Noise determination and estimating a signal along with all its details proves a challenging task in signal processing. This issue has been addressed in the past using various discrete wavelet transform (DWT) based techniques. The signal is estimated as linear average of individual estimates derived from translated and wavelet-thresholded versions of a noisy signal by cycle spinning technique. In this paper, we propose a modified cycle zpinning algorithm with a new scaled down threshold of wavelet shrinkage for denoising images containing zero mean Gaussian noise using linear average of reconstructions obtained from shifted sequences’ DWT. This considerably improves the denoising performance of the conventional recursive cycle spinning algorithm and requires drasticallyless computations. Denoising performance of the proposed algorithm is benchmarked with published Recursive Cycle spinning, Buades NL means and Dual tree Complex Wavelet algorithms visually and quantitatively.
Steganography refers to the exchange of hidden data. It deals with the study of invisible communication between the sender and the receiver. In today's modern world transferring secured data over a network is the main concern, hence for secured communication steganography is used. The data that is to be sent is concealed behind a text, image, or an audio file. The attacker or the eavesdropper, who observes the object with embedded data, will not notice it and thus would not try to decrypt the hidden data. Steganography is useful in many areas like efficient confidential communication, protection from data modification, and media database systems. It preserves the confidentiality of the information, which ensures that during communication there will be no alteration in the content of the information. Steganography can be classified into image steganography, audio/video steganography, or text steganography. This paper gives an overview of image steganography and its various techniques to hide the data behind the image. The techniques are discussed and analysed based on their ability to hide the information securely.
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