Lightness enhancement by sigmoid function

Abstract

In this paper we purposed algorithm, to enhancement the contrast and lightening  of Color image .it is use to solve the problem of low lightening or non-uniform lightening. The purposed algorithm  is called (Lightening Enhancement by Sigmoid Function) " LESF", this algorithm consist of  three parts  the first  Adaptive luminance enhancement second contrast enhancement  and third Color restoration. This algorithm compared with other algorithm like  (A new nonlinear adaptive enhancement) (NNAE), MSR( multi-scale Retinex  ) and Histogram equalization  (HE).when we compared this algorithm by using entropy, time , Mean Squared Error for hue(Mea-H) and Mean Squared Error for saturation(Mea-S)    , we find The result of (LESF) have a good  result and better visual Comparing to the other methods

Keywords: Image Enhancement, adaptation sigmoid function  histogram equalization , Illumination enhancement.