Aerial Measurements Print

MASS package
MASS video camera and motion package unit
configured for Mooney-21 installation

Airborne measurements will be comprised of visual and infrared imaging of whitecaps, processed to describe the temporal evolution of breaking waves. The Modular Aerial Sensing System, or MASS, was developed for this application.

Currently, MASS incorporates a video camera (frame size: 768x484 pixels, frame rate: 30 frames per second non-interlaced), six degrees-of-freedom motion package (three-axis gyroscope, flux gate compass, two-axis pendulum tilt sensor, and three-axis accelerometer), and GPS unit. The data are collected by a Pentium computer. All information is stored in real time to the hard drive. Camera and motion package are mounted on the same rigid frame, attached to the aircraft body with three or four elastic mounts, to dampen vibrations. The GPS antenna is mounted either outside the aircraft, or inside the plexiglass canopy. The system uses the base GPS station in order to provide differential GPS.

mooney - 21
MOONEY-21 (Newport, OR., 04/1998, Pt. Conception, CA., 07/1998)

MASS was extensively tested off the coast of North Carolina (Duck, November 1997, aircraft - Long-EZ), Oregon (Newport, April 1998, aircraft - Mooney-21), and California (Pt. Conception, July 1998, aircraft - Mooney-21). Pictures of the aircraft used in the tests are shown below.

As an example of MASS application, images of breaking waves in the open ocean are shown below. The picture on the left is a raw image taken during the Duck test in 11/97. For a 10-second long sequence of images, the pixel-wise image translation was calculated for an area on the image containing a separate breaking wave, using the information from the motion package on the aircraft and the camera. The picture on the right illustrates the motion-compensated region from the raw image.

picture of Long-EZ aircraft
(Duck, N.C., 11/1999)

Clicking on the images or links below will produce animations of the raw and motion-compensated image series. Note that the animated GIF files are rather large in size and may take some time to download. The raw image / animation is undersampled by a factor of two.

The landing gear of the aircraft can be seen obstructing the field of view. During the SHOWEX measurements, the camera will be mounted in a pod underneath the fuselage of the aircraft.

Raw image recorded at Duck, N.C., in November 1997.

cropped region from motion-compensated image sequence,
containing a single breaking wave.
scripps oceanography