Distance measuring apparatus capable of measuring a distance depending on moving status of a moving object

• US 5,760,884 A
• Filed: 10/26/1994
• Issued: 06/02/1998
• Est. Priority Date: 10/27/1993
• Status: Expired due to Term

• Current Assignee: Minolta Corporation Limited (Konica Minolta Inc.)
• Original Assignee: Minolta Corporation Limited (Konica Minolta Inc.)
• Inventors: Joko, Takuto, Yahashi, Akira
• Primary Examiner(s): Buczinski, Stephen C.
• Application Number:
  US08/329,181
• Time in Patent Office: 1,315 Days
• Field of Search: 901/47, 356/3.14, 356/3.16, 356/3.02, 356/3.05, 180/167, 180/169
• US Class Current: 356/3.14
• CPC Class Codes: B60T 7/22 initiated by contact of vehicle, e.g. bumper, with an external object, e.g. another vehicle , or by means of contactless obstacle detectors mounted on the vehicle
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• CPC Class Codes: G01S 11/12 using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/931 of land vehicles

Abstract

A distance measuring apparatus of an apparatus having a moving mechanism includes: a speed detector; and a mechanism responsive to a moving speed signal supplied from the speed detector which varies a focus lens position and a focal length of a light receiving optical system, a scanning range of a light projecting optical system, a base length, a position where light axes of a pair of light receiving optical systems or light axes of the light receiving and light projecting optical systems cross with each other, or responsive to a moving direction signal supplied from a moving direction detecting means of the apparatus having the moving mechanism which changes a measurement direction of a field of view. Thus, optimal measurement accuracy and a field of view to be measured can always be provided even though the moving speed or the moving direction of the apparatus having the moving mechanism is varied.

Claims

1. A distance measuring apparatus mounted on a moving object, comprising:

a speed detector which detects a moving speed of said object; and

a controller which varies an area to be measured and measurement accuracy of said distance measuring apparatus depending on the moving speed of said moving object detected by said speed detector.

2. The distance measuring apparatus according to claim 1, wherein

control of said controller is such that the measurement accuracy of said distance measuring apparatus is increased as said moving object moves faster, and on the other hand, the area to be measured of said distance measuring apparatus is widened as said moving object moves slower.

3. The distance measuring apparatus according to claim 1, further comprising:

a pair of light receiving optical systems spaced apart from each other by a prescribed base length which obtains images of an object to be measured, each light receiving optical system having a variable focal length;

a pair of image sensors which sense images formed by said light receiving optical systems; and

a computing unit which calculates a distance to said object to be measured in response to a pair of signals output from said image sensors, wherein

said controller changes the focal length of said light receiving optical systems depending on the moving speed of the moving object.

4. The distance measuring apparatus according to claim 3, wherein

said light receiving optical systems are zoom lenses.

5. The distance measuring apparatus according to claim 1, further comprising:

two pairs of light receiving optical systems, each pair of light receiving optical systems being spaced apart from each other by a base length, which obtain images of an object to be measured, a different base length being used for each pair;

a pair of image sensors which sense images formed by said light receiving optical systems; and

a computing unit which calculates a distance to said object to be measured in response to a pair of signals output from said image sensors, wherein

said controller selects one of the light receiving system to be used depending on the moving speed of the moving object.

6. The distance measuring apparatus according to claim 1, further comprising:

a pair of light receiving optical systems, spaced apart from each other by a variable base length, which obtains images of an object to be measured;

a pair of image sensors which sense images formed by said light receiving optical systems; and

a computing unit which calculates a distance to said object to be measured in response to a pair of signals output from said image sensors, wherein

said controller changes the base length of said light receiving optical systems depending on the moving speed of the moving object.

7. The distance measuring apparatus according to claim 1, further comprising:

a pair of light receiving optical systems which obtains images of an object to be measured;

a pair of image sensors which sense images formed by said light receiving optical systems; and

a computing unit which calculates a distance to said object to be measured in response to a pair of signals output from said image sensors, wherein

said controller changes a position where optical axes of said two light receiving optical systems cross with each other depending on the moving speed of the moving object.

8. The distance measuring apparatus according to claim 1, further comprising:

two pairs of light receiving optical systems, each pair having a different position where light axes cross with each other, which obtain images of an object to be measured;

a pair of image sensors which sense images formed by said light receiving optical systems; and

a computing unit which calculates a distance to said object to be measured in response to a pair of signals output from said image sensors, wherein

said controller selects one of said light receiving optical systems to be used depending on the moving speed of the moving object.

9. The distance measuring apparatus according to claim 1, further comprising:

a first polarizer which draws a first polarized component from light passing through itself;

a second polarizer which draws a second polarized component, which is orthogonal with respect to the first polarized component, from light passing through itself;

means for combining the components from said two polarizers into the same light path;

a light receiving optical system having a variable focal length which forms the components from said two polarizers to obtain an image of an object to be measured;

a third polarizer which re-splits said to components combined in the same light path into two orthogonally polarized components;

a pair of image sensors which senses images of said two orthogonally polarized components; and

a computing unit which calculates a distance to said object to be measured in response to a pair of signals output from said image sensors, wherein

said controller changes the focal length of said light receiving optical systems depending on the moving speed of the moving object.

10. The distance measuring apparatus according to claim 9, wherein

said light receiving optical system is a zoom lens.

11. The distance measuring apparatus according to claim 1, further comprising:

a light projecting optical system which directs light to an object to be measured;

a light receiving optical system having a variable focal length which obtains an image of the light reflected from said object to be measured;

an image sensor which senses the image formed by said light receiving optical system; and

a computing unit which calculates a distance to said object to be measured in response to a signal output from said image sensor, wherein

said controller changes the focal length of said light receiving optical system depending on the moving speed of the moving object.

12. The distance measuring apparatus according to claim 11, wherein

said light receiving optical system is a zoom lens.

13. The distance measuring apparatus according to claim 1, further comprising:

a light projecting optical system which directs light to an object to be measured;

a light receiving optical system spaced apart from the light projecting optical system by a variable base length which obtains an image of the light reflected from said object to be measured;

an image sensor which senses the image formed by said light receiving optical system; and

a computing unit which calculates a distance to said object to be measured in response to a signal output from said image sensor, wherein

said controller changes the base length depending on the moving speed of the moving object.

14. The distance measuring apparatus according to claim 1, further comprising:

a light projecting optical system which directs light to an object to be measured;

a light receiving optical system which obtains an image of the light reflected from said object to be measured;

an image sensor which senses the image formed by said light receiving optical system; and

a computing unit which calculates a distance to said object to be measured in response to a signal output from said image sensor, wherein

said controller changes a position where the light axes of said light projecting optical system and said light receiving optical system cross with each other depending on the moving speed of the moving object.

15. The distance measuring apparatus according to claim 1, further comprising:

a light emitting element;

a scanning means which scans light emitted from said light emitting element on an object to be measured;

a light receiving optical system which obtains an image of the light reflected from said object to be measured;

an image sensor which senses the image formed by said light receiving optical system; and

a computing unit which calculates a distance to said object to be measured in response to a signal output from said image sensor, wherein

said controller changes a scanning range of the scanning means depending on the moving speed of the moving object.

16. The distance measuring apparatus according to claim 1, further comprising

a moving direction detector which detects a moving direction of said moving object, wherein

said controller varies a measurement direction of said distance measuring apparatus depending on the moving direction of said moving object.

17. The distance measuring apparatus according to claim 1, wherein

said controller controls the measuring apparatus such that the measurement accuracy of said distance measuring apparatus is increased when said moving object moves, while the area to be measured by said distance measuring apparatus is widened when said moving object stops.

18. A distance measuring apparatus mounted on a moving object, comprising:

a speed detector which detects a moving speed of said moving object; and

a controller which varies measurement accuracy of said distance measuring apparatus depending on the moving speed of said moving object detected by said speed detector.

19. The distance measuring apparatus according to claim 18, wherein

the controller increases measurement accuracy of said distance measuring apparatus as said moving object moves faster.

20. The distance measuring apparatus according to claim 18, wherein

the controller sets the measurement accuracy of said distance measuring apparatus at a first accuracy when the moving object moves and sets the measurement accuracy of said distance measuring apparatus at a second accuracy when the moving object stops.

21. A distance measuring apparatus mounted on a moving object, comprising:

a speed detector which detects a moving speed of said moving object;

a light receiving optical system which defines an area to be measured, said area being varied by changing optical characteristics of the light receiving optical system;

a controller which varies the area to be measured depending on the moving speed of said moving object detected by said speed detector.

22. The distance measuring apparatus according to claim 21, wherein

the controller widens the area as said moving object moves slower.

23. The distance measuring apparatus according to claim 21, wherein

said optical system comprises a light receiving optical unit, and

said area to be measured is varied by controlling the light receiving optical unit.

24. The distance measuring apparatus according to claim 23, wherein

said area to be measured is varied by changing a focal length of the light receiving optical unit.

25. The distance measuring apparatus according to claim 23, wherein

said area to be measured is varied by changing a direction of the light receiving optical unit.

26. The distance measuring apparatus according to claim 21, wherein

the controller sets the area at a first area when the moving object moves and sets the area at a second area when the moving object stops.

27. A distance measuring apparatus mounted on a moving object, said distance measuring apparatus optically detecting a distance to an object, comprising:

a light receiving optical system which defines an area to be measured, said distance measuring apparatus measuring the distance to an object within said area;

a moving direction detector which detects a moving direction of said moving object; and

a controller which varies the direction of the area of measurement defined by said light receiving optical system depending on the detection of said moving direction detector.

28. The distance measuring apparatus as claimed in claim 27, wherein

said distance measuring apparatus detects the distance to the object by triangulation.

29. The distance measuring apparatus as claimed in claim 27, further comprising:

a unit including said light receiving optical system and a light receptor, said unit defining the direction of the area;

wherein said controller varies the direction of the area by changing the direction of said unit.

30. The distance measuring apparatus as claimed in claim 27, wherein said light receiving optical system has a least two pre-set view angles which can be alternatively selected to vary said direction.

31. A moving object, comprising:

a driving mechanism which moves said moving object;

a speed detector which detects a moving speed of said moving object;

a distance detector having a light receiving optical system which defines a detection area, said detection area being varied by changing optical characteristics of the light receiving optical system, and said distance detector detecting a distance to an object existing in the moving direction of said moving object; and

a measurement controlling portion which controls said detection area depending on said detected speed.

32. The moving object according to claim 31, further comprising

a drive controlling portion which controls said driving mechanism, wherein

said drive controlling portion controls the speed of said moving object depending on the measured distance to the object.

33. The moving object according to claim 32, further comprising:

a steering mechanism which changes a traveling direction of said moving object;

a moving direction detector which detects a moving direction of said moving object; and

a supporting mechanism which supports said distance detector and which varies a measuring direction of said distance detector, wherein

said measurement controlling portion varies the measuring direction of said measuring portion by the supporting mechanism depending on the traveling direction of said moving object.

34. The moving object according to claim 31, wherein

said distance detector detects a distance optically by triangulation.

35. The distance measuring apparatus according to claim 31, wherein

the measurement controlling portion sets the detection area at a first area when the moving object moves and sets the detection area at a second area when the moving object stops.

36. A distance measuring apparatus comprising:

a light receiving optical system which has a variable focal length, said light receiving optical system defining an area to be measured, and said area being varied by changing the focal length;

an image detector which detects an image of an object in the area defined by the light receiving optical system and generates a signal; and

a computing unit which calculates a distance between the object and the distance measuring apparatus based on the signal.

37. A distance measuring apparatus comprising:

a pair of light receiving optical systems spaced apart from each other by a variable base length, said light receiving optical systems defining an area to be measured, and said area being varied by changing the base length;

a pair of image sensors which sense images formed by said light receiving optical systems; and

a computing unit which calculates a distance between the object and the distance measuring apparatus in response to a pair of output signals from said image sensors.

38. A distance measuring apparatus mounted on a moving object comprising:

a pair of light receiving optical systems which define an area to be measured, said area being varied by changing a position where optical axes of said light receiving optical systems cross with each other;

a pair of image sensors which sense images formed by said light receiving optical systems;

a detector which detects a condition of said moving object; and

a controller which varies said area defined by said light receiving optical systems based on the condition detected by said detector and which calculates a distance between the object and the distance measuring apparatus in response to a pair of signals output from said image sensors.

39. The distance measuring apparatus as claimed in claim 38, wherein said detector detects the speed of the vehicle.

40. A distance measuring apparatus mounted on a moving object, comprising:

a speed detector which detects a moving speed of said object;

a light receiving optical system which obtains an image of an object to be measured;

an image sensor which senses the image formed by said light receiving optical system;

a computing unit which calculates a distance to said object to be measured in response to an output signal from said image sensor; and

a controller which changes a condition of the light receiving optical system depending on the moving speed of said moving object detected by said speed detector.

41. A distance measuring apparatus mounted on a moving object comprising an area changing unit which changes an area over which distance is measured by said distance measuring apparatus and a direction changing unit which changes the direction of said distance measuring unit relative to said moving object.

42. The distance measuring apparatus as claimed in claim 41, further comprising

a light receiving optical system which defines the area;

wherein said area changing unit changes the angle by changing view angle of said light receiving optical system.