The enhancement of images is studied based on dyadic wavelet theory. A great quantity of experiments show that the information entropy and contrast improvement index of images processed by lifting dyadic wavelet filter improve a great deal than the images processed by initial dyadic wavelet filter; which represents the effectiveness of the lifting filter in processing image; on the selection of enhancement function, the piecewise linear function and the continuous nonlinear function are combined to enhance the images, and according to the high frequency coefficients at different decomposition level, different threshold value and enhancement factor are chosen to enhance the images. Compared with using single enhancement function, the information entropy and contrast improvement index of images are all further improved.%在二进小波理论的基础上对图像的增强做了研究.经大量实验证明:提升二进小波滤波器处理的图像的信息熵和对比度改善指数与初始二进小波滤波器处理的图像相比有较大的提高,表明提升滤波器在图像处理中的有效性;在增强函数的选取上,将分段线性函数和连续非线性函数结合起来对图像进行增强,并根据不同分解层高频系数的特点选取不同的阈值与增强因子对图像进行增强,与使用单一的增强函数相比,图像的信息熵和对比度改善指数有了更进一步的提高.
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