The imaging system onboard the ISIIS ROTVs have a field-of-view of 13cm, with a depth-of-field of 50cm. These vehicles are used to sample large volume of water at once, in order to image larger and perhaps rarer taxa, usually from 1mm and up.
Since smaller taxa is often more abundant, the use of smaller imaging pods with a smaller field-of-view and depth-of-field is well suited for smaller, more abundant organisms where a higher resolution imaging system is required.
Using both systems in parallel can provide valuable information on plankton community interactions or predators/preys interactions for example.
A dual system also has the advantage to simplify images analysis and sorting. Smaller, more abundant taxa can be studied on the higher resolution images (small imager) and ignored on the larger system's images.
In order to miniaturize the imaging system, we have developped imaging decks able to control Gig-E cameras either from a single-board processor (based on Windows 8 OS) or from a Raspberry PI ARM based computer. We use area-scan cameras with these set-ups and acquire images at regular intervals.
Field-of-view as well as depth-of-field are about 10cm max. respectively. Images pixel-resolution and frame rates depend on the selected camera.
These systems are made to be self-contained as they can boot on their own, record, go back to sleep and wake up to record several sessions.