Optical installation and process for determining the relative positions of at least two objects in space

• US 6,424,411 B1
• Filed: 11/19/1999
• Issued: 07/23/2002
• Est. Priority Date: 11/20/1998
• Status: Expired due to Fees

• Current Assignee: FFB
• Original Assignee: Compagnie Europeenne D'Equipements De Garage (CEEG)
• Inventors: Rapidel, Jean-Loup, Rives, Gérard, Dhome, Michel, Lapreste, Jean-Thierry, Lavest, Jean-Marc
• Primary Examiner(s): Buczinski, Stephen C.
• Application Number:
  US09/443,437
• Time in Patent Office: 977 Days
• Field of Search: 332/031.8, 332/88, 356/139.09
• US Class Current: 356/139.09
• CPC Class Codes: G01B 11/002 for measuring two or more coordinates
• CPC Class Codes: G01B 11/2755 using photoelectric detection means
• CPC Class Codes: G01B 2210/12 Method or fixture for calibrating the wheel aligner
• CPC Class Codes: G01B 2210/143 One or more cameras on each side of a vehicle in the main embodiment
• CPC Class Codes: G01B 2210/30 Reference markings, reflector, scale or other passive device
• CPC Class Codes: G01B 2210/303 fixed to the ground or to the measuring station

Abstract

An optical installation for determining the relative positions of at least two objects, such as vehicle wheels, includes two optical systems for determining the position of an object in space, each with respect to its observation frame. An optical reference system includes a target visible from the other optical system in the absence of the objects. The other optical system includes a device for analyzing an image of the target and a device for positioning the target with respect to its observation frame, so as to deduce therefrom the position of the observation frame of the other optical system with respect to the observation frame of the of the optical reference system, on the basis of the positions of the target with respect to the observation frame and of the target with respect to the observation frame of the optical reference system.

Claims

1. An optical installation for determining relative positions of at least two objects, said optical installation comprising:

at least two optical systems being moveable with respect to each other, each optical system of said at least two optical systems being associated with an observation frame and being adapted to determine a position of an object of the at least two objects with respect to its observation frame based on an image of the object captured by said optical system,

wherein at least one optical system of said at least two optical systems is an optical reference system comprising a set of reference points of a known geometrical configuration, said set of reference points being secured to said optical reference system and immobilized in a known position with respect to the observation frame of said optical reference system, wherein said set of reference points is visible to at least one other optical system of said at least two optical systems in the absence of the at least two objects,

wherein said at least one other optical system comprises;

means for analyzing an image of said set of reference points,

means for positioning said set of reference points with respect to the observation frame of said at least one other optical system, and

means for deducing a position of the observation frame of said at least one other optical system with respect to the observation frame of said optical reference system based on the position of said set of reference points with respect to the observation frame of said at least one other optical system and the known position of said set of reference points with respect to the reference frame of said optical reference system.

2. An optical installation according to claim 1, comprising a central information processing unit which includes said means for analyzing, said means for positioning and said means for deducing,

wherein said central information processing unit is connected to said at least two optical systems, and

wherein each of said at least two optical systems further comprises a video camera and a support for said video camera.

3. An optical installation according to claim 1, wherein said set of reference points comprises a group of coplanar discrete visible marks and at least one non-coplanar visible mark.

4. An optical installation according to claim 1, further comprising pads operable to be secured to the at least two objects at a known position, and wherein each optical system of said at least two optical systems comprises means for determining a position of a pad of said pads with respect to the observation frame of said optical system and means for deducing the position of the object with respect to the observation frame of said optical system from the determined position of said pad with respect to the observation frame of said optical system and from the known position of said pad with respect to the object.

5. An optical installation according to claim 2, wherein said set of reference points comprises a group of coplanar discrete visible marks and at least one non-coplanar visible mark.

6. An optical installation according to claim 2, further comprising pads operable to be secured to the at least two objects at a known position, and wherein each optical system of said at least two optical systems comprises means for determining a position of a pad of said pads with respect to the observation frame of said optical system and means for deducing the position of the object with respect to the observation frame of said optical system from the determined position of said pad with respect to the observation frame of said optical system and from the known position of said pad with respect to the object.

7. An optical installation according to claim 3, further comprising pads operable to be secured to the at least two objects at a known position, and wherein each optical system of said at least two optical systems comprises means for determining a position of a pad of said pads with respect to the observation frame of said optical system and means for deducing the position of the object with respect to the observation frame of said optical system from the determined position of said pad with respect to the observation frame of said optical system and from the known position of said pad with respect to the object.

8. An installation for determining relative positions of four objects, said installation comprising:

four optical systems to be disposed substantially at vertices of a quadrilateral in which the four objects are delimited within and said four optical systems being moveable with respect to each other, each optical system of said four optical systems being associated with an observation frame and being adapted to determine a position of an object of the four objects with respect to its observation frame based on an image of the object captured by said optical system,

wherein two of said four optical systems are first and second optical reference systems, each optical reference system of said first and second optical reference systems comprising a set of reference points of a known geometrical configuration, said set of reference points being secured to said optical reference system and immobilized in a known position with respect to the observation frame of said optical reference system, wherein said set of reference points of said first optical reference system is visible from said second optical reference system in the absence of the four objects,

wherein said second optical reference system comprises;

means for analyzing an image of said set of reference points of said first optical reference system,

means for positioning said set of reference points of said first optical reference system with respect to the observation frame of said second optical reference system,

means for deducing a position of the observation frame of said second optical reference system with respect to the observation frame of said first optical reference system based on the position of said set of reference points of said first optical reference position with respect to the observation frame of said second optical reference system and the known position of said set of reference points of said first optical reference system with respect to the reference frame of said optical reference system, and

means for deducing relative positions of the observation frames of each of said four optical systems.

9. An optical installation according to claim 8, comprising a central information processing unit which includes said means for analyzing, said means for positioning and each said means for deducing,

wherein said central information processing unit is connected to said four optical systems, and

wherein each of said four optical systems further comprises a video camera and a support for said video camera.

10. An optical installation according to claim 8, wherein said sets of reference points of said first and second optical reference systems each comprise a group of coplanar discrete visible marks and at least one non-coplanar visible mark.

11. An optical installation according to claim 8, further comprising pads operable to be secured to the four objects at a known position, and wherein each optical system of said four optical systems comprises means for determining a position of a pad of said pads with respect to the observation frame of said optical system and means for deducing the position of the object with respect to the observation frame of said optical system from the determined position of said pad with respect to the observation frame of said optical system and from the known position of said pad with respect to the object.

12. A method for determining relative positions of at least two objects by using at least two optical systems being moveable with respect to each other, each optical system of the at least two optical systems being associated with an observation frame, wherein at least one optical system of the at least two optical systems is an optical reference system comprising a set of reference points of a known geometrical configuration, the set of reference points being secured to the optical reference system and immobilized in a known position with respect to the observation frame of the optical reference system, wherein the set of reference points is visible to at least one other optical system of the at least two optical systems in the absence of the at least two objects, said method comprising:

determining a position of each of the at least two objects with a respective one of the at least two optical systems with respect to the observation frame of the respective one of the at least two objects based on an image of each of the objects captured by the respective one of the at least two optical systems;

analyzing an image of the set of reference points with the at least one other optical system;

determining positioning of the set of reference points with respect to the observation frame of the at least one other optical system with the at least one other optical system; and

deducing a position of the observation frame of the at least one other optical system with respect to the observation frame of the optical reference system based on the position of the set of reference points with respect to the observation frame of the at least one other optical system and the known position of the set of reference points with respect to the reference frame of the optical reference system with the at least one other optical system.