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Author Topic: white image with reflectivity calibration  (Read 193 times)

SebaEsco

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white image with reflectivity calibration
« on: May 28, 2019, 03:46:15 PM »
Hello

I have been working with a Parrot Sequoia+ in a Inspire2. And Agisoft Photoscan Pro
Yesterday I make a small flight and process the data obtain, with the reflectivite calibration through the Sunshine Sensor.
But the image resulting is all most white, is this normal? Has anyone had this problem?
the flight was make at mid day in a clear sky day

Thanks!

Pd:I add an image as an example

Alexey Pasumansky

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Re: white image with reflectivity calibration
« Reply #1 on: May 28, 2019, 06:52:08 PM »
Hello SebaEsco,

Have you checked the resulting values of the produced orthomosaic, whether they do fit your expectations?

The screenshot that is demonstrated is related to the Shaded view mode that shows the interpolated mesh model vertex colors in 8-bit representation.
Best regards,
Alexey Pasumansky,
AgiSoft LLC

SebaEsco

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Re: white image with reflectivity calibration
« Reply #2 on: May 28, 2019, 07:32:33 PM »
Hello Alexsey

Actually no, if I calculate the NDVI value, generally is almost zero. That makes me absolutely no sense, because the prairie was almost green in the center of the model, where the cows were eating :)

The mean pixel value for the RED band was 62168 and for NIR 62825, thats say to me that almost all energy was reflected (if I understand it correctly for 16 bits resolution)

King regards
Sebastián

Alexey Pasumansky

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Re: white image with reflectivity calibration
« Reply #3 on: May 28, 2019, 08:45:02 PM »
Hello Sebastián,

Have you generated the orthomosaic after performing the reflectance calibration operation?

If the issue is reproducible on the small subset of images (like 3x3 or 4x4 cameras block), please send the subset of images to support@agisoft.com so that we could reproduce the problem on our side.
Best regards,
Alexey Pasumansky,
AgiSoft LLC

SebaEsco

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Re: white image with reflectivity calibration
« Reply #4 on: May 28, 2019, 10:06:03 PM »
Hi Alexsey

Yes, the orthomosaic present the same problem.
Ok, it seems perfect, I will send the set of images in a moments

Best wishes ;D
Sebastián

SebaEsco

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Re: white image with reflectivity calibration
« Reply #5 on: June 06, 2019, 07:46:30 PM »
Hi again

I Was wondering if you seen the subset of images I send a few day ago, to reproduce the issue with whiteness after the reflectivity calibration

Kind regards
Sebastián

Alexey Pasumansky

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Re: white image with reflectivity calibration
« Reply #6 on: June 14, 2019, 02:28:23 PM »
Hello Sebastián,

The issue seems to be related to some issues with the meta information related to the sunshine sensor.

Do you have the reflectance panel images for this project in order to compare the calibration results performed using panel and sunshine sensor independently?
Best regards,
Alexey Pasumansky,
AgiSoft LLC