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| Content Provider | Society for Industrial and Applied Mathematics (SIAM) |
|---|---|
| Author | Trefethen, Nick |
| Copyright Year | 2002 |
| Abstract | These days we are all used to typing keywords into search engines, but even so, I was startled when I asked GoogleTM for information about "phase retrieval'' just now. The response was "Results 1--10 of about 271,000. Search took 0.04 seconds."We live in an era in which optics has met IT. Once upon a time, astronomers or chemists built the best telescope or microscope they could and then set about enjoying the images it produced. Now, the raw image is often just the first step in an elaborate process of adaptive analysis or control. Mirrors flutter under laser-guided computer direction to adjust for atmospheric aberrations; we "straighten out bent starlight." Diffracted X-rays are piped directly to the computer, not the crystallographer. Whether the scale is proteins or eyeballs or galaxies, at the frontiers of science, raw data is now cooked before digestion by humans. The applied mathematicians of the 19th century would have recognized some of the formulas, but they could not have begun to imagine the computational power that we deploy each second in working with them.The following article by Luke, Burke, and Lyon describes one of the major problems of phase retrieval associated with this new kind of optics. Light has propagated from a distant point to an image, undergoing distortions along the way caused by lenses, mirrors, or irregular media. If amplitudes are measured in the image, how can phases be recovered? Once this has been done, the information can be used to construct improved images. The authors consider the particular problem of optical wavefront reconstruction, which played a role in the analysis and improvement of images from the Hubble Space Telescope launched, defective, in 1990. Their methods blend classical physics, nontrivial mathematics, and large-scale algorithms of nonconvex optimization and least squares. |
| Starting Page | 167 |
| Ending Page | 167 |
| Page Count | 1 |
| File Format | |
| ISSN | 00361445 |
| DOI | 10.1137/SIREAD000044000002000167000001 |
| e-ISSN | 10957200 |
| Journal | SIAM Review (SIREAD) |
| Issue Number | 2 |
| Volume Number | 44 |
| Language | English |
| Publisher | Society for Industrial and Applied Mathematics |
| Publisher Date | 2006-08-04 |
| Access Restriction | Subscribed |
| Content Type | Text |
| Resource Type | Article |
| Subject | Applied Mathematics Theoretical Computer Science Computational Mathematics |
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