Distance measuring apparatus capable of measuring plural distance data for calculated angle ranges

• US 5,691,725 A
• Filed: 02/29/1996
• Issued: 11/25/1997
• Est. Priority Date: 09/08/1995
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Tanaka, Shoichi
• Primary Examiner(s): Pihulic, Daniel T.
• Application Number:
  US08/609,904
• Time in Patent Office: 635 Days
• Field of Search: 342/126, 342/133
• US Class Current: 342/126
• CPC Class Codes: G01S 13/08 Systems for measuring distance only indirect measurement G01S13/46
• CPC Class Codes: G01S 17/36 with phase comparison between the received signal and the contemporaneously transmitted signal
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/46 Indirect determination of position data
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G01S 7/487 Extracting wanted echo signals , e.g. pulse detection
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating

Abstract

In a distance measuring apparatus, a large number of distance data within a certain calculation angle region are acquired so as to obtain distance data with high reliability. The distance measuring apparatus is comprised of: a transmitter/receiver device including at least one of a transmitter for projecting electromagnetic waves while scanning the electromagnetic waves, and a receiver for receiving reflection waves of the electromagnetic waves reflected from an object while scanning the reflection waves; an angle detecting apparatus for detecting at least one of an angle when the electromagnetic waves are projected and an angle when the reflection waves are received; a distance calculating apparatus for calculating a distance up to the object corresponding to the angle based upon a relationship between the electromagnetic waves and the reflection waves, and for using a calculation result as detection data; and a data processing apparatus for acquiring distance data in a calculation angle region corresponding to a plurality of the distance calculations based upon the detection data obtained during a plurality of distance calculations.

Claims

1. A distance calculating apparatus comprising:

a transmitter/receiver device including at least one of a transmitter for projecting electromagnetic waves while scanning the electromagnetic waves, and a receiver for receiving reflection waves that are electromagnetic waves reflected from an object while scanning the reflection waves;

an angle detecting device for detecting at least one of an angle when said electromagnetic waves are projected and an angle when said reflection waves are received;

a distance calculating device for calculating a distance to the object corresponding to said angle based on time measured from the projection of the electromagnetic waves and the reception of the reflection waves, thereby using said calculated distance as detection data; and

a data processing device for acquiring distance data in a calculation angle region corresponding to a plurality of said distance calculations based upon the detection data obtained during a plurality of distance calculations.

2. A distance calculating apparatus as claimed in claim 1, further comprising:

a reliability calculating apparatus for calculating reliability of the distance data in a relevant calculation angle region based on the detection data within said relevant calculation angle region.

3. A distance calculating apparatus comprising:

a transmitter/receiver device including at least one of a transmitter for projecting electromagnetic waves while scanning the electromagnetic waves, and a receiver for receiving reflection waves that are electromagnetic waves reflected from an object while scanning the reflection waves, wherein the transmitter modulates the projected electromagnetic waves with a predetermined modulation signal to thereby project modulated electromagnetic waves;

an angle detecting device for detecting at least one of an angle when said electromagnetic waves are projected and an angle when said reflection waves are received;

a distance calculating apparatus for calculating a distance to the object corresponding to said angle based upon a phase difference in the modulation of the projected electromagnetic waves and the received reflection waves, thereby using the calculated distance as detection data; and

a data processing device for acquiring distance data in a calculation angle region corresponding to a plurality of said distance calculations based upon the detection data obtained during a plurality of distance calculations.

20. A distance calculating apparatus as claimed in claim 3, further comprising:

a reliability calculating apparatus for calculating reliability of the distance data in a relevant calculation angle region based on the detection data within said relevant calculation angle region.

4. A distance calculating apparatus comprising:

a transmitter/receiver device including at least one of a transmitter for projecting electromagnetic waves while scanning the electromagnetic waves, and a receiver for receiving reflection waves that are electromagnetic waves reflected from an object while scanning the reflection waves;

an angle detecting device for detecting at least one of an angle when said electromagnetic waves are projected and an angle when said reflection waves are received;

a distance calculating device for calculating a distance to said object corresponding to said angle based upon a relationship between said electromagnetic waves and said reflection waves, thereby using the calculated distance as detection data;

a data processing device for acquiring distance data in a calculation angle region corresponding to a plurality of said distance calculations based upon the detection data obtained during a plurality of distance calculations; and

a data process determining apparatus for determining a process of the distance data based on at least one of the detection data and the distance data within the calculation angle region.

6. A distance calculating apparatus as claimed in claim 4, wherein said distance calculating apparatus calculates the distance to the object based upon the projected electromagnetic waves and the received reflection waves by way of a triangulation method, thereby using the calculated distance as the detection data.

7. A distance calculating apparatus as claimed in claim 4, wherein said data process determining apparatus invalidates the distance data when at least one of the detection data and the distance data within the calculation angle region cannot satisfy a preselected condition.

8. A distance calculating apparatus as claimed in claim 4, wherein said data precess determining apparatus invalidates the distance data when the reliability of said distance data is lower than a preselected value.

9. A distance calculating apparatus as claimed in claim 7, wherein said data process determining apparatus invalidates the distance data in the relevant calculation angle region when the number of detection data within the calculation angle region is smaller than a preselected value.

10. A distance calculating apparatus as claimed in claim 9, wherein said preselected value is determined in accordance with the distance data within the relevant calculation angle region.

11. A distance calculating apparatus as claimed in claim 7, wherein when an absolute value of a difference between a distance data value in a first calculation angle region and a distance data value in a second calculation angle region is smaller than a preselected value, said data process determining apparatus invalidates the distance data of such a calculation angle region in said first and second calculation angle regions where a detection data number is smaller than a detection data number of the other calculation angle region.

12. A distance calculating apparatus as claimed in claim 7, wherein when the number of detection data in the calculation angle region is smaller than a predetermined value and also a distribution for angles of the detection data in said calculation angle region is deviated more than a predetermined value, said data process determining apparatus invalidates the distance data in said calculation angle region.

13. A distance calculating apparatus as claimed in claim 7, wherein when the number of times at which the distance data is obtained in the same calculation angle region during a preselected scanning operation time period is smaller than a predetermined number, said data process determining apparatus invalidates all of the distance data in the relevant calculation angle region.

14. A distance calculating apparatus as claimed in claim 7, wherein said data process determining apparatus invalidates distance data when a temporal change between distance data values acquired from the same calculation angle region during a preselected scanning operation time period is larger than a predetermined value and a detection data number corresponding to said distance data is smaller than a preselected value.

15. A distance calculating apparatus as claimed in claim 6, wherein when the detection data of a first calculation angle region does not satisfy a predetermined condition but a detection data of a second calculation angle region located adjacent to said first calculation angle region satisfies said predetermined condition, said data process determining apparatus replaces distance data in the first calculation angle region with distance data in the second calculation angle region.

16. A distance calculating apparatus as claimed in claim 15, wherein when reliability of the distance data in the first calculation angle region is lower than a predetermined level, and reliability of the distance data in the second calculation angle region located adjacent to the first calculation angle region is higher than said predetermined value, said data process determining apparatus replaces the distance data in said first calculation angle region with the distance data in said second calculation angle region.

17. A distance calculating apparatus as claimed in claim 15, wherein when the detection data number within the first calculation angle region is smaller than the detection data number within the second calculation angle region, said data process determining apparatus replaces the distance data in the first calculation angle region with the distance data in the second calculation angle region.

18. A distance calculating apparatus as claimed in claim 15, wherein said data process determining apparatus replaces the distance data in said first calculation angle region with the distance data in said second calculation angle region when the detection data number in the first calculation angle region is smaller than the detection data number in the second calculation angle region and a difference in the distance data values between the first and second calculation angle regions is smaller than a predetermined value.

19. A distance calculating apparatus as claimed in claim 4, further comprising:

a reliability calculating apparatus for calculating reliability of the distance data in a relevant calculation angle region based on the detection data within said relevant calculation angle region.

5. A distance calculating apparatus comprising:

a transmitter/receiver device including at least one of a transmitter for projecting electromagnetic waves while scanning the electromagnetic waves, and a receiver for receiving reflection waves that are electromagnetic waves reflected from an object while scanning the reflection waves;

an angle detecting device for detecting at least one of an angle when said electromagnetic waves are projected and an angle when said reflection waves are received;

a distance calculating device for calculating a distance to said object corresponding to said angle based upon a relationship between said electromagnetic waves and said reflection waves, and for using a calculation result as detection data;

a data processing device for acquiring distance data in a calculation angle region corresponding to a plurality of said distance calculations based upon the detection data obtained during a plurality of distance calculations; and

a reliability calculating apparatus for calculating reliability of the distance data in a relevant calculated angle region based on a ratio between a sum of the detection data obtained and the number of distance calculations.