Adaptive real-time labeling and recognition of multiple infrared markers using FPGA

In this paper, we propose a real-time and adaptive method for labeling and recognition of multiple infrared markers. A single-frame based iteration process is developed to obtain the suitable threshold. A sliding window is proposed to propagate the preliminary labels and to reduce the capacity of equivalent tables handling. The labeling and recognition are realized by merging the results of domains with label collisions. Multi-stage pipelines are developed to implement all the operations including smoothing filter, adaptive threshold, preliminary labeling and recognition. Experimental results show that the proposed method can label and recognize multiple infrared target markers with a latency of 259ns and with an accuracy of sub-pixel. The proposed method can be applied in applications that require real-time performance such as surgery navigation, intelligent control and visual measurement.