Super-resolution algorithms for digital holography

Digital holography is an interferometric technique whereby the holographic plate is replaced with a chargedcouple device (CCD) camera sensor. By virtue of this feature, it offers several advantages over the classic technique but because of the small number of lines of the camera sensor, the viewing angle is very small (2–4 degrees). Earlier work has shown that by acquiring several, slightly shifted, low resolution holograms and combining them using super-resolution techniques, it is possible to construct a higher resolution digital hologram that enables a larger object to be imaged. However, super resolution techniques are very sensitive to camera displacement errors, consequently it is necessary either to use a closed loop piezo-actuated translator or to instrument the camera. To solve this problem we propose measuring the camera displacement using the optical flow technique. This approach yields comparable results using a much simpler experimental setup.