Calibration of a surveying instrument
First Claim
1. A method for calibrating a surveying instrument comprising a base element and a camera with an image sensor, the camera being rotatable about a vertical axis fixed with respect to said base element and being rotatable about a tilting axis, the tilting axis being rotated about the vertical axis with rotation of the camera about the vertical axis, wherein data associated with calibration points and images of the calibration points on the image sensor captured in different faces are used, the data for each of said calibration points comprising distance data representing a distance between each said calibration point and the surveying instrument and the data for each of the images of each said calibration point comprising image position data representing the position of the image of each said calibration point on said image sensor and orientation data representing a horizontal angle of rotation of the tilting axis about the vertical axis and a vertical angle of tilting of the camera about the tilting axis, and wherein on the basis of the distance data for each of the calibration points and the image position and orientation data for each of the images of the calibration points the surveying instrument is calibrated simultaneously taking into account at least one optical property of the camera and at least one of the relative orientation of the vertical axis and the tilting axis and the orientation of the camera relative to one of the base element, the vertical axis and the tilting axis.
1 Assignment
0 Petitions
Accused Products
Abstract
A method for calibrating a surveying instrument is disclosed, the survey instrument comprising a base element and a camera with an image sensor, the camera being rotatable about a vertical axis fixed with respect to said base element and being rotatable about a tilting axis, the tilting axis being rotated about the vertical axis with rotation of the camera about the vertical axis. In the method, data associated with calibration points and images of the calibration points on the image sensor captured in different faces are used, the data for each of said calibration points comprising distance data and the data for each of the images of each said calibration point comprising image position data and orientation data. Further, on the basis of the distance data for each of the calibration points and the image position and orientation data for each of the images of the calibration points the surveying instrument is calibrated simultaneously taking into account at least one optical property of the camera and at least one of the relative orientation of the vertical axis and the tilting axis and the orientation of the camera relative to one of the base element, the vertical axis and the tilting axis.
75 Citations
30 Claims
-
1. A method for calibrating a surveying instrument comprising a base element and a camera with an image sensor, the camera being rotatable about a vertical axis fixed with respect to said base element and being rotatable about a tilting axis, the tilting axis being rotated about the vertical axis with rotation of the camera about the vertical axis,
wherein data associated with calibration points and images of the calibration points on the image sensor captured in different faces are used, the data for each of said calibration points comprising distance data representing a distance between each said calibration point and the surveying instrument and the data for each of the images of each said calibration point comprising image position data representing the position of the image of each said calibration point on said image sensor and orientation data representing a horizontal angle of rotation of the tilting axis about the vertical axis and a vertical angle of tilting of the camera about the tilting axis, and wherein on the basis of the distance data for each of the calibration points and the image position and orientation data for each of the images of the calibration points the surveying instrument is calibrated simultaneously taking into account at least one optical property of the camera and at least one of the relative orientation of the vertical axis and the tilting axis and the orientation of the camera relative to one of the base element, the vertical axis and the tilting axis.
-
2. A method for calibrating a surveying instrument comprising a base element and a camera with an image sensor, the camera being rotatable about a vertical axis fixed with respect to said base element and being rotatable about a tilting axis, the tilting axis being rotated about the vertical axis with rotation of the camera about the vertical axis,
wherein images of calibration points are generated at different positions on the image sensor and in two faces, wherein for each of said calibration points the distance data representing a distance between the respective calibration point and the surveying instrument and for each image of said calibration points position data representing the position of the image of the calibration point on the image sensor, orientation data representing a horizontal angle of rotation of the tilting axis about the vertical axis and a vertical angle of tilting of the camera of the tilting axis are determined, and wherein on the basis of the distance data for each of the calibration points and the position and orientation data for each of the images of the calibration points the surveying instrument is calibrated simultaneously taking into account at least one optical property of the camera and at least one of the relative orientation of the vertical axis and the tilting axis and the orientation of the camera relative to one of the base element, the vertical axis and the tilting axis.
-
28. A surveying instrument having a camera with an image sensor, wherein imaging of an object point by the camera on the image sensor can be modeled by use of a camera model having a projection center, a display for displaying images based on images captured by the image sensor, and a control unit for controlling the display to display a mark indicating a sighting axis, the sighting axis being defined by the projection center and the intersection point or point of closest approach of the tilting axis and the vertical axis.
-
29. A surveying instrument comprising a base element and a camera with an image sensor, the camera being rotatable about a vertical axis fixed with respect to said base element and being rotatable about a tilting axis, the tilting axis being rotated about the vertical axis with rotation of the camera about the vertical axis, wherein imaging of an object point on the image sensor by the camera can be modeled by use of a camera model working a coordinate system fixed to the camera and a transformation model for transforming coordinates between an instrument coordinate system and the camera coordinate system, the instrument further comprising a data processing unit, in which program code is stored for determining a direction of an object point captured by the camera using the camera and transformation models, wherein a direction from the origin of the instrument coordinate system to the object point is calculated using a direction obtained by means of the camera model and the transformation model and the distance of the object point from the origin of the instrument coordinate system.
-
30. A computer program for a surveying instrument, the surveying instrument comprising a data processing system, a base element and a camera with an image sensor, the camera being rotatable about a vertical axis fixed with respect to said base element and being rotatable about a tilting axis, the tilting axis being rotated about the vertical axis with rotation of the camera about the vertical axis, wherein imaging of an object point on the image sensor by the camera can be modeled by use of a camera model working in a coordinate system fixed to the camera and a transformation model for transforming coordinates between an instrument coordinate system and the camera coordinate system, the computer program comprising program code for determining a direction of an object point captured by the camera using the camera and transformation models, wherein a direction from the origin of the instrument coordinate system to the object point is calculated using a direction obtained by means of the camera model and the transformation model and the distance of the object point from the origin of the instrument coordinate system when the program is executed by the data processing system.
Specification