基於空間渾沌模型之合成孔徑雷達影像變遷偵測應用於受災範圍估測

Change Detections from SAR Images for Damage Estimation Based on a Spatial Chaotic Model

曾裕強(Yu-Chang Tzeng) ； 邱順興(Shun-Hsing Chiu)

《航測及遙測學刊》 12卷4期 (2007/12) Pp. 283-290

https://doi.org/10.6574/JPRS.2007.12(4).1

摘要

合成孔徑雷達因其可全天候地提供影像，故特別適合用以監測災害事件。當災害發生時，其所影響之區域在合成孔徑雷達影像上會產生很大的改變。因此，可將變遷偵測(change detection)技術應用於合成孔徑雷達影像，以估計災害發生所影響之範圍。然而，合成孔徑雷達影像因受斑駁雜訊的影響，使得以合成孔徑雷達影像進行變遷偵測非常困難。斑駁雜訊看起來雖然像是雜訊，但實際上也是合成孔徑雷達自然所產生的訊號。理論上，合成孔徑雷達訊號可用混沌現象來描述，因其是由在同一個像素內所產生的許多散射訊號以同調相加方式產生。因此，斑駁雜訊可以一空間渾沌模型(spatial chaotic model)來表示，並以碎形維度(fractal dimension)來描述其特性。基於空間渾沌模型，本論文提出一簡化的合成孔徑雷達影像變遷偵測流程，並以實際發生之水災事件爲測試例，將此一方法應用於受水災影響範圍之估測。實驗結果顯示，本論文所提出之方法，是利用合成孔徑雷達影像以估測水災影響範圍的一個非常有實用且有效率的工具。

關鍵字

變遷偵測 ； 空間渾沌模型 ； 卡方檢定

並列摘要

Because of its all-weather and all-time characteristics, SAR image is particularly effective to monitor disaster events. When a disaster occurs, the image acquired from a SAR sensor changes dramatically. As a result, damage estimation for natural and human-made disasters from SAR images can be achieved by applying a change detection technique. However, it is very difficult to detect changes in SAR images because of the speckle noise in nature. Theoretically, SAR signal can be characterized as a chaotic phenomenon because that the scattering signals within a resolution cell are summed up coherently. Accordingly, SAR signal can be represented by a spatial chaotic model and characterized by its fractal dimension. In this paper, based on the spatial chaotic model, a simplified SAR image change detection procedure is proposed. The proposed method is then applied to estimate the flood-damage area caused by flooding events. Experimental results reveal that the proposed method is an effective and efficient tool for damage estimation from SAR images.

並列關鍵字

change detection ； spatial chaotic model ； fractal dimension