Framing aid for a document capture device

• US 20010016084A1
• Filed: 12/28/2000
• Published: 08/23/2001
• Est. Priority Date: 02/21/2000
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Goris, Andrew C., Pilu, Maurizio, Pollard, Stephen Bernard
• Granted Patent: US 7,023,483 B2
• Time in Patent Office: Days
• US Class Current: 382/317
• CPC Class Codes: H04N 1/107 with manual scanning
• 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 2201/0452 Indicating the scanned area, e.g. by projecting light marks onto the medium

Abstract

A framing aid for a handheld document capture device such as a digital camera, comprising two pattern generators (10,20) generating convergent patterns (14, 24) that are in register on a target object plane. Triangulation between the two pattern generators (10,20) and using superimposed or complementary patterns (14,24) ensures that the hand held device (1) is correctly arranged at a predetermined range and orientation above a document to be captured, such that the document is accurately framed within the field of view of the capture device (1).

Claims

1. A framing aid for use with a document capture device, comprising:

a first pattern generator (10) for generating a first visible light pattern (14); and

a second pattern generator (20) for generating a second visible light pattern (24);

wherein the first and second visible light patterns (14,24) are in register on a target object plane.

2. A framing aid as claimed in

claim 1

, wherein the first and second light patterns are convergent and align on the target object plane.

3. A framing aid as claimed in

claim 1

, wherein the first pattern (14) and the second pattern (24) are superimposed on the target object plane.

4. A framing aid as claimed in

claim 1

, wherein the first pattern (14) and the second pattern (24) are complementary on the target object plane.

5. A framing aid as claimed in

claim 1

, wherein the first pattern (14) and the second pattern (24) are at least partially superimposed on the target object plane and are at least partially complementary on the target object plane.

6. A framing aid as claimed in

claim 1

, wherein the first pattern (14) and the second pattern (24) are in register on the target object plane to determine the range and orientation of the document capture device.

7. A framing aid as claimed in

claim 1

, wherein at least one of the first pattern (14) or the second pattern (24) defines a field of view of the document capture device (1).

8. A framing aid as claimed in

claim 7

, wherein the at least one pattern (14,24) explicitly determines a field of view boundary frame.

9. A framing aid as claimed in

claim 1

, wherein at least one of the first pattern (14) or the second pattern (24) is located internally of a field of view of the document capture device (1).

10. A framing aid as claimed in

claim 1

, wherein the framing aid is suitable for use at a plurality of predetermined positions.

11. A framing aid as claimed in

claim 10

, wherein each pattern generator (10,20) is moveable to a plurality of predetermined configurations corresponding to the plurality of predetermined positions of the document capture device.

13. A pattern generating apparatus as claimed in

claim 11

, wherein the pattern generating element (13) is a diffractive optical element.

14. A pattern generating apparatus as claimed in

claim 13

, wherein the pattern generating element (13) has a fan angle greater than 50°

in at least one plane.

12. A pattern generating apparatus for use in a framing aid for a document capture device, the pattern generating apparatus comprising:

a light source (11); and

a pattern generating element (13) for generating an interference pattern in a light pattern (14) is projected on to a target object plane.

15. A framing aid for use with a document capture device, the framing aid comprising:

an image sensor (4) arranged in an image plane (4a);

a pattern generating apparatus (10) arranged laterally offset with respect to the image sensor (4), the pattern generating apparatus for producing a pattern of visible light radiation on a target object plane (6a,7a,8a) spaced apart from the image plane (4a) of the image sensor (4); and

adjustment means (9) for moving the pattern generating apparatus (10) with respect to the image sensor (4), or vice versa, according to a range from the image plane (4a) to the target object plane (6a,7a,8a).

16. A framing aid as claimed in

claim 15

, comprising a range finder (30) for determining the range between the image plane (4a) and the target object plane (6a,7a,8a), the adjustment means (9) being responsive to the range determined by the range finder (30).

17. A framing aid as claimed in

claim 15

, wherein the adjustment means (9) is arranged to move the image sensor (4) laterally to adjust the lateral offset between the sensor (4) and the pattern generating apparatus (10).

18. A method for positioning a document capture device (1) with respect to a document (2), comprising the steps of:

generating a first visible light pattern (14);

generating a second visible light pattern (24);

moving the document capture device (1) and/or the document (2) such that the first and second visible light patterns (14,24) are in register on a target object plane containing the document when the document capture device is at a predetermined position with respect to the target object plane.

19. A method as claimed in

claim 18

, wherein the first pattern (14) and the second pattern (24) are in register on the target object plane when the document capture device (1) is at a predetermined range and orientation with respect to the target object plane.

20. A method for positioning a document capture device (1) with respect to a document (2), the document capture device including an image sensor (4) located in an image plane (4a), the method comprising the steps of:

generating a visible light pattern from a pattern generating apparatus (10) laterally offset with respect to the image sensor (4), the visible light pattern being projected onto an object plane (6a) spaced apart at a range from the image plane (4a) of the image sensor (4); and

dynamically adjusting the relative position of the pattern generating apparatus (10) and the image sensor (4) according to the range between the image plane (4a) and the object plane (6a,7a,8a).