System and method for performing an optical tracking operation using relative referencing
View Patent ↗A system and method for performing an optical tracking operation computes a translated movement value of a displacement values using a relationship between a reference displacement value derived using a reference surface and a corresponding displacement value using a target surface. The displacement value is produced using image correlation by optically sensing the target surface. The translated movement value is used for the optical tracking operation.
1. A system for performing an optical tracking operation comprising:
an optical sensor unit configured to optically sense a target surface to produce at least a first displacement value along a first direction using image correlation; and
a processing unit operably connected to the optical sensor unit to receive the first displacement value, the processing unit being configured to compute a translated movement value from the first displacement value using a relationship between a reference displacement value derived using a reference surface and a corresponding displacement value derived using the target surface, the translated movement value being used for the optical tracking operation.
2. The system of claim 1 wherein the processing unit is configured to compute the translated movement value using a tracking coefficient value, the tracking coefficient value being derived by dividing the corresponding displacement value by the reference displacement value.
3. The system of claim 2 wherein the processing unit is configured to compute the translated movement value by dividing the first displacement value by the tracking coefficient value.
4. The system of claim 1 wherein the reference displacement value and the corresponding displacement value are generated by the optical sensor unit, the reference displacement value being generated using frames of image data of a surface of a movable member that is in contact with the target surface, the surface of the movable member being the reference surface, the corresponding displacement value being generated using frames of image data of the target surface.
5. The system of claim 1 further comprising a second optical sensor unit configured to produce at least another first displacement value along the first direction using image correlation, wherein the reference displacement value is generated by the second optical sensor unit using frames of image data of a surface of a movable member that is in contact with the target surface, the surface of the movable member being the reference surface, and wherein the corresponding displacement value is generated by the optical sensor unit using frames of image data of the target surface.
6. The system of claim 5 wherein the processing unit is configured to detect slippage by comparing reference displacement values from the second optical sensor unit and current displacement values from the optical sensor unit with respect to the tracking coefficient.
7. The system of claim 5 wherein the second optical sensor unit is positioned to optically track a surface of a roller that is in contact with a sheet of material, the reference surface being the surface of the roller, the target surface being a surface of the sheet of material.
8. The system of claim 5 wherein the second optical sensor unit is positioned to optically track a surface of a wheel that is in contact with a traveling surface, the reference surface being the surface of the wheel, the target surface being the traveling surface.
9. A method for performing an optical tracking operation, the method comprising:
electronically capturing frames of image data of a target surface;
correlating the frames of image data to produce a first displacement value along a first direction; and
computing a translated movement value from the first displacement value using a relationship between a reference displacement value derived using a reference surface and a corresponding displacement value derived using the target surface, the translated movement value being used for the optical tracking operation.
10. The method of claim 9 wherein the computing includes computing the translated movement value using a tracking coefficient value, the tracking coefficient value being derived by dividing the corresponding displacement value by the reference displacement value.
11. The method of claim 10 wherein the computing the translated movement value using the tracking coefficient value includes computing the translated movement value by dividing the first displacement value by the tracking coefficient value.
12. The method of claim 9 further comprising generating the reference displacement value and the corresponding displacement value using a single optical sensor unit, the reference displacement value being generated using frames of image data of a surface of a movable member that is in contact with the target surface, the surface of the movable member being the reference surface, the corresponding displacement value being generated using frames of image data of the target surface.
13. The method of claim 9 further comprising generating the corresponding displacement value using a first optical sensor unit and generating the reference displacement value using a second optical sensor unit, the reference displacement value being generated by the second optical sensor unit using frames of image data of a surface of a movable member that is in contact with the target surface, the surface of the movable member being the reference surface, and wherein the corresponding displacement value is generated by the first optical sensor unit using frames of image data of the target surface.
14. The method of claim 13 further comprising comparing reference displacement values from the second optical sensor unit and current displacement values from the first optical sensor unit with respect to the tracking coefficient to detect slippage between the movable member and the target surface.
15. The method of claim 13 wherein the second optical sensor unit is positioned to optically track a surface of a roller that is in contact with a sheet of material, the reference surface being the surface of the roller, the target surface being a surface of the sheet of material.
16. The method of claim 13 wherein the second optical sensor unit is positioned to optically track a surface of a wheel that is in contact with a traveling surface, the reference surface being the surface of the wheel, the target surface being the traveling surface.
17. A system for performing an optical tracking operation comprising:
an optical sensor unit configured to optically sense a target surface to produce at least a first displacement value along a first direction, the optical sensor unit comprising:
a light source configured to emit illumination light toward a target surface;
an image sensor array positioned to receive the illumination light reflected from the target surface, the image sensor array being configured to generate frames of image data in response to the received illumination light; and
a navigation engine operably connected to the image sensor array to receive the frames of image data, the navigation engine being configured to correlate the frames of image data to produce at least the first displacement; and
a processing unit operably connected to the optical sensor unit to receive the first displacement value, the processing unit being configured to compute a translated movement value from the first displacement value using a relationship between a reference displacement value derived using a reference surface and a corresponding displacement value derived using the target surface, the translated movement value being used for the optical tracking operation.
18. The system of claim 17 wherein the processing unit is configured to compute the translated movement value using a tracking coefficient value, the tracking coefficient value being derived by dividing the corresponding displacement value by the reference displacement value.
19. The system of claim 17 wherein the reference displacement value and the corresponding displacement value are generated by the optical sensor unit, the reference displacement value being generated using frames of image data of a surface of a movable member that is in contact with the target surface, the surface of the movable member being the reference surface, the corresponding displacement value being generated using frames of image data of the target surface.
20. The system of claim 17 further comprising a second optical sensor unit configured to produce at least another first displacement value along the first direction using image correlation, wherein the reference displacement value is generated by the second optical sensor unit using frames of image data of a surface of a movable member that is in contact with the target surface, the surface of the movable member being the reference surface, and wherein the corresponding displacement value is generated by the optical sensor unit using frames of image data of the target surface.