CIT Seminar
Abstract: Camera shake during exposure leads to objectionable image blur and ruins many photographs. Conventional blind deconvolution methods typically assume frequency domain constraints on images, or overly simplied parametric forms for the motion path during camera shake. Real camera motions can follow convoluted paths, and a spatial domain prior can better maintain visually salient image characteristics. We introduce a method to remove the effects of camera shake from seriously blurred images. The method assumes a uniform camera blur over the image, negligible in-plane camera rotation, and no blur due to moving objects in the scene. The user must specify an image region without saturation effects. I'll discuss issues in this blind deconvolution problem, and show results for a variety of digital photographs.
Invitation: I invite audience members to submit a few examples of motion-blurred photographs to me a few days before the talk. I'll show the examples and our algorithm's output on these examples during the talk. Make sure that the images have blur due to camera motion, rather than just being out-of-focus. If you have a favorite blind deconvolution algorithm, you can also send me that algorithm's result and I'll show that too.
Host: John Hughes
Joint LCDS and PDE Seminar
Brown Univeristy
Division of Engineering
Joint Materials/Solid Mechanics Seminar Series
Abstract: Single-stranded DNA forms a stable hybrid with carbon nanotubes (CNT's), rendering the latter into water-soluble colloidal rods. DNA-CNT hybrids have proven to be useful for dispersion, structure-based sorting, and aligned deposition on a substrate. Because ssDNA carries a high charge density, several phenomena associated with it are strongly influenced by electrostatic interactions in an aqueous medium with electrolytes. In this seminar we will discuss briefly how electrostatics and adhesion influence DNA-CNT structure and the ability to sort CNT's based on their electronic properties. DNA-CNT rods have been observed to deposit in an aligned fashion on a hydrophobic surface from a dilute dispersion. We will present a model for this process based on electrostatic and van der Waals interactions and the formation of a quasi-2D liquid crystal phase of DNA-CNT rods near the surface. We model spatial variation of orientation using liquid crystal elasticity with the added feature that local concentration is coupled with distortional energy. The model suggests that under sufficiently large imposed distortions, the elastic body will respond by non-smooth and possibly discontinuous changes in orientation, accompanied by discontinuities in concentration of DNA-CNT rods.
Note: There will be a dinner for Prof. Jagota after the seminar. Please contact Ms. Pat Capece at x1501 if you wish to attend.
Brown Analysis Seminar
Abstract: I will introduce the dbar-Neumann problem and explain when it exhibits subellipticity. This will lead into two notions of finite type, one geometric and one algebraic. These two notions of type are equivalent on domains in C^n with real-analytic boundary by the work of J. J. Kohn, whereas the same equivalence for a domain with smooth boundary is called the Kohn Conjecture. I will then discuss my recent work on the equivalence of types.
Transatlantic Seminar
Abstract: This seminar will continue the tutorial from 3/8/07 on spectral theory of the laplacian. This continuation will focus more on Sturm-Liouville Theory, spectral families and spectral representations, and Spectral Methods from Numerical Analysis.
Student Pizza Seminar
Abstract: This talk is an introduction to the physics and numerical simulation of photonic crystals. Photonic crystals are important because they allow the construction of nano-scale optical circuits--somewhat like computer chips, only for light. We will briefly see what photonic crystals are made out of, proceed to modelling them and finally discuss a Galerkin scheme with a set of well-adapted basis functions that promises to allow simulation of large-scale photonic circuits.
Department of Mathematics Colloquium
Abstract: An online abstract is available from the Mathematics Department seminar page.
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