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Information Fusion Based on Multiresolution and Multisensor
SAR and Optical-Sensor Segmented Images
3.3 Image segmentation
After SAR image and optical image has been denoised then à trous wavelet transform process until fourth level, next is segmentation process on fourth detail images (w1, w2, w3 and w4) on SAR image and optical image (figure 2.)
SAR
Figure 2. Detail image w1, w2, w3, w4 from segmentation result SAR (a-d) and Landsat (e-h)
The image classification is done using the ERMAPPER software since ground truth is not available, thematic map and unsupervised classification is used with 7 predetermined classes (Table 1. and Table 2.) there are river(water), swamp, woodland, tropical grass, scattered tree, mangrove and rice paddy. Variant distribution that shown on Table 1 and Table 2 had been chosen as minimum and maximum value in threshold process on detail images w4 and w3 for each classes. In this research, fusion process only done on detail images w4 and w3 from SAR and Optical images.
Table 1. Unsupervised classification w4
Table 2. Unsupervised classification w3
4. Experimental Results and Discussions
From this segmentation will choose object that would be fusion. From 7 images, result of threshold process on SAR images and Optical images, choose an object that visually looks clearly or choose an object that have wide variant distribution on Table 1 and Table 2.
Fusion for detail image w4, the image taken from threshold process 6 th , 7 th classes of SAR images to 5 th, 4 th, 3 rd, 2 nd and 1 st classes of optical images. The result of fusion shown on figure 3.
Figure 3. Fusion from w4, threshold SAR detail image to w4 threshold optical detail image
Fusion on detail image w3 done by using image from threshold process 6th , 7th classes of SAR images to 5th, 4th, 3rd, 2nd and 1st classes of optical image..The result shown on Figure 4..
Figure 4. Fusion from w3 threshold SAR detail image to w3 threshold optical detail image
V. Concluding Remarks
- Using threshold as chosen object would make fusion process easier.
- 2. The use of à trous wavelet transformation both in the denoising process and segmentation process can give several alternative segmented images.
- Composing or fusing the chosen two sensor segmented image can be done to obtain a reasonably better thematic image
References
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