Method and an arrangement for determining the spatial coordinates of at least one object point

• US 6,731,329 B1
• Filed: 05/15/2000
• Issued: 05/04/2004
• Est. Priority Date: 05/14/1999
• Status: Expired due to Fees

• Current Assignee: Trimble Jena GmbH (Trimble Inc.)
• Original Assignee: ZSP Geodaetische Systeme GmbH
• Inventors: Monz, Ludwin-Heinz, Seeber, Marcel, Feist, Wieland
• Primary Examiner(s): PHILIPPE, GIMS S
• Application Number:
  US09/570,623
• Time in Patent Office: 1,450 Days
• Field of Search: 348/135, 348/136, 348/94, 348/95, 348/172, 702/150, 702/104, 702/152, 702/153, 700/9, 700/83, 700/86, 701/207, 356/139.04, 356/141.1, 356/141.5, 250/203.2, 342/357.01, 342/357.06, 332/75.R
• US Class Current: 348/135
• CPC Class Codes: G01C 15/00 Surveying instruments or accessories not provided for in groups G01C1/00 - G01C13/00

Abstract

A method and an arrangement for determining the spatial coordinates of at least one object point P_i from the coordinates of at least two base points which serve as reference points and which do not lie in a plane by means of a video tachymeter which is arranged at a recording stand point, is swivelable about a vertical axis StA and comprises a distance measuring arrangement, a video camera with CCD matrix, a sighting device and angle measuring devices, wherein the video camera is tiltable about a horizontal axis. The coordinates of optional object points are derived from base points in the terrain which are marked and measured by a reflector, laser spot or the like. In addition, a target image containing the marked base points and the object points is recorded and stored. The coordinates of optional object points are then determined from the position data (coordinates) in the target images, which position data are contained in the target images of the marked base points determined by the tachymeter.

Claims

1. A method for determining the spatial coordinates of one or more object points P_i from the coordinates of at least two base points which serve as reference points and which do not lie in a plane by a video tachymeter which is arranged at a recording stand point, is swivelable about a vertical axis StA and comprises a distance measuring arrangement, a video camera with CCD matrix, a sighting device and angle measuring devices, wherein the video camera is tiltable about a horizontal axis, said method comprising the steps of:

marking the base points B₁ and B₂ in the terrain and sighting them by the sighting device;

measuring their coordinates by the distance measuring arrangement and angle measuring devices;

recording target images M′

₁ and M′

₂ each containing the marked base points B₁ and B₂ and the object points P_i by the video camera and storing said target images; and

determining the three-dimensional coordinates of the object points P_i from their image point coordinates in the recorded target images M′

₁ and M′

₂ and from the base points B₁ and B₂ which are marked and determined by tachymetry.

2. The method according to claim 1, wherein the marking of the base points which are determined by tachymetry is carried out in the recorded target images.

3. The method according to claim 1, wherein the selection of object points P_i to be measured at the target point is carried out on a target image which is transmitted to a screen provided at that location or is carried out subsequently during home processing with the aid of recorded and stored target images.

8. The method according to claim 1, wherein an image evaluating device controls an autofocus system in such a way that the target image coordinates of the desired object point P_i are measured in a focused position of the CCD matrix belonging to an object plane, where the base points B₁ and B₂ whose images B′

₁ and B′

₂ lie in the target image planes M′

₁;

M′

₂ are sighted.

4. A method for determining the spatial coordinates of at least one object point P_i from the coordinates of at least two base points which serve as reference points and which are determined by a video tachymeter which is arranged at a recording stand point, is swivelable about a vertical standing axis StA, and provided with a receptacle for a distance measuring arrangement, said receptacle being tiltable about a horizontal tilting axis KA, with a video camera with CCD matrix, with a sighting device and with angle measuring devices, comprising the following method steps:

sighting of at least two base points B₁ and B₂ located in the object space through the video tachymeter which is arranged at a recording stand point and is rotatable about the standing axis StA by a horizontal angle ψ

, this video tachymeter having a video camera that is tiltable about the horizontal tilting axis KA by vertical angle ζ

, and determining the oblique distances e₁₁ and e₂₂ to the at least two base points B₁ and B₂ by means of the distance measuring arrangement of the video tachymeter;

producing two target images containing the at least two base points B₁ and B₂ and storing of the same, wherein the video camera is oriented in such a way that the image B′

₁;

B′

₂ of the respective sighted base point B₁ and B₂ lies in the respective principal point H′

₁ and H′

₂ of the objective of the video camera; and

the x-, y- and z-coordinates of at least one object point P_i being located in the space encompassed by the target images and marked during the recording or marked on the recorded target images by means of the target image coordinates q′

_i1;

q′

_i2;

h′

_i1;

h′

_i2 of the selected object point P_i imaged on the CCD matrix and located in the object space, which target image coordinates q′

_i1;

q′

_i2;

h′

_i1;

h′

_i2 measured in the target images are determined from the oblique distances e₁₁ and e₂₂, from the measured horizontal angle ψ

, from the vertical angles ζ

₁ and ζ

₂, from a device constant Δ

e, and from the focal length f of the objective of the video camera, wherein these coordinates x, y, z are coordinates of a coordinate system with axes X;

Y;

Z with their coordinate origin lying at the intersection of the tilting axis and standing axis StA of the video tachymeter, and the standing axis StA extends vertical to the X-Y plane and determines the direction of the Z-axis.

5. The method according to claim 4, comprising the following method steps:

a. sighting a first base point B₁ by adjusting the axis of the video camera at a first horizontal angle ψ

₁ and at a first vertical angle ζ

₁ relative to the X-Y plane in the direction of the first base point B₁ and measuring the first vertical angle ζ

₁ and the first horizontal angle ψ

₁, wherein the vertex of this vertical angle ζ

₁ and of the horizontal angle ψ

₁ lies in the tilting axis KA of the video tachymeter;

recording and storing a first target image and measuring the oblique distance e₁₁ to this first base point B₁ with a distance measuring arrangement arranged coaxial to the axis of the video camera of the video tachymeter, wherein the video camera is oriented in such a way that the image B′

₁ of the first base point B₁ lies in the principal point H′

₁ of the objective of the video camera and, further, contains the image B′

₂ of the second base point B₂;

b. swiveling the video tachymeter about a horizontal angle ψ

formed by the two base points B₁ and B₂ and the standing axis StA of the video tachymeter, wherein the vertex of this angle is located on the standing axis StA;

c. sighting a second base point B₂ by adjusting the axis of the video camera at a second horizontal angle ψ

₂ and at a second vertical angle ζ

₂ relative to the X-Y plane in direction of the second base point B₂ and measuring the second vertical angle ζ

₂ and second horizontal angle ψ

₂, wherein the vertex of the second horizontal angle ψ

₂ lies in the tilting axis KA of the tachymeter, recording and storing a second target image and measuring the oblique distance e₂₂ to this second base point B₂ with the distance measuring arrangement of the video tachymeter, wherein the video camera is oriented in such a way that the image B′

₂ of the second base point B₂ lies in the principal point H′

₂ of the objective of the video camera and, further, contains the image B′

₁ of the first base point B₁;

d. determining the coordinates of any object points P_i contained in the recorded target images and located in the space by means of the coordinates of the first and second base point B₁ and B₂ by

da. marking the searched object point P_i during recording in the present video image or marking the searched object point P_i in the recorded video images by means of clicking on a mouse;

db. measuring the target image coordinates q′

_i1;

q′

_i2;

h′

_i1;

h′

_i2 of the object point P_i in the recorded target images (M′

₁, M′

₂);

dc. converting the target image coordinates q′

_i1;

q′

_i2;

h′

_i1;

h′

_i2 of the object point P_i which lie in the plane of the CCD matrix into analog coordinates q_i1;

q_i2 and h_i1;

h_i2 located in the object space by means of

the measured oblique distances e₁₁ and e₂₂, corrected by the device constant Δ

e,

the measured image coordinates q′

_i1;

q′

_i2 and h′

_i1;

h′

_i2,

the focal length f of the objective of the video camera, where i=a function of the quantity of object points;

dd. calculating parameters q₁₁;

q₁₂;

h₁₁;

h₁₂;

h₂₁;

q₂₁;

h₂₂;

q₂₂ of support points S₁₁;

S₁₂;

S₂₁;

S₂₂ defining straight lines g₁ and g₂ by means of

the image coordinates q_i1;

q_i2;

h_i1;

h_i2 converted in the object space,

the measured oblique distances e₁₁ and e₂₂,

the measured horizontal angle ψ

,

the measured vertical angles ζ

₁ and ζ

₂,

and the distances e₁₂ and e₂₁ which are derived from the horizontal angle ψ

, from the oblique distances e₁₁ and e₂₂ and from the vertical angles ζ

₁ and ζ

₂,

de. transforming these support point parameters into the coordinates of the coordinate system X;

Y;

Z with its origin at the intersection of the standing axis StA and tilting axis KA,

e. calculating the coordinates x;

y; and

z of the object point P_i with the coordinate origin of said coordinate system which in the intersection of the tilting axis KA and standing axis StA of the video tachymeter by means of the coordinates of the support points S₁₁;

S₁₂;

S₂₁;

S₂₂ by determining the intersection of the straight lines g₁ and g₂ determined by these support point S₁₁;

S₁₂ and S₂₁;

S₂₂.

6. The method according to claim 4, wherein a traverse comprising object points P_i is determined or fixed proceeding from a first tachymeter stand point by base points, this traverse being continued proceeding from a second stand point of the tachymeter.

7. The method according to claim 6, wherein, starting from a first tachymeter stand point, target images M′

₁ and M′

₂ with at least two base points B_i are recorded by the video camera and stored in a computer, wherein one of the two base points is mapped on two adjacent target images;

in that, starting from subsequent adjacent second to nth tachymeter stand points, target images with at least two base points B_i are recorded, wherein a common base point is mapped on two adjacent target images, such that at least one identical base point is mapped on two adjacent target images which were recorded from two adjacent tachymeter stand points; and

in that the coordinates of object points P_i mapped on the target images are determined by means of the coordinates of the base points B_i.

9. An arrangement for determining the spatial coordinates of at least one object point comprising:

at the measurement stand point, an electronic tachymeter with an automatic sighting device and a transmitter;

said electronic tachymeter being swivelable about a vertical axis (StA);

a distance measuring arrangement which is tiltable about a tilting axis KA;

a video camera with a CCD matrix;

a sighting device and angle measuring devices for measuring horizontal and vertical angle; and

at the target point, a sighting rod with reflector;

a radio device;

a receiver; and

a graphic field book with storage components;

at least a portion of the beam path of the distance measuring arrangement being arranged coaxial to the optical axis of the video camera;

a tube being provided for focusing the CCD matrix of the video camera, said tube being controllable depending on the distance measured by the distance measuring arrangement or adjustable manually in direction of the optical axis according to the sharpness or contrast of the video image; and

an image processing system being provided for detecting object points and their specifying as object points with a determined position.

10. The arrangement according to claim 9, wherein the displacement of the tube with the CCD matrix in direction of the optical axis is realizable by a drive unit which is controlled by computer according to an algorithm.

11. The arrangement according to claim 10, wherein the respective displacement path of the tube with the CCD matrix is calculated by the computer corresponding to the distances from the respective sighted base point B that are determined by the distance measuring arrangement.

12. The arrangement according to claim 10, wherein the displacement path is derived during the focusing of the CCD matrix from the object point plane P′

_i located between the target image planes of the base points B₁ and B₂ by an image transformation according to maximum contrast or maximum sharpness.

13. The arrangement according to claim 9, wherein the sighting rod located at the target point comprises a receiver, a radio device and a computer with an additional target image screen, and wherein a transmission of the target image recorded at the measurement point is provided between the measurement stand point and the target point.