2D to 3D projection
5 views (last 30 days)
Show older comments
I have a 3D point cloud of an object (3D model) also i have photographs of that object and the camera parameters (focal length, angle) and location (gps location). from the photograph i have identified 2D coordinates (x,y) of some particular features . How can i project that 2D point in 3D surface to get 3D points of that corresponding feature? Thanks
2 Comments
Walter Roberson
on 28 Jun 2012
Are there at least two photographs from different angles that contain each of the points to be identified?
You mention GPS: normal GPS has a positional accuracy of about 2-3 meters. If that is a significant fraction of the distances involved then this is going to present a calculation problem.
Richard Brown
on 28 Jun 2012
I think a really good book for you to read if you want to understand what's going on geometrically is this one: http://www.amazon.com/Multiple-View-Geometry-Computer-Vision/dp/0521540518
Accepted Answer
Richard
on 28 Jun 2012
Your 2D points correspond to a ray in 3-space that passes through the 3D feature and the optical centre of the camera. You say you know the intrinsic parameters of the camera. So if you invert the camera's intrinsic calibration matrix, then you can place the image points on a 3D plane in the same Euclidean space as your point cloud. You then need to devise a way of finding the 3D point that's on (well, near actually) the ray emanating from the camera centre and passing through the image point on the image plane. Depending on the object in question this might be easy or quite difficult.
Hope that's useful in a vague sort of way. If you can be more specific, then we may be able to be of more help!
5 Comments
Richard Brown
on 2 Jul 2012
If you send me an email with an image and the information you have, I'd be happy to have a quick look and point you in the right direction.
More Answers (0)
See Also
Categories
Find more on Camera Calibration in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!