Co-registration with SNAP
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(→Visualize geometric offset) |
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* Start SNAP Desktop | * Start SNAP Desktop | ||
* {{mitem|text=File --> Open Product...}}. Browse for Unmanned Aerial System (UAS) ortho mosaics: | * {{mitem|text=File --> Open Product...}}. Browse for Unmanned Aerial System (UAS) ortho mosaics: | ||
| − | {{typed|text= | + | {{typed|text=clip_ebee_ortho_align.tif}} is a reference image which is very well georeferenced. {{typed|text=clip_mavic_ortho_align.tif}} is an image with a positional offset. It needs to be registered to the reference image. {{button|text=Open}} or drag and drop marked files from Windows File Explorer into the SNAP '''Product Explorer''' tab. |
* Mark the reference image ''clip_ebee_ortho_align.tif'' in ToC. Right click {{mitem|text= Open RGB Image Window --> OK}}. | * Mark the reference image ''clip_ebee_ortho_align.tif'' in ToC. Right click {{mitem|text= Open RGB Image Window --> OK}}. | ||
* Mark the image to be registered ''clip_mavic_ortho_align.tif'' in ToC. Right click {{mitem|text= Open RGB Image Window --> OK}}. | * Mark the image to be registered ''clip_mavic_ortho_align.tif'' in ToC. Right click {{mitem|text= Open RGB Image Window --> OK}}. | ||
* {{mitem|text= Window --> Tile Vertically}}. Both side-by-side windows are spatially linked. Zoom in and use the {{button|text=Panning tool}} to see the offset between both images | * {{mitem|text= Window --> Tile Vertically}}. Both side-by-side windows are spatially linked. Zoom in and use the {{button|text=Panning tool}} to see the offset between both images | ||
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=Split multiband to single band files= | =Split multiband to single band files= | ||
* Mark the image to be registered ''clip_mavic_ortho_align.tif'' in ToC. {{mitem|text=Raster --> Subset --> Band Subset}}. Check exclusivly '''band_1'''. | * Mark the image to be registered ''clip_mavic_ortho_align.tif'' in ToC. {{mitem|text=Raster --> Subset --> Band Subset}}. Check exclusivly '''band_1'''. | ||
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* Repeat this step for band_2 ('''subset_1''') and band_3 ('''subset_2'''). Adjust processing parameters for each band, accordingly. | * Repeat this step for band_2 ('''subset_1''') and band_3 ('''subset_2'''). Adjust processing parameters for each band, accordingly. | ||
= Stack single bands to multiband file = | = Stack single bands to multiband file = | ||
| − | * Create a stack of all coregistered single bands. {{mitem|text=Raster --> Geometric | + | * Create a stack of all coregistered single bands. {{mitem|text=Raster --> Geometric --> Collocation}} |
| + | * Resampling Method: {{button|text=Bilinear Resampling}} | ||
[[File:snap_collocation.png|400px]] | [[File:snap_collocation.png|400px]] | ||
| + | |||
= Convert data type from float32 to uint8 = | = Convert data type from float32 to uint8 = | ||
* {{mitem|text=Raster --> Data Conversion --> Convert Datatype}} | * {{mitem|text=Raster --> Data Conversion --> Convert Datatype}} | ||
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* Scaling: '''Linear (slope and intercept)''' | * Scaling: '''Linear (slope and intercept)''' | ||
[[File:snap_datatype_io.png|400px]] [[File:snap_datatype_params.png|400px]] | [[File:snap_datatype_io.png|400px]] [[File:snap_datatype_params.png|400px]] | ||
| − | * Mark the coregistered image {{typed|collocate_cnv}} in ToC. Right click {{mitem|text= Open RGB Image Window --> OK}}. Check the geometric quality of the co-registration comparing {{typed|text=clip_ebee_ortho_align.tif}} (bottom), {{typed|text= | + | * Mark the coregistered image {{typed|text=collocate_cnv}} in ToC. Right click {{mitem|text= Open RGB Image Window --> OK}}. Check the geometric quality of the co-registration comparing the reference image {{typed|text=clip_ebee_ortho_align.tif}} (bottom), the image with an positional offset {{typed|text=clip_mavic_ortho_align.tif}} (middle) and the co-registered image {{typed|text=collocate_cnv.tif}} (top). |
[[File:check_collocation.png|600px]] | [[File:check_collocation.png|600px]] | ||
[[Category:SNAP Tutorial]] | [[Category:SNAP Tutorial]] | ||
[[Category:Tutorials]] | [[Category:Tutorials]] | ||
Latest revision as of 21:25, 6 November 2021
Contents |
[edit] Visualize geometric offset
- Start SNAP Desktop
- File --> Open Product.... Browse for Unmanned Aerial System (UAS) ortho mosaics:
clip_ebee_ortho_align.tif is a reference image which is very well georeferenced. clip_mavic_ortho_align.tif is an image with a positional offset. It needs to be registered to the reference image. Open or drag and drop marked files from Windows File Explorer into the SNAP Product Explorer tab.
- Mark the reference image clip_ebee_ortho_align.tif in ToC. Right click Open RGB Image Window --> OK.
- Mark the image to be registered clip_mavic_ortho_align.tif in ToC. Right click Open RGB Image Window --> OK.
- Window --> Tile Vertically. Both side-by-side windows are spatially linked. Zoom in and use the Panning tool to see the offset between both images
[edit] Split multiband to single band files
- Mark the image to be registered clip_mavic_ortho_align.tif in ToC. Raster --> Subset --> Band Subset. Check exclusivly band_1.
- Repeat this step for band_2 and band_3 creating separated single bands of the image to be registered .
[edit] Co-registration of single band raster files
- Raster --> Geometric operations --> GeFolki Co-registration.
- Define I/O Parameters and Processing Parameters:
- Click Run.
- Repeat this step for band_2 (subset_1) and band_3 (subset_2). Adjust processing parameters for each band, accordingly.
[edit] Stack single bands to multiband file
- Create a stack of all coregistered single bands. Raster --> Geometric --> Collocation
- Resampling Method: Bilinear Resampling
[edit] Convert data type from float32 to uint8
- Raster --> Data Conversion --> Convert Datatype
- Check Save as and select GeoTIFF from drop downlist.
- Target Data type: uint8
- Scaling: Linear (slope and intercept)
- Mark the coregistered image collocate_cnv in ToC. Right click Open RGB Image Window --> OK. Check the geometric quality of the co-registration comparing the reference image clip_ebee_ortho_align.tif (bottom), the image with an positional offset clip_mavic_ortho_align.tif (middle) and the co-registered image collocate_cnv.tif (top).
