Document periscope

• US 6,512,539 B1
• Filed: 09/29/1999
• Issued: 01/28/2003
• Est. Priority Date: 09/29/1999
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Dance, Christopher R., Taylor, Stuart A., Seeger, Mauritius
• Primary Examiner(s): Kelley, Chris
• Assistant Examiner(s): Bugg, George A
• Application Number:
  US09/408,872
• Time in Patent Office: 1,217 Days
• Field of Search: 348/37, 348/49, 348/61, 348/145, 348/146, 348/202, 348/203, 358/474, 382/317, 382/323
• US Class Current: 348/203
• CPC Class Codes: H04N 1/195 the array comprising a two-dimensional array or a combination of two-dimensional arrays
• CPC Class Codes: H04N 1/19594 using a television camera or a still video camera
• CPC Class Codes: H04N 2201/0426 Scanning an image in a series of contiguous zones
• CPC Class Codes: H04N 23/58 Means for changing the camera field of view without moving the camera body, e.g. nutating or panning of optics or image sensors

Abstract

A composite higher resolution image of an object can be obtained by combining or patching together multiple low-resolution camera images to form a composite image having a higher resolution. Each low-resolution camera image represents a subsection of an object (also referred to as “object subsection”) to be scanned. For example, each subsection may represent a quadrant of a document page. With the use of a periscope, the image visible to the camera can be shifted to capture images of the various object subsections. Mosaicing techniques are used to combine these camera images into a composite image of the object. This approach to scanning improves the resolution of documents scanned while using existing low cost video cameras.

Claims

1. An optical system, comprising:

an inner reflective surface having an axis of rotation;

a driving mechanism attached to the inner reflective surface and operable to rotate the inner reflective surface to a plurality of predetermined positions about the axis of rotation; and

a plurality of stationary outer reflective surfaces, wherein each of the outer reflective surfaces together with the inner reflective surface positioned at one of the predetermined positions about the axis of rotation forms a reflective light path for enabling a camera, with an optical axis aligned with the axis of rotation of the inner reflective surface, to capture light rays originating from one of a plurality of object subsections.

2. The optical system of claim 1, further comprising a plurality of sets of intermediate reflective surfaces, each set together with a corresponding outer reflective surface and the inner reflective surface positioned at one of the predetermined positions about the axis of rotation enables the camera to capture light rays originating from one of the plurality of object subsections.

3. The optical system of claim 2, wherein each of the sets of the intermediate reflective surfaces includes one or more intermediate reflective surfaces.

4. The optical system of claim 1, further comprising a support structure wherein the plurality of outer reflective surfaces are mounted on the support structure.

5. The optical system of claim 4, wherein the inner reflective surface is mounted on the support structure.

6. The optical system of claim 1, wherein at least one of the outer reflective surfaces is substantially parallel to the inner reflective surface when positioned at one of the predetermined positions about the axis of rotation.

7. The optical system of claim 1, wherein the driving mechanism is a motor.

8. The optical system of claim 1, further including a camera having an optical axis aligned with the axis of rotation, the camera operable to record an image of each of the object subsections within a single frame as the inner reflective surface is rotated about the axis of rotation.

9. The optical system of claim 1, wherein the inner reflective surface and the outer reflective surfaces are mirrors angled approximately 45 degrees with respect to the axis of rotation of the inner mirror such that each outer reflective surface is substantially parallel to the inner reflective surface when the inner reflective surface is positioned at one of the predetermined positions about the axis of rotation.

10. The optical system of claim 1, wherein the outer reflective surfaces are mirrors angled approximately 45 degrees with respect to the angle of rotation of the inner mirror and the inner mirror is angled less than 45 degrees with respect to the angle of rotation.

11. The optical system of claim 1, wherein the inner reflective surface is positionable along the axis of rotation.

12. The optical system of claim 8, further comprising an image processing system coupled to the camera and operable to combine the plurality of camera images to form a composite image of the object.

25. The optical system of claim 1, wherein only a single one of the plurality of outer reflective surfaces forms a reflective light path with the inner reflective surface at each of the predetermined positions.

26. The optical system of claim 2, wherein light rays from only one of the object subsections is captured by the camera at any one of the predetermined positions.

27. The optical system of claim 8, wherein only one of the object subsections is captured by the camera at any one of the predetermined positions.

13. A camera system, comprising:

an image sensor;

a lens system;

an inner reflective surface and a plurality of outer reflective surfaces operable to create a plurality of reflective light paths between the image sensor and the lens system, each reflective light path reflecting light originating from one of a plurality of subsections of an object to be captured by the image sensor;

wherein the inner reflective surface and the outer reflective surfaces are rotatable to a plurality of predetermined positions about an axis of rotation.

14. The camera system of claim 13, wherein the image sensor captures an image of one of the subsections of the object while the inner reflective surface and the plurality of outer reflective surfaces are positioned at one of the predetermined positions about the axis of rotation.

15. The camera system of claim 14 configured to record all subsections of the object by successively capturing each subsection through one of the reflective light paths.

16. The camera system of claim 13, wherein the plurality of outer reflective surfaces includes first, second and third outer reflective surface, and wherein the first and second outer surfaces are substantially parallel, and wherein the third outer surface and the inner outer surface are substantially parallel.

17. The camera system of claim 13, wherein the axis of rotation is normal to the image sensor and passes through a Centroid of the image sensor.

18. The camera system of claim 13, wherein the rotational axis is parallel to an optical axis of the lens system.

28. The camera system of claim 13, further comprising an image processing system operable to combine the plurality of subsections of an object captured by the image sensor to form a composite image of the object.

19. A camera system, comprising:

an image sensor;

a lens system;

an inner reflective surface and a plurality of outer reflective surfaces operable to create a plurality of reflective light paths between the image sensor and the lens system, each reflective light path reflecting light originating from one of a plurality of subsections of an object to be captured by the image sensor;

wherein the plurality of outer reflective surfaces are operable to translate radially about the axis of rotation.

20. The camera system of claim 19, wherein a first and second outer reflective surfaces translate radially as a unit, while a third outer reflective surface translates radially in the same direction but by twice the distance.

29. The camera system of claim 19, further comprising an image processing system operable to combine the plurality of subsections of an object captured by the image sensor to form a composite image of the object.

30. The camera system of claim 19, wherein the plurality of outer reflective surfaces includes first, second and third outer reflective surface, and wherein the first and second outer surfaces are substantially parallel, and wherein the third outer surface and the inner outer surface are substantially parallel.

31. The camera system of claim 19, wherein the axis of rotation is normal to the image sensor and passes through a centroid of the image sensor.

32. The camera system of claim 19, wherein the rotational axis is parallel to an optical axis of the lens system.

21. A method of scanning an object with a camera system, the object including N subsections and the camera system including an optical axis and a periscope having an inner reflective surface rotatable about an axis of rotation and N sets of outer reflective surfaces, comprising the steps of:

(a) aligning the optical axis of the camera system and the axis of rotation of the inner reflective surface;

(b) rotating an inner reflective surface at a first position about the axis of rotation of the inner reflective surface such that light rays originating from a first subsection of the object travel through a first reflective path formed by the inner reflective surface and a first set of outer reflective surfaces that is stationary;

(c) recording an image of the first subsection of the object;

(d) rotating the inner reflective surface at a next position about the axis of rotation of the inner reflective surface such that light rays originating from a next subsection of an object travel through a next reflective path formed by the inner reflective surface and a next set of outer reflective surfaces that is stationary;

(e) recording an image of the next subsection of the object; and

(f) repeating steps (d) and (e) until all images of the N subsections have been recorded; and

(g) combining the images of the N subsections to produce an image of the object.

22. The method of claim 21, wherein each set of outer reflective surfaces includes at least one outer reflective surface.

23. The method of claim 22, wherein step (9) includes the step of stitching together the images of the N subsections to generate the image of the object, wherein the stitched image has a higher resolution than the images of the N subsections.

24. A method of scanning an object with a camera system, the object including N subsections and the camera system including a periscope having a set of reflective surfaces including an inner reflective surface and a plurality of outer reflective surfaces, comprising the steps of:

(a) rotating the set of reflective surfaces at a first predetermined position about an axis of rotation such that light rays originating from a first subsection of the object travel through a first reflective path;

(b) recording an image of the first subsection of the object;

(c) rotating the set of reflective surface at a next predetermined position about the axis of rotation such that light rays originating from a next subsection of an object travel through a next reflective path;

(d) recording an image of the next subsection of the object; and

(e) repeating steps (c) and (d) until all images of the N subsections have been recorded; and

(f) combining the images of the N subsections to produce an image of the object.