A Flexible Architecture for Precise Gamma Correction

We present a flexible hardware architecture for precise gamma correction via piece-wise linear polynomial approximations. Arbitrary gamma values, input bit widths, and output bit widths are supported. The gamma correction curve is segmented via a combination of uniform segments and segments whose sizes vary by powers of two. This segmentation method minimizes the number of segments required, while providing an efficient way for indexing the polynomial coefficients. The outputs are guaranteed to be accurate to one unit in the last place through an analytical bit-width analysis methodology. Hardware realizations of various gamma correction designs are demonstrated on a Xilinx Virtex-4 field-programmable gate array (FPGA). A pipelined 12-bit input/8-bit output design on an XC4VLX100-12 FPGA occupies 146 slices and one digital signal processing slice. It is capable of performing 378 million gamma correction operations per second.