Airborne synthetic aperture radar (SAR) image quality considerably degrades because of motion errors. High-precision motioncompensation (MOCO) is necessary in an advanced SAR data processing scheme. In the case of ul...
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Airborne synthetic aperture radar (SAR) image quality considerably degrades because of motion errors. High-precision motioncompensation (MOCO) is necessary in an advanced SAR data processing scheme. In the case of ultra-high resolution, the conventional two-step MOCO algorithm introduces significant range cell migration correction (RCMC) error which causes a loss to resolution. Another method named one-step MOCO can avoid RCMC error, improving image quality obviously. Meanwhile, one-step MOCO can well integrate with the standard Omega-K algorithm succinctly. A comparison of the two MOCO algorithms is demonstrated by analysing the RCMC error. Point targets simulation has validated the proposed research.
When multiple radar targets are close to each other, the returned signals from these targets are overlapped in time. Therefore by applying conventional motion compensation algorithms designed for single target, the mu...
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When multiple radar targets are close to each other, the returned signals from these targets are overlapped in time. Therefore by applying conventional motion compensation algorithms designed for single target, the multiple targets cannot be resolved, and individual one cannot be clearly imaged. The authors conclude that whether the radar transmits linear frequency modulated (LFM) or stepped-frequency waveform, the chirp rate in the Doppler frequency shift induced by the translation motion is only concerned with the acceleration of the target. For different targets, the chirp rates are different from each other. Based on the different chirp rates, the signals from each target can be separated. Then a new algorithm based on the adaptive joint time frequency (AJTF) technique is proposed to separate the signals from different target in each cross-range cell. The use of the particle swarm optimisation (PSO) for multiple targets separation is a unique application of this evolutionary search. By the CLEAN technique, the number of targets need not be appointed. The simulation results confirm the efficiency of the proposed algorithm for multiple moving targets imaging.
This paper presents a new method, called Spatial Dynamic motioncompensation (SDMC), which applies the concept of global motion to the coding of motion trajectory information for the purpose of side information reduct...
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ISBN:
(纸本)0819417661
This paper presents a new method, called Spatial Dynamic motioncompensation (SDMC), which applies the concept of global motion to the coding of motion trajectory information for the purpose of side information reduction in digital video signal compression. The experimental results of the SDMC algorithms presented in this paper have shown that the new method yields significant improvements in terms of bit rate reduction of motion information over the method used in MPEG-1, while maintaining a comparable reconstructed picture quality, when the video sequences possess significant global translational motion.
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