Research Of Gray Enhancement Algorithms

Traditional gray enhancement algorithms are detailedly studied and realized in the development platform of Microsoft Visual C++ 6.0. They include linear gray transform, segmented linear gray transform, histogram equilibration and local histogram equilibration. Additionally, the grads enhancement algorithm based on wavelet transforms is analyzed and realized.An improved maximum linear enhancement algorithm by automatically revising the gray level range is proposed. Aiming at segmented linear gray transform, selecting the fit segment points and the fit enhancement parameters by an interactive means is realized. An improved enhancement algorithm by automatically assigning the idle gray levels based on threshold value is proposed in detail, aiming at reducing the possibility of combining low frequency gray levels during histogram equilibration and the algorithm complexity of local histogram equilibration.By increasing the intervals of gray levels, enhancing gray contrast is implemented by the traditional gray enhancement algorithms. When the number of gray levels used by an image is very less, anticipated effects are difficultly achieved. The grads enhancement algorithm based on wavelet transforms can achieve the better effects, increasing the number of gray levels and enhancing gray contrast.Using the gray enhancement algorithm which is fit for an image, better effects can be achieved. Experiences show that the improved algorithms proposed by the paper achieved better effects than the existing algorithms.