To reduce the risk for patients during neurosurgical procedures, an intraoperative imaging system is required for the identification and localisation of functional areas and brain tumours. Thermography is based on the measurement of long-wave infrared radiation and constitutes a promising non-invasive and marker-free technique for intraoperative functional imaging. In this paper, different methods for the fusion of thermographic and white-light images are discussed and appropriate architectures for digital hardware implementations are proposed. We demonstrate the real-time capability of the derived architectures implemented on a Xilinx Zynq FPGA.