Due to energy efficiency, heterogeneous computing is gaining more and more attention. Since FPGA implementations are time consuming, high-level synthesis (HLS) is used to close the productivity gap. OpenCL has become accepted as a good programming model for HLS, due to its portability, good capability of design verification and rich instruction set. This work implements different optimization strategies using OpenCL for a heterogeneous system containing CPU, integrated GPU, GPU and FPGA. Energy efficiency and performance of the architectures are compared using a feature detection algorithm. It is shown how to maximize performance while hitting the maximum memory bandwidth and keeping the resource utilization low for the SDAccel tool from Xilinx. The evaluation shows the great streaming capability of OpenCL for FPGAs. The FPGA achieves a speed up of 62.8 and consumes 49 times less energy for the application in comparison to an optimized single threaded CPU implementation in full HD.