Digital Image and MPEG Movie Information

written by S. Beaton, NCAR/RAF, 2008-04-10

Digital Camera Information

The forward-facing camera is located in the right wing pylon.  It is a Point Grey Research Hi-Res Flea - Color, 1024x768 resolution.  The Navitar DO-412 lens has a focal length of 4 mm.  The field of view is about 62 degrees horizontally by 48 degrees vertically with some barrel distortion.

Images were acquired once per second. The raw pixel intensity is converted to a color image, sharpened (ImageMagick SHARPEN 0.0x1.0), and stored as JPEG-compressed files, roughly 95 kB each. The UTC date and time are encoded in the filename as YYMMDD-HHMMSS.jpg and in the upper left of the image.  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 movies each image was processed with the Linux ImageMagick toolkit.  The image was first cropped 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 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 if darkness falls.

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

Quicktime (Apr. 2008) Mac http://www.apple.com/quicktime/download/
Quicktime (Apr. 2008) Win http://www.download.com/QuickTime/3000-2139_4-10002208.html
xine Linux http://xinehq.de
mplayer Linux, Mac, Win http://www.mplayerhq.hu/homepage/design6/info.html

 

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