While high-resolution ROV video is invaluable for gaining knowledge about many animals and processes found in the deep sea, the two-dimensional perspective view offered by the ROV cameras can not offer direct measurements of the surrounding three-dimensional (3D) space. Sizing lasers can be used as a ‘ruler’ for linear measurements, and photogrammetry techniques can help reconstruct 3D structures, but it is not possible to get a 3D representation of moving objects with these techniques. EyeRIS (RIS = Remote Imaging System), funded by the Gordon and Betty Moore Foundation and developed by MBARI’s Bioinspiration Lab, is an ROV instrument that addresses these limitations of existing tools, by offering a calibrated measurement of the entire volume imaged by the camera, at 60 frames per second. This allows researchers to quantitatively study the form and function of organisms, small-scale fluid dynamics, and particle fields, all in 3D.

EyeRIS instrument on ROV Doc Ricketts — The EyeRIS instrument, rated for ROV deployments up to 4000 meters deep, can record objects in three dimensions within a volume of 15 cm x 15 cm x 5 cm.

This 3D capture is achieved by using a specialized, high-resolution plenoptic (lightfield) camera, which has a dense array of microlenses in front of the camera sensor. This allows multiple different views of each point in the image, all with a single sensor. The raw image is difficult to interpret directly, but specialized software running on a powerful computer reconstructs a sharp image similar to what a regular monochrome camera would generate, as well as a 3D position for each location in the image. This can be visualized with a false-color overlay that represents the distance from the sensor, giving ROV pilots and researchers a real-time view of the 3D volume in front of the instrument, allowing immediate 3D measurements within the image locations, and recordings that can be analyzed in more detail after the ROV dive.

Tumbleweed anemone (Liponema brevicornis), imaged by EyeRIS — EyeRIS images of a tumbleweed anemone (Liponema brevicornis). Raw data (left) from the instrument requires processing to get a sharp “total focus” image (middle). The three dimensional component to the image can be visualized using a colored overlay (right), where blue = far, and red = close.

We have used this capability to capture kinematics data for a host of different organisms, including shrimp as they move through the water column, octopus crawling on the seafloor, and swimming of fish and a host of other organisms, including siphonophores, medusae, and ctenophores. In addition, we’ve looked at density and size distribution of particulate matter suspended in the water, an important food source for many organisms at all depths. We’ve used this data to cross-calibrate our other particle imaging instrument, Chiton, and to look at small-scale fluid dynamics, such as the food capture mechanics of coral polyps, and flow around deep-sea sponges.
As of May 2023, EyeRIS has been operated on more than 46 dives with 4 different ROVs, and has been deployed at various locations off the Central and South California coast including Station M. Visit the Bioinspiration Lab page for expedition reports, and to explore more instruments developed and deployed by the lab.