Author Affiliations
1Department of Advanced Space Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, Jilin 130033, China2College of Material Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, Chinashow less
Fig. 1. Schematic of whiskbroom scanning imaging of space camera
Fig. 2. Distortion process of target image
Fig. 3. Calculation of pixel number of nadir ground scene perpendicular to track
Fig. 4. Schematic of corresponding pixels of distorted and extended images perpendicular to track
Fig. 5. Schematic of width of imaging area along track
Fig. 6. Schematics of corresponding pixels of distorted and extended images along track. (a) Original distorted image; (b) extended image
Fig. 7. Architecture of SRCNN
Fig. 8. Architecture of wbi-SRCNN
Fig. 9. Schematic of experimental device of satellite whiskbroom scanning imaging
Fig. 10. Distortion correction result of whiskbroom scanning image. (a) Ground truth; (b) simulated whiskbroom scanning image; (c) distortion-corrected whiskbroom scanning image
Fig. 11. Distortion correction result of whiskbroom scanning linear target. (a) Simulated whiskbroom scanning linear target; (b) distortion-corrected whiskbroom scanning linear target
Fig. 12. Enhanced results of distortion-corrected whiskbroom scanning images. (a) Distortion-corrected whiskbroom scanning images; (b) result of Bicubic; (c) result of SRCNN; (d) result of wbi-SRCNN. Left is wall and right is roof
On-orbit imaging parameter | Value | Ground simulation parameter | Value |
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Radius of earth /km | 6400 | Curvature radius of LED screen /m | 32 | Focal length of camera /m | 8 | Focal length of camera /mm | 7 | Pixel size /μm | 8 | Pixel size /μm | 7 | Orbital height /km | 500 | Object distance /m | 4 | Ground resolution /m | 0.5 | Imaging resolution /m | 0.004 | Attitude angle /(°) | ±35 | Attitude angle /(°) | ±35 | Satellite speed relative to earth /(km·s-1) | 7.5 | Target movingspeed /(pixel·s-1) | 6 | Satellite whiskbroom angular speed /[(°)·s-1] | 8 | Turntable whiskbroom angular speed /[(°)·s-1] | 8 | Line shift time /s | 7.2×10-6 | Line shift time /s | 7.2×10-3 |
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Table 1. Parameters for on-orbit imaging and ground simulation
Evaluating indicator | NR-IQA result for Wall image | NR-IQA result for Roof image | |
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Bicubic | SRCNN | wbi-SRCNN | Bicubic | SRCNN | wbi-SRCNN |
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NPGD | 35.3271 | 161.3976 | 215.4396 | 53.1318 | 240.5480 | 343.1014 | EPS | 45.9590 | 88.3334 | 104.6274 | 54.4708 | 108.4588 | 132.1151 | NIQE | 31.4268 | 27.2762 | 21.7448 | 30.5295 | 27.7579 | 24.7264 | PIQUE | 94.5689 | 90.0698 | 90.0849 | 89.4362 | 87.8337 | 84.3469 |
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Table 2. NR-IQA results of test images