Relative radiation calibration method of multichip linear CCD (charge coupled device) camera

Abstract

The invention relates to a relative radiation calibration method of a multichip linear CCD (charge coupled device) camera. The relative radiation calibration method includes steps of establishing a focal plane coordinate system and a geographic coordinate system of the multichip linear CCD camera obliquely arranged in a remote sensing satellite; calculating a geocentric angle of an origin of the geographic coordinate system deviated from a sub-satellite point at the imaging moment; establishing transformational relation from the geographic coordinate system to the focal plane coordinate system; calculating yaw rate of the satellite according to the transformational relation during imaging of a calibration mode, so that all pixels of the multichip linear CCD camera can be imaged to the same region of the ground; setting up a histogram lookup table by a histogram matching method. On the basis of the strict transformational relation, the pixels of the multichip linear CCD camera obliquely arranged are imaged to the same region, so that the pixels can have same input.

Description

technical field [0001] The invention relates to a relative radiation calibration method for a multi-chip linear array CCD camera, belonging to the technical field of remote sensing satellite calibration. Background technique [0002] At present, space remote sensing CCD cameras are developing towards higher resolution and large width, so as to ensure higher spatial resolution and temporal resolution. Under the premise of a certain orbital height, the improvement of the resolution of the ground pixel of the space camera leads to the increase of the focal length of the camera, and the increase of the focal length and the increase of the field of view lead to the need to use multiple linear array CCD splicing to form a large-width space camera the focal plane. [0003] Due to the inconsistency of the optical response of different pixels of the linear array CCD, the inconsistency of the readout circuit itself and its coupling with the CCD, the inconsistency of the amplification...

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Problems solved by technology

[0004] In the currently commonly used remote sensing satellite relative radiation calibration method, the calibration coefficient obtained by the relative radiation calibration in the laboratory will become invalid as the performance of the remote sensor decreases after the satellite is launched; the uniform ground scene method requires lakes, grasslands Calibration fields such as glaciers, glaciers, and artificial uniform fields are difficult and costly to find or construct; on-orbit statistics of a large number of satellite image data is a relatively widely used method in China at present, accumulating multi-track image data, but the premise of this method It is to ensure the stability of the image data of each track; the Side-slither calibration method widely used in foreign countries rotates the satellite yaw angle by 90°, and selects relatively uniform scenes such as rain forests, deserts, and ice sheets as the calibration source. Therefore, for High requirements for calibration sources lead to limited selection of calibration areas

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