Method and apparatus for image acquisition utilizing a hollow shaft motor and a concave, cylindrical reflector

• US 4,413,180 A
• Filed: 01/18/1983
• Issued: 11/01/1983
• Est. Priority Date: 02/26/1982
• Status: Expired due to Fees

• Current Assignee: Automatix, Inc. (Acuity Brands, Inc.)
• Original Assignee: Automatix, Inc. (Acuity Brands, Inc.)
• Inventors: Libby, Charles J.
• Primary Examiner(s): Nelms, David C.
• Assistant Examiner(s): Hostetter, Darwin R.
• Application Number:
  US06/458,836
• Time in Patent Office: 287 Days
• Field of Search: 250/560, 250/561, 250/234, 250/235, 250/236, 350/6.6, 350/6.9, 350/293, 356/1, 356/4, 356/376
• US Class Current: 250/236
• CPC Class Codes: G01B 11/024 by means of diode-array scanning
• CPC Class Codes: G01B 11/2518 Projection by scanning of the object

Abstract

A method and apparatus for image acquisition utilizing a non-planar beam of electro-magnetic radiation, such as, a hollow conical beam of light, to illuminate at least a portion of an object. The conical beam of light is generated by impinging a light beam on the surface of a concave, cylindrical reflector. The light beam enters the concave cylindrical reflector through the hollow shaft of a motor. The illuminated portion of the object is imaged on an array of photosensitive elements to produce corresponding signals that are representative of the image on the array. These signals can be used to obtain identification information concerning the object and guidance information for a plural axis manipulator employed in conjunction with the object. In one application the image acquisition apparatus is used in a robot to provide control signals for guiding the robot tool along a path, such as, a welding seam.

Claims

1. Method for image acquisition comprising the steps of:

A. passing a beam of collimated light through a hollow, rotatable motor shaft to a beam directing mirror that is secured with respect to and rotatable with said hollow, rotatable motor shaft;

B. reflecting said beam of collimated light from said beam directing mirror

C. impinging the resulting reflected beam of collimated light on a concave, cylindrical reflective surface to produce a conical beam of light having an angular arc that is a function of the radius of the concave, cylindrical reflective surface and the width of the collimated light beam impinging thereon;

D. illuminating at least a portion of an object with said conical beam of light; and

,

E. imaging at least part of said light beam illuminated portion of the object on an array of photosensitive elements to produce corresponding signals representative of the image on said array.

2. The method of claim 1 wherein at least a portion of the imaging path is coaxial with the axis of the conical beam extending from the apex thereof.

3. The method of claim 1 further comprising the step of rotating said hollow, rotatable motor shaft.

4. The method of claim 1 wherein said concave, cylindrical reflective surface is secured with respect to and rotatable with said hollow rotatable motor shaft so that the concave, cylindrical reflective surface rotates upon rotation of the hollow, rotatable motor shaft.

5. Method for image acquisition comprising the steps of:

A. passing a beam of collimated light through a hollow, rotatable motor shaft to a beam directing mirror that is secured with respect to and rotatable with said hollow, rotatable motor shaft;

B. reflecting said beam of collimated light from said beam directing mirror

C. impinging the resulting reflected beam of collimated light on a concave, cylindrical reflective surface to produce a conical beam of light having an angular arc that is a function of the radius of the concave, cylindrical reflective surface and the width of the collimated light beam impinging thereon;

D. illuminating at least a portion of an object with said conical beam of light;

E. imaging at least part of said light beam illuminated portion of the object on an array of photosensitive elements to produce corresponding signals representative of the image on said array; and

;

F. controlling the angular width of the arc of said conical light beam as a function of the ambient light noise at said object.

6. The method of claim 5 further comprising the step of rotating said hollow, rotatable motor shaft.

7. The method of claim 5 wherein said concave, cylindrical reflective surface is secured with respect to and rotatable with said hollow rotatable motor shaft so that the concave, cylindrical reflective surface rotates upon rotation of the hollow, rotatable motor shaft.

8. Method for image acquisition comprising the steps of:

A. passing a beam of collimated light through a hollow, rotatable motor shaft to a beam directing mirror that is secured with respect to and rotatable with said hollow, rotatable motor shaft;

B. reflecting said beam of collimated light from said beam directing mirror

C. impinging the resulting reflected beam of collimated light on a concave, cylindrical reflective surface to produce a conical beam of light having an angular arc that is a function of the radius of the concave, cylindrical reflective surface and the width of the collimated light beam impinging thereon;

D. illuminating at least a portion of an object with said conical beam of light;

E. imaging at least part of said light beam illuminated portion of the object on an array of photosensitive elements to produce corresponding signals representative of the image on said array; and

,

F. controlling the angular arc of said conical beam of light by sweeping the collimated beam of light transversely across said concave, cylindrical reflective surface with the angular arc length being related to the beam sweep width.

9. The method of claim 8 further comprising the step of rotating said hollow, rotatable motor shaft.

10. The method of claim 8 wherein said concave, cylindrical reflective surface is secured with respect to and rotatable with said hollow rotatable motor shaft so that the concave, cylindrical reflective surface rotates upon rotation of the hollow, rotatable motor shaft.

11. An apparatus for image acquisition comprising:

A. a rotatable reflective cylinder means having a concave reflective surface;

B. means for rotating said reflective cylinder means;

C. beam directing mirror means secured with respect to and rotatable with said rotatable reflective cylinder means for directing a beam of collimated light to said concave reflective surface to produce a conical beam of light having an angular arc that (i) is a function of the radius of the concave reflective surface and the width of the collimated light beam impinging thereon and (ii) illuminates at least a portion of an object;

D. an array means of photosensitive elements, said elements producing signals representative of the light impinging thereon;

E. means for imaging at least part of said light beam illuminated portion of the object on said array means of photosensitive elements to produce corresponding signals representative of the image on said array; and

,

F. utilization means responsive to said signals.

12. The apparatus of claim 11 wherein at least a portion of the imaging path is coaxial with the axis of the conical beam extended from the apex thereof.

13. An apparatus for image acquisition comprising:

A. a rotatable reflective cylinder means having a concave reflective surface;

B. means for rotating said reflective cylinder means

C. beam directing mirror means secured with respect to and rotatable with said rotatable reflective cylinder means for directing a beam of collimated light to said concave reflective surface to produce a conical beam of light having an angular arc that (i) is a function of the radius of the concave reflective surface and the width of the collimated light beam impinging thereon and (ii) illuminates at least a portion of an object;

D. an array means of photosensitive elements, said elements producing signals representative of the light impinging thereon;

E. means for imaging at least part of said light beam illuminated portion of the object on said array means of photosensitive elements to produce corresponding signals representative of the image on said array;

F. means for controlling the angular width of the arc of said conical light beam as a function of the ambient light noise at said object; and

,

G. utilization means responsive to said signals.

14. An apparatus for image acquisition comprising:

A. a rotatable reflective cylinder means having a concave reflective surface;

B. means for rotating said reflective cylinder means;

C. beam directing mirror means secured with respect to and rotatable with said rotatable reflective cylinder means for directing a beam of collimated light to said concave reflective surface to produce a conical beam of light having an angular arc that (i) is a function of the radius of the concave reflective surface and the width of the collimated light beam impinging thereon and (ii) illuminates at least a portion of an object;

D. an array means of photosensitive elements, said elements producing signals representative of the light impinging thereon;

E. means for imaging at least part of said light beam illuminated portion of the object on said array means of photosensitive elements to produce corresponding signals representative of the image on said array;

F. means for controlling the angular arc of said conical beam of light by sweeping the collimated beam of light transversely across said reflective cylinder means with the angular arc length being related to the beam sweep width; and

,

G. utilization means responsive to said signals.

16. The apparatus of claim 14 wherein at least a portion of the imaging path is coaxial with the axis of the conical beam extended from the apex thereof.

15. In a robot having a tool for use with a workpiece, an image acquisition apparatus comprising:

A. a rotatable reflective cylinder means having a concave reflective surface and a longitudinal axis, said longitudinal axis having a selected positional relationship with respect to the tool of the robot;

B. means for rotating said reflective cylinder means

C. beam directing mirror means secured with respect to and rotatable with said rotatable reflective cylinder means for directing a beam of collimated light to said concave reflective surface to produce a conical beam of light having an angular arc that (i) is a function of the radius of the concave reflective surface and the width of the collimated light beam impinging thereon and (ii) illuminates at least a portion of the workpiece;

D. an arrary means of photosensitive elements, said elements producing signals representative of the light impinging thereon;

E. means for imaging at least part of said light beam illuminated portion of the workpiece on said array means of photosensitive elements to produce corresponding signals representative of the image on said array; and

,

F. utilization means responsive to said signals for controlling the position of the tool with respect to the workpiece.

17. In a robot having a tool for use with a workpiece an image acquisition apparatus comprising:

A. a rotatable reflective cylinder means having a concave reflective surface and a longitudinal axis, said longitudinal axis having a selected positional relationship with respect to the tool of the robot

B. means for rotating said reflective cylinder means

C. beam directing mirror means secured with respect to and rotatable with said rotatable reflective cylinder means for directing a beam of collimated light to said concave reflective surface to produce a conical beam of light having an angular arc that (i) is a function of the radius of the concave reflective surface and the width of the collimated light beam impinging thereon and (ii) illuminates at least a portion of the workpiece;

D. an array means of photosensitive elements, said elements producing signals representative of the light impinging thereon;

E. means for imaging at least part of said light beam illuminated portion of the workpiece on said array means of photosensitive elements to produce corresponding signals representative of the image on said array;

F. controlling the angular width of the arc of said conical light beam as a function of the ambient light noise at said workpiece; and

,

G. utilization means responsive to said signals for controlling the position of the tool with respect to the workpiece.

18. An apparatus for image acquisition comprising:

A. a rotatable reflective cylinder means having a concave reflective surface;

B. means for rotating said reflective cylinder means

C. beam directing mirror means secured with respect to and rotatable with said rotatable reflective cylinder means for directing a beam of collimated light to said concave reflective surface to produce a conical beam of light having an angular arc that (i) is a function of the radius of the concave reflective surface and the width of the collimated light beam impinging thereon and (ii) illuminated at least a portion of an object;

D. an array means of photosensitive elements, and elements producing signals representative of the light impinging thereon;

E. means for imaging at least part of said light beam illuminated portion of the object on said array means of photosensitive elements to produce corresponding signals representative of the image on said array;

F. controlling the angular width of the arc of said conical light beam as a function of the ambient light noise at said object; and

,

G. utilization means responsive to said signals.

19. An apparatus for image acquisition comprising:

A. a rotatable reflective cylinder means having a concave reflective surface;

B. means for rotating said reflective cylinder means

beam directing mirror means secured with respect to and rotatable with said rotatable reflective cylinder means for directing a beam of collimated light to said concave reflective surface to produce a conical beam of light having an angular arc that (i) is a function of the radius of the concave reflective surface and the width of the collimated light beam impinging thereon and (ii) illuminates at least a portion of an object;

D. an array means of photosensitive elements, said elements producing signals representative of the light impinging thereon;

means for imaging at least part of said light beam illuminated portion of the object on said array mens of photosensitive elements to produce corresponding signals representative of the image on said array;

F. means for controlling the angular arc of said conical beam of light by sweeping the collimated beam of light transversely across said concave reflective surface with the angular arc length being related to the beam sweep width; and

,

G. utilization means responsive to said signals.

20. An apparatus for image acquisition comprising:

A. a reflective cylinder means having a concave reflective surface;

B. motor means having a hollow, rotatable motor shaft

C. beam directing mirror means secured with respect to and rotatable with said hollow rotatable motor shaft for directing a beam of collimated light that passes through said hollow, rotatable motor shaft to said concave reflective surface to produce a conical beam of light having an angular arc that (i) is a function of the radius of the concave reflective surface and the width of the collimated light beam impinging thereon and (ii) illuminates at least a portion of an object;

D. an array means of photosensitive elements, said elements producing signals representative of the light impinging thereon;

E. means for imaging at least part of said light beam illuminated portion of the object on said array means of photosensitive elements to produce corresponding signals representative of the image on said array; and

,

F. utilization means responsive to said signals.

21. The apparatus of claim 20 wherein at least a portion of the image path is coaxial with the axis of the conical beam extended from the apex thereof.

22. An apparatus for image acquisition comprising:

A. a reflective cylinder means having a concave reflective surface;

B. motor means having a hollow, rotatable motor shaft;

C. beam directing mirror means secured with respect to and rotatable with said hollow rotatable motor shaft for directing a beam of collimated light that passes through said hollow, rotatable motor shaft to said concave reflective surface to produce a conical beam of light having an angular arc that (i) is a function of the radius of the concave reflective surface and the width of the collimated light beam impinging thereon and (ii) illuminates at least a portion of an object;

D. an array means of photosensitive elements, said elements producing signals representative of the light impinging thereon;

E. means for imaging at least part of said light beam illuminated portion of the object on said array means or photosensitive elements to produce corresponding signals representative of the image on said array;

F. means for controlling the angular width of the arc of said conical light beam as a function of the ambient light noise at said object; and

,

G. utilization means responsive to said signals.

23. An apparatus for image acquisition comprising:

A. a reflective cylinder means having a concave reflective surface;

B. motor means having a hollow, rotatable motor shaft;

C. beam directing mirror means secured with respect to and rotatable with said hollow rotatable motor shaft for directing a beam of collimated light that passes through said hollow, rotatable motor shaft to said concave reflective surface to produce a conical beam of light having an angular arc that (i) is a function of the radius of the concave reflective surface and the width of the collimated light beam impinging thereon and (ii) illuminates at least a portion of an object;

D. an array means of photosensitive elements, said elements producing signals representative of the light impinging thereon;

E. means for imaging at least part of said light beam illuminated portion of the object on said array means of photosensitive elements to produce corresponding signals representative of the image on said array;

F. means for controlling the angular arc of said conical beam of light by sweeping the collimated beam of light transversely across said reflective cylinder means with the angular arc length being related to the beam sweep width; and

,

G. utilization means responsive to said signals.

25. The apparatus of claim 23 wherein at least a portion of the imaging path is coaxial with the axis of the conical beam extended from the apex thereof.

24. In a robot having a tool for use with a workpiece, an image acquisition apparatus comprising:

A. a reflective cylinder means having a concave reflective surface and a longitudinal axis, said longitudinal axis having a selected positional relationship with respect to the tool of the robot;

B. motor means having a hollow, rotatable motor shaft;

C. beam directing mirror means secured with respect to and rotatable with said hollow rotatable motor shaft for directing a beam of collimated light that passes through said hollow, rotatable motor shaft to said concave reflective surface to produce a conical beam of light having an angular arc that (i) is a function of the radius of the concave reflective surface and the width of the collimated light beam impinging thereon and (ii) illuminates at least a portion of the workpiece;

D. an array means of photosensitive elements, said elements producing signals representative of the light impinging thereon;

E. means for imaging at least part of said light beam illuminated portion of the workpiece on said array means of photosensitive elements to produce corresponding signals representative of the image on said array; and

,

F. utilization means responsive to said signals for controlling the position of the tool with respect to the workpiece.

26. In a robot having a tool for use with a workpiece an image acquisition apparatus comprising:

A. a reflective cylinder means having a concave reflective surface and a longitudinal axis, said longitudinal axis having a selected positional relationship with respect to the tool of the robot

B. motor means having a hollow, rotatable motor shaft;

C. beam directing mirror means secured with respect to and rotatable with said hollow rotatable motor shaft for directing a beam of collimated light that passes through said hollow, rotatable motor shaft to said concave reflective surface to produce a conical beam of light having an angular arc that (i) is a function of the radius of the concave reflective surface and the width of the collimated light beam impinging thereon and (ii) illuminates at least a portion of the workpiece;

D. an array means of photosensitive elements, said elements producing signals representative of the light impinging thereon;

E. means for imaging at least part of said light beam illuminated portion of the workpiece on said array means of photosensitive elements to produce corresponding signals representative of the image on said array;

F. controlling the angular width of the arc of said conical light beam as a function of the ambient light noise at said workpiece; and

,

G. utilization means responsive to said signals for controlling the position of the tool with respect to the workpiece.

27. An apparatus for image acquisition comprising:

A. a reflective cylinder means having a concave reflective surface;

B. motor means having a hollow, rotatable motor shaft;

C. beam directing mirror means secured with respect to and rotatable with said hollow rotatable motor shaft for directing a beam of collimated light that passes through said hollow, rotatable motor shaft to said concave reflective surface to produce a conical beam of light having an angular arc that (i) is a function of the radius of the concave reflective surface and the width of the collimated light beam impinging thereon and (ii) illuminates at least a portion of an object;

D. an array means of photosensitive elements, said elements producing signals representative of the light impinging thereon;

E. means for imaging at least part of said light beam illuminated portion of the object on said array means of photosensitive elements to produce corresponding signals representative of the image on said array;

F. controlling the angular width of the arc of said conical light beam as a function of the ambient light noise at said object; and

,

G. utilization means responsive to said signals.

28. An apparatus for image acquisition comprising:

A. a reflective cylinder means having a concave reflective surface;

B. motor means having a hollow, rotatable motor shaft;

C. beam directing mirror means secured with respect to and rotatable with said hollow rotatable motor shaft for directing a beam of collimated light that passes through said hollow, rotatable motor shaft to said concave reflective surface to produce a conical beam of light having an angular arc that (i) is a function of the radius of the concave reflective surface and the width of the collimated light beam impinging thereon and (ii) illuminates at least a portion of an object;

D. an array means of photosensitive elements, said elements producing signals representative of the light impinging thereon;

E. means for imaging at least part of said light beam illuminated portion of the object on said array mens of photosensitive elements to produce corresponding signals representative of the image on said array;

F. means for controlling the angular arc of said conical beam of light by sweeping the collimated beam of light transversely across said concave reflective surface with the angular arc length being related to the beam sweep width; and

,

G. utilization means responsive to said signals.