Hi
I have landsat TM and OLI surface reflectance scenes (land sat L2 product) with 20 years gap. The final rasters has not good visual quality, thus I have enhanced both by 1std. Now the problem is I am getting different color tones on images for same feature. Kindly let me know is it acceptable due to difference in sensors? or I will need perform some other tasks to make both images in same tones.
Note: I am using same band combination for both.
(Attached snapshot for reference)
Dear Asid Ur Rehman,
OLI and TM are different sensors. They even differ in the bandwidth you select fot your RGB picture, as well as in many other features. You could find a lot of useful information in the US Geological survey web site (for example: http://gisgeography.com/landsat-program-satellite-imagery-bands/)
or NASA web site : https://landsat.gsfc.nasa.gov/landsat-8/landsat-8-bands/
In addition (in my experience), the automated algorithms for the atmospheric correction provided by USGS are not always perfect for all the scenes, especially, for TM imagery. Thus, irrelevant reflectance values could be produced for some images.
There is some information here, as the USGS site is not fully operational now:
http://gisgeography.com/landsat-program-satellite-imagery-bands/
Finally, to get similar surface reflectances for OLI and TM images they need to be cross-calibrated. There are some algorithms like relative radiometric normalization, universal pattern decomposition, etc
Regards,
Maria
Dear Asid Ur Rehman,
OLI and TM are different sensors. They even differ in the bandwidth you select fot your RGB picture, as well as in many other features. You could find a lot of useful information in the US Geological survey web site (for example: http://gisgeography.com/landsat-program-satellite-imagery-bands/)
or NASA web site : https://landsat.gsfc.nasa.gov/landsat-8/landsat-8-bands/
In addition (in my experience), the automated algorithms for the atmospheric correction provided by USGS are not always perfect for all the scenes, especially, for TM imagery. Thus, irrelevant reflectance values could be produced for some images.
There is some information here, as the USGS site is not fully operational now:
http://gisgeography.com/landsat-program-satellite-imagery-bands/
Finally, to get similar surface reflectances for OLI and TM images they need to be cross-calibrated. There are some algorithms like relative radiometric normalization, universal pattern decomposition, etc
Regards,
Maria
Thank you Maria,
You are right, I think most important is the difference in dynamic ranges of TM and OLI images i.e. 8 bit and 16 bit data.
Hi Asid,
Try converting them to same radiometric resolution and also you can do histogram matching if you want to compare them.
Regards
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