Radiometric correction of RISAT-1 data

Upadhayay, Swati; Rani, B Asha; Pandey, Sumit Kumar; Mishra, Neeraj; Patra, S. K.; Chowdhury, S. K.

doi:10.1109/iccsp.2016.7754452

Cited by 1 publication

(1 citation statement)

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“…The echo energy gets weaker as the irradiation range increases therefore the grey scale of SAR image is not uniform. The radiation correction [40] that compensates the grey scale of the SAR image can effectively solve this problem.…”

Section:  mentioning

confidence: 99%

Extended Polar Format Algorithm for Large-Scene High-Resolution WAS-SAR imaging

Chen

Wang

et al. 2021

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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The polar format algorithm (PFA) is a frequencydomain algorithm with high computational efficiency especially for the high resolution imaging applications in wide angle staring synthetic aperture radar (WAS-SAR). Because of the image distortion and defocus caused by plane wave assumption, the effective imaging scene is limited to a small region which is defined as defocus-negligible region. In this paper, a novel sub-block imaging algorithm which firstly applied to WAS-SAR is proposed. This method combines sub-block imaging and spatially variant post filtering (SVPF) which can not only effectively extend depth of focus (DOF) of PFA but also greatly reduces computational burden. What's more, the method of mosaic image is proposed in this paper which can eliminate discontinuity between adjacent sub-blocks. Firstly, the large scene is segmented into multiple regions along range direction and the size of each region is still larger than that of defocus-negligible region. Secondly, refocusing is implemented by a phase compensation of the already de-chirped signal with the center of sub-blocks respectively and each sub-block image is formed by PFA. Thirdly, the region in each sub-block that exceeds the defocus-negligible region is corrected by SVPF and the image distortion can be corrected by 2-D interpolation. Finally, mosaic image method is applied to get the large-scene image with high quality. The algorithm proposed in this paper is efficient and solve the problems in the process of SAR image mosaic such as dislocation and grey scale differences. The simulated and experimental data results demonstrate the effectiveness and practicability of the proposed algorithm.Index Terms-wide angle staring synthetic aperture radar (WAS-SAR), polar format algorithm (PFA), large scene, high resolution, sub-block imaging, SVPF

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Section:  mentioning

confidence: 99%