  In this paper, an efficient skin detection system is proposed. The algorithm
is based on a very fast efficient pre-processing step utilizing the concept of
ternary conversion in order to identify candidate windows and subsequently, a
novel local two-stage diffusion method which has F-score accuracy of 0.5978 on
SDD dataset. The pre-processing step has been proven to be useful to boost the
speed of the system by eliminating 82% of an image in average. This is obtained
by keeping the true positive rate above 98%. In addition, a novel segmentation
algorithm is also designed to process candidate windows which is quantitatively
and qualitatively proven to be very efficient in term of accuracy. The
algorithm has been implemented in FPGA to obtain real-time processing speed.
The system is designed fully pipeline and the inherent parallel structure of
the algorithm is fully exploited to maximize the performance. The system is
implemented on a Spartan-6 LXT45 Xilinx FPGA and it is capable of processing 98
frames of 640*480 24-bit color images per second.
