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Noncontact metrology probe, process for making and using same

Laser Trackers are the “bread and butter” for precision spatial metrology. They are typically used to measure the 3D or 6D features of larger objects for manufacturing, machine and robot calibration, assembly of modern machines, airplanes, vehicles, and device assembly. However, current laser tracker probes are limited by the fact that the object needs to be something solid and tangible. This new imaging probe does not rely on the object having to be tangible. It therefore fills in aspects of spatial metrology current laser tracker probes miss. Additionally, current touch probes: 1. need a tangible object; 2. must physically contact the object (accuracy relies on pressure); 3. limited to large objects (approximately 1 cm); and 4. not reliable at accurately measuring edges and corners.

The mother of laser trackers inventions - the NIST non-contact metrology probe: is a novel imaging-based laser tracker probe that: 1. combines camera inspection and laser tracker capability into one; 2. is Non-contact; 3. allows small objects <<1mm to be measured by a laser tracker with an accuracy of tens of microns (limited by laser tracker 4. allows one to track small objects <1mm with laser tracker 5. easily measures edges and corners 6. can measure objects that reflect as well as emit light 7. can measure objects that are not solid and not tangible (e.g., an image of an object, computer screen, hologram, laser beam, a liquid, etc.); 8. allows for multi-physics measurements with laser tracker; 9. in a single measurement, relates physical properties that correspond to camera information to the location measured with the laser tracker and 10. discriminates structural components in an object made of different materials based on spectral discrimination. The figure below illustrates the NIST non-contact metrology probe measuring the center of a small circular antenna aperture (1.5 mm diameter).


Presented here is a new and novel laser tracker target for measuring, in three dimensions (3D), the spatial location of small features, which are on the order of tens of microns, on a physical object without having to actually physically touch or make contact with the object under inspection. The system uses a multi-camera approach to generate a virtual point in space that is co-located with the centroid of a spherical mirror reflector target (SMR). The cameras are used to determine the center of the SMR. The center of the SMR is also simultaneously measured by a laser tracker system thus linking this virtual point in space to the laser tracker coordinate system. This system vastly extends the capability of current laser tracking systems to be able to perform touch-less high precision spatial metrology to the tens of micron level. This capability is not achievable with laser tracker targets. Furthermore, this system provides a direct link of touch-less 3D spatial data to a laser tracker coordinate systems and thus is a considerable advancement in laser tracker target technology. The uses for this touch-less high resolution 3D spatial metrology system are numerous and include but no limited to: more accurate robot calibration for advanced manufacturing, precision determination of tooling position such as is needed for precision drilling in automotive and aerospace applications, and high frequency antenna alignment.


More accurate robot calibration for advanced manufacturing; Precision determination of tooling position such needed for precision drilling in automotive and aerospace applications; and high frequency antenna alignment.


Joshua Gordon

Patent Number: 
Technology Type(s): 
laser applications, advanced manufacturing processes, manufacturing, calibration research, atomic physics, nanometrology, physics, precision measurement,
Internal Laboratory Ref #: 
Patent Issue Date: 
September 18, 2018
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