359/237, 359/263, 359/298
• US Class Current: 355/32
• CPC Class Codes: G06K 15/1252 using an array of light modulators, e.g. a linear array
• CPC Class Codes: H04N 1/50 Picture reproducers for halftone screening H04N1/52

Abstract

A digital photograph printer comprising a transport mechanism, a modulated light source (1206), and an exposure controller (1302). The transport mechanism for advancing a photosensitive medium (1202) through an exposure region (1200) such that said photosensitive medium advances one row of pixel locations each row period. The modulated light source (1206) is operable to selectively provide a beam of light to an array of individually modulated regions (1300, 1306, 1310) in an exposure region (1200). As the photosensitive medium (1202) moves through the exposure region (1200) the individually modulated regions in the exposure region (1200) have the opportunity to expose each pixel locations in the exposure region (1200) once each row period. The exposure controller (1302) operable to control the modulated light source (1206) based on image data provided to modulated light source. The image data comprises optical density data for each pixel in an image to be formed on the photosensitive medium for each of at least three primary colors. The controller selectively exposes the photosensitive medium at a number of exposure opportunities, each selective exposure performed for a period no greater than 50% of the row time, and the duration of at least two of the exposure periods having a non-binary relationship.

Claims

1. A method of exposing a full-color pixelated image on a photosensitive medium, the method comprising the steps of:

providing an exposure region;

providing a photosensitive medium comprising an array of rows of pixel locations, said photosensitive medium moving through said exposure region such that said photosensitive medium advances one row of said pixel locations at a time, the advance of said photosensitive medium by one row of pixel locations being defined as a row period;

providing a modulated light source to selectively provide a beam of light to an array of individually modulated regions in said exposure region, said individually modulated regions in said exposure region corresponding to said pixel locations in said exposure region once each exposure opportunity with the number of rows of pixel locations operable in said modulated light source determining a maximum number of exposure opportunities and with each said row defining an exposure opportunity;

controlling said modulated light source based on image data provided to said modulated light source, said image data comprising optical density data for each pixel in an image to be formed on said photosensitive medium for each of at least three primary colors, said controlling step comprising the step of;

selectively exposing said photosensitive medium at a number of said exposure opportunities, said selective exposure performed for a period no greater than 50% of the row time, the duration of at least two of said exposure periods having a non-binary relationship.

2. The method of claim 1, said step of providing a modulated light source comprises providing a modulated light source having a periodically varying color.

3. The method of claim 1, said controlling step varying the exposure sequence from one row of pixel locations to the next.

4. The method of claim 1, said step of providing a photosensitive medium comprising the step of providing a photographic paper.

5. The method of claim 1, said step of providing a modulated light source comprising the steps of:

providing a light source for projecting a beam of light along a path;

providing a color filter device on said light path for filtering said beam of light; and

providing a spatial light modulator on said light path.

6. The method of claim 5, further comprising the step of providing a neutral density filter function on said light path.

7. The method of claim 1, said step of providing a modulated light source comprising the steps of:

providing at least one solid state light source for projecting a beam of light along a path.

8. A method of exposing a full-color pixelated image on a photosensitive medium, the method comprising the steps of:

providing an exposure region;

providing a photosensitive medium comprising an array of rows of pixel locations, said photosensitive medium moving through said exposure region such that said photosensitive medium advances one row of said pixel locations at a time, the advance of said photosensitive medium by one row of pixel locations being defined as a row period;

providing a modulated light source, said modulated light source operable to selectively provide a beam of light to an array of individually modulated regions in said exposure region, said individually modulated regions in said exposure region corresponding to said pixel locations in said exposure region once each exposure opportunity, wherein the number of rows of pixel locations operable in said modulated light source determines a maximum number of exposure opportunities with each said row defining an exposure opportunity;

controlling said modulated light source based on image data provided to said modulated light source, said image data comprising optical density data for each pixel in an image to be formed on said photosensitive medium for each of at least three primary colors, said controlling step comprising selectively exposing said photosensitive medium at a number of exposure opportunities, said selective exposure performed for a period no greater than 50% of the row time, the duration of at least two of said exposure periods having a non-binary relationship;

said controlling step providing a maximum exposure period no greater than 25% of the row period.

9. A method of exposing a full-color pixelated image on a photosensitive medium, the method comprising the steps of:

providing an exposure region;

providing a photosensitive medium comprising an array of rows of pixel locations, said photosensitive medium moving through said exposure region such that said photosensitive medium advances one row of said pixel locations at a time, the advance of said photosensitive medium by one row of pixel locations being defined as a row period;

providing a modulated light source, said modulated light source operable to selectively provide a beam of light to an array of individually modulated regions in said exposure region, said individually modulated regions in said exposure region corresponding to said pixel locations in said exposure region once each exposure opportunity, wherein the number of rows of pixel locations operable in said modulated light source determines a maximum number of exposure opportunities with each said row defining an exposure opportunity;

controlling said modulated light source based on image data provided to said modulated light source, said image data comprising optical density data for each pixel in an image to be formed on said photosensitive medium for each of at least three primary colors, said controlling step comprising selectively exposing said photosensitive medium at a number of exposure opportunities, said selective exposure performed for a period no greater than 50% of the row time, the duration of at least two of said exposure periods having a non-binary relationship;

said controlling step providing a minimum exposure period of at least ten LSB periods.

10. A method of exposing a full-color pixelated image on a photosensitive medium, the method comprising the steps of:

providing an exposure region;

providing a photosensitive medium comprising an array of rows of pixel locations, said photosensitive medium moving through said exposure region such that said photosensitive medium advances one row of said pixel locations at a time, the advance of said photosensitive medium by one row of pixel locations being defined as a row period;

providing a modulated light source, said modulated light source operable to selectively provide a beam of light to an array of individually modulated regions in said exposure region, said individually modulated regions in said exposure region corresponding to said pixel locations in said exposure region once each exposure opportunity, wherein the number of rows of pixel locations operable in said modulated light source determines a maximum number of exposure opportunities with each said row defining an exposure opportunity;

controlling said modulated light source based on image data provided to said modulated light source, said image data comprising optical density data for each pixel in an image to be formed on said photosensitive medium for each of at least three primary colors, said controlling step comprising selectively exposing said photosensitive medium at a number of exposure opportunities, said selective exposure performed for a period no greater than 50% of the row time, the duration of at least two of said exposure periods having a non-binary relationship;

said controlling step providing at least 84 exposure opportunities for each of three colors said 84 exposure opportunities comprising one exposure opportunity having a duration of ten LSBs, five exposure opportunities having a duration of eleven LSBs, four exposure opportunities having a duration of eighteen LSBs, and seventy-four exposure opportunities having an exposure period of 56 LSBs.

11. A digital photograph printer, said photograph printer comprising:

a transport mechanism for advancing a photosensitive medium through an exposure region, said photosensitive medium comprising an array of pixel locations, said photosensitive medium moving through said exposure region such that said photosensitive medium advances one row of said pixel locations each row period;

a modulated light source operable to selectively provide a beam of light to an array of individually modulated regions in said exposure region, wherein as said photosensitive medium moves through said exposure region said individually modulated regions in said exposure region correspond to said pixel locations in said exposure region once each exposure opportunity, where in the number of rows operable in said modulated light source determines a maximum number of exposure opportunities;

an exposure controller, said exposure controller operable to control said modulated light source based on image data provided to said modulated light source, said image data comprising optical density data for each pixel in an image to be formed on said photosensitive medium for each of at least three primary colors, said controller selectively exposing said photosensitive medium at a number of exposure opportunities for a period no greater than 50% of the row time, the duration of at least two of said exposure periods having a non-binary relationship;

said controller providing a maximum exposure period no greater than 25% of the row period.

12. A digital photograph printer, said photograph printer comprising:

a transport mechanism for advancing a photosensitive medium through an exposure region, said photosensitive medium comprising an array of pixel locations, said photosensitive medium moving through said exposure region such that said photosensitive medium advances one row of said pixel locations each row period;

a modulated light source operable to selectively provide a beam of light to an array of individually modulated regions in said exposure region, wherein as said photosensitive medium moves through said exposure region said individually modulated regions in said exposure region correspond to said pixel locations in said exposure region once each exposure opportunity, where in the number of rows operable in said modulated light source determines a maximum number of exposure opportunities;

an exposure controller, said exposure controller operable to control said modulated light source based on image data provided to said modulated light source, said image data comprising optical density data for each pixel in an image to be formed on said photosensitive medium for each of at least three primary colors, said controller selectively exposing said photosensitive medium at a number of exposure opportunities for a period no greater than 50% of the row time, the duration of at least two of said exposure periods having a non-binary relationship;

said controller providing a minimum exposure period of at least ten LSB periods.

13. A digital photograph printer, said photograph printer comprising:

a transport mechanism for advancing a photosensitive medium through an exposure region, said photosensitive medium comprising an array of pixel locations, said photosensitive medium moving through said exposure region such that said photosensitive medium advances one row of said pixel locations each row period;

a modulated light source operable to selectively provide a beam of light to an array of individually modulated regions in said exposure region, wherein as said photosensitive medium moves through said exposure region said individually modulated regions in said exposure region correspond to said pixel locations in said exposure region once each exposure opportunity, where in the number of rows operable in said modulated light source determines a maximum number of exposure opportunities;

an exposure controller, said exposure controller operable to control said modulated light source based on image data provided to said modulated light source, said image data comprising optical density data for each pixel in an image to be formed on said photosensitive medium for each of at least three primary colors, said controller selectively exposing said photosensitive medium at a number of exposure opportunities for a period no greater than 50% of the row time, the duration of at least two of said exposure periods having a non-binary relationship;

said controller providing at least eighty-four exposure opportunities for each of three colors, said eighty-four exposure opportunities comprising one exposure opportunity having a duration of ten LSBs, five exposure opportunities having a duration of eleven LSBs, four exposure opportunities having a duration of eighteen LSBs, and seventy-four exposure opportunities having an exposure period of 56 LSBs.

14. A digital photograph printer, said photograph printer comprising:

a transport mechanism for advancing a photosensitive medium through an exposure region having an array of individually modulated regions, said photosensitive medium comprising an array of rows of pixel locations, said transport mechanism moving said photosensitive medium through said exposure region such that said photosensitive medium advances one row of said pixel locations each row period, a row period being defined as the advance of said photosensitive medium by one row of pixel locations;

a modulated light source operable to selectively provide a beam of light to said array of individually modulated regions in said exposure region, said photosensitive medium moving under control of said transport mechanism through said exposure region so that said individually modulated regions in said exposure region correspond to said pixel locations in said exposure region once each exposure opportunity and the number of rows operable in said modulated light source determine a maximum number of exposure opportunities;

an exposure controller controlling said modulated light source in response to image data provided to said modulated light source, said image data comprising optical density data for each pixel in an image to be formed on said photosensitive medium for each of at least three primary colors, said controller selectively exposing said photosensitive medium at a number of exposure opportunities for a period no greater than 50% of the row time, the duration of at least two of said exposure periods having a non-binary relationship.

15. The digital photograph printer of claim 14, said modulated light source providing a modulated light source having a periodically varying color.

16. The digital photograph printer of claim 14, said controller varying the exposure sequence from one row of pixel locations to the next.

17. The digital photograph printer of claim 14, said photosensitive medium comprising a photographic paper.

18. The digital photograph printer of claim 14, said modulated light source comprising:

a light source for projecting a beam of light along a path;

a color filter device on said light path for filtering said beam of light; and

a spatial light modulator on said light path.

19. The digital photograph printer of claim 18, said modulated light source further comprising a neutral density filter function on said light path.

20. The digital photograph printer of claim 14, said modulated light source comprising at least one solid state light source for projecting a beam of light along a path.

21. The digital photograph printer of claim 14, further comprising a negative printer, said digital photograph printer printing index prints of the photographs formed by said negative printer.