Computational imaging and spectroscopy
Traditionally, optical sensors have been designed to collect the most directly interpretable and intuitive measurements possible. For example, a standard digital camera directly measures the brightness of a scene at different spatial locations. The problem is that the combination of direct measurement systems with large or expensive (e.g., infrared) sensors typically translates into low system resolution. Recent advances in the fields of image reconstruction, inverse problems, and compressed sensing indicate, however, that substantial performance gains may be possible in some contexts via computational methods. In particular, by designing optical sensors to collect carefully chosen measurements of a scene, we can use sophisticated computational methods to infer more information about critical structure and content. As described above, photon limitations have a significant impact on the performance of computational imagers, so we face complex tradeoffs among photon efficiency (i.e., how much of the available light in harnessed), measurement diversity, and resolution. My lab has helped develop novel new computational optical systems for spectroscopy and spectral imaging that address these challenges. Our approach yields up to an 84% reduction in error from conventional approaches.
- Scott McCain, Rebecca Willett, and David Brady. “Multi-excitation Raman spectroscopy technique for fluorescence rejection“, Optics Express, vol 16, no. 15, pp 10975-10991.
- Ashwin Wagadarikar, Renu John, Rebecca Willett, and David Brady, “Single disperser design for coded aperture snapshot spectral imaging,” Applied Optics, vol. 47, no. 10, pp. B44-B51, 2008.
- Michael Gehm, Renu John, David Brady, Rebecca Willett, and Timothy Schultz. ”Single-shot compressive spectral imaging with a dual-disperser architecture,” Optics Express, Vol. 15, No. 21, pp. 14013-14027, 2007.
- Z. Harmany, R. Marcia, and R. Willett. “Spatio-temporal Compressed Sensing with Coded Apertures and Keyed Exposures.” arXiv:1111.7247, 2011.