Multiple channel scanning device using oversampling and image processing to increase throughput

• US 20020110077A1
• Filed: 11/26/2001
• Published: 08/15/2002
• Est. Priority Date: 06/02/1998
• Status: Abandoned Application

• Current Assignee: SAIC Limited (Wipro Limited)
• Original Assignee: SAIC Limited (Wipro Limited)
• Inventors: Green, Albert Myron, Drobot, Adam Thomas, White, Robert Courtney, Wyeth, Newell Convers, Phillips, Edward Alan
• Application Number:
  US09/991,655
• Publication Number:
  US 20020110077A1
• Time in Patent Office: Days
• US Class Current: 369/112.27
• CPC Class Codes: G11B 7/005 Reproducing G11B7/0065 takes precedence
• CPC Class Codes: G11B 7/124 the integrated head arrangements including waveguides

Abstract

A multiple channel scanning device has a scanning head with multiple columns of apertures that emit light which is projected to a small spot on the surface of a recorded medium. Light returned from the medium reenters the apertures and is conducted to detectors. In a preferred embodiment, the scanning head is rapidly oscillated (may be on the order of 100 kHz rate), in a direction parallel to the columns. The medium is moved in a direction perpendicular to the columns so that the same recorded regions pass beneath successive columns of apertures. The data from the detectors is image-processed to improve the quality of data reading using the successive readings of the same data regions. This allows errors to be corrected and throughput to be improved.

Claims

1. A scanning device for scanning a target surface having data written thereon, said data being arranged in adjacent data cells on said target surface, each of said cells having one of a set of possible configurations representing data, comprising:

a read/write head with at least one reading laser source connected to emit light from an array of output apertures and receive light through an array of input apertures;

an image processor;

said read/write head and said target surface being supported to move relative to each other to scan said target surface;

said array of output apertures being arranged such that multiple ones of said output apertures scans substantially a same cell of said surface;

said read/write head including detectors to produce detection signals, each corresponding to a respective one of said multiple ones and connected to said image processor;

said image processor being configured to generate an estimate of a configuration of said same cell and to generate a signal stream representing said estimate.

2. A device as in claim 1, wherein said output apertures are coaxial with said input apertures.

3. A device as in claim 1, wherein said read/write head includes a optoelectronic chip having light guides formed therein, each of said light guides being connected to a one of said output apertures.

4. A device as in claim 1, wherein said optoelectronic chip includes at least one optical switch to modulate an output of one of said reading laser source and a writing laser source.

5. A device as in claim 4, wherein said at least one optical switch modulates said laser source by selectively directing said output between a write output aperture and another direction leading ultimately to dissipation of energy of said writing laser source, whereby said writing laser source is enabled to operate in a continuous manner while writing.

6. A device as in claim 1, wherein said read/write head further comprises multiple reading laser sources, each connected to an array of light guides interconnected to split a laser output of said each of said multiple reading laser sources into multiple paths, each connected to a one of said output apertures.

7. A device as in claim 6, wherein said array of light guides are interconnected with respective optical switches controlled by a controller programmed to cause said laser output to be shared among multiple ones of said output apertures by shunting said laser output to a first fraction of said multiple ones at a first time and shunting said laser output to second fraction of said multiple ones at a second time.

8. A device as in claim 7, wherein said first fraction of said multiple ones is equal to a single one of said output apertures.

9. A device as in claim 1, wherein:

said read/write head further comprises multiple reading laser sources, each connected to an array of light guides interconnected to split a laser output of said each of said multiple reading laser sources into multiple paths defined by said light guides, each path being connected to a one of said output apertures; and

said array of light guides are interconnected with respective optical switches controlled by a controller programmed to cause said laser output to be shared among multiple ones of said output apertures by shunting a percentage of said laser output to a first fraction of said multiple ones at a first time and shunting a second fraction of said laser output to second fraction of said multiple ones at a second time.

10. A scanning device for scanning a target surface having data written thereon, said data being arranged in columns of adjacent data cells on said target surface, each of said columns of data cells having one of a set of possible configurations representing data, comprising:

a read/write head with an array of input apertures arranged in successive columns such that each of said columns receives light from a same one of said columns of data cells;

at least one detector connected to detect light received by said array of input apertures;

said detector generating a signal indicating an estimate of a one of said possible configurations by combining information derived from light received by all of said successive columns.

11. A device as in claim 10, wherein said detector combines said information by detecting light from each of said columns and synthesizing an improved estimate of said one of said possible configurations from a combination of signals generated thereby.

13. A device as in claim 12, wherein said scanning head includes at least one laser connected to conduct light to said array of input apertures, whereby said array of input apertures functions as an array of output apertures from which light is emitted.

14. A device as in claim 13, further comprising an imaging optical element positioned between said scanning head and said target surface to image light emitted from said output apertures onto said target surface, said light from said same one of said columns of data cells being light emitted from said array of output apertures, returned from said target surface, and imaged by said imaging optical element back onto said input apertures.

15. A device as in claim 14, wherein at least one detector is an array of detectors, each being respective of one of said array of input apertures and said scanning head includes a light guide leading from each of said input apertures of said array of input apertures to said respective detector.

17. A method as in claim 16, wherein:

said first step of receiving includes receiving light at a first input aperture corresponding to said first output aperture; and

said second step of receiving includes receiving light at a second input aperture corresponding to said second output aperture.

19. A method as in claim 18, wherein:

said first step of receiving includes receiving light at a first input aperture corresponding to said first output aperture; and

said second step of receiving includes receiving light at a second input aperture corresponding to said second output aperture.

12. A scanning device for scanning a target surface having data written thereon, said data being arranged in columns of adjacent data cells on said target surface, each of said columns of data cells having one of a set of possible configurations representing data, comprising:

a scanning head with an array of input apertures arranged in successive columns such that each of said columns receives light from a same one of said columns of data cells and each;

at least one detector connected to detect light received by said array of input apertures;

said detector generating a signal indicating an estimate of a one of said possible configurations by combining information derived from light received by all of said successive columns.

16. A method of reading data from a recorded surface having successive columns of data cells, said successive columns comprising at least one row of said data cells, comprising the steps of:

moving said recorded surface such that light from a first output aperture is focused onto a first of said successive columns;

receiving light returned from said recorded surface responsively to said first step of moving;

detecting light returned from said recorded surface and storing a first result thereof;

moving said recorded surface such that light from a second output aperture is focused onto said first of said successive columns;

receiving light returned from said recorded surface responsively to said second step of moving;

detecting light returned to said first input aperture and storing a second result thereof,

calculating data represented by said first of said respective columns responsively to a computed combination of said first and second results.

18. A method of reading data from a recorded surface having successive columns of data cells, said successive columns comprising at least one row of said data cells, comprising the steps of:

moving said recorded surface such that light from a first output aperture is focused onto a first of said successive columns;

receiving light returned from said recorded surface responsively to said first step of moving;

detecting light returned from said recorded surface and storing a first result thereof;

moving said recorded surface such that light from a second output aperture is focused onto said first of said successive columns;

receiving light returned from said recorded surface responsively to said second step of moving;

detecting light returned to said first input aperture and storing a second result thereof,

calculating data represented by said first of said respective columns responsively to a computed combination of said first and second results.

20. A scanning device for scanning a medium with data written thereon, said data being arranged in columns of adjacent data cells on said target surface, each of said columns of data cells having one of a set of possible configurations representing data, comprising:

a scanning head with an array of input apertures arranged in successive columns such that each of said columns receives light from a same one of said columns of data cells;

at least one detector connected to detect light received by said array of input apertures;

said detector generating a signal indicating an estimate of a one of said possible configurations by combining information derived from light received by all of said successive columns;

a frame connected to said scanning head;

said medium being attachable to said frame such that said medium is movable relative to said read/write head, whereby said media moves in a first direction relative to said read/write head;

an oscillating motor connected between said frame and said read/write head to oscillate said scanning head relative to said medium, whereby a spacing of said input apertures may exceed a spacing of said adjacent cells while permitting light returned from substantially all of said adjacent cells to be detected by said at least one detector.

21. A device as in claim 20, wherein said medium is moved continuously in said first direction at a constant speed.

22. A device as in claim 20, wherein a direction of an oscillation of said read/write head has a component substantially perpendicular to said first direction.

23. A device as in claim 22, wherein said scanning head includes at least one laser connected to conduct light to said array of input apertures, whereby said array of input apertures functions as an array of output apertures from which light is emitted.

24. A device as in claim 23, further comprising an imaging optical element positioned between said scanning head and said target surface to image light emitted from said output apertures onto said target surface, said light from said same one of said columns of data cells being light emitted from said array of output apertures, returned from said target surface, and imaged by said imaging optical element back onto said input apertures.

25. A device as in claim 24, wherein at least one detector is an array of detectors, each being respective of one of said array of input apertures and said scanning head includes a light guide leading from each of said input apertures of said array of input apertures to said respective detector.