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Add NDVI-scaled hybrid green correction #2280
Add NDVI-scaled hybrid green correction #2280
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Is this correct? I thought that for very green objects we wanted more of the 0.8 channel, not less - as we miss the chlorophyll peak in the FCI/AHI 0.5 micron band we need to boost it.
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Well this is the interesting bit with the green band correction. The location of the AHI/FCI green bands has two effects:
The green color of vegetation can be boosted with a higher contribution from the NIR channel. Similarly, the reddishness of barren is reduced with an increasing contribution from the NIR channel. However, more contribution from NIR is required to get the proper color of barren, compared to vegetation. Hence, I came up with the solution of increasing the contribution from NIR with decreasing NDVI.
Below are a few examples using the default hybrid green method, with decreasing contribution from the NIR channel. As you can see the color of Australia starts to get too red when the color of vegetation start to look realistic. I also included the result of the NDVIHybridGreen (with just qualitative tuning) and VIIRS RGB from NASA worldview as reference.
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Your solution, does this mean that this is just for FCI so is "new" or is this being applied to AHI by some other group and documented in some paper?
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This is only internal developments in preparation for FCI. We are testing with AHI since we have the same scenario with sub-optimal position of the green band there. Hopefully we can publish it at some point though.