We propose a two-pass median filter for impulse noise suppression in color images. The first pass is our previously presented algorithm, PNN-VMF [2]. The second pass routine is chosen dynamically on the basis of the number of pixel modifications performed by the first pass filtering. Such an approach is likely to avoid harm (e.g., blurring edges) resulting from excessive filtering. The effectiv...

Digital watermarking is a method of copyright protection of audio, images, video and text. We propose a new robust watermarking technique based on contourlet transform and singular value decomposition. The paper also proposes a novel encryption algorithm to store a signed double matrix as an RGB image. The entropy of the watermarked image and correlation coefficient of extracted watermark image...

In the Transmission of images over channels, Images are corrupted by salt and pepper noise, due to faulty communications. Salt and Pepper noise is also referred to as Impulse noise. The objective of filtering is to remove the impulses so that the noise free image is fully recovered with minimum signal distortion. The best-known and most widely used nonlinear digital filters, based on order stat...

In digital image processing noise removal or noise filtering plays an important role, because for meaningful and useful processing images should not be corrupted by noises. In recent years, high quality televisions have become very popular but noise often affects TV broadcasts. Impulse noise corrupts the video during transmission and acquisition of signals. A number of denoising techniques have...

A spatial domain non linear filtering algorithm for the restoration of gray scale, and Color images that are corrupted by high density impulse noise is proposed. The proposed algorithm well suited for suppressing impulse and also Gaussian noises with different noise leves.It shows better results than the Standard Median Filter (MF), Trimmed Median Filter (TMF) and Weighted Median Filter. Experi...

In this work, an algorithm has been developed for automatic detection of blood vessels in normal and abnormal retinal images. The algorithm comprises of four steps: second derivative Gaussian function filtering, local entropy thresholding, median filtering and length filtering. The algorithm so developed has been tested on twenty ocular fundus images. The results of this algorithm are compared ...

This work shows that the following problems are equivalent, both in theory and in practice: • median filtering : given an n-element vector, compute the sliding window median with window size k, • piecewise sorting : given an n-element vector, divide it in n/k blocks of length k and sort each block. By prior work, median filtering is known to be at least as hard as piecewise sorting: with a sing...

-This paperdescribes the various image filtering algorithms and techniques used for image filtering/smoothing. Image smoothing is one of the most important and widely used operation in image processing .We have explained various algorithms and techniques for filter the images and which algorithm is the be the best for smoothing and filtering the images, especially we have mainly concentrate on ...

The use of medians as filtering windows in digital signal processing is known since many years and applied especially when linear filters could not be used, because of specific character of disturbances which are to be removed. This is the case, if, for instance, impulsive disturbances, having very wide spectra, are observed, and linear filters are not suitable for their elimination. Median pro...