Real-time Velocity Estimation Based on Optical Flow and Disparity Matching

A high update rate of metric velocity values is crucial for a robust operation of navigation control loops of mobile robots such as micro aerial vehicles (MAVs). An efficient way for obtaining metric velocity of robots without external reference are image-based optical flow measurements, scaled with the distance between camera and the observed scene. However, since optical flow and stereo vision are computationally intensive tasks, metric optical flow calculations on embedded systems are typically only possible at limited frame rate. In this work, we therefore present an FPGA-based platform with the capability of calculating real-time metric optical flow at 127 frames per second and 376×240 resolution. Radial undistortion, image rectification, disparity estimation and optical flow calculation tasks are performed on a single FPGA without the need for external memory. The platform is perfectly suited for mobile robots or MAVs due to its low weight and low power consumption.