关键词: 对比度;线性变换;分段点;直方图

Abstract:

Due to illumination or the object itself,images often become low contrast or blurred in the acquisition process and need further pretreatment before they are used.Grayscale subsection linear transformation is an effective technology for contrast enhancement by means of the rational choice of subsection points.The maximum and minimum values are always used for subsection points,but this method does not work when the original image has wide dynamic range of gray value.Through the analysis of the original image histogram,a robust method is proposed which selects subsection points by setting thresholds in the accumulation of the gray histogram.Experimental results show that the method can enhance the region of low contrast and provide satisfactory images for further processing.

Key words: contrast;linear transformation;subsection point;histogram