In this paper, the hardware acceleration of a tone-mapping algorithm for High-Dynamic-Range image processing is presented. Starting from the C++ source code, High-Level Synthesis has been performed using Xilinx SDSoC for a Xilinx Zynq SoC device. After an initial code optimization to improve the memory access bottleneck, SDSoC pragmas have been introduced to boost system performance through an increased parallelism. Preliminary results have shown significant reductions in the execution time and the energy consumption compared to the conventional software implementation.