Image rotation modeling for two-dimensional plane mirror scanning and its application in precise image positioning for linear sensor imager on geostationary platform

摘要

In the domain of modern space-borne remote sensing in optical band, the operation mode of multiple-element or linear sensor with plane mirror's two-dimensional (2-D) scanning is popular and has been applied in some real applications successfully. Three basic image rotation models of different 2-D plane mirror scanning modes are analyzed in mathematic detail, and their performances are also compared in the aspects of scanning coverage, observing efficiency and degree of image rotation respectively. It is shown that two of them are feasible for real applications and have some advantages with each other. On the other hand, some raw observed sub-image series of Indian National Satellite (INSAT) Charge Coupled Device (CCD) imager, whose plane mirror uses one of the modes to complete the full-disc view of the Earth, are used to validate the authenticity of the image rotation models above. It is shown that, the accuracy of image positioning (about 2approx3 pixels) is some better than that (about 5 pixels) achieved by the investigators who cared the launch and the first accuracy assessment of this satellite. Moreover, both the image rotation model based on the plane mirror's 2-D scanning and the corresponding image derotation method are useful for end-user who wants to utilize the images quantitatively on ground.