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A Non-Contact, Remote, Micron Accuracy, Laser Fresnel Distance Ranging System
NASA’s Marshall Space Flight Center is offering a state-of-the-art distance measurement system, with micron accuracy, at ranges of up to 20 meters from the target. Such measurement accuracy is accomplished by employing changes in laser Fresnel patterns, which are extraordinarily sensitive to changes in distance. Differences in patterns are compared with known pattern/distance relationships, allowing the range to be uniquely determined. The technology could be especially useful in a variety of aerospace, industrial, and consumer systems where verification of a target’s dimensional consistency can only be performed through remote, noncontact methods.
- Micron accuracy: Distances measured with high precision, potentially to sub-micron accuracy
- Real-time scanning: Results available immediately after measurements are made
- Range: Measurements can be made from 20 meters away
- Easy to use: Complex hardware unnecessary
- Simple computing requirements: Distance data ports easily to a laptop or PC
- Lightweight and compact: Small component of a larger system
- Quality control operations (profiling to detect errors)
- Mold manufacturing (aerospace, automotive, shipbuilding, consumer products, and wind turbines)
- Steel work manufacturing
- Defense applications for careful machining of missile and other weapon system parts
- Milling machine calibration
- Computer hardware manufacturing (measuring thickness of hard drives to ensure balance)
- Dental/orthodontic appliance manufacturing
How it works
This laser technology measures distance to
micron accuracy at ranges up to 20 meters
from the measuring device to the target object.
Micron accuracy at this range is made possible
by leveraging Fresnel patterns, which are
highly sensitive to changes in distance. This
novel approach compares the resulting Fresnel
pattern’s unique distance ‘signature’ to the
device’s database, resulting in a precise distance
measurement. More specifically, a laser beam is
aimed at the target object through a pinhole in
an opaque screen. A portion of the beam passing
through the aperture generates a region of
diffraction, which varies as a function of distance
from the aperture. A digital imaging system built
into the measuring device focuses on a target
plane in the region of diffraction with the generated
image being compared to known diffraction patterns. Each known diffraction pattern has a
unique value associated with it that is indicative of a specific distance from the aperture.
With software embedded in the device, this pattern lookup and matching process occurs
within approximately 1 millisecond, then it is ported to a laptop or other computing device
via a standard cable (universal serial bus (USB) or Ethernet). Industry- or applicationspecific
software on the computer takes the raw distance measurements and displays them
in whatever format is needed by the operator performing the distance measurement.
Why it is better
Beyond a range of 10-15 meters, current technologies cannot measure distances with
micron accuracy. In heat- or robotic-intensive settings, measuring devices cannot be placed
within 10 meters of the object. In addition, some targets must be measured within a larger
object – such as components inside an airplane airframe. NASA’s measuring device overcomes
these challenges. The Nonintrusive, Remote, Micron Accuracy, Laser Fresnel Ranging
System has several additional benefits, including the ability to measure non-reflective materials
such as ceramics and curved surfaces without information on the curve being inputted
ahead of time. This measuring system can also map non-uniform surfaces and measure
target surfaces that are off perpendicular from the laser beam by 15 to 20 degrees or
even more if the object is not completely reflective. It is accurate in field conditions and in
manufacturing environments; normal air currents and routine amounts of dust or particles in
the air do not hamper measurements. Capable of recording a measurement in 1 to 10 milliseconds,
this innovative measuring system does not require complex processing to transmit
data. Only a USB or Ethernet cable is required to transfer the data from the measuring unit
to a laptop, PC, or other handheld computing device. The technology is not bulky, and is
capable of being miniaturized to a unit about the size of a laser pointer.
Licensing and Partnering Opportunities
This technology is part of NASA’s technology transfer program. The program seeks to stimulate development of commercial uses of NASA-developed technologies. NASA is flexible in its agreements, and opportunities exist for licensing and joint development. MSFC is interested in a partnership to commercialize the technology.
Marshall has patented this technology.
- 7,446,860 [link opens new browser window]
If you would like more information about this technology or about NASA’s technology transfer program, please contact:
Sammy Nabors
NASA's Marshall Space Flight Center
Manager, Technology Commercialization and Licensing
Phone: (256) 544-5226
Fax: (256) 544-4810
E-mail: sammy.nabors@nasa.gov