Study Of Large Field Push-broom Imaging Spectrometer Using CCD Detector

Visible and near-infrared imaging spectrometer which can get the image and detailedspectral information of target at the same time plays an important role in ocean colorobservations. Due to the low reflectivity of the water and the need for a large oceanobservation area, ocean remote sensing requires instruments with high sensitivityand large field of view. Our country has achieved some positive results in the fieldof ocean imaging spectral sensing at present, but still has a lot to do to catch up withthe international level.Visible and near-infrared imaging spectrometer is an important component in awide-band imaging spectrometer project. Based on this project, this paper gave thesystem solution which can get the proposed performance. The Imaging spectrometerhad three push-broom sub-systems to stitch a large field. CCDs with large pixel sizeand long slits were also used to meet the requirements of sensitivity and field ofview.The main creative work includes:1. A complete electronic system was designed, which could work in eitherchannel programmable mode or full-frame readout mode. The full-frame mode dataformat was compatible with the mass of the channel mode, which made it possibleto obtain the full-frame image of the calibration lamps;2. A plan of system alignment was given, in which the defocus of system invacuum and the non-ideal factors of spectral components were fully considered andthe quality of the integrated instrument was maximized. After the system wasintegrated, the core parameters were tested, which showed good field imagingresults and high sensitivity;3. A detailed CCD smear model was set for push-broom imaging spectrometer.The corresponding smear deduction method was also given. In this method, theoutput image was used to estimate the spectral distribution of the target and twoadjacent smear frames were used to calculate the level of smear signal in eachchannel. This method showed very good effect;4. The stray light characteristics of the push-broom system were studied and astray light model was given. The whole model consisted of the sub-models of frontcamera, grating with abnormal vertical lines and other components. Experimentswere designed to measure the detailed model parameters. According to the model a stray light correction method was given and good results were achieved.