written by S. Beaton and J. Aquino, NCAR/RAF, 2011-02-14

Digital Camera Information

During PREDICT, the GV_N677F flew three digital cameras for in-flight video capture: forward, left, and right facing. All three cameras are Point Grey Research Hi-Res Flea - Color, 1024x768 resolution.  The Navitar DO-412 lenses have a focal length of 4 mm and the field of view is about 62 x 48 degrees with some barrel distortion. The forward-facing camera is located in the right wing pylon. The left-facing camera is located ahead of the left wing. The right-facing camera is located ahead of the right wing.

Images were acquired once per second and stored as JPEG-compressed files, roughly 70 kB each.  No processing of the images was performed beyond converting the raw pixel signal into a 24 bit color image. Applying a sharpening filter as is ordinarily done by consumer digital cameras will considerably improve the appearance. The UTC date and time are encoded in the filename as YYMMDD-HHMMSS.jpg.  These are the archived images stored in one-hour TAR files. The TAR files have file names with encoded flight number, date and time period as [RTF]F##.FWD.YYYYMMDD.HsMsSs_HeMeSe.jpg.tar, where:

          R = research,  T = test,  F = Ferry
         ## = flight number
        FWD = forward-looking
       YYYY = 4-digit year
         MM = 2-digit month
         DD = 2-digit day
     HsMsSs = 6-digit start time (HMS)
     HeMeSe = 6-digit end time (HMS)
    

Movie File Information

For the MPEG-4 forward-looking movies each image was processed with the Linux ImageMagick toolkit.  The image was first scaled to 512x384 pixels.  Sharpening and gamma adjustments were then performed [SHARPEN(0.0x1.0), GAMMA(1.1)]. Each image was then annotated on the right side of the image with the flight data corresponding to the time derived from the image name and the resulting image scaled to 725x384 pixels.  These 1-second annotated images were compiled into a video stream running at 15 frames/s, 1500 k bps data rate using the MPEG-4/h.264 (AKA "MPEG-4 Part 10" and "AVC") codec. If you notice that the movie start or stop times do not match the netCDF data file times it is usually because A) The camera starts about 10 seconds after takeoff when the anti-ice power is applied (powers the camera) and B) The movie is stopped early or started late if images are after dark. Occasionally the cameras may not be recording becuase of operational issues.

The movies can be played by Quicktime 7 or later (Mac and Windows), xine (linux) and mplayer (multiplatform, not tested).

Flight-Specific Comments

Test and ferry flights, as well as right- and left-looking images for research flights, have not been made into Movies. If you would like these movies, please send and email to the RAF Data Manager, Janine Aquino.