一种基于小波和尺度型扩散的带噪图像放大方法

将小波多分辨分析和尺度型扩散的离散迭代相结合，利用原图像作为放大图像的小波低频子带，估计高频，重构后的放大图像用前向-后向扩散方程离散一步迭代，得到了一种新的带噪图像放大方法．由于小波系数阈值和该扩散方程在图像梯度小的区域具有正扩散性，使得放大图像的同时去除了噪声，该扩散方程在梯度大的区域具有逆扩散性，又有效地保持了边缘．仿真实验结果证实此方法在放大图像的同时也增强了图像的清晰度和对比度．

Noisy image zooming algorithm based on the wavelet and scalar-valued diffusion equation

Combining wavelet multi-resolution analysis and the discrete iteration of scalar valued diffusion,a new noisy image zooming model is proposed that presents the original image as the low pass filter of wavelet analysis,and we estimate its high pass filter and use the discrete one iteration of the forward and backward(FAB) diffusion equation to the zoomed image.Because of the threshold of the wavelet coefficients and the property that FAB diffusivity acts as local forward diffusion in the small gradient region,the image is denoised as well as enlarged,and as local backward diffusion in the large gradient region the zoomed image is edge preserved.Some numerical experiments illustrate that not only does the proposed method zooms images,but also the processed images look much clearer and smoother.