Optical imaging with scanning MEMS mirror - A single photodetector approach

This paper describes an optical system for low-complexity optical image acquisition based on a single scanning MEMS mirror and a single photodetector. The overall aim of the research is to investigate techniques for image acquisition at electromagnetic wavelengths where the cost and/or technical maturity of detector arrays pose a limitation. In contrast to similar systems built using a digital micromirror device (DMD), the present configuration has advantages of lower cost and potential applicability across a wide spectrum, ranging from visible to Terahertz frequencies. In the present arrangement, light at visible wavelengths from the object passes through a telescope and falls onto a small, scanning MEMS micromirror. The entire image of the object is projected onto the mirror surface and reflected towards a single photodetector with a pinhole at its entrance. Similarly to conventional scanning, by finely changing the tilt-angle of the mirror, the detector sees different areas of the projected image, thereby building up an image pixel-by-pixel. Resolution is increased by allowing for an overlap between neighbouring scanned areas. Iterative bilinear interpolation and wavelet denoising are employed to enhance image quality.