Robot vision and optical location systems

• US 4,939,439 A
• Filed: 09/01/1988
• Issued: 07/03/1990
• Est. Priority Date: 09/26/1985
• Status: Expired due to Fees

• Current Assignee: Unisearch Limited (University Of New South Wales)
• Original Assignee: Unisearch Limited (University Of New South Wales)
• Inventors: Dalglish, Robert L.
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): IP, SHIK LUEN PAUL
• Application Number:
  US07/239,080
• Time in Patent Office: 670 Days
• Field of Search: 318/565-572, 318/632, 318/573, 364/513, 364/731, 358/125, 358/126, 358/212, 358/210, 358/160, 358/211, 358/134, 358/11, 358/75, 901/9, 901/16, 901/33, 901/47, 901/46, 340/728, 342/93
• US Class Current: 318/568.1
• CPC Class Codes: G01S 17/06 Systems determining position data of a target
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G06V 10/10 Image acquisition document image scanning and transmission H04N1/00; control of digital cameras H04N23/60

Abstract

Robot vision and optical location systems capable of recovery of "depth" information normally lost from the two-dimensional image collected by a conventional image system comprises a radiation source for projecting a beam of light or other suitable radiation from a known location onto a field of vision in a manner that provides information indicating the direction of projection of the beam, a detection device situated at a second known location for receiving light or other radiation of the projected beam, scattered or reflected by objects within the field of vision and providing information indicating the direction of the source of scattered or reflected radiation and an analyzer for comparing the projection location, direction of projection, detection location and direction of the source of detected, scattered or reflected radiation to determine the location of objects in the field of vision.

Claims

1. An object location system for generating a three-dimensional map of the visible surfaces of objects disposed within a predefined field of view comprising:

projection means situated at a first known location for projecting a beam of radiation into the field of view and periodically scanning said beam over the entire field of view;

encoding means for continuously encoding said beam of radiation with information indicative of its instantaneous direction of projection;

detection means situated at a second known location spaced apart from said first known location for monitoring the field of view to detect radiation from said beam scattered or reflected from surfaces of the objects in said field and producing detection signals indicative of the directions from which said scattered or reflected radiation is received by said detection means;

decoding means connected to said detection means and responsive to the encoding carried on the projected beam direction;

map storage means comprising an array of memory elements representing a map of the field of view having one more dimension than that of said detection means; and

map generating means responsive to successive detected signals and decoded signals to store information in respective memory array elements to model the location in said field of view of detected points on the surfaces of the objects located therein.

2. A system as claimed in claim 1 wherein:

said projecting means comprises a aster scanning means for scanning said beam systematically across said field of view; and

said detection means comprises a two-dimensional detector array means so that the system produces a three-dimensional map of the field of view.

3. A system as claimed in claim 1 wherein:

said projection means comprises means for scanning said beam across the field of view in one plane; and

said detection means comprises a one-dimensional detector array means so that the system produces a two-dimensional map of the field of view.

4. A system as claimed in claim 1 wherein said projection means comprises:

a plurality of projection means, each situated at different known locations for projecting beams of known encoding into said field so that a plurality of maps of the field of view are produced, each representing a viewpoint corresponding to a respective one of the projection means whereby surfaces hidden from one projection means will be scanned by another of the plurality of projection means.

5. A system as claimed in claim 1 and further comprising an analyzer means comprising:

means for comparing and analyzing the contents of said map storage on a real time basis and for generating spatial co-ordinates and vector velocities for objects moving within said field.

6. A system as claimed in claim 1 and further comprising cancellation means for minimizing background illumination effects on said detection means comprising:

modulation means for modulating said beam in time with a predetermined modulation signal; and

filter means to remove from said detection signal any components which are not modulated with said modulation signal.

7. A system as claimed in claim 1 and further comprising cancellation means for minimizing background illumination effects on said detection means, comprising:

means for modulating said beam in time said beam being continuously turned on and off for like periods and;

signal subtraction means whereby detection signals received for a given point in the field of view during a period when the projected beam is off is subtracted from the respective signal received when the beam is on.

8. An object location and surface mapping system comprising:

projection means situated at a first known location for projecting a beam of radiation into a target area, for scanning the target area with said beam and for producing signals indicative of the instantaneous direction of the projected beam;

detection means situated at a second known location spaced apart from said first location for detecting radiation scattered or reflected from said beam by objects in said target area, and for producing signals indicative of the directions from which said scattered or reflected radiation is received by said detection means; and

map generating means for receiving said signals from said detection means indicative of the directions from which scattered or reflected light is received and said signals from said projection means indicative of the instantaneous direction of said projected beam and in response to said signals building a map having one more dimension than said detection means of surfaces of all visible objects within the target area from which scattered or reflected radiation is detected and determining the location of said objects using said map.

9. A system as claimed in claim 8 wherein:

said projecting means comprises a raster scanning means for scanning said beam systematically across said target area; and

said detection means comprises a two-dimensional detector array means so that the system produces a three-dimensional map of the target area.

10. A system as claimed in claim 8 wherein:

said projection means comprises means for scanning said beam across the field of view in one plane; and

said detection means comprises a one-dimensional detector array means so that the system produces a two-dimensional map of the target area.

11. A system as claimed in claim 8 wherein:

said projection means is controlled by said map generating means.

12. A system as claimed in claim 8 wherein said projection means comprises:

means for automatically scanning said target area and providing signals indicative of said direction of projection of said beam to said map generating means.

14. A system as claimed in claim 8 wherein said projection means comprises:

means for modulating said beam in time, the beam being continuously turned on and off for like periods; and

signal subtraction means whereby a detection signal received for a given point in the target area during a period when the projected beam is off is subtracted from the respective signal received when the beam is on.

13. A system as claimed in 8 wherein said map generating means comprises:

means for comparing and analyzing the contents of said map generating means on a real time basis and for generating spatial co-ordinates and vector velocities for objects moving within said field.

15. A method of locating objects and mapping the shape of surfaces in a target area comprising the steps of:

(a) projecting a beam of radiation into the target area in a known direction from a first known location for producing scattered or reflected radiation from objects or surfaces in the target area;

(b) detecting said scattered or reflected radiation at a second known location and determining the direction from which said scattered or reflected radiation is received;

(c) determining the co-ordinates of said objects or surfaces within the target area from which said projected radiation was scattered or reflect by performing calculations on said known direction of projection and said determined direction from which said scattered or reflected radiation is received; and

(d) systematically altering the angle of projection of said beam until the whole target area has been scanned by said beam and at the same time building a map of the surfaces detected in the target area from the respective calculated co-ordinates.

16. A method of locating objects and mapping the three dimensional shape of all object surfaces visible in a target area comprising the steps of:

(a) simultaneously illuminating the entire target area by projecting a plurality of discrete beams of radiation into the target area from a known location so that each beam illuminates a fraction of the target area with each fraction of the target area being illuminated by only one of the beams, whereby scattered or reflected radiation is produced from objects or surfaces in the target area;

(b) encoding each beam by modulation with information indicative of is respective direction of projection;

(c) detecting elements of said scattered or reflected radiation at a second known location and determining the direction from which each element of said scattered or reflected radiation is received;

(d) decoding the encoded beam direction information carried by each received element of the scattered or reflected radiation to determine the original direction of projection of the beam from which that element originated;

(e) correlating said information carried by said detected radiation relating to projected beam directions with the directions from which respective scattered or reflected radiation is received; and

f) deriving a series of surface co-ordinates from which a map can be constructed of the surfaces in the target area from which the scattered or reflected radiation from the beam has been detected.

17. An object location system for mapping surfaces of objects disposed within a predefined field of view comprising:

projection means situated at a first known location for projecting a plurality of beams of radiation into the field of view, each beam illuminating a fraction of the field so that every point in the field is directly illuminated by only one beam;

encoding means for encoding each beam of radiation with information indicative of its direction of projection;

detection means situated at a second known location spaced apart from said first known location for monitoring the field of view to detect radiation from said beams scattered or reflected from surfaces of the objects in said field and producing detection signals indicative of the directions from which said scattered or reflected radiation is received by said detection means;

decoding means connected to said detection means and responsive to the encoding carried on each projected beam for producing decoded signals indicative of each projected beam direction;

map storage means comprising an array of memory elements representing a map of the field of view; and

map generating means responsive to successive detected signals and decoded signals to store information in respective memory elements to model the location in said field of view of detected points on the surfaces of the objects located therein.

18. A system as claimed in claim 17 and further comprising an analyzer means comprising:

means for comparing and analyzing the contents of said map storage means on a real time basis and for generating spatial co-ordinate and detector velocities for objects moving within said field.

19. A system as claimed in claim 17 wherein:

said detection means comprises a two-dimensional detector array means so that the system produces a three-dimensional map of the field of view.

20. A system as claimed in claim 17 wherein:

said detection means comprises a one dimensional detector array means so that the system produces a two dimensional map of the field of view.

21. A system as claimed in claim 17 wherein said projection means comprises:

a plurality of projection means, each situated at different known locations for projecting beams of known encoding into said field of view so that a plurality of maps of the field of view are produced, each representing a viewpoint corresponding to a respective one of said projection means whereby surfaces hidden from one projection means will be scanned by another of the plurality of projection means.

22. A system as claimed in claim 17 and further comprising cancellation means for minimizing background illumination effects on detection means comprising:

modulation means for modulating each beam in time with a predetermined terminal modulation signal; and

filter means to remove from the detection signal any components which are not modulated with said modulation signal.

23. A system as claimed in claim 17 and further comprising cancellation means minimizing background illumination effects on said detection means comprising:

means for modulating each beam in time so that each beam is continuously turned on and off for like periods.