On-Orbit Modulation Transfer Function Detection of High Resolution Optical Satellite Sensor Based on Reflected Point Sources

Weiwei, 徐伟伟 Xu; Liming, 张黎明 Zhang; Xiaolong, 司孝龙 Si; Xin, 李鑫 Li; Baoyun, 杨宝云 Yang; Zhengguo, 沈政国 Shen

doi:10.3788/aos201737.0728001

Cited by 4 publications

(2 citation statements)

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“…The PSF for the image motion is obtained by adding up and normalizing the PSFs of the optical system with multiple instantaneous moments, which are sampled in a single exposure time by changing the position of the intensity matrix based on MATLAB. Thus, the MTF for the image motion can be calculated by Equation (25). Considering the actual working process of the FSM in an optical system, we proposed a simulation method to calculate the MTF in an optical system affected by vibration.…”

Section: Simulation Methodsmentioning

confidence: 99%

“…The exposure time was 1 s. The frequency range of the sinusoidal vibration generated by the FSM was from 0.5 to 4 Hz. Figure 12 shows the MTF for the complex motion measured by the point-source method [25], when the frequencies of the sinusoidal motions are different. Compared with Figure 2, the MTFs in Figure 12 have the same tendency.…”

Section: Laboratory Experiments For Validationmentioning

confidence: 99%

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Analysis of Dynamic Modulation Transfer Function for Complex Image Motion

et al. 2019

Applied Sciences

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In remote-sensing imaging, the modulation transfer function (MTF) for image motion relevant to the mixing of multiple forms of motions is hard to calculate because of the complicated image motion expression. In this paper, a new method for calculating the MTF for complex image motion is proposed. The presented method makes it possible to obtain an analytical MTF expression derived from the mixing of linear motion and sinusoidal motion at an arbitrary frequency. On this basis, we used the summation of infinitely many terms involving the Bessel function to simplify the MTF expression. The truncation error obtained by the use of finite order sum approximations instead of infinite sums is investigated in detail. In order to verify the MTF calculation method, we proposed a simulation method to calculate the variation of MTF in an actual optical system caused by image motion. The mean value of the relative error between the calculation method and the simulation method is less than 5%. The experimental results are consistent with the MTF curve calculated by our method.

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Section: Simulation Methodsmentioning

confidence: 99%

Section: Laboratory Experiments For Validationmentioning

confidence: 99%

Analysis of Dynamic Modulation Transfer Function for Complex Image Motion

et al. 2019

Applied Sciences

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Improved On-Orbit MTF Measurement Method Based on Point Source Arrays

Cao

Wei

et al. 2023

Remote Sensing

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The modulation transfer function (MTF) is a key characteristic used to assess the performance of optical remote sensing satellite sensors. MTF detection can directly measure a sensor’s two-dimensional (2D) point spread function (PSF); therefore, it has been applied to various high-resolution remote sensing satellites (e.g., Pleiades) using point sources. However, current point source methods mainly use 2D Gaussian functions to fit the discrete digital number (DN) of the point source on the image to extract the center of the point source and fit the PSF after encrypting multiple point sources; thus, noise robustness is poor and measurement accuracy varies widely. In this study, we developed a noise-resistant on-orbit MTF detection method based on the object space constraint among point source arrays. Utilizing object space constraint relationships among points in a point source array, a homography transformation model was established, enabling accurate extraction of sub-pixel coordinates for each point source response. Subsequently, aligning the luminosity distribution of all point sources concerning a reference point source, the encrypted PSF was obtained and then fitted to obtain the MTF. To validate the method, Gaofen-2 (GF-2) satellite images were used to conduct an in-orbit imaging experiment on the point source array of the Chinese Zhongwei remote sensing satellite calibration site. Compared with the Gaussian model methods, the proposed method yielded more accurate peak positions for each point source. Standard deviations of peak position constant ratios in along- and cross-track directions improved by 2.8 and 4.8 times, respectively. The root-mean-square error (RMSE) of the collinearity test results increased by 92%, and the noise resistance of the MTF curve improved by two times. Dynamic MTF values at the Nyquist frequency for the GF-2 panchromatic band in along- and cross-track directions were 0.0476 and 0.0705, respectively, and MTF values in different directions were well distinguished.

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High-Precision Automatic Calibration Modeling of Point Light Source Tracking Systems

Zhang

Wang

et al. 2021

Sensors

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To realize high-precision and high-frequency unattended site calibration and detection of satellites, automatic direction adjustment must be implemented in mirror arrays. This paper proposes a high-precision automatic calibration model based on a novel point light source tracking system for mirror arrays. A camera automatically observes the solar vector, and an observation equation coupling the image space and local coordinate systems is established. High-precision calibration of the system is realized through geometric error calculation of multipoint observation data. Moreover, model error analysis and solar tracking verification experiments are conducted. The standard deviations of the pitch angle and azimuth angle errors are 0.0176° and 0.0305°, respectively. The root mean square errors of the image centroid contrast are 2.0995 and 0.8689 pixels along the x- and y-axes, respectively. The corresponding pixel angular resolution errors are 0.0377° and 0.0144°, and the comprehensive angle resolution error is 0.0403°. The calculated model values are consistent with the measured data, validating the model. The proposed point light source tracking system can satisfy the requirements of high-resolution, high-precision, high-frequency on-orbit satellite radiometric calibration and modulation transfer function detection.

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On-Orbit Modulation Transfer Function Detection of High Resolution Optical Satellite Sensor Based on Reflected Point Sources

Cited by 4 publications

References 0 publications

Analysis of Dynamic Modulation Transfer Function for Complex Image Motion

Analysis of Dynamic Modulation Transfer Function for Complex Image Motion

Improved On-Orbit MTF Measurement Method Based on Point Source Arrays

High-Precision Automatic Calibration Modeling of Point Light Source Tracking Systems

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