A view through the waves

When using the term underwater imaging, what is underwater? Is it the camera? Is it the imaged object, or the light source? In most studies and engineered systems, the camera, object, and light source are all submerged. However, there may be exceptions in systems designed to operate in shallow waters, where part of the setup is above the water’s surface or where natural illumination is needed from above the surface. Significantly less research and development has been conducted to image objects through a “wavy” water-air interface, where either the camera or the object is underwater, but not both. This commentary seeks to shed more light on this emerging domain, referred to as intermedia imaging.