Rolling Shutter (RS) cameras are predominant in the tablet and smartphone market due to their low cost and small size. However, these cameras require specific geometric models when either the camera or the scene is in motion to account for the sequential exposure of the different lines of the image. This paper proposes to improve a state-of-the-art model for RS cameras through the use of Non Uniformly Time-Sampled B-splines. This allows to interpolate the pose of the camera taking into account the varying dynamic of the motion by adding more control points where needed while keeping a low number of control points where the motion is smooth. Two methods are proposed to determine adequate distributions for the control points, using either an IMU sensor or an iterative reprojection error minimization. Results on simple synthetic data sets are shown to prove the concept and future works are introduced that should lead to the integration of our model in a SLAM algorithm.