The Definition of the OTF and the Measurement of Aliasing for Sampled Imaging Systems

Wittenstein, Wolfgang; Fontanella, J. C.; Newbery, A. R.; Baars, J.

doi:10.1080/713820741

Cited by 63 publications

(24 citation statements)

References 5 publications

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“…Any response beyond the Nyquist frequency is folded back into the lower frequency data through aliasing. 11 We found it useful to use a tilted knife-edge to construct a superresolution representation of the edge, from which the MTF can be calculated out to the full detector sampling frequency, or even beyond. 2,3,9,12 Additional limitations of MTF measurements for digital imaging systems can arise from phase errors and detector noise.…”

Section: Sampling Considerations For the Mtf Of Digitalmentioning

confidence: 99%

Measuring the modulation transfer function of an imaging spectrometer with rooflines of opportunity

et al. 2010

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Measuring the modulation transfer function (MTF) of digital imagers focused at or near infinity in laboratory or field settings presents difficulties because the optical path is longer than a typical laboratory. Also, digital imagers can be hindered by low-resolution detectors, resulting in the resolution of the optics surpassing that of the detector. We measure the MTF for a short-wave infrared hyperspectral imager developed by Resonon, Inc., of Bozeman, Montana, which exhibits both characteristics. These difficulties are overcome with a technique that uses images of building rooflines in an oversampled, tilted knife-edge-based MTF measurement. The dark rooftops backlit by a uniformly cloudy sky provide the high-contrast edges required to perform knife-edge MTF measurements. The MTF response is measured at five wavelengths across the imager's spectral band: 1085, 1178, 1292, 1548, and 1629 nm. The MTF also is observed at various distances from the roof to investigate performance change with distance. Optimum imaging is observed at a distance of 150 m, potentially a result of imperfect infinity focus and atmospheric turbulence. In a laboratory validation of the MTF algorithm using a monochrome visible imager, the roofline MTF results are similar to results from point-source and sine-card MTF measurements. C 2010 Society of Photo-Optical Instrumentation Engineers.

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Section: Sampling Considerations For the Mtf Of Digitalmentioning

confidence: 99%

Measuring the modulation transfer function of an imaging spectrometer with rooflines of opportunity

et al. 2010

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“…To preserve the convenience of a transfer function approach, a way to generalize the concept of impulse response to define a shift invariant quantity is needed. Following Park and Wittenstein [3,4] , we can consider the spatially averaged response about the fiber optical element to the different position of the element with respect to the sampling sites is spatial invariant. According to Barnard and Boreman [10,11] , the overall MTF of fiber optical element could also be considered as the product of the imaging MTF which is the Fourier transform of the point spread function of the single fiber and the sampling MTF which depends on the spatial arrangement of the fibers, namely Where the sampling MTF sampling is an inherent feature in the process of sampling imaging, which is the average all possible MTFs depending on the relative position between an object and fiber optical element.…”

Section: Stationary Modulation Transfer Function Of Fiber Optic Tapermentioning

confidence: 99%

“…Although there were some research works with the MTF measuring methods and results for evaluating the quality of output images from the fiber optical plate [1,2] , the theoretical optic analysis and the methods for evaluating the modulation transfer function of fiber tapers are few. In this paper, the transmission characteristic of energy in the taper is analyzed firstly, and following the generalized definition of the modulation transfer function for sampled imaging system by Park et al [3,4] , the theoretical analysis and the methods for evaluating the modulation transfer function of fiber optic taper are put forward, also the mathematical model for fiber optic taper has been built. Finally, the dynamic and static modulation transfer function curves simulated by computer have been exhibited.…”

Section: Introductionmentioning

confidence: 99%

Theoretical model of the modulation transfer function for fiber optic taper

2005

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Fiber optic taper has been used more and more widely as a relay optical component in the integrated taper assembly image intensified sensors for military and medical imaging application. In this paper, the transmission characteristic of energy in the taper is analyzed, and following the generalized definition of the modulation transfer function for sampled imaging system, a spatial averaged impulse response and a corresponding MTF component that are inherent in the sampling process of taper are deduced, and the mathematical model for evaluating the modulation transfer function of fiber optic taper is built. Finally, the dynamic and static modulation transfer function curves simulated by computer have been exhibited.

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“…. (2) where 4 is the relative position of the sampling comb with respect to the image of the line. The values of 4 are restricted to the range 0 < 4 < p. Finally we have: where FT2(s) = FT(12(x)) = FT(Io(x)).OTFlns(s).OTFdet(s) .…”

Section: Introductionmentioning

confidence: 99%