Image contrast enhancement in spatial domain using fuzzy logic based interpolation method

Contrast enhancement is one of the most important issue of image processing. Contrast enhancement can be done in spatial domain or in frequency domain; in spatial domain, the pixel intensity data of the image is mapped to new intensity level via an intensity level transformation function. The intensity level transformation function can be defined using some mathematical equation derived from the image pixel intensity information, such as in histogram equalization, or using mathematical equation for contrast stretching around a local pixel intensity, like in cubic spline interpolation. This paper proposes a new method of interpolation by using fuzzy logic interpolation. The proposed method is used to define pixel intensity level transformation function form a set of locally stretched pixel intensity. The transformation function obtained from proposed method is applied to colored image and then compared with the results obtained from cubic spline interpolation method. The comparison results illustrates that the proposed method can be used for interpolation to enhance contrast of an image.