24-10-2012, 01:39 PM
Sizing Up the Situation
ABSTRACT
Hailstorm damage to the Space Shuttle’s External Tank inspired a NASA innovation with extensive photography
applications. In order to measure the defects caused by the storm, Kennedy Space Center used telephoto lenses to zoom in
on the tank and view the damage clearly. However, since there was no reference object in the image, the engineers could not
determine the scale of the damage. In photographic situations similar to this, an object, such as a ruler, is placed within the
field of view. This allows a person to look at a photograph and have a visual indication of the scale of the objects in it. In the
External Tank situation, however, this procedure was not possible. As a solution, Kennedy developed the Scaling and
Measurement Device for Photographic Images, which provides a non-intrusive means of adding a scale to a photograph. In
addition to meeting Kennedy’s needs, scaling images is extremely important in crime and accident scene investigations, oil
and chemical tank monitoring, and aerial photography. The innovation consists of a tool that attaches directly to a camera or
charge coupled device using a standard screw. Two lasers fitted to the device provide parallel beams that are set 1 inch apart.
These lasers enable the device to project a pattern into the field of view. When a photograph is taken, the image of the laser
pattern appears, along with the image of the object under investigation, allowing the viewer quantifiable information as to the
size of the object. The laser beams are accurate to approximately 200 feet. Windows-based software was developed to work
with the scaling device tool. The software provides further techniques to measure objects in photographs and digital images.
By using the software, any object in the image can be measured diagonally, vertically, and horizontally. The device and its
software enable the user to determine two-dimensional measurements within a photograph.