Convert rotation vector or matrix to Quaternion

I have a rotation vector in opencv and would like to apply that rotation to a game object. I have the rotation matrix as well (given by Rodrigues) if that helps. I tried various approaches, like this
but nothing helped.
Any idea on how to achieve this?

Hi, I just saw that the rotation vector is an angle-axis representation, just a litte different. I was able to figure out how to translate it to angle-axis and use Quaternions static AngleAxis function to get to my Quaternion:

float theta = (float)(Math.Sqrt(m.xr*m.xr + m.yr*m.yr + m.zr*m.zr)*180/Math.PI);
Vector3 axis = new Vector3 (m.xr, m.yr, m.zr);
Quaternion rot = Quaternion.AngleAxis (theta, axis);