Reference grid rectilinear correction

• US 5,604,601 A
• Filed: 08/24/1994
• Issued: 02/18/1997
• Est. Priority Date: 08/24/1994
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Edgar, Albert D., Penn, Steven C.
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): JARDIEU, DEREK
• Application Number:
  US08/295,319
• Time in Patent Office: 909 Days
• Field of Search: 358/302, 358/406, 358/504, 358/448, 358/471, 358/474, 358/486
• US Class Current: 358/302
• CPC Class Codes: H04N 1/047 Detection, control or error compensation of scanning velocity or position H04N1/0402 and H04N1/17 take 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 1/40068 Modification of image resolution, i.e. determining the values of picture elements at new relative positions H04N1/3935 takes precedence
• CPC Class Codes: H04N 2201/02425 Self-adjusting arrangements, e.g. compensating for temperature fluctuations
• CPC Class Codes: H04N 2201/02439 Positioning method
• CPC Class Codes: H04N 2201/03162 Original guide plate
• CPC Class Codes: H04N 2201/0408 Scanning film strips or rolls
• CPC Class Codes: H04N 2201/04708 which remain outside the scanned image area
• CPC Class Codes: H04N 2201/0472 on or adjacent the sheet support
• CPC Class Codes: H04N 2201/04729 in the main-scan direction
• CPC Class Codes: H04N 2201/04731 in the sub-scan direction
• CPC Class Codes: H04N 2201/04732 Detecting at infrequent intervals, e.g. once or twice per line for main-scan control
• CPC Class Codes: H04N 2201/04734 Detecting at frequent intervals, e.g. once per line for sub-scan control
• CPC Class Codes: H04N 2201/04749 Detecting position relative to a gradient, e.g. using triangular-shaped masks, marks or gratings
• CPC Class Codes: H04N 2201/04787 by changing or controlling the addresses or values of pixels, e.g. in an array, in a memory, by interpolation
• CPC Class Codes: H04N 2201/04789 in the main-scan direction
• CPC Class Codes: H04N 2201/04791 in the sub-scan direction
• CPC Class Codes: H04N 2201/04794 Varying the control or compensation during the scan, e.g. using continuous feedback or from line to line

Abstract

A scanner for copying an image from substrate including a substrate holder for holding the substrate having a reference grid preferably disposed to one side of the substrate. The scanning means, e.g., a CCD array, simultaneously scans the image and the reference grid as the substrate holder is moved relative to the scanning means. The scanner contains software and/or hardware for interpreting the sensed portion of the reference grid as a position. The position is associated with the raw scan line of the image which was sensed at the same time as the sensed portion of the reference grid.

Claims

1. A scanner for copying an image from substrate comprising:

a scanning means for sensing the substrate image and a reference grid disposed proximate to the substrate;

transport means for moving the substrate and reference grid relative to the scanning means;

means for interpreting a sensed portion of the reference grid as a position and associating the position with a contemporaneously sensed raw scan line of the image; and

means for processing sensed pixels in raw scan lines to processed pixels at a chosen spacing in an image buffer according to the positions associated with the raw scan image buffer lines, wherein several sensed pixels are weighted together to calculate a processed pixel.

2. The scanner as recited in claim 1 wherein the reference grid has a first area which is interpreted to establish a vertical position of the raw scan line.

3. The scanner as recited in claim 2 wherein the reference grid has a second area which is interpreted to establish a relative horizontal position of the raw scan line.

4. The scanner as recited in claim 3 wherein the reference grid has a third area which is interpreted to establish an absolute horizontal position of the raw scan line.

5. The scanner as recited in claim 4 wherein the first area contains a continuous horizontal line, the second area contains a set of slanted lines and the third area contains a set of horizontal clock lines.

6. The scanner as recited in claim 1 wherein the reference grid is at least one reference track disposed one side of the substrate.

7. A method for copying an image from substrate comprising the steps of:

scanning the substrate and a reference grid disposed proximate to the substrate;

interpreting a sensed portion of the reference grid as a position;

associating the position with a contemporaneously sensed raw scan line of the image; and

processing sensed pixels in raw scan lines to processed pixels at a chosen spacing in an image buffer according to the positions associated with the raw scan lines, wherein several sensed pixels are weighted together to calculate a processed pixel.

8. The method as recited in claim 7 wherein the interpreting step interprets a first area of the reference grid to establish a vertical position of the raw scan line.

9. The method as recited in claim 8 wherein the interpreting step interprets a second area of the reference grid to establish a relative horizontal position of the raw scan line.

10. The method as recited in claim 9 wherein the interpreting step interprets a third area of the reference grid to establish an absolute horizontal position of the raw scan line.

11. The method as recited in claim 10 wherein the first area contains a continuous horizontal line, the second area contains a set of slanted lines and the third area contains a set of horizontal clock lines.

12. The method as recited in claim 7 wherein the reference grid is at least one reference track disposed on at least one side of the substrate.

13. A scanner for copying an image from substrate comprising:

a scanning means for sensing the substrate image and a reference grid disposed proximate to the substrate;

transport means for moving the substrate and reference grid relative to the scanning means; and

means for interpreting a sensed portion of the reference grid as a horizontal and vertical position and associating the position with a contemporaneously sensed raw scan line of the image to establish a relative horizontal and vertical position of the raw scan line.

14. The scanner as recited in claim 13 wherein the reference grid is also used to establish an absolute horizontal position of the raw scan line.

15. The scanner as recited in claim 14 wherein a first area of the reference grid contains a continuous horizontal line which is used to establish the vertical position of the raw scan line, a second area of the reference grid contains a set of slanted lines which is used to establish the relative horizontal position of the raw scan line and a third area of the reference grid contains a set of horizontal clock lines which is used to establish the absolute horizontal position of the raw scan line.

16. A method for copying an image from substrate comprising the steps of:

scanning the substrate and a reference grid disposed proximate to the substrate;

interpreting a sensed portion of the reference grid as a horizontal and vertical position; and

associating the position with a contemporaneously sensed raw scan line of the image to establish a relative horizontal and vertical position of the raw scan line.

17. The method as recited in claim 16 wherein the interpreting step interprets the sensed portion of the reference grid to establish an absolute horizontal position of the raw scan line.

18. The method as recited in claim 17 wherein interpreting step interprets a first area of the referenced grid which contains a continuous horizontal line to establish the vertical position of the raw scan line, the second area of the reference grid which contains set of slanted lines to establish the relative horizontal position of the raw scan line and the third area of the reference grid which contains a set of horizontal clock lines to establish the absolute horizontal position of the raw scan line.