Pose estimation of a needle

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Hi, I would like to real-time to estimate the pose of a needle hold by the hand. The needle has 10cm length and 0.5 cm diameter. I have the geometry model of the needle. But since part of the needle was hidden by the hand I think it is hard to estimate the pose directly. So I want to add a cubic marker on one of the end of the needle. It is not convenient to use a big marker. So I want to know if it is possible to real-time to estimate the pose of the cubic marker with a size around 2cm x 2cm x 2cm with a distance around 1 meter from the camera? Can anybody provide me an example?

Many thanks.

YL