Reflectance/Radiometric Calibration on MicaSense Sequoia

[RHenriques]

Hello

For those using panels in % values (Airnov for instance), divide % values by 100 to obtain reflectance values that Photoscan can use.
I've received a CSV file from Micasense for my pannel and values came in % reflectance and not reflectance. I had to divide all values by 100 to obtain a file that Photoscan can use without any problem and images do not got overexposed.
I attach the original file for my panel and the corrected one.
Cheers

[groob]

Hello All, It was (and still is) unclear to me how the different combinations of the check-boxes in the 'Calibrate Reflectance' dialog influence NDVI results of the resulting orthos. Therefore, I conducted a comparison of NDVI values from 3 separate projects for the following combinations of the check-boxes:

1) 'Use Sun Sensor' Checked
2) 'Use Reflectance Panels' Checked
3) 'Use Sun Sensor' and Use Reflectance Panels' both checked.


As noted by other users my images and resulting orthos were very washed out when I calibrated using options 2 and 3. The NDVI values for these were similar, but nonsensical (basically shadowed areas were the only pixels that contained positive NDVI values). I've attached my results displayed as a classification of NDVI with a range of -1.0-0.35 for dead vegetation (red) and 0.35-1.0 for live vegetation (green). Also included is the average NDVI value for each project. I used the same calibration panel images and photoscan workflow settings to process the three projects. I'm using a reflectance panel from MicaSense, a CSV containing reflectance values provided from MicaSense, and a Parrot Sequoia.

Is it recommended to use both check-boxes when you have calibration panel imagery collected for your project both pre and post-flight?

What do these settings actually do to the exif data?

How can you tell if your calibration was successful (right now I just notice the washed out imagery and the sensitivity values changing in the 'camera calibration' dialog)? I notice it normally takes 1-2 seconds for photoscan to perform the calibration.

Thanks

Hello all,

I would like to echo these questions.

I am processing imagery from the MicaSense RedEdge with the goal of obtaining point clouds with reflectance values for each band attached. The program automatically detects the calibration panels just fine but when "use reflectance panels" is checked, the images appear very dark, and the resulting NDVI values are extreme. Using only the sun sensor gives much more plausible results.

I have attached histograms of my NDVI values with (first) and without (second) calibration.

And, it would be useful to have the option of normalized reflectance values.

Thanks!