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Focal length and focal depth of metallic superlens
SPIE Proceedings, 2012We consider the problems of focal length and focal depth of subwavelength imaging via a silver slab of metallic superlens . The performance limit of the metallic superlens was associated with the losses in the metallic film. The transmittance through a metal film is quite low and decreases exponentially with the thickness of ...
Pengfei Cao +6 more
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Two-focal-length optical correlator
Applied Optics, 1989A two-focal-length coherent optical correlator design is presented that uses simple, single element lenses. Experimental autocorrelation results using a binary phase-only filter verify the performance of this compact design.
J L, Horner, C K, Makekau
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Optimal focal length calibration system
Proceedings of 1993 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS '93), 2002An optimal grid is designed so that the reliability of the camera focal length calibration using it is theoretically maximized. The analysis is based on a statistical error model of the line fitting in digital images. The reliability of the focal length is quantitatively computed from the reliability of the edges to which lines are fitted.
Kenichi Kanatani, Tamotsu Maruyama
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Mean focal length of an aberrated lens
Journal of the Optical Society of America A, 2011We outline an approach for the calculation of the mean focal length of an aberrated lens and provide closed-form solutions that show that the focal length of the lens is dependent on the presence of defocus, x-astigmatism, and spherical aberration. The results are applicable to Gaussian beams in the presence of arbitrary-sized apertures.
Cosmas, Mafusire, Andrew, Forbes
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Focal length change compensation for monocular slam
2015 IEEE International Conference on Image Processing (ICIP), 2015In this paper, we propose a method for handling focal length changes in the SLAM algorithm. Our method is designed as a pre-processing step to first estimate the change of the camera focal length, and then compensate for the zooming effects before running the actual SLAM algorithm.
Takafumi Taketomi, Janne Heikkilä
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Equivalent focal length measurements
SPIE Proceedings, 1999Converting linear coordinates in the plane of the detector of an astronomical instrument to celestial coordinates involves in principle the equivalent focal length of the instrument. However, most methods in astrometry manage to reduce observations in a global manner without actually measuring a focal length.
Guy E. Artzner +3 more
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A variable-focal-length telescope
Astronomical & Astrophysical Transactions, 2005A special additional optical system (AOS) to develop any telescope into a zoom or a variable-focal-length telescope (variotelescope) is proposed. This system permits the telescope optics and detector (charge-couped device) to be matched in order to obtain the best resolution.
Bahor Irkaev +2 more
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Focal Length Measurement Method for Lenses with Small Aperture and Long Focal Length
Acta Optica Sinica, 2020赵磊 Zhao Lei +2 more
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Liquid crystal lenses with tunable focal length
Liquid Crystals Reviews, 2017Yi-Hsin Lin +2 more
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