The Experts below are selected from a list of 93 Experts worldwide ranked by ideXlab platform
Thomas M Gasaway - One of the best experts on this subject based on the ideXlab platform.
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osiris a diffraction limited integral field spectrograph for keck
New Astronomy Reviews, 2006Co-Authors: James E. Larkin, Randy Campbell, Sean M. Adkins, Paola Amico, Matthew Barczys, A Krabbe, Ted Aliado, George Brims, John Canfield, Thomas M GasawayAbstract:Abstract We present an overview of the OSIRIS integral field spectrograph which was recently commissioned on the Keck II Telescope. OSIRIS works with the Keck Adaptive Optics system and utilizes an infrared transmissive lenslet array to sample a rectangular field of view at close to the Keck diffraction limit. By packing the spectra very closely together (2 pixel rows per spectrum) and using the Rockwell Hawaii-2 detector (wavelengths between 1 and 2.5 μm), we achieve a relatively large field of view (up to 6.4″) while maintaining full broad-band spectral coverage at a resolution of 3800. Among the challenges of the instrument are: a fully cryogenic design (approximately 250 kg are brought down to 55 K); four spatial scales from 0.02 to 0.10″; extremely low wavefront Error (approximately 25 nm of non-common Path Error); large all aluminum optics for the spectrograph; extremely repeatable spectral formats; and a sophisticated data reduction pipeline.
James E. Larkin - One of the best experts on this subject based on the ideXlab platform.
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osiris a diffraction limited integral field spectrograph for keck
New Astronomy Reviews, 2006Co-Authors: James E. Larkin, Randy Campbell, Sean M. Adkins, Paola Amico, Matthew Barczys, A Krabbe, Ted Aliado, George Brims, John Canfield, Thomas M GasawayAbstract:Abstract We present an overview of the OSIRIS integral field spectrograph which was recently commissioned on the Keck II Telescope. OSIRIS works with the Keck Adaptive Optics system and utilizes an infrared transmissive lenslet array to sample a rectangular field of view at close to the Keck diffraction limit. By packing the spectra very closely together (2 pixel rows per spectrum) and using the Rockwell Hawaii-2 detector (wavelengths between 1 and 2.5 μm), we achieve a relatively large field of view (up to 6.4″) while maintaining full broad-band spectral coverage at a resolution of 3800. Among the challenges of the instrument are: a fully cryogenic design (approximately 250 kg are brought down to 55 K); four spatial scales from 0.02 to 0.10″; extremely low wavefront Error (approximately 25 nm of non-common Path Error); large all aluminum optics for the spectrograph; extremely repeatable spectral formats; and a sophisticated data reduction pipeline.
Maxim Morozov - One of the best experts on this subject based on the ideXlab platform.
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machining based coverage Path planning for automated structural inspection
IEEE Transactions on Automation Science and Engineering, 2018Co-Authors: Charles Macleod, Gordon Dobie, S G Pierce, Rahul Summan, Maxim MorozovAbstract:The automation of robotically delivered nondestructive evaluation inspection shares many aims with traditional manufacture machining. This paper presents a new hardware and software system for automated thickness mapping of large-scale areas, with multiple obstacles, by employing computer-aided drawing (CAD)/computer-aided manufacturing (CAM)-inspired Path planning to implement control of a novel mobile robotic thickness mapping inspection vehicle. A custom postprocessor provides the necessary translation from CAM numeric code through robotic kinematic control to combine and automate the overall process. The generalized steps to implement this approach for any mobile robotic platform are presented herein and applied, in this instance, to a novel thickness mapping crawler. The inspection capabilities of the system were evaluated on an indoor mock-inspection scenario, within a motion tracking cell, to provide quantitative performance figures for positional accuracy. Multiple thickness defects simulating corrosion features on a steel sample plate were combined with obstacles to be avoided during the inspection. A minimum thickness mapping Error of 0.21 mm and a mean Path Error of 4.41 mm were observed for a 2 m2 carbon steel sample of 10-mm nominal thickness. The potential of this automated approach has benefits in terms of repeatability of area coverage, obstacle avoidance, and reduced Path overlap, all of which directly lead to increased task efficiency and reduced inspection time of large structural assets. Note to Practitioners —Current industrial robotic inspection approaches largely consist of a manual control of robotic platform motion to desired points, with the aim of producing a number of straight scans for larger areas, often spaced meters apart. The structures featuring large surface area and multiple obstacles are routinely inspected with such manual approaches, which are both labor intensive and Error prone, and do not guarantee acquisition of full area coverage. The presented system addresses these limitations through a combined hardware and software approach. Core to the operation of the system is a fully wireless, differential drive crawler with integrated active ultrasonic wheel probe, to provide remote thickness mapping. Automation of the Path generation algorithms is produced using the commercial CAD/CAM software algorithms, and this paper sets out an adaptable methodology for producing a custom postprocessor to convert the exported G-codes to suitable kinematic commands for mobile robotic platforms. The differential drive crawler is used in this paper to demonstrate the process. This approach has benefits in terms of improved industrial standardization and operational repeatability. The inspection capabilities of the system were documented on an indoor mock-inspection scenario, within a motion tracking cell to provide quantitative performance figures for the approach. Future work is required to integrate the on-board positioning strategies, removing the dependence on global systems, for full automated deployment capability.
D J Christian - One of the best experts on this subject based on the ideXlab platform.
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correction of non common Path Error for extreme adaptive optics
Publications of the Astronomical Society of the Pacific, 2012Co-Authors: Deqing Ren, Bing Dong, Yongtian Zhu, D J ChristianAbstract:The future direct imaging of exoplanets depends critically on wave-front corrections. Extreme adaptive optics is being proposed to meet such a critical requirement. One limitation to the performance of adaptive optics is the differential wave-front aberration that is not measured by a conventional wave-front sensor because of the so-called non–common-Path Error. In this article, we propose a simple approach that can be used to eliminate differential aberration with extreme adaptive optics and is optimized for best image performance or directly optimized for high-contrast coronagraphic imaging. The approach that we propose can correct differential aberration in a single step, which guarantees high accuracy and allows adaptive optics to correct the differential aberration on a real-time scale. This approach is based on an iterative optimization algorithm that commands the deformable mirror directly and uses the focal-plane point-spread function as a metric function to evaluate the correction performance.
A Krabbe - One of the best experts on this subject based on the ideXlab platform.
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osiris a diffraction limited integral field spectrograph for keck
New Astronomy Reviews, 2006Co-Authors: James E. Larkin, Randy Campbell, Sean M. Adkins, Paola Amico, Matthew Barczys, A Krabbe, Ted Aliado, George Brims, John Canfield, Thomas M GasawayAbstract:Abstract We present an overview of the OSIRIS integral field spectrograph which was recently commissioned on the Keck II Telescope. OSIRIS works with the Keck Adaptive Optics system and utilizes an infrared transmissive lenslet array to sample a rectangular field of view at close to the Keck diffraction limit. By packing the spectra very closely together (2 pixel rows per spectrum) and using the Rockwell Hawaii-2 detector (wavelengths between 1 and 2.5 μm), we achieve a relatively large field of view (up to 6.4″) while maintaining full broad-band spectral coverage at a resolution of 3800. Among the challenges of the instrument are: a fully cryogenic design (approximately 250 kg are brought down to 55 K); four spatial scales from 0.02 to 0.10″; extremely low wavefront Error (approximately 25 nm of non-common Path Error); large all aluminum optics for the spectrograph; extremely repeatable spectral formats; and a sophisticated data reduction pipeline.