Rationale for 3-D Measurement One obviously important facet of every organism's existence is its patterns of movement within its habitat, both in space and through time.
Ethologists routinely record animal behavior optically in the field for later analysis.
The cameras are fitted with fixed-focus lenses and wide angle adapters and are permanently mounted in custom housings. Wide angle adapters are necessary because the cameras on the submersible toe in toward each other so that their fields of view intersect approximately 2 m in front of the submersible. Each camera's field of view must be as wide as possible because images outside the volume of water viewed by both cameras are recorded on only one videotape, and are useless for 3-D analysis. The camera housings are rigidly mounted on either side of the submersible because the positions of the cameras relative to each other must remain constant to track an object accurately. A control box remotely powers both cameras and electrically controls the irises.