Systems and methods for streak detection in image array scanning

• US 20050135709A1
• Filed: 12/22/2003
• Published: 06/23/2005
• Est. Priority Date: 12/22/2003
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Gusmano, Donald J., Hosier, Paul A., Tandon, Jagdish C.
• Granted Patent: US 7,528,997 B2
• Time in Patent Office: Days
• US Class Current: 382/309
• CPC Class Codes: H04N 1/00002 Diagnosis, testing or measuring; Detecting, analysing or monitoring not otherwise provided for error detection, error correction or monitoring in digital computers or digital computer components G06F11/00
• CPC Class Codes: H04N 1/00013 Reading apparatus
• CPC Class Codes: H04N 1/00023 Colour systems
• CPC Class Codes: H04N 1/00029 Diagnosis, i.e. identifying a problem by comparison with a normal state
• CPC Class Codes: H04N 1/0005 in service, i.e. during normal operation
• CPC Class Codes: H04N 1/00063 using at least a part of the apparatus itself, e.g. self-testing
• CPC Class Codes: H04N 1/1215 Feeding using one or more cylindrical platens or rollers in the immediate vicinity of the main scanning line
• 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

Abstract

In a system and method for streak detection in a fixed imaging array digital scanning system, redundant information regarding individual lines of a scanned image collected by multiple discrete rows or sets of scanning sensors in the imaging array are compared. Stationary obstructions in the field of view of the imaging array are detected through this comparison which would otherwise appear repeatedly reproduced as streaks or lines in the reproduced output image.

Claims

1. A system for streak detection in an image scanning device, comprising:

an imaging array comprising a plurality of rows or sets of positionally discrete sensors;

an interface that transmits image data obtained from each of the plurality of rows or sets of positionally discrete sensors to a comparison unit; and

a comparison unit that receives the image data and compares positionally redundant discrete image data obtained from each of a plurality of positionally separated rows or sets of sensors in the imaging array that has been normalized based on the presence of different filtering elements within the positionally separated rows or sets of sensors.

2. The system of claim 1, further comprising a transparent element overlying the imaging array wherein the imaging array is fixed with respect to the overlying transparent element.

3. The system of claim 1, further comprising a transport unit usable to transport an image to be scanned past the imaging array.

4. The system of claim 1, further comprising an image revision unit that applies revisions to image data based on differences between the normalized discrete image data determined by the comparison unit.

5. The system of claim 1, further comprising a scanned image data storage unit that stores discrete image data obtained from each of the plurality of rows or sets of positionally discrete sensors in the imaging array.

6. The system of claim 1, further comprising an output image data storage unit that stores revised or unrevised image data formatted for output to an image data sink.

7. An image scanning device including the system of claim 1.

8. A photocopying device including the system of claim 1.

9. A xerographic image reproducing device including the system of claim 1.

10. An image reproducing device including the system of claim 1.

11. A method for streak detection in a scanning device, comprising:

redundantly scanning an image with separate rows or sets of a plurality of positionally separated rows or sets of sensors in an imaging array;

normalizing the image data collected from each of at least two of the separate rows or sets of a plurality of positionally separated rows or sets of sensors to account for the presence of different filtering elements within the positionally separated rows or sets of sensors;

comparing normalized image data collected from each of at least two of the separate rows or sets of a plurality of positionally separated rows or sets of sensors; and

detecting the presence of non-image data in the image data obtained from each of at least two of the separate rows or sets of a plurality of positionally separated rows or sets of sensors.

12. The method of claim 11, wherein comparing image data collected from each of at least two of the separate rows or sets of a plurality of positionally separated rows or sets of sensors comprises comparing image data collected from a transparent or no-filter row of sensors with composite image data from a plurality of rows or sets of color filtered sensors.

13. The method of claim 11, wherein comparing image data collected from each of at least two of the separate rows or sets of a plurality of positionally separated rows or sets of sensors comprises detecting edge variations between the data collected from each of at least two of the separate rows or sets of a plurality of positionally separated rows or sets of sensors.

14. The method of claim 11, further comprising revising the image data to compensate for the non-image data.

15. The method of claim 11, further comprising storing image data collected from at least two of the separate rows or sets of a plurality of positionally separated rows or sets of sensors.

16. The method of claim 11, further comprising formatting revised or unrevised output image data for output to an image data sink.

17. The method of claim 16, further comprising storing revised or unrevised output image data formatted for output to an image data sink.