In this paper we present a hardware unit for real time component labelling with Centre of Gravity (COG) calculation. The main targeted application area is light spots used as references for robotic navigation. COG calculation can be done in parallel with a single pass component labelling unit without first having to resolve merged labels. We present hardware architecture suitable for implementation of this COG unit on Field programmable Gate Arrays (FPGA). As result, we get high frame speed, low power and low latency. The device utilization and estimated power dissipation are reported for Xilinx Virtex II pro device simulated at 86 VGA sized frames per second. Maximum speed is 410 frames per second at 126 MHz clock.