Longitudinal profile measuring apparatus

• US 20020007562A1
• Filed: 05/29/2001
• Published: 01/24/2002
• Est. Priority Date: 05/30/2000
• Status: Active Grant

• Current Assignee: Tokimec Construction Systems Incorporated
• Original Assignee: Tokimec Construction Systems Incorporated
• Inventors: Takahashi, Mutsumi, Suyama, Takehiko, Ochi, Tatsuyuki, Kumazawa, Masakuni
• Granted Patent: US 6,618,954 B2
• Time in Patent Office: Days
• US Class Current: 33/533
• CPC Class Codes: G01B 21/20 for measuring contours or curvatures, e.g. determining profile
• CPC Class Codes: G01B 21/30 for measuring roughness or irregularity of surfaces

Abstract

A longitudinal profile measuring apparatus including a relative distance meter located on a frame supported by more than two wheels in a row in a direction of a measuring line for measuring relative distance to a target surface, a moving distance meter for measuring moving distance of movement along the measuring line on the target surface, and a data processing unit for finding spatial data, which shows a rough profile of the target surface, along the measuring line from the relative distance measured by the relative distance meter. The data processing unit storing moving distance data associated with relative distance data to the target surface and transforming the relative distance data of the stored data into amplitude corresponding to frequency, multiplying the amplitude corresponding to frequency by a coefficient of correction for allowing the apparatus to have a gain with a desired frequency characteristic for correction, and inverse transforming the corrected amplitude to find the corrected spatial data of the target surface.

Claims

1. A longitudinal profile measuring apparatus, comprising:

a frame supported by more than two wheels in a row in a direction of a measuring line;

a relative distance meter located on the frame for measuring relative distance to a target surface;

a moving distance meter for measuring moving distance of movement along the measuring line on the target surface; and

data processing means for finding spatial data, which shows a rough profile of the target surface, along the measuring line from the relative distance measured by the relative distance meter, wherein said data processing means comprises;

storing means for storing relative distance data to the target surface measured by the relative distance meter associated with moving distance data measured by the moving distance meter when moving along the measuring line;

frequency transforming means for transforming the relative distance data of the data stored by said storing means into amplitude corresponding to frequency;

correction coefficient multiplying means for multiplying the amplitude corresponding to frequency by coefficient of correction for allowing the apparatus to have a gain with a desired frequency characteristic; and

inverse frequency transforming means for inverse transforming the corrected amplitude to find the corrected spatial data of the target surface.

2. The longitudinal profile measuring apparatus according to claim 1, wherein said desired frequency characteristic is an IRI (International Roughness Index) characteristic.

3. The longitudinal profile measuring apparatus according to claim 2, further comprising:

variation accumulating means for accumulating variations of gradient over a desired section of the measuring line, said variation of gradient being obtained from the corrected spatial data from said inverse frequency transforming means.

4. The longitudinal profile measuring apparatus according to claim 1, wherein spaces between said plurality of wheels and said relative distance meter are set such that the apparatus has the desired frequency characteristic.

5. The longitudinal profile measuring apparatus according to claim 4, wherein said desired frequency characteristic is an IRI (International Roughness Index) characteristic.

6. The longitudinal profile measuring apparatus according to claim 5, further comprising:

variation accumulating means for accumulating variations of gradient over a desired section of the measuring line, said variation of gradient being obtained from the corrected spatial data from said inverse frequency transforming means.

7. A longitudinal profile measuring apparatus, comprising:

a frame supported by more than two wheels in a row in a direction of a measuring line;

a relative distance meter located on the frame for measuring relative distance to a target surface;

a moving distance meter for measuring moving distance of movement along the measuring line on the target surface; and

data processing means for finding spatial data, which shows a rough profile of the target surface, along the measuring line from the relative distance measured by the relative distance meter,

wherein a space between one wheel and the relative distance meter is set to be about ½

of a longer wavelength in a frequency band to be measured of the longitudinal profile and a space between the other wheel and the relative distance meter is set to be about ½

of a shorter wavelength in the frequency band to be measured of the longitudinal profile.

8. The longitudinal profile measuring apparatus according to claim 7, wherein said data processing means comprises:

storing means for storing relative distance data to the target surface measured by the relative distance meter associated with moving distance data measured by the moving distance meter when moving along the measuring line;

frequency transforming means for transforming the relative distance data of the data stored by said storing means into amplitude corresponding to frequency;

correction coefficient multiplying means for multiplying the amplitude corresponding to frequency by coefficient of correction for allowing the apparatus to have a gain with a desired frequency characteristic for correction; and

inverse frequency transforming means for inverse transforming the corrected amplitude to find the corrected spatial data of the target surface.

9. The longitudinal profile measuring apparatus according to claim 8, wherein said desired frequency characteristic is an IRI (International Roughness Index) characteristic.

10. The longitudinal profile measuring apparatus according to claim 9, further comprising:

variation accumulating means for accumulating variations of gradient over a desired section of the measuring line, said variation of gradient being obtained from the corrected spatial data from said inverse frequency transforming means.

11. A longitudinal profile measuring apparatus, comprising:

a plurality of relative distance meters located in a row in a direction of a measuring line on the vehicle for respectively measuring relative distance to a target surface;

a moving distance meter located on the vehicle for measuring moving distance of movement along the measuring line on the target surface, and

data processing means for finding spatial data, which show a rough profile of the target surface, along the measuring line from the relative distance measured by the relative distance meter, wherein said data processing means comprises;

storing means for storing relative distance data to the target surface measured by the plurality of relative distance meters associated with moving distance data measured by the moving distance meter when moving along the measuring line; and

relative distance calculating means for calculating relative distances to be outputted by a main relative distance meter from the relative distance data measured by each relative distance meter, said main relative distance meter being assumed to be substituted for one of the relative distance meter on the same vertical line as the main relative distance meter and being to be supported a phantom frame supported by phantom wheels which are assumed to be substituted for the other relative distance meters, thereby finding spatial data based on the relative distance from the relative distance calculating means and said plurality of relative distance meter being set so that spaces between said main relative distance meter and the other relative distance meters such that the apparatus has a gain with a desired frequency characteristic.

12. The longitudinal profile measuring apparatus according to claim 11, wherein said data processing means comprises:

frequency transforming means for transforming the relative distance data from the relative distance calculating means into amplitude corresponding to frequency;

correction coefficient multiplying means for multiplying the amplitude corresponding to frequency by coefficient of correction for allowing the apparatus to have gain with a desired frequency characteristic; and

inverse frequency transforming means for inverse transforming the corrected amplitude to find the corrected spatial data of the target surface.

13. The longitudinal profile measuring apparatus according to claim 12, wherein said desired frequency characteristic is an IRI (International Roughness Index) characteristic.

14. The longitudinal profile measuring apparatus according to claim 13, further comprising:

variation accumulating means for accumulating variations of gradient over a desired section of the measuring line, said variation of gradient being obtained from the corrected spatial data from said inverse frequency transforming means.

15. A method of measuring a longitudinal profile, comprising:

measuring relative distance to a target surface;

measuring moving distance of movement along the measuring line on the target surface; and

finding spatial data showing a rough profile of the target surface, along the measuring line from the measured relative distance.

16. The method of measuring a longitudinal profile, according to claim 15, wherein said finding spatial data comprises:

storing measured relative distance data to the target surface associated with measured moving distance data when moving along the measuring line;

transforming the relative distance data of the stored data stored into amplitude corresponding to frequency;

multiplying the amplitude corresponding to frequency by a coefficient of correction to have a gain with a desired frequency characteristic; and

inverse transforming the corrected amplitude to find a corrected spatial data of the target surface.

17. The method of measuring a longitudinal profile, according to claim 16, further comprising:

accumulating variations of a gradient over a desired section of the measuring line, said variation of gradient being obtained from the corrected spatial data from said inverse.