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I have two Landsat8 images and they are side by side, but they are from different Dates. They look similar, but the color of the same forest is a bit different.

I tried a color correction in QGIS with the tool "r.blend - Blends color components of two raster maps by a given ratio" from GRASS GIS. The result is not what I expected and wanted and the tool even combine the rectangular frame from the Raster.

Is there any other tool in QGis for a color correction from two Rasters?

I am a beginner in QGIS and I am not a native English speaker.

  • Have you done any atmospheric correction? – Aaron Jul 14 '18 at 20:24
  • atmospheric correction is done. – Alex Jack Jul 17 '18 at 16:57
  • What process was used for the atmospheric correction? Also, TOA or BOA? – Aaron Jul 17 '18 at 17:03
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If I have understood correctly, you are trying to make two different rasters, side by side, look similar to each other (e.g. contrast, colour balance etc). If so, this is easily done using the 'Colour Rendering' options located under that layer's Symbology.

Adjust the brightness, saturation and contrast until you get a result you are happy with. Hitting the apply button shows you the result almost immediately, negating the need for processing, saving etc.

If the 3 adjustments don't quite achieve what you need, adding a 'Hue' may help. Use this like a white balance on a camera, applying a blue tint on images that are too warm, and a red tint on images that are too cold.

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  • Yes, I have two Rasters side by side from different Dates. I never thougt about it. But it´s a good way to adjust the colors. Using the Colour Rendering is just an optical change of the rasters, right? In this case the value of the pixel remains the same. If I do some calculations or processing on the rasters, there are maybe different results for each raster. Is there any kind of possibility, too adjust even the value of the pixel? – Alex Jack Jul 17 '18 at 17:05
  • Correct - the Colour Rendering does not change pixel values. To make permanent changes to the raster, suggest trying Orfeo Toolbox (OTB). This is available within QGIS 2.18 (under the Processing Toolbox), but hasn't been brought over to QGIS 3 yet. If you are using QGIS 3.x, suggest trying the stand alone OTB program. – James Jul 18 '18 at 3:03

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