Optical remote sensing satellites, utilized for Earth observation applications, provide the essential information for space, scientific, and technological aspects. The design of a remote sensing satellite camera is the outcome of a huge effort performed by the satellite camera designers and several trade-off studies, to fulfil the requirements. The capability of estimating the quality of the images acquired by the satellite camera is a basic part of the design analysis procedure. This paper proposes a model for estimating the image quality based on a detailed simulation of the imaging chain within the entire space system. Two different types of imaging sensors are involved in the simulation; the TDI-CCD and the new concept of the TDI-CMOS. Numerous issues are considered in the simulation involving the radiometry, atmosphere, optics, imaging sensor, satellite attitude, and smear perspectives. The modeling and simulation processes start with a ground original image as an input to the model. The input radiance is computed using MODTRAN software to simulate the main atmospheric effects. The image radiance is calculated and converted into photons producing digital numbers, representing the simulated image. The assessment of the simulated images is performed through different quality metrics; the modulation transfer function (MTF), signal-to-noise ratio (SNR), and minimum resolvable contrast (MRC). Finally, it may conclude that, for a definite case study, the performance of the TDI CCD is slightly better than that of TDI CMOS in the case of image MTF. On the other hand, the TDI CMOS has better SNR and MRC than TDI CCD.
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