Apparatus and method for determining spatial orientation

• US 20020048404A1
• Filed: 03/21/2001
• Published: 04/25/2002
• Est. Priority Date: 03/21/2000
• Status: Abandoned Application

• Current Assignee: Anoto Group AB
• Original Assignee: Anoto Group AB
• Inventors: Persson, Erik, Burstrom, Stefan, Pettersson, Mats Petter, Fahraeus, Christer
• Application Number:
  US09/812,902
• Publication Number:
  US 20020048404A1
• Time in Patent Office: Days
• US Class Current: 382/188
• CPC Class Codes: G06F 3/0321 by optically sensing the absolute position with respect to a regularly patterned surface forming a passive digitiser, e.g. pen optically detecting position indicative tags printed on a paper sheet constructional details of pen-shaped pointing devices G06F3/03545, G06F3/03542, G06F3/037
• CPC Class Codes: G06F 3/03545 Pens or stylus

Abstract

A system and a corresponding method for determining a spatial relationship between a surface having a predetermined pattern and an apparatus are disclosed. A portion of the surface may be imaged and compared with the predetermined pattern. The comparison produces at least one reference measurement that may be used to determine a spatial relationship expressed in at least parameters that define an orientation of the surface. By using knowledge of the predetermined pattern together with an algebraic model of the image formation by the apparatus, a numerical adaptation can be performed. Parameters obtained from the adaptation can then be used to calculate the spatial relationship between the apparatus and the surface in terms of, for example, a distance between the apparatus and the surface or an angle between the surface and an axis extending through the apparatus.

Claims

1. A system for determining a three-dimensional spatial relationship between a surface provided with a predetermined pattern and an apparatus, the system comprising:

means for imaging a portion of the pattern;

means for comparing the imaged portion with the predetermined pattern to obtain at least one reference measurement, wherein the reference measurement depends on the orientation of the surface; and

means for determining a spatial relationship expressed in parameters defining the orientation of the surface.

2. The system according to claim 1, wherein the means for comparison includes means for comparing a number of directed stretches in the image and vectors from the predetermined pattern.

3. The system according to claim 2, wherein the means for determining further includes means for calculating vectors using the least square method.

4. The system according to claim 3, wherein the spatial relationship includes a distance vector between the apparatus and the surface.

5. The system according to claim 4, wherein the spatial relationship includes an angle between an axis extending through the apparatus and the surface.

6. The system according to claim 5, wherein the means for comparison includes means for determining a set of parameters defining a vector that, in relation to a plane extending through the apparatus, determines an inclination for the surface.

7. The system according to claim 5, wherein the means for comparison includes means for determining a set of parameters defining a vector, wherein the vector identifies a normal vector for the surface.

8. The system according to claim 5, wherein the means for comparison includes means for determining at least one parameter defining an angular orientation for the imaged pattern about a normal vector.

9. The system according to claim 5, wherein the imaging means includes means for one-dimensional pattern imaging.

10. The system according to claim 5, wherein the imaging means includes means for two-dimensional pattern imaging.

11. The system according to claim 5, wherein the means for comparison comprise means for determining at least one parameter which unambiguously defines at least one of rotation, tilt and skew of the apparatus.

12. The system according to claim 1, wherein the apparatus is hand-held.

13. The system according to claim 12, wherein the apparatus is in the general form of a pen and comprises means for determining the position of a tip of the pen.

14. The system according to claim 1, further including means for wireless communication.

16. An apparatus according to claim 15, wherein the image-processor is further configured to compare a number of directed stretches in the image with predetermined vectors that follow from the predetermined pattern.

17. An apparatus according to claim 16, wherein the image-processor is further configured to perform calculations according to the least square method.

18. An apparatus according to claim 17, wherein the spatial relationship includes a distance vector between the apparatus and the surface.

19. An apparatus according claim 17, wherein the spatial relationship includes an angle between an axis extending through the sensor and the surface.

20. An apparatus according claim 17, wherein the image-processor is further configured to determine a set of parameters defining a vector that, in relation to a plane extending through the sensor, establish an inclination for the surface.

21. An apparatus according to claim 17, wherein the image-processor is further configured to determine a set of parameters defining a vector, wherein the vector is a normal vector for the surface having the pattern.

22. An apparatus according claim 21, wherein the image-processor is further configured to determine at least one parameter defining an angular orientation for the imaged pattern about a normal vector for the partial surface.

23. An apparatus according to claim 15, wherein the image-processing is further configured for one-dimensional pattern imaging.

24. An apparatus according to claim 15, wherein the image-processing is further configured for two-dimensional pattern imaging.

25. An apparatus according to claim 15, wherein the apparatus is hand-held.

26. An apparatus according to claim 25, wherein the apparatus is in the general form of a pen and comprises means for determining the position of a tip of the pen.

27. An apparatus according to 26, wherein the apparatus includes means for wireless transmission of information.

29. A method according to claim 28, wherein the predetermined pattern includes predetermined vectors and wherein comparing includes comparing the predetermined vectors to a number of directed stretches in the image portion.

30. A method according to claim 29, wherein detecting includes calculating the spatial relationship using a least square method.

31. A method according to claim 30, wherein calculating the spatial relationship includes calculating a distance between the apparatus and the surface.

32. A method according to claim 30, wherein calculating the spatial relationship includes calculating at least an angle between an axis extending through the apparatus and the surface.

33. A method according to claim 31, wherein comparing further includes determining a set of parameters defining a vector that, in relation to a plane extending through the apparatus, establish an inclination for the surface.

34. A method according to claim 31, wherein comparing further includes determining a set of parameters defining a vector, and wherein the vector is a normal vector for the surface having the pattern.

35. A method according to claim 31, wherein comparing further includes determining at least one parameter defining an angular orientation for the imaged pattern about a normal vector for the partial surface.

36. A method according to claim 31, wherein imaging comprises imaging a one-dimensional pattern.

37. A method according to 36, wherein imaging comprises imaging a two-dimensional pattern.

39. A method according to claim 38, wherein comparing further includes comparing a number of directed stretches in the image to predetermined vectors in the predetermined pattern.

40. A method according to claim 39, wherein determining includes calculating the spatial relationship using a least square method.

41. A method according to claim 40, wherein calculating the spatial relationship includes calculating a distance between an imaging sensor and the partial surface having the position-coding pattern.

42. A method according to claim 40, wherein calculating the spatial relationship includes calculating an angle between an axis extending through an imaging sensor and the partial surface having the position-coding pattern.

43. A method according to claim 40, further including determining a set of parameters defining a vector that, in relation to a plane extending through an imaging sensor, establish an inclination for the surface.

44. A method according to claim 40, further including determining a set of parameters defining a vector, wherein the vector is a normal vector for the surface having the pattern.

45. A method according to claim 40, further including determining at least one parameter defining an angular orientation for the imaged pattern about a normal vector for the partial surface.

46. A method according to claim 45, further including determining at least one parameter which unambiguously defines at least one of rotation, tilt and skew of the image sensor.

47. A method according to claim 46, wherein producing the image includes forming one-dimensional pattern imaging.

48. A method according to 47, wherein producing the image includes forming a two-dimensional pattern imaging.

49. A method according to claim 48, wherein the image sensor is in the general form of a pen and the method comprises determining the position of a tip of the pen.

57. An apparatus according to claim 18, wherein the image processor further includes means for determining at least one parameter which unambiguously defines at least one of a rotation, a tilt and a skew of the apparatus.

58. A method according to claim 31, wherein the comparing further includes determining at least one parameter which unambiguously defines at least one of a rotation, a tilt and a skew of the apparatus.

15. An apparatus for position determination, comprising:

a sensor configured to detect an image from one partial surface of a plurality of partial surfaces on a principle surface, wherein the principle surface includes a position-coding pattern; and

an image-processor, in communication with the sensor and configured to;

identify a predetermined plurality of symbols in the image, wherein each symbol is defined by a raster point and at least one marking, wherein the raster point forms part of a raster that extends over the principle surface and wherein the position of the marking in relation to the raster point indicates a value of each symbol;

determine the value of each symbol in the plurality of symbols;

translate the value of each symbol into at least one first digit for the first position code and at least one second digit for the second position code;

obtain a first coordinate using the first position code and a second coordinate by using the second position code;

compare the detected image with the predetermined pattern;

obtain at least one reference measurement, wherein the reference measurement depends on the orientation of the surface;

determine, using the reference measurement, a three-dimensional spatial relationship expressed in at least the parameters that define the orientation of the surface; and

obtain a third coordinate using the measurement of the spatial relationship.

28. A method for determining a spatial relationship between a surface having a predetermined pattern and an apparatus, the method comprising:

imaging a portion of the pattern;

comparing the imaged portion with the predetermined pattern to obtain at least one reference measurement, wherein the reference measurement depends on the orientation of the surface; and

determining, using the reference measurement, the spatial relationship expressed in at least the parameters defining the orientation of the surface.

38. A method of determining information from a principle surface of a product, comprising:

producing an image of one partial surface from a plurality of partial surfaces on the principle surface;

providing a position-coding pattern within the image;

locating a predetermined plurality of symbols in the image, each symbol having a raster point and at least one marking, the raster point forming part of a raster extending over the principle surface, and wherein a value of each symbol indicates a position of the marking in relation to a raster point;

determining the value of each symbol in the plurality of symbols;

translating the value of each symbol into at least one first position code and at least one second position code;

calculating a first coordinate using the first position code and a second coordinate using the second position code;

comparing the detected image with the pattern;

calculating at least one reference measurement, wherein the reference measurement depends on an orientation of the principle surface;

determining, using the reference measurement, a spatial relationship expressed in at least parameters that define the orientation of the principle surface; and

calculating a third coordinate using the determined spatial relationship.

50. A system comprising:

a sensor configured to detect an image from one partial surface of a plurality of partial surfaces on a surface, wherein the surface includes a position-coding pattern; and

a computer-readable medium containing a program including instructions to

identify a predetermined plurality of symbols in the image, wherein each symbol includes a raster point and at least one marking, wherein the raster point forms part of a raster that extends over the surface and wherein a position of the marking in relation to the raster point indicates a value each symbol;

determine the value of each symbol in the plurality of symbols;

translate the value of each symbol into at least one first digit for the first position code and at least one second digit for the second position code;

calculate a first coordinate using the first position code and a second coordinate by using the second position code;

compare the detected image with the position-coding pattern;

calculate at least one reference measurement, wherein the reference measurement depends on an orientation of the surface;

determine, using the reference measurement, a spatial relationship expressed in at least parameters that define the orientation of the surface; and

calculate a third coordinate using the determined spatial relationship.

51. The system of claim 50, wherein the sensor includes a wireless transceiver configured to communicate with the computer.

52. An apparatus for determining a three dimensional spatial relationship between a surface provided with a known pattern, the apparatus comprising:

means for imaging a part of the pattern,

means for comparing the imaged part of the pattern with the predetermined pattern, at least one reference measurement being obtained, which depends on the orientation of the surface,

means for determining, by means of the reference measurement, the spatial relationship expressed in at least the parameters which define the orientation of the surface.

53. A system for determining a three dimensional spatial relationship between a surface containing a known pattern and an apparatus for reading the pattern, the system comprising:

a sensor contained in the apparatus and for detecting markings within the pattern;

wherein the sensor is configured to detect at least one reference measurement which depends on the orientation of the surface, at least one reference measurement including a measurement of a relationship between at least one raster point and at least one marking; and

a processor for comparing the detected markings with the predetermined pattern, and for determining the spatial relationship based in part upon the reference measurement.

54. The system according to claim 53, wherein the determined spatial relationship includes a distance vector between the surface and a portion of the apparatus.

55. The system according to claim 54, wherein the determined spatial relationship includes an axis of the apparatus.

56. The system according to claim 55, wherein the raster point is virtual.

59. A method according to claim 58, wherein the apparatus is in the general form of a pen and the method further includes determining the position of a tip of the pen.

60. A method comprising:

using an apparatus to capture an image of a patterned surface

using a distortion in the image to calculated a relative spatial orientation between the surface and the apparatus for capturing the image.

61. The method claim 60, wherein said relative spatial orientation includes any one of a rotation, a tilt, a skewing or a distance between the surface and the apparatus.

62. The method claim 61, wherein the apparatus is a digital pen.