FPGA-based relative distance estimation for indoor robot control using monocular digital camera

Distance measurement methodologies based on the digital camera usually require time-consuming calibration procedures, some are even derived from complicated image processing algorithms resulting in low picture frame rates. In a dynamic camera system, due to the unpredictability of intrinsic and extrinsic parameters, odometric results are highly dependent on the quality of extra sensors. In this paper, a simple and efficient algorithm is proposed for relative distance estimation in robotic active vision by using a monocular digital camera. Accuracy of the estimation is achieved by judging the 2D perspective projection image ratio of the robot labels obtained on a TFT-LCD (Thin Film Transistor - Liquid Crystal Display) monitor without the need of any additional sensory cost and complicated calibration effort. Further, the proposed algorithm does not contain any trigonometric functions so that it can be easily implemented on an embedded system using the Field Programmable Gate Array (FPGA) technology. Experimental results are included to demonstrate the effectiveness of the technique.