to past images.
|The VISSER project uses Argus video images
to make quantative nearshore measurements
High resolution video cameras are mounted on the top of the 43 m tall (141 ft)
FRF observation Tower.
Camera C0 faces NNE,
C1 faces E (offshore), C2 faces SSE, C3 faces NE, C4 faces SE, C5 faces N, and C6 faces S. Each image has GCP's (ground control points) which
are used to determine the camera's orientation relative to the ground topography. The most
noticeable GCP's are three disks from camera C0.
These GCP's allow for a photogrammetric transformations of image coordinates to ground coordinates. Thus, time sequences of these images can be used to monitor changes in sand bar morphology or shoreline position and potentially other variables. Also, these cameras are used to collect data on horizontal distributions of wave-breaking and shoreline movement. One application of these systems is the imaging of the sandbar location as it effects wave breaking.
Each camera takes a snapshot (*snap.jpg) and a 10 minute time-averaged image (*timex.jpg) every hour. Timex are created by averaging 600 frames taken once per second. These images are useful at revealing the underlying morphology as waves break over the submerged sandbars. The 10 minute averaging serves to smooth out variations in wave dissipation (white water) due to wave groups. File names contain the date, time, camera, and image type information. These file names come in two formats, a "long" name and a "very long" name. For example:
This video technique was developed by Dr. Rob Holman of the Coastal Imaging Lab in the Oceanography Department of Oregon State University. Mr. Kent Hathaway is the FRF video expert.