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Author Topic: Use of calibration panel in Photosann Version 1.4.0  (Read 5465 times)

ppant

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Use of calibration panel in Photosann Version 1.4.0
« on: January 19, 2018, 04:55:22 PM »
Hello
In the new version of photosacn 1.4 there a option to locate the calibration panel
Code: [Select]
chunk.locateReflectancePanels()
When I see the documentation for this says "Locate reflectance panels based on QR-codes." From this, I can understand that calibration panel without QR code cannot be used ?. Because I have Spectralon  Reflectance panel and I can measure spectral reflectance factor at any time. Furthermore, 1.4 calibration process is only for RedEdge sensor or process works for Sequoia sensor too.

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ppant   

Alexey Pasumansky

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Re: Use of calibration panel in Photosann Version 1.4.0
« Reply #1 on: January 19, 2018, 05:06:38 PM »
Hello ppant,

If the panel cannot be detected automatically, you should apply the masks manually for each band on every calibration image of the reflectance panel.

Does the Spectralon Reflectance panel has any additional elements that can be used for automatic panel recognition?
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Alexey Pasumansky,
Agisoft LLC

ppant

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Re: Use of calibration panel in Photosann Version 1.4.0
« Reply #2 on: January 19, 2018, 06:13:33 PM »
Alexy
It is just a while panel nothing there to make the recognition. Except Photoscan has an option to load panel separately.
it like if locatereflectece fails to locate the panel, a user has the option to load the panel and its reflectance value.


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Alexey Pasumansky

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Re: Use of calibration panel in Photosann Version 1.4.0
« Reply #3 on: January 19, 2018, 06:29:37 PM »
Hello ppant,

If the panel cannot be detected automatically, you need to move all the images with it to new camera group called "Calibration images" in the chunk contents, manually apply the mask for each band on every calibration image, then go to Calibrate Reflectance dialog and input the reflectance values for each each band related to the panel.
Best regards,
Alexey Pasumansky,
Agisoft LLC

pk

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Re: Use of calibration panel in Photosann Version 1.4.0
« Reply #4 on: January 23, 2018, 08:46:22 PM »
Where can I find the instructions explaining how to use reflectance panels in Photoscan? I can't find anything...

ppant

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Re: Use of calibration panel in Photosann Version 1.4.0
« Reply #5 on: January 24, 2018, 06:31:34 PM »
Pk
There is no proper explanation How to do that. While seeing the API document and some thinking. For the reflectance panel with QR code (micasense)
This piece of code seems to work. I get the same results on using GUI version and the running the python script.  I am not sure if this the correct way or there is something other too

Code: [Select]
chunk.addPhotos(plist, PhotoScan.MultiplaneLayout)
chunk.locateReflectancePanels()
chunk.loadReference('path to panel csv file you get from micasense')
chunk.calibrateReflectance()


Furthermore, I am not sure how to work when there are different reflectance panel

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Alexey Pasumansky

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Re: Use of calibration panel in Photosann Version 1.4.0
« Reply #6 on: January 24, 2018, 06:37:11 PM »
Hello ppant,

.loadReference() function is not related to the reflectance panel and calibration process. It populates the content of the Reference pane.
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Alexey Pasumansky,
Agisoft LLC

ppant

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Re: Use of calibration panel in Photosann Version 1.4.0
« Reply #7 on: January 24, 2018, 07:37:57 PM »
Alexey,
If Load reference is not a function to load the reflectance panel csv file. How can we read those? I am not able to catch that in API documentation. Could you help in this case?

Is there any documentation on using other white reflectance panels than using Micasense QR one.

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Alexey Pasumansky

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Re: Use of calibration panel in Photosann Version 1.4.0
« Reply #8 on: January 24, 2018, 08:20:45 PM »
Hello ppant,

Currently you need to add meta information to the cameras related to the calibration images. I've posted the example previously in another thread:

Code: [Select]
albedo = {"Blue": "0.65952", "Green": "0.67788", "Red": "0.67718", "NIR": "0.66653", "Rededge": "0.6223266"} #reflectance values for the panel for each band
for camera in chunk.cameras:
    if camera.group.label != "Calibration images":
        continue
    for plane in camera.planes:
        plane.meta["ReflectancePanel/Calibration"] = albedo[plane.sensor.bands[0]]
« Last Edit: January 24, 2018, 10:08:16 PM by Alexey Pasumansky »
Best regards,
Alexey Pasumansky,
Agisoft LLC

ppant

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Re: Use of calibration panel in Photosann Version 1.4.0
« Reply #9 on: January 25, 2018, 05:08:31 PM »
Thanks Alexey for help in loading that albedo. This works When I have QR based Reflectance panel.
Now I have a question. When I have another panel which does not have QR code but I know albedo from them. I load those reflectance panels in a camera group as mutiplanelayout. Now when I create the mask I only see one band could not able to create masks for all the bands. Likewise, I see a function called.
Code: [Select]
chunk.importMasks (path= source=MaskSourceBackground,operation=MaskOperationReplacement,tolerance=10 ..)
   

Could you explain what is this function can I create using this function to create the mask for other reflectance panels.





Alexey Pasumansky

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Re: Use of calibration panel in Photosann Version 1.4.0
« Reply #10 on: January 25, 2018, 05:20:25 PM »
Hello ppant,

Without the QR-code the panel cannot be masked automatically. Do you have any external file that defines the mask borders?
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Alexey Pasumansky,
Agisoft LLC

ppant

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Re: Use of calibration panel in Photosann Version 1.4.0
« Reply #11 on: January 25, 2018, 06:10:30 PM »
Alexey
For the mask, I can write a simple image processing function to generate the mark image file for each band of a panel. I can do that in the data preparation stage before running image mosaic

Thanks
ppamt

Alexey Pasumansky

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Re: Use of calibration panel in Photosann Version 1.4.0
« Reply #12 on: January 25, 2018, 09:22:15 PM »
Hello ppant,

Common command to import the mask from the external files (black&white images) would be the following:
Code: [Select]
chunk.importMasks(path='/masks/{filename}_mask.png', source=PhotoScan.MaskSourceFile, operation=PhotoScan.MaskOperationReplacement)In the path argument you can use filename macros, thus providing the correspondence between each source image and mask image.
Best regards,
Alexey Pasumansky,
Agisoft LLC

marlonfgj

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Re: Use of calibration panel in Photosann Version 1.4.0
« Reply #13 on: March 01, 2018, 12:51:13 AM »
Buenas tardes, quisiera saber cual seria el proceso para el Panel de Sequoia parrot, pongo buscar el pnael en la opciĆ³n pero esta no las encuentra, de igual manera tengo las fotos del panel previo al vuelo y los trato de ubicar manualmente, pero parece que no lee el formato del archivo el programa y no me salen las fotos a manera de seleccionarlas.... existe un flujo de trabajo correcto para sequoia.