Wavelet Based Resolution Enhancement with Noise Reduction Method for Panoramic Dental X-ray Images

Abstract: The Panoramic Dental X-ray images are important tool for a thorough dental examination. But they may contain noise and have low resolution. Therefore de-noising and resolution enhancement are very important factors in any subjective evaluation of the quality of images. A wavelet based enhancement technique along with a denoising approach is introduced in this paper. The input image after Median filtering is decomposed into different sub-band images by means of Discrete Wavelet Transform (DWT). Stationary Wavelet Transform (SWT) is also introduced as an intermediate stage. Then the high frequency sub-bands of both DWT and SWT are added together. Then these high frequency sub-bands as well as the input image are interpolated. A new enhanced image is obtained by using inverse DWT (IDWT). A comparison of this technique can be done with different wavelet functions including db9, Bior 3.5 and Haar. Performance evaluation can be done by means of MSE calculation. Also a comparison of the proposed method with two conventional image resolution enhancement techniques in terms of PSNR calculation can be done. The whole work has been done on the MATLAB. Keywords: Bior3.5, db9, De-noising, Discrete wavelet transform, Enhancement, Haar, IDWT, MSE, PSNR, Stationary wavelet transform.