Target apparatus and method of making a measurement with the target apparatus
First Claim
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1. A method comprising steps:
- providing the target, wherein the target has a target frame of reference and includes a first retroreflector and a body, the body having a spherical exterior portion that has a sphere center and a sphere radius, the body containing a cavity, the cavity sized to hold the first retroreflector, the cavity open to the exterior of the body, the first retroreflector at least partially disposed in the cavity, the first retroreflector having a first retroreflector reference point in the target frame of reference;
providing the device, wherein the device has a device frame of reference and a first light source, the device being configured to measure a distance and two angles from the device to the first retroreflector reference point;
determining at least one vector length component in the target frame of reference of a vector that extends from the first retroreflector reference point to the sphere center, the vector having a length greater than zero;
illuminating the first retroreflector with light from the first light source to provide a first reflected light that is returned to the device;
measuring, from the device to the first retroreflector reference point, a first distance and a first set of two angles based at least in part on the first reflected light, the first distance based at least in part on a speed of light over a path traveled by the light from the device to the first retroreflector reference point;
determining three orientational degrees of freedom of the target frame of reference in the device frame of reference, wherein the three orientational degrees of freedom are sufficient to fully define the orientation of the target frame of reference in the device frame of reference;
calculating three dimensional coordinates of the sphere center within the device frame of reference based at least in part on the first distance, the first set of two angles, the three orientational degrees of freedom, and the at least one vector length component; and
storing the three dimensional coordinates of the sphere center;
in the step of providing the target, the first retroreflector is selected to be a cube corner retroreflector having three planar reflectors, each planar reflector capable of reflecting light, each planar reflector perpendicular to the other two planar reflectors, each planar reflector intersecting the other two planar reflectors in a common vertex, and each planar reflector having two intersection junctions, each intersection junction shared with an adjacent planar reflector for a total of three intersection junctions within the cube corner retroreflector, the cube corner retroreflector having an axis of symmetry relative to the three planar reflectors; and
in the step of determining at least one vector length component, the first retroreflector reference point is the vertex.
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Abstract
A target includes a contact element having a region of spherical curvature, a retroreflector rigidly connected to the contact element, a transmitter configured to emit an electromagnetic signal, a temperature sensor disposed on the target, configured to measure an air temperature, and configured to send the measured air temperature to the transmitter.
237 Citations
14 Claims
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1. A method comprising steps:
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providing the target, wherein the target has a target frame of reference and includes a first retroreflector and a body, the body having a spherical exterior portion that has a sphere center and a sphere radius, the body containing a cavity, the cavity sized to hold the first retroreflector, the cavity open to the exterior of the body, the first retroreflector at least partially disposed in the cavity, the first retroreflector having a first retroreflector reference point in the target frame of reference; providing the device, wherein the device has a device frame of reference and a first light source, the device being configured to measure a distance and two angles from the device to the first retroreflector reference point; determining at least one vector length component in the target frame of reference of a vector that extends from the first retroreflector reference point to the sphere center, the vector having a length greater than zero; illuminating the first retroreflector with light from the first light source to provide a first reflected light that is returned to the device; measuring, from the device to the first retroreflector reference point, a first distance and a first set of two angles based at least in part on the first reflected light, the first distance based at least in part on a speed of light over a path traveled by the light from the device to the first retroreflector reference point; determining three orientational degrees of freedom of the target frame of reference in the device frame of reference, wherein the three orientational degrees of freedom are sufficient to fully define the orientation of the target frame of reference in the device frame of reference; calculating three dimensional coordinates of the sphere center within the device frame of reference based at least in part on the first distance, the first set of two angles, the three orientational degrees of freedom, and the at least one vector length component; and storing the three dimensional coordinates of the sphere center; in the step of providing the target, the first retroreflector is selected to be a cube corner retroreflector having three planar reflectors, each planar reflector capable of reflecting light, each planar reflector perpendicular to the other two planar reflectors, each planar reflector intersecting the other two planar reflectors in a common vertex, and each planar reflector having two intersection junctions, each intersection junction shared with an adjacent planar reflector for a total of three intersection junctions within the cube corner retroreflector, the cube corner retroreflector having an axis of symmetry relative to the three planar reflectors; and in the step of determining at least one vector length component, the first retroreflector reference point is the vertex. - View Dependent Claims (2)
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3. A method of measurement of a target by a device, the method
comprising steps: - providing the target, wherein the target has a target frame of reference and includes a first retroreflector and a body, the body having a spherical exterior portion that has a sphere center and a sphere radius, the body containing a cavity, the cavity sized to hold the first retroreflector, the cavity open to the exterior of the body, the first retroreflector at least partially disposed in the cavity, the first retroreflector having a first retroreflector reference point in the target frame of reference;
providing the device, wherein the device has a device frame of reference and a first light source, the device being configured to measure a distance and two angles from the device to the first retroreflector reference point; determining at least one vector length component in the target frame of reference of a vector that extends from the first retroreflector reference point to the sphere center, the vector having a length greater than zero; illuminating the first retroreflector with light from the first light source to provide a first reflected light that is returned to the device; measuring, from the device to the first retroreflector reference point, a first distance and a first set of two angles based at least in part on the first reflected light, the first distance based at least in part on a speed of light over a path traveled by the light from the device to the first retroreflector reference point; determining three orientational degrees of freedom of the target frame of reference in the device frame of reference, wherein the three orientational degrees of freedom are sufficient to fully define the orientation of the target frame of reference in the device frame of reference; calculating three dimensional coordinates of the sphere center within the device frame of reference based at least in part on the first distance, the first set of two angles, the three orientational degrees of freedom, and the at least one vector length component; and storing the three dimensional coordinates of the sphere center; the step of providing the device includes providing an first camera, wherein the first camera includes a first photosensitive array and a first lens system; and the step of determining three orientational degrees of freedom includes capturing on the first photosensitive array a first illumination pattern produced by the first reflected light, obtaining a digital representation of the first illumination pattern captured by the first photosensitive array, the determining of the three orientational degrees of freedom of the target frame of reference in the device frame of reference based at least in part on the digital representation of the first illumination pattern; in the step of providing the target, the first retroreflector is selected to be a cube corner retroreflector having three planar reflectors, each planar reflector capable of reflecting light, each planar reflector perpendicular to the other two planar reflectors, each planar reflector intersecting the other two planar reflectors in a common vertex, and each planar reflector having two intersection junctions, each intersection junction shared with an adjacent planar reflector for a total of three intersection junctions within the cube corner retroreflector, the cube corner retroreflector having an axis of symmetry relative to the three planar reflectors; and in the step of determining at least one vector length component, the first retroreflector reference point is the vertex. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
- providing the target, wherein the target has a target frame of reference and includes a first retroreflector and a body, the body having a spherical exterior portion that has a sphere center and a sphere radius, the body containing a cavity, the cavity sized to hold the first retroreflector, the cavity open to the exterior of the body, the first retroreflector at least partially disposed in the cavity, the first retroreflector having a first retroreflector reference point in the target frame of reference;
Specification