Kinect v2 and Orbbec Astra Pro Cameras for Gait Analysis a Preliminary Comparison

In this paper, we compare the concordance in spatiotemporal variables from two RGB-D cameras with the aim to assess similarity and interchangeability. Depth cameras like Kinect have been used for gait analysis for some years, but the Kinect is currently out of market and is necessary to find a replacement with similar performance. Orbbec Astra seems to have similar or even better specifications and is proposed to replace the Kinect in our system. For this, we obtain measurements for two devices, the Orbbec Astra Pro and MS Kinect v2, which has been validated in previous studies. We analyze arm swing and ankles for the comparison, using typical gait variables like speed, swing time, asymmetry, among others described in the paper. Then, we apply previously tested DSP methods to obtain spatiotemporal variables from gait and arm signals. Finally, we compare the results obtained using both devices with a statistical test to measure the concordance between both groups of variables and analyze results. The results obtained suggest that this new and unexplored RGB-D camera could be used to measure some spatiotemporal variables, relevant in the clinical context and useful for rehabilitation, although with some disadvantages respect the Kinect v2, like the measurement distance. (Abstract)