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Suppose you are given TSAI calibration parameters of a camera(f, kappa, cx, cy, sx, rx, ry, rz, tx, ty, tz). If we have a point X,Y,Z in the world co-ordinate system. What would be the image co-ordinate(u,v) for that point in terms of these parameters?

I came across this article and got confused. R and T do not seem to be extrinsic parameters.

Francesco Callari
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Rahul Sankhwar
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1 Answers1

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R and T are respectively the rotation matrix from the world to the camera coordinate frames and the displacement vector from the camera center to the world origin.

The article you point to is correct. Just follow the recipe therein to build R & T from (rx, ry, rz, tx, ty, tz), then apply them to a point in world coordinates to bring it into camera coordinates.

Francesco Callari
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  • It might be obvious to you, but I am having a very hard time getting it. Shouldn't we transform to a new co-ordinate system with origin as the camera and its co-ordinate axis aligned to the camera axis. Since, R,T are w.r.t. world and if we have Pw as a world point, then in camera world, its co-ordinate would be, **Pi=(Pw-T)*_transpose(R)_**. Can you correct me where I went wrong. – Rahul Sankhwar Mar 30 '16 at 05:15
  • Read the article one more time, you have the equations spelled out in detail right there. – Francesco Callari Mar 30 '16 at 13:34
  • I was confused that extrinsic parameters are with respect to world co-ordinates. Thanks – Rahul Sankhwar Apr 07 '16 at 13:16