二进小波滤波器的构造及其应用

Construction and Application of Dyadic Wavelet Filter Based on Dyadic Lifting Scheme

雾天获取的图像对比度低,图像模糊。为获取较为清晰的图像,利用二进提升格式,分析二进提升方案,提出一种构造提升二进小波滤波器的方法。将构造的二进小波滤波器作为初始二进小波滤波器,通过控制滤波器的提升参数,构造了新的提升二进小波,并将其在图像去雾中进行了应用。首先将雾图像进行二进小波变换一次分解,对低频分量采用灰度线性拉伸,以增强图像的整体对比度,使用阈值函数对高频分量中的细节信息进行增强处理,对处理后的高低频部分进行二进小波逆变换。为了达到更为理想的视觉效果,再利用传统的增强算法对图像进行全局处理。实验结果表明,与原始图像相比,新构造的滤波器在图像去雾中的效果较为理想,其对比度和清晰度都有了极大的提高,而比较两种滤波器,提升二进小波滤波器在效果上好于初始二进小波滤波器。

The image acquired in foggy days has low contrast and blurry image.To obtain a clear image,with dyadic format to analyze dyadic lifting scheme,a method of constructing the dyadic lifting wavelet filter is proposed.The constructed dyadic wavelet filter is used as the initial dyadic wavelet filter.By controlling the ascension parameters of the filter,a new dyadic wavelet is constructed and applied to image defogging.Firstly,the fog image is decomposed by dyadic wavelet transform,and the gray scale linear stretch is used to enhance the overall contrast of the image.The threshold function is used to enhance the detail information in the high frequency component and the inverse dyadic wavelet transform is carried out for the high and low frequency parts.In order to achieve a more ideal visual effect,the traditional enhancement algorithm is used to process the image globally.The experiment shows that compared with the original image,the newly constructed filter has an ideal effect in image defogging,and its contrast and sharpness are greatly improved.Compared with the two filters,the improved dyadic wavelet filter has a better effect than the original dyadic wavelet filter.