A comparison of the accuracy and precision of measurements from single and stereo-video systems

Underwater tests using plastic silhouettes of fish were used to compare the accuracy and precision of measurements made with a single video camera system to those made from live, stereo-video systems (one using digital camcorders, the other using Hi8 camcorders). Test,measurements made across a variety of ranges and angles of silhouette orientation in the fields of view showed the length estimates from both the digital and Hi8 stereo-video systems were substantially more accurate and precise than those obtained by the single video camera system, and had the great advantage that the position (range and bearing) and orientation of a fish target could be measured directly. Measurements made with stereo-video were much less restricted by range and subject orientation than those made with single video. The data resulting from these trials are used to propose a set of guidelines to optimize the accuracy and precision of underwater measurements of fish length using single and stereo-video systems.