Relation between ground features and mathematical morphology using JERS-1/SAR data during flooding time in paddy areas

摘要

The conventional method of detecting flood extent using satellite SAR data is derived from signal intensity changes for each pixel between before and during the flood time. But if we employ this single pixel (pixel to pixel) image processing strategy, we will be confronted with many difficulty to detect flood inundated areas especially existing paddy fields or floating rice growing regions just like South-east Asia. Because we can see the water surface at the early period of rice plant growing season in such areas, it will be difficult to distinguish the flood inundated areas with such water surface of paddy fields. But the SAR signal intensity should include the information of interaction between ground features and microwave radar. Using mathematical morphology, we can investigate particular ground feature, such as regularly straight lined levees of consolidated paddy fields. The natural corner reflectance effect for SAR signal will occur only in the flood time at some isolated trees or human habitat areas. Some lined segment structuring elements, such as river courses, irrigation canals, will be derived from an application of directional morphological operators. Then the author would like to introduce some sample images as for such relationship between ground features and morphological methods.