Inertial aided dense & semi-dense methods for robust direct visual odometry

In this paper we give an evaluation of different direct methods for computing frame-to-frame motion estimates of a moving sensor rig composed of an RGB-D camera and an inertial measurement unit. In particular, we compare how semi-dense and fully dense tracking methods, with and without the aid of an inertial measurement unit (IMU), perform with respect to changes in image resolution, shutter speed, frame-rates, as well as image and depth noise. To perform an accurate and unbiased evaluation we employ a series of synthetically generated datasets using a simulated sensor rig composed of an RGB-D camera and an IMU. Our findings show that in the absence of motion blur or for cameras with high enough frame-rates relative to the camera motion, the methods are comparable when taking in consideration both accuracy and computation time.