Distance measuring apparatus

• US 5,959,724 A
• Filed: 01/06/1998
• Issued: 09/28/1999
• Est. Priority Date: 01/09/1997
• Status: Expired due to Fees

• Current Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Original Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Inventors: Shimizu, Hideo, Sugiyama, Osamu, Izumi, Akio, Hirata, Nobuo
• Primary Examiner(s): Buczinski, Stephen C.
• Application Number:
  US09/003,129
• Time in Patent Office: 630 Days
• Field of Search: 180/167, 356/3.13-3.16, 356/4.02
• US Class Current: 356/3.14
• CPC Class Codes: G01C 3/085 with electronic parallax measurement
• CPC Class Codes: G01S 11/12 using electromagnetic waves other than radio waves

Abstract

A distance measuring apparatus of the invention includes an arithmetic operation device which uses the degree of shift detected when the distance to a reference object is measured and a known distance to the reference object, to determine the difference between the offsets of image-forming positions on optical sensor arrays caused by a windshield present between a measuring object and the optical sensor arrays. The arithmetic operation device uses the difference between the offsets of the image-forming positions, an optical characteristic amount of the image-forming lenses, and the amount of shift detected when the distance to the measuring object is measured, to determine the distance to the measuring object.

Claims

1. A distance measuring apparatus comprising:

imaging logic means including a pair of image-forming lenses and a pair of optical sensor arrays; and

arithmetic operation logic means connected to the imaging logic means for calculating a distance to a measuring object to be measured based on two images of the measuring object obtained by the imaging logic means;

said arithmetic operation logic means having means to calculate, by using a degree of a shift detected when a distance to a reference object is measured with respect to a known distance to the reference object, a difference between offsets of image-forming positions on the optical sensor arrays caused by a medium present between the measuring object and the optical sensor arrays, and having means to obtain a distance to the measuring object by the difference between the offsets of the image-forming positions and the degree of the shift.

2. A distance measuring apparatus according to claim 1, wherein said arithmetic operation logic means calculates the degree of the shift by locating the reference object at a plurality of positions different in distances from the distance measuring apparatus.

3. A distance measuring apparatus according to claim 1, further comprising direction adjustment means for adjusting a mounting angle of the apparatus so that an image of the reference object is formed at predetermined positions of the optical sensor arrays.

4. A distance measuring apparatus according to claim 1, further comprising a finder having an optical axis parallel to optical axes of the image-forming lenses.

5. A distance measuring apparatus according to claim 4, wherein said finder is detachable.

6. A distance measuring apparatus comprising:

imaging logic means including a pair of image-forming lenses and a pair of optical sensor arrays;

a collimator as a reference object situated away from the imaging logic means and including a collimator lens and a chart disposed near the collimator lens; and

arithmetic operation logic means connected to the imaging logic means for calculating a distance to a measuring object to be measured based on two images of the measuring object obtained by the imaging logic means, said arithmetic operation logic means obtaining a distance to the measuring object by a degree of a shift detected from an image of the chart and a degree of a shift detected when a distance to the reference object is measured.

7. A distance measuring apparatus according to claim 6, wherein said chart is located at a focal position of the collimator lens.

8. A distance measuring apparatus according to claim 6, wherein said chart is located at a predetermined distance away from a focal position of the collimator lens, said arithmetic operation logic means calculating, by a length of a focal position of the chart and a focal length of the collimator lens, a distance to the chart and a pseudo distance thereof, and obtaining the distance to the measuring object by the distance to the chart and the pseudo distance thereof together with the degree of the shift detected from the image of the chart and the degree of the shift detected when the distance to the reference object is measured.

9. A distance measuring apparatus according to claim 6, wherein said chart is movable from a focal position of the collimator lens along an optical axis of the collimator lens, said collimator further including measuring means for detecting an amount of movement of the chart;

said arithmetic operation logic means calculating, by the amount of movement of the chart obtained from the measuring means and a focal length of the collimator lens, a distance to the chart and a pseudo distance thereof, and obtaining the distance to the measuring object by the distance to the chart and the pseudo distance thereof together with the degree of the shift detected from the image of the chart and the degree of the shift detected when the distance to the reference object is measured.

10. A distance measuring apparatus according to claim 6, wherein said collimator includes a finder having an optical axis at least parallel to an optical axis of the collimator including an identical optical axis.

11. A distance measuring apparatus according to claim 10, wherein said finder is disposed so as to be focused at a predetermined finite distance.

12. A distance measuring apparatus according to claim 10, wherein said finder has focus adjustment means.

13. A distance measuring apparatus according to claim 6, wherein said collimator includes a finder having an optical axis coaxial with an optical axis of the collimator, said finder adjusting a focus by moving the collimator lens along the optical axis of the collimator lens.

14. A distance measuring apparatus according to claim 6, further comprising direction adjustment means for adjusting a mounting angle of the apparatus so that an image of the reference object is formed at predetermined positions of the optical sensor arrays.

15. A distance measuring apparatus according to claim 6, further comprising a finder having an optical axis parallel to optical axes of the image-forming lenses.

16. A distance measuring apparatus according to claim 15, wherein said finder is detachable.