  We present the Caltech Fish Counting Dataset (CFC), a large-scale dataset for
detecting, tracking, and counting fish in sonar videos. We identify sonar
videos as a rich source of data for advancing low signal-to-noise computer
vision applications and tackling domain generalization in multiple-object
tracking (MOT) and counting. In comparison to existing MOT and counting
datasets, which are largely restricted to videos of people and vehicles in
cities, CFC is sourced from a natural-world domain where targets are not easily
resolvable and appearance features cannot be easily leveraged for target
re-identification. With over half a million annotations in over 1,500 videos
sourced from seven different sonar cameras, CFC allows researchers to train MOT
and counting algorithms and evaluate generalization performance at unseen test
locations. We perform extensive baseline experiments and identify key
challenges and opportunities for advancing the state of the art in
generalization in MOT and counting.
