Difference between cvPOSIT and cvFindExtrinsicCameraParams2

Another OpenCV question;

Without me having to implement 2 versions - can anyone enlighten me to what the differences are between cvPOSTIT and cvFindExtrinsicCameraParams2 and maybe the advantages of each.

The inputs and outputs appear to be the开发者_如何学编程 same.

From my experience, cvFindExtrinsicCameraParams2() works for coplanar points (so it is probably an implementation of http://dl.acm.org/citation.cfm?id=228149), while cvPOSIT() doesn't. But I am not 100% sure.

It appears that cvPOSIT() only exists in OpenCV's old C API and not in the new C++ API. Conversely, cvFindExtrinsicCameraParams2() is in both. While not a perfect indicator, my best guess is that they both implement the POSIT algorithm with minor modifications and the former exists only for legacy reasons.

Beyond that, your guess is good as mine. If you want a definitive answer, I suggest asking on the OpenCV mailing list.

I've used cvPOSIT already. It only works on 3D non-coplanar points on the object. Because it bases on the algorithm from "DAVIS, D. F. D. A. L. S. 1995. Model-Based Object Pose in 25 Lines of Code". So you will have to find a way around for coplanar features

With cvFindExtrinsicCameraParams2(), it also works on planar features, solve the transformation using cvFindHomography and then refine the result by levenberg-marquardt approximation. For non-coplanar points, the preprocessing is done by a different method DLT (Direct Linear Transformation) (not ".. 25 lines of Code" article anymore)

I'm not pretty sure about thier performance, which one is faster. As I know, ".. 25 lines of code" is very fast, and suitable for realtime vision up to now.