Speaker: Sam Hasinoff
Massachusetts Institute of Technology Computer Science and Artificial Intelligence Laboratory (MIT CSAIL)
Title: Fragmented Lenses and High ISO for Efficient Photography
I'll describe two projects that address basic technical challenges in photography: (1) minimizing defocus blur, and (2) capturing high dynamic range. In both cases we characterize fundamental limits, and propose new methods which improve efficiency over the state-of-the-art.
First, I'll describe our new lens design, the "lattice-focal" lens, that can capture in-focus images over a greater range of depths than previous approaches. The design follows from our analysis of lens defocus over the 4D space of light rays. As we show, the only usable energy lies on a 3D subset of this space in the Fourier domain. We establish an upper bound on performance (ie. over any possible lens design), and show that the lattice-focal lens is closer to this bound than any previous design.
Second, I'll show how existing cameras can be used more efficiently, to capture high dynamic range scenes. For a given scene and camera, our analysis lets us compute the optimal sequence of photos to capture, maximizing worst-case SNR. This provides significant gains over standard exposure bracketing, typically 10 dB better or 3 times
faster, when capture time is limited. As I'll explain, most our gains come from using high (but varying) ISO settings -- counterintuitively, "turning up the amplifier" can help reduce noise.
Bio: Sam Hasinoff received the BSc degree in computer science from the University of British Columbia in 2000, and the MSc and PhD degrees in computer science from the University of Toronto in 2002 and 2008, respectively. He is currently an NSERC Postdoctoral Fellow at the Massachusetts Institute of Technology. In 2006, he received an honorable mention for the Longuet-Higgins Best Paper Award at the European Conference on Computer Vision. He is the recipient of the Alain Fournier Award for the top Canadian dissertation in computer graphics in 2008.
For more information visit: http://www.csail.mit.edu/~hasinoff/