Research Of Information Acquisition System For High Resolution Space-borne Push-broom Hyperspectral Imagers Based On CMOS Detector

Space-borne push-broom hyperspectral imagery is an important earth observationtechnology. With the improvement of the spatial resolution and the increase of thespectral bands, high sensitivity information acquisition technology has become a keytechnology of high resolution hyperspectral imager. Currently, the informationacquisition systems based on ready-made detectors has met the design limitations,which becomes the bottle-neck of the development toward higher resolution. In thispaper, the detector, the whole information acquisition system and their matchingtechnology are deeply researched based on the fast-developing CMOS detectors. Themain contents of the research include:1) Theoretical analysis of the factors which limit the system sensitivity is provided.The method of suppressing the system dynamic range in order to enhance the sensitivityis proposed based on the specialty of the hyperspectral imaging system. According tothis method and the principle of CMOS sensors, the modeling, analysis and calculationof the detector parameters are presented. The high sensitivity detector design matchingthe hyperspectral information acquisition system is given and simulated.2) The feasibility and the spatiality of CMOS detector for hyperspectral imagingare researched in this paper. The non-uniformity, exposure method and working modeare analyzed. Specific application suggestions are also given. Based on the flexibility ofthe CMOS detector, several special applications for hyperspectral imagers are provided,including adjustable spectral gain, programmable hyperspectral imaging, real-timein-orbit calibration, etc.3) Based on the CMOS detectors designed by this paper, the applicationtechnology is also studied. Electronic noise control methods are analyzed and conducted.A high sensitivity information acquisition system is built. The total noise of the systemis less than40e-at the frame rate of450Hz, in which the circuit noise is less than10e-.The calculation shows that the noise level has met the shot-noise limitation of the highresolution space-borne hyperspectral imagers. 4) A whole hyperspectral imaging information acquisition system is designed,developed and tested in this paper. A hyperspectral imaging experiment instrument isbuilt and based on which450Hz hyperspectral imaging is realized. This frame rate willsupport16m ground resolution hyperspectral imaging at500km orbit.5) The SNR model of hyperspectral imager is researched in this paper. Based onthe classical SNR model, the image-based new SNR model is presented. Theatmospheric scattering influence to the image quality is included in the new model. Thetheoretical calculation and the experimental demonstration of the model are alsoprovided.Some suggestions are proposed for the future development and the engineeringapplications.