不积跬步之IMU预积分

IMU预计分论文：On-Manifold Preintegration for Real-Time Visual-Inertial Odometry(http://arxiv.org/abs/1512.02363)

IMU初始化论文：Visual-Inertial Monocular SLAM with Map Reuse(https://arxiv.org/abs/1610.05949)