Pose from four known points
A square tag with known object-frame corners projects to fixed observed pixels. You drag the estimated pose and the reprojection error updates; the solve button runs a damped Gauss–Newton loop that recovers the pose the way a real PnP does.
Try this
Get the error as low as you can by hand, note the number, then press solve.
Try it: find the camera pose
Where this lab comes from
Camera Models, End to End: K, the Extrinsics, Calibration & PnP, with OpenCVHow a 3-D point becomes a pixel and back again: the intrinsic matrix K, the extrinsics R|t that place the camera in the world, Zhang calibration to 0.35 px reprojection error, and solvePnP recovering a 68-px-off pose to ~0. The math, two interactive labs, and runnable OpenCV in Python and C++.
More in cameras and geometry
- Focus, aperture and depth of field — Move the subject and watch the focus plane and the blur follow.
- Four ways a fisheye maps angle to radius — Plot r(θ) for the classical designs against a fitted curve.
- The scene, and what the camera sees — Orbit a 3-D scene on the left; the pinhole view updates on the right.