System and method for capturing document orientation information with a digital camera

• US 6,741,279 B1
• Filed: 07/21/1998
• Issued: 05/25/2004
• Est. Priority Date: 07/21/1998
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Allen, Ross R.
• Primary Examiner(s): HO, TUAN V
• Application Number:
  US09/120,096
• Time in Patent Office: 2,135 Days
• Field of Search: H04/N.5225, 348/207, 348/239, 348/222, 348/370, 348/371, 348/372, 348/61, 348/141, 348/143, 348/135, 348/169, 348/187, 348/220.1, 382/201, 382/209, 382/288, 382/294, 382/151, 382/291, 382/296, 382/152, 382/154, 382/106, 382/107, 382/108, 382/109, 250/566, 250/205.1, 396/106, 428/333, 235/462.45
• US Class Current: 348/239
• CPC Class Codes: G01B 11/2513 with several lines being projected in more than one direction, e.g. grids, patterns
• CPC Class Codes: G01B 11/306 for measuring evenness
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light
• 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 2201/043 Viewing the scanned area
• CPC Class Codes: H04N 2201/0434 specially adapted for scanning pages of a book
• CPC Class Codes: H04N 2201/0436 Scanning a picture-bearing surface lying face up on a support H04N2201/0434 takes precedence; using cylindrical picture bearing surfaces H04N1/06; with manual scanning H04N1/107
• CPC Class Codes: H04N 2201/04717 on the scanned sheet, e.g. a reference sheet
• CPC Class Codes: H04N 2201/04743 by detecting the image directly detecting reference images H04N2201/04717
• CPC Class Codes: H04N 2201/04749 Detecting position relative to a gradient, e.g. using triangular-shaped masks, marks or gratings

Abstract

The present invention provides a digital camera capturing technique for documents. In one embodiment, a method for a digital camera capturing technique includes determining an orientation of an object (e.g., a document) relative to an optical axis of the digital camera, and determining a distance of the object from the digital camera. The method also includes determining a planarity of the object (e.g., a curl of the document). The method further includes projecting a pattern on the object, and detecting the projected pattern, which is then processed to determine the orientation of the object relative to the optical axis of the digital camera, the distance of the object from the digital camera, and the planarity of the object.

Claims

1. A method for a digital camera capturing technique, the method comprising:

detecting an orientation of an object relative to an optical axis of the digital camera using light-emitting means for projecting a pattern on the object, and image sensor circuitry of the digital camera; and

capturing the object with the image sensor circuitry.

2. The method of claim 1 further comprising:

detecting a planarity of the object with the image sensor circuitry.

4. The method of claim 1 wherein the projected pattern is detected with the image sensor circuitry.

6. The method of claim 4 wherein the projected pattern comprises at least four projected spots.

7. The method of claim 4 wherein the projecting a pattern comprises emitting multiple beams of light.

8. The method of claim 7 wherein the multiple beams of light comprise parallel beams of light.

9. The method of claim 7 wherein the multiple beams of light comprise infrared beams.

10. The method of claim 7 wherein the multiple beams of light comprise diverging beams of light.

11. The method of claim 7 further comprising:

storing data that represents the orientation of the object and the planarity of the object.

3. A method for a digital camera capturing technique, the method comprising:

detecting an orientation of an object relative to an optical axis of the digital camera using image sensor circuitry of the digital camera;

capturing the object with the image sensor circuitry; and

detecting a curl of the object with the image sensor circuitry, wherein the object comprises a document.

5. A method for a digital camera capturing technique, the method comprising:

detecting an orientation of an object relative to an optical axis of the digital camera using image sensor circuitry of the digital camera;

capturing the object with the image sensor circuitry;

projecting a pattern on the object with emitter circuitry;

detecting a projected pattern with the image sensor circuitry; and

processing a detection of the projected pattern, with image processing circuitry, to determine the orientation of the object and the planarity of the object, wherein the object comprises a document.

12. An apparatus for a digital camera capturing technique, the apparatus comprising:

an image sensor, the image sensor detecting a spot pattern projected on an object; and

an image processor, the image processor in communication with the image sensor, the image processor determining an orientation of the object relative to an optical axis of the digital camera, wherein the image sensor captures the object.

13. The apparatus of claim 12 further comprising:

the image processor determining a planarity of the object.

14. The apparatus of claim 13 further comprising:

a plurality of emitters, the plurality of emitters projecting the spot pattern on the object.

15. The apparatus of claim 14 further comprising:

the image sensor comprising a plurality of CMOS sensors.

18. The apparatus of claim 14 wherein the plurality of emitters emit multiple beams of light.

19. The apparatus of claim 18 wherein the multiple beams of light comprise parallel beams of light.

20. The apparatus of claim 18 wherein the multiple beams of light comprise infrared beams.

21. The apparatus of claim 18 wherein the multiple beams of light comprise diverging beams of light.

22. The apparatus of claim 18 further comprising:

a memory, the memory storing data that represents the orientation of the object and the planarity of the object.

16. An apparatus for a digital camera capturing technique, the apparatus comprising:

an image sensor, the image sensor detecting a spot pattern projected on an object;

an image processor, the image processor in communication with the image sensor, the image processor determining an orientation of the object relative to an optical axis of the digital camera, wherein the image sensor captures the object, and wherein the image processor determines a planarity of the object;

a plurality of emitters, the plurality of emitters projecting the spot pattern on the object; and

logic that processes the projected spot pattern to determine the planarity of the object, wherein the object comprises a document.

17. An apparatus for a digital camera capturing technique, the apparatus comprising:

an image sensor, the image sensor detecting a spot pattern projected on an object;

an image processor, the image processor in communication with the image sensor, the image processor determining an orientation of the object relative to an optical axis of the digital camera, wherein the image sensor captures the object, and wherein the image processor determines a planarity of the object;

a plurality of emitters, the plurality of emitters projecting the spot pattern on the object; and

logic that processes the projected spot pattern to determine the orientation of the object, wherein the object comprises a document.

23. An apparatus for a digital camera capturing technique, the apparatus comprising:

an image sensor, the image sensor detecting a spot pattern projected on an object;

an image processor, the image processor in communication with the image sensor, the image processor determining an orientation of the object relative to an optical axis of the digital camera, wherein the image sensor captures the object, and wherein the image processor determines a planarity of the object;

a plurality of emitters, the plurality of emitters projecting the spot pattern on the object, wherein the plurality of emitters emit multiple beams of light; and

the image sensor detecting the multiple beams of light projected on the object, wherein the object comprises a document, whereby the image processor analyzes a detection of the multiple beams of light projected on the document to determine an orientation of the document, the planarity of the document, a curl of the document, and a distance of the document.

24. A method for a digital camera capturing technique for documents, the method comprising:

projecting a spot pattern on a document to be captured by the digital camera;

detecting the projected spot pattern;

analyzing the projected spot pattern to determine an orientation of the document relative to an optical axis of the digital camera and a planarity of the document.

25. The method of claim 24 further comprising:

(storing data that represents the orientation and the planarity of the document.

26. The method of claim 25 further comprising:

processing the data prior to capturing the document, whereby the image sensor captures the document in sharp focus and without geometric distortions.

27. The method of claim 24 further comprising:

processing multiple exposures of the document to capture portions of the document that are at multiple distances in sharp focus.

28. The method of claim 24 further comprising:

outputting a signal to indicate that the digital camera should be reoriented with respect to the document.

29. The method of claim 24 wherein the projected spot pattern comprises a projection of multiple beams of light.

30. The method of claim 29 wherein the multiple beams of light comprise parallel infrared beams.

31. The method of claim 24 further comprising:

analyzing the projected spot pattern to determine a distance of the document from the digital camera.

32. The method of claim 24 further comprising:

determining a curl of the document.

33. A method for a digital camera capturing technique the method comprising:

detecting an orientation of an object relative to an optical axis of the digital camera using image sensor circuitry of the digital camera and means for projecting a pattern on the object, wherein the detected orientation is relative to an axis normal to the plane of the object; and

capturing the object with the image sensor circuitry.

34. A digital camera for capturing an object, the digital camera comprising:

a light source for projecting a spot pattern on the object;

an image sensor for detecting the projected spot pattern; and

a processor, responsive to an output of the sensor, for determining an orientation of an object relative to an optical axis of the digital camera.

36. The digital camera of claim 34, wherein the processor further determines planarity of the object in response to the output of the sensor.

37. The digital camera of claim 34, wherein the processor also determines curl of the object in response to the output of the sensor.

38. The digital camera of claim 34, wherein the processor also determines a distance of the document from the digital camera in response to the output of the sensor.

39. The digital camera of claim 34, wherein the light source projects the spot pattern by projecting multiple beams of light.

35. A digital camera for capturing an object, the digital camera comprising:

means for projecting a spot pattern on the object;

means for detecting the projected spot pattern; and

means for using the detected spot pattern to determine orientation of the object relative to an optical axis of the digital camera.