Real-time HDR video imaging on FPGA with compressed comparametric lookup tables

Video cameras can only take photographs with limited dynamic range. One method to overcome this is to combine differently exposed images of the same subject matter (i.e. a Wyckoff Set), producing a High Dynamic Range (HDR) result. Implementations for real-time HDR videos have relied upon methods that are less accurate. Instead of weighted-sum approaches that adds up noise for large number of LDR images, lookup tables that contains results calculated using a probabilistic model can be generated. This lookup table, when compressed using quadtree structure, can be implemented on a medium-sized FPGA. The work presented in this paper improves over the earlier publication to support high-definition videos. To achieve the required bandwidth for HDR composition, the evaluation of the camera response function is performed within a compressed lookup table that has its address retrieved using a pipelined multiplexer network. We are able to generate the entire circuit using software. It is parameterizable by user-specified error constraints, allowing us to explore the trade-offs in resource usage and precision of the implementation.