How to compute Grid Plane coordinates for a pixel using RealityScan v2.1 exports (XMP intrinsics/extrinsics + depth)
Hello — I’m using RealityScan v2.1 and would like help understanding how to compute a precise 3D point in the model’s Grid Plane coordinate system from a pixel in an aligned image.
Summary / workflow I followed
- I reconstructed a model from a UAV image set (images include GPS). The reconstruction and mesh look correct.
- In the 3Ds window I used Scene 3D → Add Control Points to pick a point on the reconstructed mesh. RealityScan automatically finds the corresponding pixel(s) in source images; when I select two images the software computes the 3D coordinate of that model point (export CRS shown as EPSG:4326 — GPS / WGS84). This built-in control-point workflow is very useful.
- I exported the aligned camera parameters (XMP files) and the Maps & Masks depth maps for the aligned images.
- Example pixel: img_012168.JPG at (712.43, 423.96). Using the exported intrinsics/extrinsics plus the depth value at that pixel I can reproject the pixel to 3D and obtain a georeferenced position (Actual position).
- I have now exported the model coordinate system as Grid Plane, and the camera parameters (XMP) are also reported in the Grid Plane coordinate system.
My current question / goal
I want to compute the 3D coordinates of a given pixel in the model’s Grid Plane coordinate system (not EPSG:4326). Concretely: given an aligned image, a pixel coordinate (e.g., img_012168.JPG, (712.43, 423.96)), the exported XMP intrinsics/extrinsics, and the depth map, how do I compute the corresponding (X, Y, Z) in RealityScan’s Grid Plane? I need to know the exact conversion relationship and the Grid Plane conventions RealityScan uses.
If someone can confirm RealityScan v2.1 conventions for the items above (especially: depth units and meaning, XMP extrinsic convention, Grid Plane axis/origin/units, and the form of the model→EPSG:4326 mapping), or can provide a compact example (pseudo-code or Python snippet) that reproduces pixel→GridPlane and GridPlane→EPSG:4326 correctly, I would greatly appreciate it.
Thank you.
