Laboratory evaluation of videography included a systematic sampling of video tape or frames in both visual and image analysis procedures. Visual analysis involves direct freeze frame evaluation from a standard 4 head VCR and television viewing. Image analysis techniques involve image capture by frame set with a graphics board and microcomputer. In this report we discuss the process and data synthesis of information gathered by visual analysis only. Tests to calibrate and validate spectral summaries of image analysis are ongoing.
Visual analysis constitutes the least technical and efficient means of video interpretation.
Evaluations included both qualitative and quantitative measures of tree and forest condition. Video frames were systematically sampled by pausing the track every 30 seconds of tape time. With each freeze frame, we assessed the percent of disturbed or downed canopy cover, percent water coverage, azimuth and length of downed trees. Intermittent audio transmissions were transcribed at or between frame evaluations to obtain explicit flight position, altitude, speed, direction and coincident ground observations. Compass direction of downed trees was corrected for based on known flight bearing.