Correction of phase errors in fourier spectroscopy

Porter, Christopher; Tanner, D. B.

doi:10.1007/bf01008607

Cited by 30 publications

(17 citation statements)

References 8 publications

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“…The technique described here uses apodization to reduce errors from detector noise and phase correction techniques that enable the MTF to decay to zero. These methods were developed originally to correct Fast Fourier transform (FFT) artifacts in Fourier transform spectrometers 13 and have been used previously for noise rectification in MTF calculations of digital imaging systems. 14 …”

Section: Sampling Considerations For the Mtf Of Digitalmentioning

confidence: 99%

“…Apodization improves the MTF directly by reducing the contribution of noise-dominated regions, thereby smoothing the resulting MTF. We followed the approach of LaVeigne et al 14 and LaVeigne and Burks 15 in using apodization routines with weighting functions similar to those used in Fourier transform spectroscopy 13 (FTS).…”

Section: Deriving the Phase-corrected Mtfmentioning

confidence: 99%

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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%

Section: Deriving the Phase-corrected Mtfmentioning

confidence: 99%

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

et al. 2010

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“…In the alternative case of using a simple linear phase correction (Porter and Tanner, 1983), as produced by a simple ZPD point misplacement, a residual non linear phase error is still present. On the other side, by taking the modulus of the FFT, the spectral noise gives a bias error in the spectrum.…”

Section: Fourier Transform and Phase Correctionmentioning

confidence: 99%

Technical Note: REFIR-PAD level 1 data analysis and performance characterization

Bianchini

Palchetti

2008

Atmos. Chem. Phys.

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Abstract. The outgoing long-wave radiation from the Earth's atmosphere in the far infrared spectral region is mostly unexplored, while is well recognized that the water vapour contribution to greenhouse trapping is dominant in this region. The Radiation Explorer in the Far InfraRed (RE-FIR) study has proven the feasibility of a space-borne Fourier transform spectrometer able to perform the measurement in the 100-1100 cm −1 range with a resolution of 0.5 cm −1 . Following this work a prototype of the spectrometer named REFIR-PAD (Prototype for Applications and Development) has been developed to observe the atmospheric radiance from both ground-based sites and from stratospheric balloon platforms. In this work we describe the REFIR-PAD level 1 data analysis procedure, that, starting from raw instrumental data produces the calibrated atmospheric spectral radiance. Performances of the procedure are also described.

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“…Asymmetry causes a frequency dependent phase delay, which, if asymmetry is the only complication, is the same for both inputs so that at each frequency a scalar combination of the two corresponding signals is still made. Therefore, the phase delay is easily corrected with a phase error correction procedure [2][3][4][5][6] in which the real part of the complex spectrum is retrieved.…”

Section: Introductionmentioning

confidence: 99%