Color Enhancement in Endoscopic Images Using Adaptive Sigmoid Function and Space Variant Color Reproduction

Table 1

Sigmoid image with different combination of gain () and cutoff values ().

Number	Original gray scale image	Sigmoid image	Used gain and cutoff values
1			= 5; = 0.7
2			= 6; = 0.1
3			= 8; = 0.5
4			= 7.5; = 0.4
5			= 9; = 0.6