A Day and Night Separation Alternative Calibration Method for High Resolution Satellite Wide Field Imager

Abstract

The invention discloses a day and night separation vicarious calibration method for a high-definition satellite wide-view filed imager. The method comprises steps: (1) remote sensing image data of the high-definition satellite wide-view filed imager in a night ocean scene are read, and offset of dark noise in each wave band is calculated according to the gray value generated by the dark noise of each detection unit; (2) a spectral radiation brightness calculation module at the entrance pupil of the satellite imager is determined; (3) the imager observes a specific field and imaging is carried out, auxiliary data needed by calculation of the model in the second step are synchronously observed on the ground, and the average counting value of each wave band of the specific field is extracted according to the remote sensing image data outputted when the imager observes the specific field; (4) the spectral radiation brightness at the entrance pupil of each wave band of the satellite imager is calculated, and in combination with features of the imager wave band spectral response function, wave band equivalent radiation brightness at the entrance pupil of the imager is calculated; and (5) according to the dark noise offset in the first step, the average counting value of each wave band of the specific field in the third step and the wave band equivalent radiation brightness at the entrance pupil of the imager of the fifth step, the on-orbit absolute radiometric calibration coefficient is calculated.

Description

technical field [0001] The invention relates to a day-night separation alternative calibration method for a high-resolution satellite wide-field imager, in particular to a day-night separation alternative calibration method for the Gaofen-1 satellite wide-field imager. Background technique [0002] The high-resolution satellite wide-field imager is an optical remote sensor that can quickly obtain the optical radiation information of large-area ground objects. Effective information resources, and the premise of the in-depth quantitative application of remote sensing information is to convert the output signal of the remote sensor into the actual physical quantity corresponding to the target, that is, to determine the quantitative relationship between the digital quantity and the physical quantity through absolute radiation calibration. [0003] At present, there are many achievements in absolute radiometric calibration at home and abroad, but due to the various differences in...

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Problems solved by technology

[0003] At present, there are many achievements in absolute radiometric calibration at home and abroad, but due to the various differences in the parameter settings, characteristics and on-board functions of satellite optical remote sensors, plus the conditions of use, calculation process and The accuracy of the model is also different, especially in the absence of real-time dark noise signal monitoring function on the satellite, it is difficult to directly apply an absolute radiometric calibration method to the on-orbit replacement calibration of the high-resolution satellite wide-field imager

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