Industry Radiographic Image De-noising Technology Based On Wavelet Transform

Real-time digital radiography is an important developmental tendency for radiographic inspection and diagnosis technique, and enhancement of image is the key to improve resolution and sensitivity of radiographic inspection。The paper expounds the digital process of X ray and the feature of the noise in it,by Which we estimate the parameter of noise. It investigates the traditional de-noising method for X-ray digital image such as time space and transforms space。And analysis the advantage and disadvantage of the de-noising methods using traditional wavelet transform。Producing the Gibbs Phenomena in the feature-point produced in the process of traditional wavelet threshold de-nosing, we disquisition the de-noising method using stationary wavelet transform. It compares with stationary wavelet transform (SWT) and discrete wavelet transform (DWT).The result proves that the former is better. The paper proposes a improved threshold de-noising method based on SWT,which using the sub-image to estimate the parameter of the noise,thus it can select different threshold for different types of X-ray digital. Experiment results indicate that this method make the image more clear and velvet,and improved the PSNR greatly. This paper applies the principle of Wiener filtering to the profess of X ray digital image de-noising Based on stationary wavelet, Provides a method of X-ray digital image de-noising based on stationary wavelet in Wiener filtering. Experiment shows that now method not only can eliminate the Gibbs phenomenon,but also can retains detail information of X ray digital image.