Method and system for multi-sensor signal detection

• US 6,924,911 B1
• Filed: 10/11/2000
• Issued: 08/02/2005
• Est. Priority Date: 10/12/1999
• Status: Expired due to Term

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Lee, Raymond S., Dundon, Thomas A., Edgar, Albert D., Potucek, Martin, Ford, Gordon D.
• Primary Examiner(s): Williams, Kimberly
• Assistant Examiner(s): Worku, Negussie
• Application Number:
  US09/686,336
• Time in Patent Office: 1,756 Days
• Field of Search: 358/506, 358/505, 358/504, 358/487, 358/475, 358/509, 358/496, 358/497
• US Class Current: 358/506
• CPC Class Codes: H04N 1/04 Scanning arrangements , i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versaH04N1/387 takes precedence
• CPC Class Codes: H04N 1/12 using the sheet-feed movement or the medium-advance or the drum-rotation movement as the slow scanning component, e.g. arrangements for the main-scanningsheet-feed movement by translatory movement of a flat picture-bearing surface H04N1/1008; main-scanning using oscillating or rotating mirrors H04N1/113; using multi-element arrays H04N1/19
• CPC Class Codes: H04N 1/193 using electrically scanned linear arrays , e.g. linear CCD arrays
• CPC Class Codes: H04N 1/4097 Removing errors due external factors, e.g. dust, scratches
• CPC Class Codes: H04N 1/486 with separate detectors, each detector being used for one specific colour component
• CPC Class Codes: H04N 2201/0081 Image reader H04N2201/0091 - H04N2201/0094 take precedence

Abstract

A method and apparatus for defect detection through color-filter channels is provided. The present invention includes an electronic scanner or similar device having a multilinear imager, a computer, and software that implements all the color channels of the multilinear imager to collect IR information in order to detect defects on a physical medium. The present invention implements methods to increase IR gathering speed and/or increase the clarity of captured images on multilinear-imager devices. These improvements are accomplished by capturing infrared (IR) light through each color-filter channel such that image defects such as dust and scratches are removed. In one embodiment of the present invention, IR information is collected from each color channel at different scan positions in either a one-pass or a two-pass scanning system. In another embodiment of the present invention, each RGB color channel is used to collect both image and detect information at every scan line, again, either a one-pass or a two-pass scanning system.

Claims

1. A method for capturing image and defect information from an image scanned from a medium, comprising the steps of:

capturing image and defect information by a sensor unit during every scan position while transmitting visible light from a first light source through the medium; and

capturing defect information by the sensor unit during every third scan position while transmitting infrared light from a second light source through the medium.

2. A method according to claim 1, further comprising the steps of:

aligning the sensor unit and/or the medium in a first alignment during transmission of visible light; and

aligning the sensor and/or the medium in a second alignment during transmission of infrared light.

3. A method according to claim 1, wherein visible light and infrared light are not transmitted simultaneously through the medium.

4. A method according to claim 1, wherein the medium comprises one of a film, a document, and a photograph.

5. A method according to claim 1, wherein the steps of transmitting visible light and infrared light through the medium occur during a first pass.

6. A method according to claim 1, wherein the step of transmitting visible light occurs during a first pass and the step of transmitting infrared light occurs during a second pass.

7. A method according to claim 1, wherein every scan position comprises three separate scan lines, each scan line associated with either a red, green, and blue channel of the sensor unit.

8. A method for capturing image and defect information from an image scanned from a medium, comprising the step of:

(1) alternatively transmitting visible light and infrared light through the medium for each scan line up to n lines in conjunction with capturing image and defect information during visible light transmission and capturing defect information during infrared light transmission;

(2) transmitting only visible light through the medium at each scan line for the next 2n scan lines in conjunction with capturing image information during visible light transmission after performing step (1); and

(3) repeating steps (1) and (2) until all image and defect information is captured for the medium.

9. A method according to claim 8, wherein n equals a pixel pitch multiplied by a sensor line pitch divided by a scanning rate.

10. A method for capturing image and defect information from an image scanned from a medium, comprising the steps of:

transmitting visible light from a first light source through the medium to capture image and defect information by a sensor unit during every scan position with the sensor unit and/or the medium in a first alignment; and

transmitting infrared light from a second light source through the medium to capture defect information by the sensor unit during every scan position after moving the sensor and/or the medium to a second alignment different than the first alignment.

11. A method according to claim 10, wherein visible light is transmitted through the medium before the infrared light is transmitted.

12. A method according to claim 10, wherein the medium comprises one of a film, a document, and a photograph.

13. A method according to claim 10, wherein the steps of transmitting visible light and infrared light through the medium occur during a first pass.

14. A method according to claim 10, wherein the step of transmitting visible light occurs during a first pass and the step of transmitting infrared light occurs during a second pass.

15. A method according to claim 10, wherein every scan position comprises three separate scan lines, each scan line associated with either a red, green, and blue channel of the sensor unit.

16. A scanner used for capturing image and defect data from a surface of a medium containing an image thereon, comprising:

a first light source and a second light source;

a first switch coupled to the first light source and a second switch coupled to the second light source;

a power supply coupled to the first and second light switches;

a sensor unit having a multi-linear imager and optical lens, the optical lens adapted to focus light transmitted through the surface of the medium to the multi-linear imager, thereby capturing image and defect information;

an analog to digital converter adapted to convert the image and defect information to digital image and defect data;

a transport mechanism adapted to align the sensor unit and/or the medium for capturing the image and defect information, wherein the transport mechanism is configured for aligning the sensor unit and/or the medium in a first alignment for capturing image information and for moving the sensor unit and/or the medium to a second alignment different than the first alignment for capturing defect information; and

a controller adapted to control the first switch, the second switch, the transport mechanism, and the sensor unit.

17. An apparatus according to claim 16, wherein the first light source generates visible light, and the second light source generates infrared light.

18. An apparatus according to claim 16, wherein the first light source is used to capture image and defect information and the second light source is used to capture defect information.

19. An apparatus according to claim 16, wherein the first light source and the second light source do not generate light simultaneously.

20. An apparatus according to claim 16, wherein the medium comprises one of a film, a document, and a photograph.

21. A method of digitizing a source image, comprising:

collecting visible light data and infrared light data simultaneously on at least two color sensor channels at a first increment of scan positions; and

collecting visible light data during a second increment of scan positions greater than the first increment of scan positions on at least one of said color sensor channels.