Smart tracking system

• US 5,231,483 A
• Filed: 01/27/1992
• Issued: 07/27/1993
• Est. Priority Date: 09/05/1990
• Status: Expired due to Fees

• Current Assignee: Visionary Products, Inc.
• Original Assignee: Visionary Products, Inc.
• Inventors: Stewart, William K., Sieber, Joseph S., Sieber, Jonathan D.
• Primary Examiner(s): Lobo, Ian J.
• Application Number:
  US07/825,833
• Time in Patent Office: 547 Days
• Field of Search: 364/455, 364/516, 358/125, 358/126
• US Class Current: 348/169
• CPC Class Codes: G01S 3/807 the desired condition being maintained automatically

Abstract

A smart tracking system includes a digital processor for selectively processing error signals representing the angular error between a tracked subject and the orientation of the tracking device/camera. In one embodiment, the user selects a set of data values representating the operating parameters of the system in a specific operational mode. The processor uses the selected variables to perform a series of computations which selectively modify the angular error signals in a manner that will produce a video picture which is visually and aesthetically pleasing to human viewers. In a second embodiment, the set of data values characterizing the operational mode of the system automatically are selected by the processor based on the past history of the subject'"'"'s motion and the current operation mode of the system.

Claims

1. A system for permitting a device to point at and track the movements of a moving subject, comprising:

a. a signal source for generating signals which can be tracked;

b. control means for receiving signals from the source and for generating relative orientation data therefrom in the form of control signals, said orientation data varying as continuous functions with changes in the relative angular position of the subject;

c. means for storing plural sets of data values, each of said data value sets representing selected values for processing said control signals in anticipation of future relative motion of the subject based on past motion of the subject;

d. means for selecting one of said sets of data values;

e. means for processing said control signals in accordance with the one of said sets of data values selected by said selecting means to produce processed control signals; and

f. a drive unit for moving the device about at least one axis in response to said processed control signals to maintain the device pointed at the subject.

2. The system of claim 1 wherein each of said data value sets comprises data values representing selected acceleration rates of the device and selected deceleration rates of the device, for a particular range of anticipated motion by the subject.

3. The system of claim 1 where each of said data value sets comprises data values representing a selected angular velocity of the device, and a maximum allowable angular error between the axis of the device and the subject, for a particular range of anticipated motion by the subject.

4. The system of any of claims 1, 2 or 3 wherein said means for selecting comprises a user-defined signal for indicating which of said plural sets of data values is to be selected.

5. The system of any of claims 1, 2 or 3 wherein said means for selecting comprises means for automatically selecting one of said plural sets of data values in anticipation of future relative motion of the subject based on past motion of the subject.

6. A method of intelligently and automatically tracking a moving subject with a camera comprising the steps of:

a. determining a last direction in which the camera moved about an axis;

b. calculating an elapsed time value representing the elapsed time interval since the camera last moved;

c. determining an error direction representing the present orientation of the subject relative to the camera;

d. comparing said last direction with said error direction;

e. moving the camera about the axis in the error direction if said last direction and said error direction are equal;

f. comparing said elapsed time value with a predetermined value if said last direction and said error direction are not equal; and

g. moving the camera about the axis in the error direction if the elapsed time value at least equals the predetermined value.

7. The method of claim 6 further comprising the step of:

h. maintaining the current angular orientation of the camera if the elapsed time value is less than the predetermined value.

8. The method of claim 6 wherein said predetermined value is selected to represent the average time between directional changes by a subject for a predetermined class of motions.

9. An apparatus for intelligently and automatically tracking a moving subject with a camera comprising:

a. means for determining an error direction in representing the present orientation of the subject relative to the camera;

b. means for sensing a last direction in which the camera moved about an axis;

c. means for calculating an elapsed time value representing the elapsed time interval since the camera last moved;

d. means for comparing the last direction with the error direction, and for comparing the elapsed time value with a predetermined value if the error direction and the last direction are not equal; and

e. a drive unit, responsive to said means for determining and said means for comparing, for moving the camera in the error direction about said one axis if the elapsed time value at least equals the predetermined value or the last direction equals the error direction.

10. The apparatus of claim 9 wherein said means for determining comprises:

control means for receiving source signals from the subject and for continuously generating therefrom control signals representing the angular error between the position of the subject and the camera long at least one plane.

11. A method of intelligently and automatically tracking a moving subject within the frame of a camera comprising the steps of:

a. moving the camera about an axis to bring the subject within the camera frame;

b. establishing predetermined limits for the angular velocity and angular acceleration of the camera about the axis;

c. defining a central zone within the camera frame and substantially symmetrical about the center of the subject;

d. moving the camera about the axis at rates not to exceed the predetermined limits to maintain the subject within the zone;

e. calculating a first percentage representing the total time the subject was outside said central zone during a given time interval;

f. calculating the maximum angular speed and maximum regular acceleration of the subject within said given time interval; and

g. redefining said predetermined limits for the angular acceleration and angular velocity of the camera in accordance with the anticipated motion of the subject.

12. The method of claim 11 wherein step (g) comprises comparing the first percentage with a preferred maximum allowable percentage and selecting new predetermined limits having increased values for the angular velocity and angular acceleration of the camera when the first percentage exceeds the established predetermined limits.

13. The method of claim 11 wherein step (g) comprises selecting new predetermined limits having decreased values for the angular velocity and angular acceleration of the camera when the maximum angular speed and maximum angular acceleration of the subject are less than the predetermined limits for the angular velocity and angular acceleration of the camera.

14. An apparatus for permitting a camera to maintain a moving subject within the frame of a camera in a manner which is visually pleasing to a view, the apparatus comprising:

a. means for storing a plurality of predetermined limits for the angular velocity and angular acceleration of the camera about an axis;

b. a drive unit, responsive to said means for storing, for moving the camera about the axis at rates not in excess of the predetermined limits to maintain the subject within the zone;

c. means for defining a central zone within the camera frame and substantially symmetrical about the center of the subject;

d. first means for calculating a first percentage representing the total time the subject was outside the central zone during a given time interval;

e. second means for calculating the maximum angular velocity and maximum angular acceleration of the subject within the given time interval; and

f. means, responsive to said first and said second means, for selecting new predetermined limits from the means for storing for the angular acceleration and angular velocity of the camera in anticipation of future motion of the subject.

15. The apparatus of claim 14 wherein the means for selecting comprises means for comparing the first percentage with a predetermined maximum allowable percentage storage in said means for storing and for selecting new predetermined limits for the angular velocity and the angular acceleration of the camera when the first percentage exceeds the predetermined maximum allowable percentage.

16. The apparatus of claim 14 wherein said means for selecting comprises means for comprising the maximum angular velocity and maximum angular acceleration of the subject with the current predetermined limits for angular velocity and angular acceleration of the camera, and for selecting new predetermined limits for the angular acceleration and angular velocity of the camera when the maximum angular velocity and maximum angular acceleration of the subject are substantially less than or substantially greater than the current predetermined limits.

17. A method of intelligently and automatically tracking a moving subject within the frame of a camera comprising the steps of:

a. defining a central zone within the camera frame by a pair of angular coordinates along one axis and substantially symmetric about the center of the subject at a first time;

b. determining an angular error along said one axis between the subject and the camera at a second time;

c. determining whether the angular error is within the central zone;

d. determining an error direction representing the direction the camera must move to reduce the angular error at the second time, if the angular error is not within the central zone;

e. moving the camera about said one axis in the error direction; and

f. redefining the angular coordinates of the central zone so that the central zone is shifted in a direction which is opposite the error direction.

18. The method of claim 17 wherein step (f) comprises the steps of:

f.1 subtracting the value of one of the angular coordinates of the central zone from the value of the angular error to form a difference value; and

f.2 subtracting the difference value from each of the angular coordinates to form new angular coordinates.

19. The method of claim 17 further comprising the steps of:

g. maintaining the camera in its current orientation if the angular error is within the central zone.

20. An apparatus for intelligently and automatically tracking a moving subject within the frame of a camera comprising:

a. means for defining a central zone within the camera frame by a pair of angular coordinates along one axis and substantially symmetric about the center of the subject at a first time;

b. means for determining an angular error along said one axis between the subject and the camera at a second time;

c. means for determining whether the angular error is within the central zone;

d. means for determining an error direction representing the direction in which the camera must move to reduce the angular error at a second time, if the angular error is not within the central zone;

e. a drive unit for moving the camera about said one axis in the error direction; and

f. means for redefining the angular coordinates of the central zone so that the central zone is shifted in a direction which is opposite the error direction.

21. The apparatus of claim 20 wherein said means for redefining comprises:

means for subtracting the value of one of the angular coordinates defining the central zone from the value of the angular error to form a difference value; and

means for subtracting the difference value from each of the angular coordinates to form new angular coordinates.

22. A method of intelligently and automatically tracking a moving subject within the frame of a camera comprising the steps of:

a. receiving signal from the subject and continuously generating relative orientation data therefrom in the form of control signals, said orientation data being a continuous function of the relative angular position of the subject;

b. defining a central zone within the camera frame with a pair of angular coordinates along one axis;

c. determining, from said control signals, whether the subject is within the central zone;

d. selectively processing said control signals if the subject is not within the central zone;

e. redefining the angular coordinates describing said central zone to reorient the central zone within the camera frame; and

moving the camera about an axis to maintain the subject within the central zone.

23. An apparatus for intelligently and automatically tracking a moving subject within the frame of a camera comprising:

a. means for receiving signals from the subject and for generating relative orientation data therefrom in the form of control signals, said orientation data being a continuous function of the relative angular position of the subject;

b. means for defining a central zone within the camera frame with a pair of angular coordinates along one axis;

c. means for determining, from the control signals, whether the subject is within the central zone;

d. means for processing the control signals if the subject is not within the central zone;

e. means for redefining the angular coordinates describing the central zone to reorient the central zone within the camera frame; and

f. a drive unit, responsive to the means for processing, for moving the camera about an axis to maintain the subject within the central zone.

24. An apparatus for permitting a camera to maintain a moving subject within the camera frame in a manner that is visually pleasing to a viewer, the system comprising:

a. a subject for generating signals which can be tracked;

b. control means for receiving signals from the subject and for continuously generating relative orientation data therefrom in the form of control signals, said control signals representing the angular error between the position of the subject and the camera along at least one plane;

c. means for anticipating future relative motion of the subject based on past motion of the subject;

d. means, responsive to said control signals, for determining whether the angular error represented by the control signals is within an acceptable range given anticipated motion by the subject, and for processing said control signals if said angular error is not within the acceptable range; and

e. a drive unit, responsive to said processed control signals, for selectively moving the camera about an axis to maintain the subject within the camera frame.

25. An apparatus for tracking the motion of a subject, comprising:

a. means for storing a plurality of predetermined limits for each of the angular acceleration and angular velocity of the apparatus about an axis;

b. control means for storing periodic values for each of the angular speed and angular acceleration of the subject during a given time interval and for determining the motion characteristics of the subject during the given time interval from said period values;

c. means, responsive to the control means, for selecting one of said plurality of predetermined limits for each of the angular acceleration and angular velocity of the apparatus in accordance with the motion characteristics of the subject; and

e. a drive unit, responsive to the means for selecting and the means for storing, for moving the apparatus about the axis at rates not in excess of the selected predetermined limits.

26. The apparatus of claim 25 wherein the means for selecting further comprises a user-defined signal for indicating which of the predetermined limits in the means for storing are to be selected.

27. The apparatus of claim 25 wherein the means for selecting comprises means for automatically selecting said predetermined limits in anticipation of future relative motion of the subject based on the motion characteristics of the subject.

28. The apparatus of claim 25 wherein the motion characteristics of the subject comprise the average angular speed and maximum angular speed of the subject during the given time interval.

29. The apparatus of claim 28 wherein the motion characteristics of the subject further comprise the average angular acceleration and maximum angular acceleration of the subject during the given time interval.

30. The apparatus of claim 29 wherein said means for selecting comprises means for comprising the maximum angular speed and maximum angular acceleration of the subject with the current predetermined limits for angular velocity and angular acceleration of the apparatus, and for selecting new predetermined limits for the angular acceleration and angular velocity of the apparatus when the maximum angular speed and maximum angular acceleration of the subject are substantially less than the current predetermined limits.

31. The apparatus of claim 29 wherein said means for selecting comprises means for comprising the maximum angular speed and maximum angular acceleration of the subject with the current predetermined limits for angular velocity and angular acceleration of the apparatus, and for selecting new predetermined limits for the angular acceleration and angular velocity of the apparatus when the maximum angular speed and maximum angular acceleration of the subject are substantially greater than the current predetermined limits.

32. The apparatus of claim 25 wherein the motion characteristics of the subject comprise the average displacement and maximum displacement of the subject during the given time interval.

33. The apparatus of claim 25 wherein the motion characteristics of the subject comprise a first time value representing the average elapsed time between direction reversals by the subject during the given time interval.

34. The apparatus of claim 33 wherein the means for storing further stores a plurality of predetermined limits for a second time value representing the minimum allowable elapsed time between direction reversals by the apparatus about the axis;

and

said drive unit further comprises means for reversing the direction of the apparatus about the axis once the second time value is at least equaled.

35. The apparatus of claim 34 wherein the means for selecting comprises means for comparing the first time value with the current predetermined limit for the second time value, and for selecting a new predetermined limit for the second time value when the first time value is greater than the current predetermined limit for the second time value.

36. An apparatus for tracking the motion of a subject with an apparatus comprising the steps of:

a. storing a plurality of predetermined limits for each of the angular acceleration and angular velocity of the apparatus about an axis;

b. determining the motion characteristics of the subject during the given time interval in accordance with the motion history of the subject during the time interval;

c. selecting one of said plurality of predetermined limits for each of the angular acceleration and angular velocity of the apparatus in accordance with the motion characteristics of the subject; and

d. moving the apparatus about the axis at rates not in excess of the selected predetermined limits.

37. The method of claim 36 wherein steps (c) comprises receiving a user-defined signal for indicating which of the predetermined limits in the means for storing are to be selected.

38. The method of claim 36 wherein steps (c) comprises automatically selecting the predetermined limits in anticipation of future relative motion of the subject based on the motion characteristics of the subject.

39. The method of claim 36 wherein the motion characteristics of the subject comprise the average angular speed and maximum angular speed of the subject during the given time interval.

40. The apparatus of claim 39 wherein the motion characteristics of the subject further comprise the average angular acceleration and maximum angular acceleration of the subject during the given time interval.

41. The method of claim 40 wherein step (c) comprises the steps of:

c.1 comparing the maximum angular speed and maximum angular acceleration of the subject with the current predetermined limits for angular velocity and angular acceleration of the apparatus; and

c.2 selecting new predetermined limits for the angular acceleration and angular velocity of the apparatus when the maximum angular speed and maximum angular acceleration of the subject are substantially less than the current predetermined limits.

42. The method of claim 40 wherein step (c) comprises the steps of:

c.1 comparing the maximum angular speed and maximum angular acceleration of the subject with the current predetermined limits for angular velocity and angular acceleration of the apparatus; and

c.2 selecting new predetermined limits for the angular acceleration and angular velocity of the apparatus when the maximum angular speed and maximum angular acceleration of the subject are substantially greater than the current predetermined limits.

43. The method of claim 36 wherein the motion characteristics of the subject comprise the average displacement and maximum displacement of the subject during the given time interval.

44. The apparatus of claim 36 wherein the motion characteristics of the subject comprise a first time value representing the average elapsed time between direction reversals by the subject during the given time interval.

45. The apparatus of claim 44 wherein the step of storing a plurality of predetermined limits further comprises:

storing a plurality of predetermined limits for second time value representing the minimum allowable elapsed time between direction reversals by the apparatus about the axis.

46. The method of claim 45 wherein step (c) comprises the step of:

c.1 comparing the first time value with the current predetermined limit for the second time value; and

c.2 selecting a new predetermined limits for the second time value when the first time value is greater than the current predetermined limit for the second time value.