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Author Topic: How do I build a multispectral orthophoto?  (Read 8335 times)

rodriguez

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How do I build a multispectral orthophoto?
« on: October 05, 2016, 01:23:32 AM »
I have a set of images of several bands. How do I build a multispectral orthophoto? Thanks in advance

Gall

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Re: How do I build a multispectral orthophoto?
« Reply #1 on: October 05, 2016, 10:43:05 AM »
Hello rodriguez,

to build a multispectral orthomosaic you first need to create a multispectral project and you have two options for that:
  • just use "Add Photos" and choose "Create multispectral cameras from files as bands" or from layer
  • if you don't have the options mentioned above, you have to put each band into a separate folder (make sure to have each index for all bands), use "Add Folder", choose the parent folder of your band folders and choose "Create multispectral cameras from folder as bands"
After this step, the rest of the process is the same (Alignment, Optimization, DEM or Mesh, build orthomosaic) and you will have a multi layer orthomosaic when you export it. If you want a separate orthomosaic per band, you can use the raster calculator:
  • open the orthomosaic by double clicking on it in the workspace pane
  • click on the raster calculator (a little palette icon in the tool bar)
  • select only a single band name by double clicking on it in the formula tab and check "Enable transform"
  • in the palette tab, select "Gray" preset, check "Interpolate colors" then input in range the full pixel range of your images (depends if its 8 bit, 16 bit, etc...)
  • export the orthomosaic and select "Index color" in "Raster transform"
  • reapeat for the other bands

rodriguez

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Re: How do I build a multispectral orthophoto?
« Reply #2 on: October 07, 2016, 01:43:38 AM »
Thanks for your reply Gall, I think you can make a small tutorial for beginners.
By the way, I forgot to say that the images were taken with a multispectral sensor Sequoia. This sensor integrates nicely with Pix4D. I want to see if Photoscan can get the same results.
Thanks again

Flamas

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Re: How do I build a multispectral orthophoto?
« Reply #3 on: November 16, 2018, 03:53:54 PM »
Hello friends, I need to export each band separately, but I do not know how to do it.
I get lost in step 5 that indicates GALL, would be so kind to explain this step in more detail?

thank you


I modify, I think I already understood. I'm applying each band 1 in 1 I'm refreshing the palette so that I consider everything. and then export ...

probe and it works fine ... but all the output raster have 3 bands? Is the band repeated on all 3 channels?

I took it to ENVI conbine RGB on all channels 1 and it shows me the perfect natural color.
« Last Edit: November 16, 2018, 04:13:01 PM by Flamas »

Alexey Pasumansky

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Re: How do I build a multispectral orthophoto?
« Reply #4 on: November 16, 2018, 07:48:07 PM »
Hello Flamas,

If you need to export the orthomosaic for each band individually, I suggest to use Raster Calculator:

- use only single formula for each band each time, like "B1", "B2" and etc.
- in the Export Orthomosaic dialog use "Index Value" option in the Raster Transform section.
Best regards,
Alexey Pasumansky,
Agisoft LLC

juacarri

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Re: How do I build a multispectral orthophoto?
« Reply #5 on: October 20, 2022, 06:37:58 PM »
Edit: Metashape currently exports all bands when exporting a tif of the orthomosaic.