Digital Camera Imagery and Movie Notes

During DC3, the GV flew three digital cameras for in-flight video capture: forward, left, and right-looking.

The forward camera is a Point Grey Research Hi-Res Flea - Color, 1024x768 resolution. The Navitar DO-412 lens has a focal length of 4 mm and the field of view is about 62° x 48° with some barrel distortion. This camera is located on the right wing pylon.

The left-looking camera is a Point Grey Research Hi-Res Flea - Color, 1024x768 resolution. The Navitar DO-412 lens has a focal length of 4 mm and the field of view is about 62° x 48° with some barrel distortion. This camera is located looking out the fourth side window (from the front).

The right-looking camera is a Point Grey Research Flea 3 (FL3-FW-14S3C-C) - Color, 1280x960 resolution. The Navitar DO-3514 lens has a 3.5 mm focal length and 94° x 73° field of view. This camera is located looking out the fourth side window (from the front).

Images were acquired once per second. Images are stored as JPEG-compressed files, roughly 100 kB each. No image processing was performed beyond converting the raw pixel data to 24 bit color images. 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.

H.264 compressed, half-resolution movies (.mp4) were created. Each 1-second image was processed with the linux ImageMagick toolkit. The image was first cropped to 512x384 pixels. Sharpening was then performed [SHARPEN(0.0x1.0)] and forward, left, and right-looing images were combined into a single frame. Each image was then annotated in the lower left with the time the image was recorded and in the upper right with the pointing. Data values at the image time for a select set of data paramters chosen by the researchers were appended to the left of each image block. These 1-second annotated images were compiled into a video stream running at 15 frames/s, 1500 kbps data rate.

The movies are playable with Quicktime, WIndows media player from Windows 7, mplayer, VLC, and others.

Flight comments:

The forward imagery starts late in some flights. The forward camera window anti-ice heating is not always sufficient and the window occasionally remains iced over. In this case use the left or right imagery to see the current conditions.

J. Aquino
S. Beaton
NCAR/RAF
2012-08-14