ETM+ Cloud Removal
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Select the "Clone Stamp Tool" from the floating toolbar as shown below.
Adjust the "Brush" size "Master Diameter" by clicking on the small down arrow to the right of the "Brush:" button.
Move the slider to the left as needed. You may need to adjust this size again, either smaller or bigger later as needed for the clouds you are working with.
This process is a bit like performing surgery on the image. Your brush strokes need to be small and both artistic yet surgical in precision. You will need to be very aware of colors, shapes, shades, land needs and usage. You'll need to be especially aware of the difference between creeks, rivers, ponds, farmland, forests, jungles, deserts, tundra, freeways, ranch land, cities, urban areas, costal waters, lakes, canals, mountains, glaciers, pit mines, crops, reservoirs, trenches, irrigation channels, city blocks, parking lots, shopping centers, beaches, reefs, harbors, wetlands, marshes, rocky outcrops, waterfalls, or anything else that might look different from one part of the image to other parts.
Set the "Opacity" to "100"% and the "Flow" to "100"%. Click on the arrow to the right of the field and drag the slider, or click on the number and type in "100".
Begin the cloud removal process by holding down the "Alt" key on the keyboard and clicking where you want the source data to be copied from. You need to pick an area that you expect to look similar to the region under the cloud, or where the cloud shadow is.
Remember that you need to clean up both the cloud and the cloud shadow.
For areas as shown in the image below, there are clouds over the freeway. You need to click your mouse with the "Alt" key held down over this part of the freeway, then release the "Alt" key and move your mouse to another part of the freeway hidden by the cloud. Click and drag across the cloud along the expected path of the freeway. If you go to far without releasing, then the source will be painting cloud again which you may have just painted over. You will need to release between strokes to let the image update itself before continuing.
Be aware of possible repeat data, or the pattern repetition that becomes visible when you do to much of this action in one place. That is why it is important to use the "Alt" key often and select a new source to copy over the area you want to airbrush away. This will give it a more natural look. Don't expect to get it right the first time, you will need to practice at it before it becomes natural to you.
Click on the image for a larger view.
Now that the freeway is cleaned up we can move outward from it and have an easier time removing the clouds from the outer more uniform forest texture. Remember to keep a special eye on the subtle hues and variations in color or pattern of the land. Don't airbrush a dry parched land over a cloud in a forest area. Everyone will easily be able to tell that you did the airbrushing, very bad!
That is why doing is like performing surgery on the image.
Click on the image for a larger view.
In the image below you can clearly see that all the clouds have been removed. Yet the land looks completely natural, as if the clouds where never there. In some cases it is extremely difficult to get this effect. In the very worst cases it might be a good idea to try and find an alternate image source of the same area that does not have the clouds, or a greatly reduced amount of clouds. Feel free to contact me about this if you feel you need to.
Click on the image for a larger view.
Now working with a uniform forest texture is reasonably simple. You will also need to learn to work with more complex land textures as well. In the image below I've given suggested areas to use as source data for airbrushing the clouds away. For each circle you need to hold down the "Alt" key and press the left mouse button over those areas. Then move your mouse to the cloud or cloud shadow region and then airbrush that part. Always be aware of where you are sourcing from, because some times there is an image feature directly adjacent to where you are sourcing your new paint from, accidentally coping that part of the source might destroy your final result for the area of the cloud you are trying to remove. So take extreme caution especially in these circumstances.
Click on the image for a larger view.
Now you can see even in the farm land and suburban areas it is possible to completely remove both the clouds and the cloud shadows and make it appear as if neither where ever in the image at all.
Click on the image for a larger view.
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