Trade-off between resolution and frame rate of visual tracking of mini-robots on an experimental planar platform

Accurate and fast visual localization is required in many applications of mini-robotics. Obtaining the best possible result for a given platform requires a balanced combination of camera settings and efficient image processing of the acquired image. In this paper, we study the trade-off between a high-resolution and a high-speed acquisition mode of a conventional camera for an experimental platform of magnetically-propelled mini-robots. Specifically, we propose a two stage localization algorithm based on fast pre-location using block matching followed by optical flow correction for subpixel accuracy of localization. In the experimental evaluation, we show that the difference in localization using two images of the same scene in resolutions 1000 x 1000px and 200 x 200px is only 0.2px of the higher resolution. The computational cost of the lower resolution is 16times lower than that of the higher resolution. This allows greater accuracy localization at a higher frame rate, which significantly improves the dynamics of control. Experimental results demonstrate the precision and speed of the proposed algorithm in the task of tracking a magnetically propelled robot on the platform.