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Visitor Information

PHOTOMETRICS


Sandia National Laboratories' Photometrics Department in Albuquerque, New Mexico, provides exceptional still, motion, and specialized photography for diverse applications in field and laboratory testing.
Typical photometrics capabilities include:
  • High-speed digital imaging and photography
  • Ultra high-speed digital imaging and photography
  • Streak photography
  • Digital Image Correlation
  • Infrared imaging radiometry
  • Schlieren photography
  • Still and time-lapse digital imaging and photography

High-Speed Cameras

High-speed cameras produce pictures at rates faster than standard projection rates, creating a slow-motion effect that gives dramatic insight into high-speed events or processes. Some field operations have required up to 40 high-speed cameras to fully document all test objectives.

High-speed digital imaging cameras operate from 100 – 100,000 frames/second.  These cameras can be synchronized for digital image correlation techniques providing full-field measurements of moving objects.

High-speed film cameras include pin-registered cameras operating up to 400 frames/second and rotating prism cameras from 500 to 10,000 frames/second.


Ultra High-Speed Cameras

Ultra high-speed cameras use a high-speed rotating mirror to provide 50,000 to 4,000,000 frames/second with 60 discreet 1,000 x 1,000 CCD’s.  In addition film cameras can operate from 50,000 to 26,000,000 frames/second.  These cameras have operated on tests that range from micron-scale events to in excess of 10,000 lb explosive events.


At 2,750 ft/s, a 30-cal. bullet disintegrates as it impacts an armor plate.

 


Streak Cameras

Streak cameras are used to obtain time critical events where time differences down to nanoseconds can be resolved. There is no shutter in this camera allowing film to be continuously exposed for such timing measurements.

 

Digital Image Correlation

Three-dimensional digital image correlation uses a pair of digital cameras to view a test subject and determine its location and shape in space. The technology is a combination of single camera image correlation and two camera photogrammetry. Photogrammetry is a measurement technology in which the three-dimensional coordinates of points on an object are determined by measurements made in two or more photographic images taken from different positions. Common points are identified on each image. A line of sight (or ray) can be constructed from the camera location to the point on the object. It is the intersection of these rays from different perspectives that determines the three-dimensional location of the point. In practice, a random high contrast pattern is applied to the surface of the test object to supply a grid of unique points to correlate. This pattern then deforms or moves along with the object. The deformation under different load conditions is recorded by the digital cameras and then evaluated by the software. The initial image processing involves defining unique correlation areas known as areas of interest (AOI’s) across the entire imaging area. These facets are tracked in each successive image with sub-pixel accuracy. Then, using photogrammetric principles the 3D coordinates of the entire surface of the specimen are precisely calculated. The results are the 3D shape of the component, the 3D displacements, and the plane strain tensor.
dic setup
Typical Digital Image Correlation system setup

 

Digital Image Correlation provides:

  • Full-field shape, displacement, rotation, pose, strain and velocity
  • Scales from meters to nanometers
  • Rates from static to MHz
  • Full-field experimental results for full-field model validation

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Infrared Imaging Radiometers


Infrared imaging radiometers are comparable to standard portable video cameras, but they respond to the infrared radiation emitted by an object. The radiometer produces a video output signal of gray tones or false color images that represents different intensities of radiation and, thus, temperatures in the object.

A mid-wave 3 – 5 micron system features a 14-bit extended dynamic range
and high frame rate capability.  Frame rates in excess of 900 frames/second are possible at reduced resolutions.  Extremely small temperature variations can be detected by the cooled InSb (Indium Antimonide) sensor. When coupled with black body calibrations the InSb detector offers imaging performance and provides measurement accuracy and superior image resolution for high-temperature targets, such as military engine compartments, flames, or the central receiver at a solar tower.

 





tank
Infrared image of a tank recorded with
the 3-5
micron infrared imaging camera.



Schlieren Techniques


Schlieren techniques record optical inhomogeneities as well as various components of shock waves and their interaction with surrounding objects in a transparent medium (i.e. air) not visible to the human eye. Changes in the refractive index of air are made visible by the Schlieren optical system.


Still Photography

Still cameras can be used to obtain one or more pictures of a test event. Digital cameras provide modern convenience with all common file formats and resolution up to 12 megapixels. Still images of test build-up, instrumentation and activity documentation are provided.


Motion Analysis

Motion analysis software provides the capability of quantitative measurement of test events.  Measurements include velocity, angle, deceleration/acceleration.  Uncertainty quantification of these measurements can be supplied as needed.

Image data can be linked through a common time base to instrumentation data allowing images to be tied with instrumentation signals showing what event is occurring with a particular oscilloscope event.

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Two dimensional point tracking to
measure angle and velocity.
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Digital Image Correlation of selected areas
on target to measure angle, velocity and rotation.

 

rocket

In this series of images four image-motion cameras captured detailed photographs of this directed-dispersal weapon test. Photo 1 verifies that test equipment was intact just before detonation. Photo 2 shows the moment just after detonation. In Photo 3, projectiles begin to exit the center of the fireball. Photo 4 shows further dispersal of projectiles.


Additional Information

Sandia's Photometrics Department can provide photography for a wide variety of tests.







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Contact

Bianca Keeler
(505) 845-8876
bekeele@sandia.gov

Anthony Tanbakuchi
(505) 284-4306
atanbak@sandia.gov