Position and orientation detection system

• US 6,587,809 B2
• Filed: 05/15/2002
• Issued: 07/01/2003
• Est. Priority Date: 07/14/1999
• Status: Expired due to Fees

• Current Assignee: Ascension Technology Corporation (Roper Technologies, Inc.)
• Original Assignee: Hypervision, Ltd.
• Inventors: Majoe, Dennis
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): LE, JOHN H
• Application Number:
  US09/979,370
• Publication Number:
  US 20020152040A1
• Time in Patent Office: 412 Days
• Field of Search: 702/92, 702/94, 702/150, 702/155, 356/141.1, 356/139.03, 250/559.44, 700/259, 382/103, 382/107
• US Class Current: 702/150
• CPC Class Codes: G01B 11/00 Measuring arrangements characterised by the use of optical techniques
• CPC Class Codes: G01B 11/002 for measuring two or more coordinates
• CPC Class Codes: G01B 11/16 for measuring the deformation in a solid, e.g. optical strain gauge
• CPC Class Codes: G01S 3/783 using amplitude comparison of signals derived from static detectors or detector systems
• CPC Class Codes: G01S 5/163 Determination of attitude using inertial means G01C9/00; control of attitude G05D1/49

Abstract

A system for determining the position, orientation and deformation in 3 dimensional space of a moving object in real-time is provided having a plurality of activatable markers which are mounted onto the object and a sensor section comprising a plurality of individual sensors as shown diagrammatically in FIG. 1. Individual markers are activated in sequence with only one marker energized at any time. Energy emitted by each activated marker is detected by the plurality of sensors positioned remotely. Since only one marker is activated at any time individual determination of the position of the particular energized marker is simplified. Individual sensors are arranged such that each sensor receives a different energy level from an energized marker depending on the relative position of the marker to the sensor. A control unit analyzes the energy distribution range to determine the actual marker position. The system compensates for ambient energy and sensor saturation.

Claims

1. A system for determining position, orientation and deformation in 3-D space of at least one moving object in real time, the system comprising:

a plurality of energy emitting markers for placing for movement with the object;

driving means coupled to the markers for driving the markers;

a plurality of stationary sensors, each for sensing energy emitted from the markers;

detection means coupled to the sensors for detecting the energy sensed by the sensors; and

processing means for controlling the driving means so that the markers emit energy in a predetermined order and for processing the detected energies to derive position, orientation and deformation information for the object;

wherein;

the sensors are arranged in a linear array along an axis; and

each sensor in the array has a respective collimator arranged so that;

the respective sensor receives full energy from a marker when the angle between the line which connects the sensor to the marker and the plane which is perpendicular to the array axis is zero;

the collimator increasingly attenuates the received energy as said angle increases from zero; and

the collimator blocks the energy from the marker when said angle exceeds a predetermined angle.

2. A system as claimed in claim 1, wherein the pitch of the sensors in the array is constant.

3. A system as claimed in claim 1, wherein each collimator is provided by a slot in a panel covering the respective sensor, and the longitudinal axis of each slot is orthogonal to the array axis.

4. A system as claimed in claim 3, wherein the pitch of the slots is constant.

5. A system as claimed in claim 3, wherein the distance between each slot and the respective sensor is similar to the length of the slot.

6. A system as claimed in claim 3, wherein the width of each slot is similar to the width of the respective sensor.

7. A system as claimed in claim 1, wherein the processing means is operable, in the case where the energy emitted from one of the markers is detected by a plurality of the sensors in the array, to calculate from the detected energies a position of a maximum in the energy distribution falling on the sensors.

8. A system as claimed in claim 1, wherein the processing means is operable:

to determine detected ambient energies for the sensors when the markers are not driven;

to subtract the detected ambient energy for each sensor from the detected energy for that sensor when the markers are driven to obtain a compensated energy for that sensor; and

to process the compensated energies to derive the position, orientation and deformation information for the object.

9. A system as claimed in claim 1, wherein:

the driving means is operable to drive the markers with a first drive energy and with a second drive energy that is half of the first drive energy; and

the processing means is operable;

to determine whether or not the detected energy for any of the sensors in the array when the markers are driven with the first drive energy indicates saturation of that sensor and,

if so, to process the detected energies when the markers are driven with second drive energy to derive the position, orientation and deformation information for the object,

but, if not, to process the detected energies when the markers are driven with the first drive energy to derive the position, orientation and deformation information for the object.

10. A system as claimed in claim 1, including at least three such arrays of the sensors.

11. A system as claimed in claim 10, wherein, for each array, the processing means is operable to determine the positions of the respective markers relative to that array by processing the detected energies for the sensors in that array.

12. A method of determining position, orientation and deformation in 3-D space of at least one moving object in real time, the method comprising:

placing a plurality of energy emitting markers for movement with the object;

driving the markers;

using a plurality of stationary sensors, each for sensing energy emitted from the markers;

detecting the energy sensed by the sensors;

controlling the driving step so that the markers emit energy in a predetermined order; and

processing the detected energies to derive position, orientation and deformation information for the object;

wherein;

arranging at least some of the sensors in a linear array along an axis; and

providing a respective collimator for each sensor in the array arranged so that;

the respective sensor receives full energy from a marker when the angle between the line which connects the sensor to the marker and the plane which is perpendicular to the array axis is zero;

the collimator increasingly attenuates the received energy as said angle increases from zero; and

the collimator blocks the energy from the marker when said angle exceeds a predetermined angle.

13. A method as claimed in claim 12, wherein the processing step includes, in the case where the energy emitted from one of the markers is detected by a plurality of the sensors in the array, a step of calculating from the detected energies a position of a maximum in the energy distribution falling on the sensors.

14. A method as claimed in claim 12, wherein the processing step includes:

determining detected ambient energies for the sensors when the markers are not driven;

subtracting the detected ambient energy for each sensor from the detected energy for that sensor when the markers are driven to obtain a compensated energy for that sensor; and

processing the compensated energies to derive the position, orientation and deformation information for the object.

15. A method as claimed in claim 12, wherein:

the controlling step includes controlling the markers so that they are driven with a first drive energy and with a second drive energy that is half of the first drive energy; and

the processing step includes;

determining whether or not the detected energy for any of the sensors in the array when the markers are driven with the first drive energy indicates saturation of that sensor and,

if so, processing the detected energies when the markers are driven with the second drive energy to derive the position, orientation and deformation information for the object,

but, if not, processing the detected energies when the markers are driven with the first drive energy to derive the position, orientation and deformation information for the object.

16. A method as claimed in claim 12, including the step of providing at least three such arrays of the sensors.

17. A method as claimed in claim 16, wherein, for each array, the processing step includes determining the positions of the respective markers relative to that array by processing the detected energies for the sensors in that array.