Blended transfer function for computer pointing devices
View Patent ↗A transfer function is provided for use with computer pointing devices such as trackpads. The transfer function includes a first component having characteristics of a positional transfer function and a second component having characteristics of a velocity-based transfer function. The first (positional) component and the second (velocity-based) component of the transfer function are blended so that the transfer function exhibits purely positional behavior in response to a first range of inputs and exhibits combined positional and velocity-based behavior in response to a second range of inputs. The first range of inputs may, for example, correspond to a region in the input coordinate space that is bounded by a circle having a predetermined threshold radius.
1. A computer-implemented method for use with a pointing device for providing input to a computing device, the method comprising steps of:
(A) receiving an input vector representing input coordinates relative to a center of an input coordinate space associated with the pointing device, the input coordinate space comprising a first region and a second region;
(B) determining whether the input coordinates are within the first region of the input coordinate space;
(C) selecting a first transfer function if the input coordinates are determined to be within the first region;
(D) selecting a second transfer function if the input coordinates are determined not to be within the first region, the second transfer function comprising a non-constant function relating the input vector to velocity; and
(E) selecting a position and velocity of an on-screen pointer based on the selected transfer function.
2. The method of claim 1 , wherein the first transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h+kp*r,
wherein h comprises a vector representing a center of a positional range of the pointer, wherein kp comprises a positional gain, and wherein the first transfer function relates the velocity dh/dt of the center of the positional range of the pointer to the input vector r using the formula:
dh/dt= 0.
3. The method of claim 2 , wherein the positional gain kp comprises a value of about two millimeters per millimeter.
4. The method of claim 2 , further comprising steps of:
(F) identifying coordinates of the on-screen pointer upon commencement of a pointing operation; and
(G) setting the coordinates of the home vector h equal to the coordinates identified in step (F).
5. The method of claim 2 , wherein the positional gain kp comprises a value of about two millimeters per millimeter.
6. The method of claim 1 , wherein the second transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h+kp*r,
wherein h comprises a vector representing a center of a positional range of the pointer, wherein kp comprises a positional gain, and wherein the second transfer function relates the velocity dh/dt of the on-screen pointer to the input vector r using the formula:
dh/dt=kv*r,
wherein kv comprises a velocity gain.
7. The method of claim 5 , wherein the velocity gain kv comprises a value of about ten per second.
8. The method of claim 5 , further comprising steps of:
(F) identifying coordinates of the on-screen pointer upon commencement of a pointing operation; and
(G) setting the coordinates of the home vector h equal to the coordinates identified in step (F).
9. The method of claim 1 , wherein the step (B) comprises steps of:
(B) (1) identifying a distance between the input coordinates and the center of the input coordinate space;
(B) (2) determining whether the distance is less than a transition radius;
(B) (3) determining that the input coordinates are within the first region if the distance is determined to be less than the transition radius; and
(B) (4) determining that the input coordinates are not within the first region otherwise.
10. The method of claim 9 , wherein the transition radius comprises a value within a range of about two millimeters to about six millimeters.
11. The method of claim 1 , wherein the input coordinate space further comprises a third region, and wherein the step (D) comprises steps of:
(D) (1) determining whether the input coordinates are within the second region;
(D) (2) selecting the second transfer function if the input coordinates are determined to be within the second region; and
(D) (3) selecting a third transfer function if the input coordinates are determined not to be within the second region.
12. The method of claim 11 , wherein the first transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h+kp*r,
wherein h comprises a vector representing a center of a positional range of the pointer, and wherein kp comprises a positional gain, and wherein the first transfer function relates the velocity dh/dt of the center of the positional range of the pointer to the input vector r using the formula:
dh/dt= 0.
13. The method of claim 11 , wherein the third transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h,
wherein h comprises a vector representing a center of a positional range of the pointer, and wherein the first transfer function relates the velocity dh/dt of the on-screen pointer to the input vector r using the formula:
dh/dt=kv*r,
wherein kv comprises a velocity gain.
14. The method of claim 1 , wherein the second transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h +(( kr 2 −|r |)/( kr 2 −kr ))* kp*r,
wherein h comprises a vector representing a center of a positional range of the pointer, wherein kp comprises a positional gain, wherein kr comprises a first transition radius, wherein kr2 comprises a second transition radius, and wherein the first transfer function relates the velocity dh/dt of the on-screen pointer to the input vector r using the formula:
dh/dt=kv*r,
wherein kv comprises a velocity gain.
15. The method of claim 1 , wherein the first region comprises a region bounded by a rectangle.
16. An apparatus for use with a pointing device for providing input to a computing device, the apparatus comprising:
reception means for receiving an input vector representing input coordinates relative to a center of an input coordinate space associated with the pointing device, the input coordinate space comprising a first region and a second region;
determination means for determining whether the input coordinates are within the first region of the input coordinate space;
first selection means for selecting a first transfer function if the input coordinates are determined to be within the first region;
second selection means for selecting a second transfer function if the input coordinates are determined not to be within the first region, the second transfer function comprising a non-constant function relating the input vector to velocity; and
third selection means for selecting a position and velocity of an on-screen pointer based on the selected transfer function.
17. The apparatus of claim 16 , wherein the first transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h+kp*r,
wherein h comprises a vector representing a center of a positional range of the pointer, wherein kp comprises a positional gain, and wherein the first transfer function relates the velocity dh/dt of the center of the positional range of the pointer to the input vector r using the formula:
dh/dt =0.
18. The apparatus of claim 17 , wherein the positional gain kp comprises a value of about two millimeters per millimeter.
19. The apparatus of claim 17 , further comprising:
means for identifying coordinates of the on-screen pointer upon commencement of a pointing operation; and
means for setting the coordinates of the home vector h equal to the coordinates identified by the means for identifying.
20. The apparatus of claim 17 , wherein the positional gain kp comprises a value of about two millimeters per millimeter.
21. The apparatus of claim 16 , wherein the second transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h+kp*r,
wherein h comprises a vector representing a center of a positional range of the pointer, wherein kp comprises a positional gain, and wherein the second transfer function relates the velocity dh/dt of the on-screen pointer to the input vector r using the formula:
dh/dt=kv*r,
wherein kv comprises a velocity gain.
22. The apparatus of claim 21 , wherein the velocity gain kv comprises a value of about ten per second.
23. The apparatus of claim 21 , further comprising:
means for identifying coordinates of the on-screen pointer upon commencement of a pointing operation; and
means for setting the coordinates of the home vector h equal to the coordinates identified in step (F).
24. The apparatus of claim 16 , wherein the determination means comprises:
means for identifying a distance between the input coordinates and the center of the input coordinate space;
means for determining whether the distance is less than a transition radius;
means for determining that the input coordinates are within the first region if the distance is determined to be less than the transition radius; and
means for determining that the input coordinates are not within the first region otherwise.
25. The apparatus of claim 24 , wherein the transition radius comprises a value within a range of about two millimeters to about six millimeters.
26. The apparatus of claim 16 , wherein the input coordinate space further comprises a third region, and wherein the second selection means comprises:
means for determining whether the input coordinates are within the second region;
means for selecting the second transfer function if the input coordinates are determined to be within the second region; and
means for selecting a third transfer function if the input coordinates are determined not to be within the second region.
27. The apparatus of claim 26 , wherein the first transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h+kp*r,
wherein h comprises a vector representing a center of a positional range of the pointer, and wherein kp comprises a positional gain, and wherein the first transfer function relates the velocity dh/dt of the center of the positional range of the pointer to the input vector r using the formula:
dh/dt =0.
28. The apparatus of claim 26 , wherein the third transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h,
wherein h comprises a vector representing a center of a positional range of the pointer, and wherein the first transfer function relates the velocity dh/dt of the on-screen pointer to the input vector r using the formula:
dh/dt=kv*r,
wherein kv comprises a velocity gain.
29. The apparatus of claim 16 , wherein the second transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h +(( kr 2 −|r |)/( kr 2 −kr ))* kp*r,
wherein h comprises a vector representing a center of a positional range of the pointer, wherein kp comprises a positional gain, wherein kr comprises a first transition radius, wherein kr2 comprises a second transition radius, and wherein the first transfer function relates the velocity dh/dt of the on-screen pointer to the input vector r using the formula:
dh/dt=kv*r,
wherein kv comprises a velocity gain.
30. The apparatus of claim 16 , wherein the first region comprises a region bounded by a rectangle.
31. A computer-implemented method for use with a pointing device for providing input to a computing device, the method comprising steps of:
(A) receiving an input vector representing input coordinates relative to a center of an input coordinate space associated with the pointing device;
(B) determining whether the input coordinates are within a first transition radius of the center of the input coordinate space;
(C) selecting a first transfer function if the input coordinates are determined to be within the first transition radius of the center of the input coordinate space;
(D) selecting a second transfer function if the input coordinates are determined not to be within the first transition radius of the center of the input coordinate space; and
(E) selecting a position and velocity of an on-screen pointer based on the selected transfer function.
32. The method of claim 31 , wherein the first transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h+kp*r,
wherein h comprises a vector representing a center of a positional range of the pointer, and wherein kp comprises a positional gain, and wherein the first transfer function relates the velocity dh/dt of the on-screen pointer to the input vector r using the formula:
dh/dt =0.
33. The method of claim 32 , wherein the positional gain kp comprises a value of about two millimeters per millimeter.
34. The method of claim 32 , wherein the positional gain kp comprises a value of about two millimeters per millimeter.
35. The method of claim 31 , wherein the second transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h+kp*r,
wherein h comprises a vector representing a center of a positional range of the pointer, wherein kp comprises a positional gain, and wherein the second transfer function relates the velocity dh/dt of the on-screen pointer to the input vector r using the formula:
dh/dt=kv*r,
wherein kv comprises a velocity gain.
36. The method of claim 34 , wherein the velocity gain kv comprises a value of about ten per second.
37. The method of claim 31 , further comprising steps of:
(F) obtaining coordinates of an initial input point in the input coordinate space; and
(G) setting the coordinates of the home vector h equal to the input coordinates obtained in-step (F).
38. The method of claim 31 , wherein the first transition radius comprises a value within a range of about two millimeters to about six millimeters.
39. The method of claim 31 , wherein the step (D) comprises steps of:
(D) (1) determining whether the input coordinates are within a second transition radius of the center of the input coordinate space, wherein the second transition radius is greater than the first transition radius;
(D) (2) selecting the second transfer function if the input coordinates are determined to be within the second transition radius of the center of the input coordinate space; and
(D) (3) selecting a third transfer function if the input coordinates are determined not to be within the second transition radius of the input coordinate space.
40. The method of claim 39 , wherein the first transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h+kp*r,
wherein h comprises a vector representing a center of a positional range of the pointer, and wherein kp comprises a positional gain, and wherein the first transfer function relates the velocity dh/dt of the on-screen pointer to the input vector r using the formula:
dh/dt =0.
41. The method of claim 39 , wherein the third transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h,
wherein h comprises a vector representing a center of a positional range of the pointer, and wherein the first transfer function relates the velocity dh/dt of the on-screen pointer to the input vector r using the formula:
dh/dt=kv*r,
wherein kv comprises a velocity gain.
42. The method of claim 31 , wherein the second transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h +(( kr 2 −|r |)/( kr 2 −kr ))* kp*r,
wherein h comprises a vector representing a center of a positional range of the pointer, wherein kp comprises a positional gain, wherein kr comprises the first transition radius, wherein kr2 comprises the second transition radius, and wherein the first transfer function relates the velocity dh/dt of the on-screen pointer to the input vector r using the formula:
dh/dt=kv*r,
wherein kv comprises a velocity gain.
43. An apparatus for use with a pointing device for providing input to a computing device, the apparatus comprising:
reception means for receiving an input vector representing input coordinates relative to a center of an input coordinate space associated with the pointing device;
determination means for determining whether the input coordinates are within a first transition radius of the center of the input coordinate space;
first selection means for selecting a first transfer function if the input coordinates are determined to be within the first transition radius of the center of the input coordinate space;
second selection means for selecting a second transfer function if the input coordinates are determined not to be within the first transition radius of the center of the input coordinate space; and
third selection means for selecting a position and velocity of an on-screen pointer based on the selected transfer function.
44. The apparatus of claim 43 , wherein the first transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h+kp*r,
wherein h comprises a vector representing a center of a positional range of the pointer, and wherein kp comprises a positional gain, and wherein the first transfer function relates the velocity dh/dt of the on-screen pointer to the input vector r using the formula:
dh/dt =0.
45. The apparatus of claim 44 , wherein the positional gain kp comprises a value of about two millimeters per millimeter.
46. The apparatus of claim 44 , wherein the positional gain kp comprises a value of about two millimeters per millimeter.
47. The apparatus of claim 43 , wherein the second transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h+kp*r,
wherein h comprises a vector representing a center of a positional range of the pointer, wherein kp comprises a positional gain, and wherein the second transfer function relates the velocity dh/dt of the on-screen pointer to the input vector r using the formula:
dh/dt=kv*r,
wherein kv comprises a velocity gain.
48. The apparatus of claim 47 , wherein the velocity gain kv comprises a value of about ten per second.
49. The apparatus of claim 43 , further comprising:
means for obtaining coordinates of an initial input point in the input coordinate space; and
means for setting the coordinates of the home vector h equal to the input coordinates obtained in step (F).
50. The apparatus of claim 43 , wherein the first transition radius comprises a value within a range of about two millimeters to about six millimeters.
51. The apparatus of claim 43 , wherein the second selection means comprises:
means for determining whether the input coordinates are within a second transition radius of the center of the input coordinate space, wherein the second transition radius is greater than the first transition radius;
means for selecting the second transfer function if the input coordinates are determined to be within the second transition radius of the center of the input coordinate space; and
means for selecting a third transfer function if the input coordinates are determined not to be within the second transition radius of the input coordinate space.
52. The apparatus of claim 51 , wherein the first transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h+kp*r,
wherein h comprises a vector representing a center of a positional range of the pointer, and wherein kp comprises a positional gain, and wherein the first transfer function relates the velocity dh/dt of the on-screen pointer to the input vector r using the formula:
dh/dt =0.
53. The apparatus of claim 51 , wherein the third transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h,
wherein h comprises a vector representing a center of a positional range of the pointer, and wherein the first transfer function relates the velocity dh/dt of the on-screen pointer to the input vector r using the formula:
dh/dt=kv*r,
wherein kv comprises a velocity gain.
54. The apparatus of claim 43 , wherein the second transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h +(( kr 2 |r |)/( kr 2 −kr ))* kp*r,
wherein h comprises a vector representing a center of a positional range of the pointer, wherein kp comprises a positional gain, wherein kr comprises the first transition radius, wherein kr2 comprises the second transition radius, and wherein the first transfer function relates the velocity dh/dt of the on-screen pointer to the input vector r using the formula:
dh/dt=kv*r,
wherein kv comprises a velocity gain.