| 25 Mar 2011 03:48 AM |
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Dear all,
I have some landsat7 image, which have clouds. It is really difficult for me to classify with these data. i want to remove these clouds by replacing with other free images at the same study area. But I dont know how to do it.
Any reply would be appreciate. Thanks for the advance.
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MariM
Veteran Member
Posts:2396  
| 25 Mar 2011 08:56 AM |
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You could create a mask of the clouds using ROIs or vectors, then apply the mask to change those areas to 0 values in the image. Then mosaic with another image that has good values in those areas using the background value to ignore of 0.
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Deleted User
New Member
Posts: 
| 28 Mar 2011 03:19 AM |
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Dear MariM,
Thanks so much for your answer. Unfortunately, I am just familiar with ENVI. So could you please tell me how to change those ROIs to 0 values.
I am looking forward your helping.
Best
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MariM
Veteran Member
Posts:2396
| 28 Mar 2011 07:44 AM |
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You have to create ROIs or vectors of your cloud areas by either drawing them on, or using Band Threshold to ROI and entering the range of values that the clouds consist of, or you could classify the image and use Cloud as one of the classes, and then convert that class to an ROI or vector. Once you have an ROI or vector that delineates your cloud areas, then you can build a mask from using using Basic tools ->Masking->Build Mask and build a mask from the ROI or vector. Then apply the mask using Masking ->Apply Mask which allows you to specify the value of the masked areas. You can set these to 0. Then you can do the mosaic. All of these tools are discussed in the ENVI online help.
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Deleted User
New Member
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| 29 Mar 2011 07:22 AM |
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It is great. I can do it. Once again, thanks MariM.
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