类尺度不变特征变换的陆探1号卫星影像初配准算法——以积石山地震为例

Image Initial Registration Algorithm for Lutan-1 Satellite Based on Scale-Invariant Feature Transform-Like Algorithm —A Case Study of the Jishishan Earthquake

  • 摘要: 陆探 1 号(Lutan-1, LT-1) SAR 卫星是我国首个以干涉为核心任务的 L 波段全极化民用 SAR 卫星星座,适用于地震、滑坡等灾害的监测和应急响应。然而,受该卫星实时轨道数据不精确 的影响, LT-1 SAR 影像的初始配准精度不高, 容易导致配准失败, 影响影像自动化处理效率。针 对该问题, 提出基于类尺度不变特征变换的 LT-1 影像初配准算法和处理策略, 旨在提高其配准成 功率。以 2023 年 12 月 18 日甘肃积石山 Ms 6.2 级地震为例, 验证算法的可靠性, 将配准成功率 由 34.5%提高到 100%, 成功获取了该地震的同震形变场。 同时也获取了 Sentinel-1A/B 升、降轨 形变结果,用于对 LT-1 结果进行精度验证和分析。综合 LT-1 和 Sentinel-1A/B 的结果表明, 该 地震以抬升为主,最大抬升量达 6.3 cm,属于逆冲型地震。通过震前 Sentinel-1 升、降轨时序形 变结果分别识别出 195 和 179 个滑坡,并发现该地震触发的草滩村液化滑坡-泥流在震前已出现明 显形变,形变速率超过 9 mm/a。讨论了 LT-1 影像分幅不规则对算法有效性的影响,并展望了 LT- 1 卫星在地震及同震地质灾害监测领域的应用潜力。

     

    Abstract: Objectives: The Lutan-1 (LT-1) Synthetic Aperture Radar (SAR) satellite, the first group of Lband fully polarimetric civilian SAR satellites in China with interferometry as its core mission, is suitable for monitoring and emergency response to disasters such as earthquakes and landslides. However, due to the inaccuracy of the satellite's real-time orbit data, the initial registration precision of the LT-1 SAR images is not high, which easily leads to registration failure and affects the efficiency of the image-automated registration process. Methods: In response to this issue, this study proposes an LT-1 image initial registration method and processing strategy based on a Scale Invariant Feature Transform Like (SIFT-Like) algorithm to enhance the registration success rate. Taking the Ms6.2 earthquake in Jishishan, Gansu, on December 18, 2023, as an example, the algorithm's reliability was verified, with the registration success rate increased from 34.5% to 100%, successfully obtaining the co-seismic deformation field of this earthquake. Furthermore, the co-seismic deformation results of Sentinel-1A/B for this earthquake were also acquired for precision validation and analysis of the LT-1 results. Results: Integration of LT-1 and Sentinel-1A/B results indicates that the earthquake was primarily characterized by uplift, with a maximum uplift of 6.3 cm, classifying it as a thrust earthquake. Using pre-earthquake Sentinel-1 ascending and descending orbit interferometric results, 195 and 179 landslides were respectively identified, and it was observed that the liquefaction landslide-debris flow triggered by the earthquake in Caotan Village had exhibited significant deformation before the event, with a deformation rate exceeding 9 mm/yr. Finally, the impact of irregular segmentation of LT-1 images on algorithm effectiveness is discussed, and the potential applications of LT- 1 satellites in earthquake and geological hazard monitoring are highlighted. Conclusions: The proposed algorithm effectively eliminates the registration issue of the LT-1 satellite. With the increasing archive data of LT-1, this algorithm can better highlight its advantages. Combining the LT-1 data and the algorithm can better serve the deformation monitoring and emergency response of earthquakes and geological disasters in the future.

     

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