ASP 3.4 alpha gcp_gen

[Baharul Islam]

Dear All,

I have few queries:

I have used ASP 3.4 binaries and one tool is "gcp_gen" in https://stereopipeline.readthedocs.io/en/latest/tools/gcp_gen.html#gcp-gen.

1.  My question is how reliable these ground control points for registration of input images (Cartosat series) w.r.t reference image?

2. In "gcp_gen" the option gcp_gen --camera-image camera_image.tif whether  camera_image.tif should be geotagged or only normal TIFF image without coordinates in header will run?

3.  How generate GCPs using "gcp_gen" from stereo pair (along track) i.e. two image points with same ground point?

4.  I tried to build by compiling from https://stereopipeline.readthedocs.io/en/latest/building_asp.html for ASP 3.4  alpha version. I could successfully compile Vision Workbench and failed to compile StereoPipeline.

Regards,

B. Islam

[Alexandrov, Oleg (ARC-TI)[KBR Wyle Services, LLC]]

>I have used ASP 3.4 binaries and one tool is "gcp_gen" in https://stereopipeline.readthedocs.io/en/latest/tools/gcp_gen.html#gcp-gen.

>1.  My question is how reliable these ground control points for registration of input images (Cartosat series) w.r.t reference image?

If your orthoimage reflects correctly the coordinates of features on the ground, you have a decent DEM, and this program successfully finds lots of matches between the camera image and the orthoimage, you should get pretty accurate GCP. Then these an be passed to bundle_adjust to refine your camera orientation given the GCP. You can check the accuracy by mapprojecting the camera image with the updated camera adjustments produced by bundle_adjust (option --bundle-adjust-prefix) onto your DEM, and overlaying with your prior orthoimage in a GIS program.

>. In "gcp_gen" the option gcp_gen --camera-image camera_image.tif whether  camera_image.tif should be geotagged or only normal TIFF image without coordinates in header will run?

The camera_image.tif file should be raw, as acquired by the camera. It does not need a georeference. That will be borrowed from the orthoimage.

>  How generate GCPs using "gcp_gen" from stereo pair (along track) i.e. two image points with same ground point?

That for now is not supported. You'd have to create GCP from each image individually. Then can run bundle_adjust with all images, all cameras, and all GCP files at once. That should be good enough.

>  I tried to build by compiling from https://stereopipeline.readthedocs.io/en/latest/building_asp.html for ASP 3.4  alpha version. I could successfully compile Vision Workbench and failed to compile StereoPipeline.

You do not need to build the software. Building is broken for now as some dependencies changed too much (this will be fixed at the next release). You can get the binaries as mentioned at: https://stereopipeline.readthedocs.io/en/latest/installation.html