Description

Recover continuous-tone (contone) images from halftone images developed novel based approach. Halftoning is a quantization process that reduces the bit-depth of a digital image while trying to maintain its gray-scale appearance. Descreening, or retrieving a contone image from a halftone, is a problem not only of great theoretical interest as an ill posed inverse problem but also of significant practical usage. In our project new model of scanned halftone image process is implemented. This new approach considered both printing distortions and halftone patterns. By means of removing distortion in the image an adaptive filtering techniques applied. Initially BM3D algorithm proposed in which Collaborative filtering is a special procedure developed to deal with these 3D groups. This BM3D is based on this novel denoising strategy. Next feature extraction process is proposed such as Screen Frequency Estimation and Local Gradient Extraction. Image gradient is a directional change in the intensity or color in an image. Image gradients may be used to extract information from images. Next Adaptive Filtering Algorithm is used for filtering the scanned image with required threshold value. An adaptive filter is a system with a linear filter that has a transfer function controlled by variable parameters and a means to adjust those parameters according to an optimization algorithm. Then Edge-Preserving Algorithm has been proposed to preserve the edge of the scanned image. Here NLM algorithm is used for Edge-Preserving. Non-local means is an algorithm in image processing for image denoising Which take the mean value of a group of pixels surrounding a target pixel to smooth the image, non-local means filtering takes a mean of all pixels in the image, weighted by how similar these pixels are to the target pixel. Finally the Descreened of the scanned image obtained.