Project Website http://web.mit.edu/optics/www/dhi.htm
Three-Dimensional Holographic Imaging of Aquatic Species (Underwater Holography) The goal of this research project is to develop a Three-Dimensional Holographic Imaging system for aquatic species. The 3D Holographic camera will be carried inside an Underwater Autonomous Vehicle (UAV) that will be sent in an exploration mission to a depth of around 11,000 meters, currently the greatest depth attempted to image aquatic ecosystems.
The images are recorded in a high-resolution CCD sensor using Digital Holography in a lens-free in-line configuration. The captured images (holograms) contain information about the phase and amplitude of the optical field propagated after illuminating the desired object. This information is encoded in the hologram as a set of fringes that are later decoded using image-processing algorithms to recover the intensity distribution at an image plane. This is located at a distance similar to the distance from the object to the CCD camera.
We are currently working in reducing the size of the imaging system. In addition, a pulsed laser will be implemented to reduce the motion of the UAV to less than one pixel.
Other configurations are also being explored, such as: off-axis, reflective (backward-scattering), spherical reference-wave, high-pass Fourier-filter, Mach-Zehnder among others.