Study On Algorithm Of Image Zooming Based On Wavelet Transformation And Partial Differential Equations

Digital image processing and computer vision are always a major field of computer science. In current years,image zooming is always an important research topic in the field of digital image processing and it will have comprehensive future prospects in applying field.Wavelet have wide applications in image processing due to its time-frequency localization and multiscale analysis property.Recently,another active research is the application of partial differential equation in image processing.In this dissertation,we focus on combining wavelet and PDEs into image processing.The main work can be summarized in the following:1. We introduce several common image zooming methods based on the wavelet transform,and we make improvements on the high and low coefficient of wavelet transform. We propose an improved image super-resolution method based on wavelet transform and interpolation. The test results show the effectiveness of the new algorithm.2. For the thermal diffusion equation will increasingly smooth the image with the evolution of the scale. Also the P-M diffusion equation is unstable, and it can't preserve the details of the edges. So these equations will produce the phenomena of smooth and lattice in the zoomed image.We modify the diffusion coefficient and get a new anistropic diffusion equation.In order to enhance the high-frequency characteristics of the amplified image,we combine the wavelet multi-resolution analysis with the new anistropic diffusion equation and get better zoomed image in which the noise is removed and the edges are preserved at the same time.3. Based on the improvement of the traditional wavelet super-resolution method and the fourth-order PDE model,we combine the wavelet transform with the fourth-order PDE. On the basis of guaranteeing the processing speed, the texture features and edges of the zoomed image are clearly enhanced. Also the fine characteristics of the original image and the continuity between the image gray level are preserved better.