Device and method for recording hand-written information

• US 6,985,643 B1
• Filed: 04/30/1999
• Issued: 01/10/2006
• Est. Priority Date: 04/30/1998
• Status: Expired due to Term

• Current Assignee: Anoto IP LIC HB
• Original Assignee: Anoto Group AB
• Inventors: Fåhraeus, Christer, Hugosson, Ola, Ericson, Petter
• Primary Examiner(s): Chen, Wenpeng
• Application Number:
  US09/673,702
• Time in Patent Office: 2,447 Days
• Field of Search: 382/314, 382/312, 382/313, 382/321, 382/324, 382/181, 382/182, 382/185, 382/186, 382/187, 382/284, 382/294, 358/473
• US Class Current: 382/313
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text
• CPC Class Codes: G06V 10/19 by sensing codes defining pattern positions
• CPC Class Codes: G06V 30/142 using hand-held instruments; Constructional details of the instruments
• CPC Class Codes: G06V 30/1423 the instrument generating sequences of position coordinates corresponding to handwriting preprocessing or recognising digital ink G06V30/32

Abstract

A device for recording hand-written information in the form of characters, symbols, graphs, drawings, calligraphy and similar hand-written information defined by a hand movement, comprises recording means (3) which are adapted to be moved by a hand which carries out the hand movement and to record a plurality of images with partially overlapping contents while the recording means are being moved. The device further comprises image-processing means (4) which are adapted to determine the relative position of the images with the aid of the partially overlapping contents for providing a description in digital format of how the unit has been moved and, in this way, a digital representation of the hand-written representation. A method of recording hand-written information is also disclosed.

Claims

1. A method of recording handwritten information defined by a hand movement, said method comprising:

providing a surface having a preexisting pattern;

providing an imaging device;

moving the imaging device with a hand which is carrying out the hand movement relative to the surface while recording with the imaging device a plurality of images of the preexisting pattern with partially overlapping contents;

comparing said images in pairs to determine, with the aid of the partially overlapping contents, a relative shift of the preexisting pattern between each pair of images; and

providing a description in digital format of how the imaging device has been moved over the surface based at least in part on the thus-determined relative shifts.

2. A method according to claim 1, wherein the handwritten information comprises characters and further comprising identifying the characters with the aid of the description and storing them in character-coded digital format.

3. A method according to claim 1, further comprising displaying the handwritten information based on said description.

4. A method according to claim 1, further comprising determining, on the basis of the partially overlapping contents of the images, the speed at which the device has been moved between recording of two images.

5. A method according to claim 4, further comprising comparing the speed with pre-recorded speed data for checking the authenticity of the handwritten information.

6. A method according to claim 1, further comprising indicating on the surface the movement of the device.

7. A method according to claim 1, further comprising recording pre-existing information on an information carrier by imaging the pre-existing information with the aid of a plurality of images with partially overlapping contents.

8. A method according to claim 7, further comprising adjusting the device from a first operational mode for recording the handwritten information to a second operational mode for recording the pre-existing information.

9. The method according to claim 1, further comprising storing the handwritten information by storing said description.

10. The method according to claim 1, wherein said comparing the images in pairs is performed in parallel with said providing a description in digital format.

11. A method according to claim 1, wherein the imaging device comprises a light-sensitive sensor with a two-dimensional sensor surface for recording the images, and a light source, further comprising selectively activating the light source to illuminate said surface while controlling said light-sensitive sensor to capture images of the thus-illuminated surface.

12. A method according to claim 11, further comprising selectively activating the light source to strobe at a predetermined frequency.

13. A method according to claim 1, further comprising selectively operating a transceiver to transfer said description to an external device.

14. A method according to claim 13, wherein the transceiver communicates wirelessly with the external device.

15. A method according to claim 1, further comprising operating a pen tip connected to the imaging device to generate permanent marks on said surface, said marks being undetectable to said imaging device.

16. A method according to claim 1, further comprising operating a pen tip connected to the imaging device to generate permanent marks on said surface, such that said marks are excluded from said images.

17. A method according to claim 1, wherein said preexisting pattern includes graphics printed on the surface.

18. A method according to claim 1, wherein said comparing said images in pairs comprises evaluating every possible candidate shift between said pair of images.

19. A method according to claim 1, wherein said comparing said images in pairs comprises evaluating, based on a plurality of element values for each image, different candidate shifts between said pair of images by:

applying said candidate shifts to one image with respect to the other image in said pair of images;

effecting, for each candidate shift, a comparison of each element value of said one image and an overlapping element value of said other image; and

when the comparison fulfills a predetermined criterion, selectively updating a match rate value for the candidate shift.

20. A method according to claim 19, wherein said comparing said images in pairs further comprises determining said relative shift as the candidate shift that has an optimum match rate value.

21. A device for recording handwritten information defined by a hand movement, comprising:

an imaging device configured to be moved by a hand which carries out the hand movement and to record a plurality of images with partially overlapping contents of a surface having a preexisting pattern while the imaging device is being moved; and

an image processor configured to compare said images in pairs to determine, with the aid of the partially overlapping contents, a relative shift of the preexisting pattern between each pair of images and to provide a description in digital format of how the imaging device has been moved over the surface based at least partially on the thus-determined relative shifts.

22. A device according to claim 21, wherein said description comprises a plurality of movement vectors each indicating how the imaging device has been moved between said pair of images.

23. A device according to claim 21, wherein said description comprises turning indications, each indicating how the imaging device has been turned between said pair of images.

24. A device according to claim 21, wherein said device is configured to determine, on the basis of the partially overlapping contents of the images, the speed at which the imaging device has been moved between said pair of images.

25. A device according to claim 24, wherein said device is configured to compare the speed with pre-recorded speed data for checking the authenticity of the inputted information.

26. A device according to claim 21, wherein the handwritten information comprises characters and wherein the image processor is further configured to identify the characters with the aid of said description and to store the identified characters in character-coded format.

27. A device according to claim 21, wherein said image processor is configured to determine the relative shift both horizontally and vertically.

28. A device according to claim 21, further comprising a tracer for indicating on the surface the movement of the imaging device.

29. A device according to claim 28, wherein the tracer comprises an illuminator which projects light onto the surface.

30. A device according to claim 21, wherein the imaging device and the image processor are arranged in a common casing which is configured to be moved by the hand carrying out the hand movement.

31. A device according to claim 21, wherein the imaging device is arranged in a first casing and the image processor in a second casing.

32. A device according to claim 21, wherein said device is adjustable to an operational mode in which it is configured to record predefined information located on an information carrier, by imaging the predefined information with the aid of a plurality of images with partially overlapping contents.

33. A device according to claim 21, wherein said device is adjustable to an operational mode in which it is configured to image an object located at a distance from the device.

34. A device according to claim 21, further comprising a display for reproducing the handwritten information based on said description.

35. A device according to claim 21, wherein the imaging device comprises a controller, a light-sensitive sensor with a two-dimensional sensor surface for recording the images, and a light source, said controller selectively activating the light source to illuminate said surface while said light-sensitive sensor is being controlled to capture images of the thus-illuminated surface.

36. A device according to claim 35, wherein said controller selectively activates the light source to strobe at a predetermined frequency.

37. A device according to claim 21, wherein the image processor is configured to store said description in a memory.

38. A device according to claim 37, which is configured to selectively derive said description from the memory and operate a transceiver to transfer said description to an external device.

39. A device according to claim 38, wherein the transceiver is configured for wireless communication with the external device.

40. A device according to claim 21, further comprising a pen tip for generating permanent marks on said surface, said marks being undetectable to said imaging device.

41. A device according to claim 21, further comprising a pen tip for generating permanent marks on said surface, said device being configured to exclude said marks from said images.

42. A device according to claim 21, wherein said preexisting pattern includes graphics printed on the surface.

43. A device according to claim 21, wherein the imaging device comprises a lens system with automatic focus control.

44. A device according to claim 21, wherein the image processor is configured to evaluate every possible candidate shift between said pair of images.

45. A device according to claim 21, wherein the image processor is configured to evaluate, based on a plurality of element values for each image, different candidate shifts between said pair of images by:

applying said candidate shifts to one image with respect to the other image in said pair of images;

effecting, for each candidate shift, a comparison of each element value of said one image and an overlapping element value of said other image; and

when the comparison fulfills a predetermined criterion, selectively updating a match rate value for the candidate shift.

46. A device according to claim 45, wherein the image processor is configured to determine said relative shift as the candidate shift that has an optimum match rate value.