Optical Diagnostics and Imaging - Applied Optics Fundamentals and Device Applications - page 309

(a) (b)

FIGURE 6.16
Representative high-speed video cameras. (a) Photron SA-5 (b) Vision Research V1.3.

6.12.1 Parametric Analysis of Digital Imagery

Digital image processing suites available for commercial licensing include
ARAMIS, TrackEye, ProAnalyst, Correlated Solutions, PixelRay, and develop-
mental MATLAB routines. Customized routines for specific test applications
are available, along with data fusion processes for enhanced visualization
and accuracy.
Two-dimensional parametric analysis requires a single imager with a cali-
bration sample in the plane of motion either before or during the event. This
provides measurement of 2-D flight characteristics such as pitch, yaw, posi-
tion, velocity, and acceleration as well as angle, distance, and area, using the
interactive feature tracking overlays. Distance and velocity, for example, gun
bolt movement or the height an object moves into the air from a mine blast,
are readily determined from 2-D imagery.
Three-dimensional (3-D) parametric analysis requires at least two imagers
and a 3-D calibration fixture. This provides 3-D flight characteristics such as
pitch, yaw, position, velocity, and acceleration as well as angle, distance, and
area. Coordinate location and distance calculation for a traveling object are
derived from the world reference points collected in a 3-D calibration. This is
compared with time or fused with data from additional sensors.
Pitch and yaw for slugs and projectiles traversing a known path are cal-
culated with a single 2-D image or, with 2 cameras, a 3-D image of the pro-
jectile flight.
Area and volume for smoke cloud or flash evaluation are performed in
2-D and utilize a 2-D calibration in the event plane. Volume measurements
utilize 3-D analysis and calibration.
Surface deformation/3-D image correlation can be used for measurement
of backface deformation during armor tests (exploitation). Surface deforma-
tion analysis utilizes a uniform random black and white speckle pattern on
the surface and two calibrated high-speed cameras. Full field deformation
analysis provides displacement and velocity in three coordinates, x-y strain,
principal strain angle, in-plane rotation, 3-D contours, and curvature angles.