SNR estimation for advanced hyperspectral space instrument

Eckardt, Andreas; Höfer, Stefan; Neumann, Christian; Skrbek, W.

doi:10.1117/12.609236

Cited by 4 publications

(3 citation statements)

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“…The EMI in-orbit SNR is estimated by using the SNR model and MODTRAN (Berk et al, 1989). The SNR estima- (Eckardt et al, 2005;Lang et al, 2013). The electrons generated by a signal pixel can be calculated by the following equation:…”

Section: Signal-to-noise Ratiomentioning

confidence: 99%

Preflight calibration of the Chinese Environmental Trace Gases Monitoring Instrument (EMI)

Zhao

Zhou

et al. 2018

Atmos. Meas. Tech.

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Abstract. An environmental trace gases monitoring instrument (EMI) is a nadir-viewing wide-field imaging spectrometer, which aims to quantify the global distribution of tropospheric and stratospheric trace gases, and is planned to be launched on 9 May 2018. The selected wavelength bands for EMI are ultraviolet channels: UV1 (240–315 nm), UV2 (311–403 nm) and visible channels: VIS1 (401–550 nm), and VIS2 (545–710 nm). The spectral resolution is 0.3–0.5 nm, and the swath is approximately 114∘ wide to achieve a one-day global coverage. The preflight calibration of the EMI is discussed in this paper. A tunable laser and rotating platform are adopted for an EMI wavelength calibration of the entire field of view. The accuracy of the wavelength calibration is less than 0.05 nm. In addition, the solar calibration mode shows the same results compared with Earth observation mode. A thermal vacuum test is performed to investigate the influence of in-orbit thermal vacuum conditions on the EMI, and EMI spectral response changes with pressure, optical bench temperature, and charge-coupled device (CCD) detector temperature are obtained. For a radiometric calibration of UV1, a diffuser plate with a 1000 W xenon lamp, which produces sufficient UV output, is selected. An integrating sphere system with tungsten halogen lamp is selected for the UV2, VIS1, and VIS2. The accuracies of radiance calibration are 4.53 % (UV1), 4.52 % (UV2), 4.31 % (VIS1), and 4.30 % (VIS2). The goniometry correction factor and irradiance response coefficient of the EMI are also calibrated on the ground for an in-orbit calibration of the solar. A signal-to-noise ratio (SNR) model of the EMI is introduced, and the EMI in-orbit SNR is estimated using the SNR and MODTRAN radiance models.

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Section: Signal-to-noise Ratiomentioning

confidence: 99%

Preflight calibration of the Chinese Environmental Trace Gases Monitoring Instrument (EMI)

Zhao

Zhou

et al. 2018

Atmos. Meas. Tech.

View full text Add to dashboard Cite

show abstract

“…The EMI in-orbit SNR is estimated by using the SNR model and MODTRAN (Berk et al, 1989). The SNR estima- tion for advanced hyperspectral space instruments have been discussed elsewhere (Eckardt et al, 2005;Lang et al, 2013). The electrons generated by a signal pixel can be calculated by the following equation:…”

Section: Signal-to-noise Ratiomentioning

confidence: 99%

Modified manuscript

Zhao¹

2018

Preprint

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An environmental trace gases monitoring instrument (EMI) is a nadir-viewing wide-field imaging spectrometer, which aims to quantify the global distribution of tropospheric and stratospheric trace gases, and is planned to be launched on 9 May 2018. The selected wavelength bands for EMI are ultraviolet channels: UV1 (240-315 nm), UV2 (311-403 nm) and visible channels: VIS1 (401-550 nm), and VIS2 (545-710 nm). The spectral resolution is 0.3-0.5 nm, and the swath is approximately 114 • wide to achieve a oneday global coverage. The preflight calibration of the EMI is discussed in this paper. A tunable laser and rotating platform are adopted for an EMI wavelength calibration of the entire field of view. The accuracy of the wavelength calibration is less than 0.05 nm. In addition, the solar calibration mode shows the same results compared with Earth observation mode. A thermal vacuum test is performed to investigate the influence of in-orbit thermal vacuum conditions on the EMI, and EMI spectral response changes with pressure, optical bench temperature, and charge-coupled device (CCD) detector temperature are obtained. For a radiometric calibration of UV1, a diffuser plate with a 1000 W xenon lamp, which produces sufficient UV output, is selected. An integrating sphere system with tungsten halogen lamp is selected for the UV2, VIS1, and VIS2. The accuracies of radiance calibration are 4.53 % (UV1), 4.52 % (UV2), 4.31 % (VIS1), and 4.30 % (VIS2). The goniometry correction factor and irradiance response coefficient of the EMI are also calibrated on the ground for an in-orbit calibration of the solar. A signal-to-noise ratio (SNR) model of the EMI is introduced, and the EMI in-orbit SNR is estimated using the SNR and MODTRAN radiance models.

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“…Based on which the SNR model of hyperspectral imagers were built [4] [5] . This model is able to show the sensitivity of the imaging instrument itself effectively and matches the laboratory tests well.…”

Section: Introductionmentioning

confidence: 99%

A new SNR model for space-borne hyperspectral imagers including atmospheric scattering influence

Lang

Wang

2013

SPIE Proceedings

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Space-borne hyperspectral imagery is widely used in the fields of earth science and mineral detection. High signal-to-noise ratio (SNR) of imaging spectrometers is required to guarantee the image data validity. To describe the system sensitivity, previous SNR models mainly focused on the optical parameters and the detector characteristics.However, the sensitivity of space-borne hyperspectral imagers is also limited by the atmospheric scattering effect to a large extent. A quantified and complete SNR model including atmospheric scattering influence is valuable for the development of imaging spectrometers.In this paper, scattering influence on hyperspectral imaging quality was analyzed in the spectral range of 0.4μm-2.5μm. Atmospheric simulation was presented and system performance reduction caused by the scattering effect was also quantified. The results show that the scattered light will occupy a large proportion of the system dynamic range and bring additional shot noise, which causes evident SNR attenuation.Based on the analysis a new SNR model including atmospheric parameters was provided. Hyperspectral imaging quality was calculated with both the new SNR model and the classical SNR model respectively, and comparative study of the two models was given in this paper.In order to validate the new SNR model, a hyperspectral imaging system and a multiband camera were built, and the imaging experiments were conducted. The results show that the atmospheric scattering effect could lead to significant SNR reduction and contrast attenuation of spectral images, especially at visible bands. Using the new SNR model could allow designers to estimate the system performance more precisely. Corresponding instrument design measures were also proposed based on the analysis and experiments.

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SNR estimation for advanced hyperspectral space instrument

Cited by 4 publications

References 1 publication

Preflight calibration of the Chinese Environmental Trace Gases Monitoring Instrument (EMI)

Preflight calibration of the Chinese Environmental Trace Gases Monitoring Instrument (EMI)

Modified manuscript

A new SNR model for space-borne hyperspectral imagers including atmospheric scattering influence

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