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Secret image is converted into meaningful shares using a technique called visual sharing. Information is not disclosed by any single share except for all shares. Printing the encrypted secret on transparencies and stacking them will reveal the secret. More than one secret is encrypted by the visual sharing of multiple secrets and thus encryption capacity is increased when compared to a single secret...
Visual Cryptography is a technique, which is used to conceal the secret image into transparencies and these transparencies are distributed to the intended recipients. They demonstrated a visual secret sharing scheme, where an image was broken up into n shares so that only someone with all n shares could decrypt the image, while any n−1 shares revealed no information about the original image. In this...
The main goal of hiding data is to conceal the very existence of the hidden information, therefore there is a significant demand for steganographic approaches that can ensure imperceptibility of such infromation. However, there is a limited corresponding evaluation parameters available. Most of the studies use the Peak Signal to Noise Ratio (PSNR) as a metric for imperceptibility evaluation, although...
In this paper, we introduce a novel block-based multiscale error concealment method using low-rank completion. The proposed method searches for similar blocks and utilizes low-rank completion to recover the missing pixels. In order to make the full use of the hidden redundant information of images, we seek for more similar blocks by building an image pyramid. The blocks collected from the pyramid...
In this paper, an effective self-embedding fragile watermarking method for tampering detection and content recovery is proposed. The halftone mechanism and the extension operation are utilized to generate recovery bits from the resized original image. Watermark bits including recovery bits and authentication bits only occupy one LSB plane of the original image. The located, tampered blocks can be...
This work describes a comparative study on the ability of Full-Reference versus No-Reference quality metrics to measure the Quality of Experience created by images that suffer chromatic variations. Considering this, some well known Full-Reference (PSNR, UQI, MSSIM) and No-Reference (GM, FTM, RTBM) will be compared with the MOS results. Although the quality metrics considered are usually applied to...
A new technique for the filling-in of missing blocks in wireless transmission of block based compressed images is proposed. By intentionally (and automatically) dropping image blocks and using filling-in approach, the performance of the compression ratio can be improved. The approach removes only partial regions in the image and generates a smaller image of same size as the original. This provides...
Based on poly-phase sampling and lookup table encryption techniques, a new image sharing scheme is presented with several aspects of innovations in this paper. Each shadow can be independently decrypted to obtain part of the original image, any pair of decrypted sub-images has very high correlation, it still obtains acceptable image quality when channel congestion occurs, and quality refinement of...
The performance of objective quality metrics for high-definition (HD) video sequences is well studied, but little is known about their performance for ultra-high definition (UHD) video sequences. This paper analyzes the performance of several common objective quality metrics (PSNR, VSNR, SSIM, MS-SSIM, VIF, and VQM) on three different 4K UHD video sequences using subjective scores as ground truth...
This paper provides a study on the ability of Full-Reference quality metrics to measure the Quality of Experience that results on images that suffer chromatic errors. Considering this, the well known PSNR, MSSIM and VIFP will be compared with the MOS results. It is important to highlight that these measures are usually applied to the image luminance channel. However, in this study only the chromatic...
Spatially scalable video coding (SSVC in short) provides an efficient way to deliver one video at different resolutions. Based on the development of emerging High Efficiency Video Coding (HEVC), we propose a SSVC scheme to provide both single-loop and multi-loop solutions by enabling different inter-layer prediction mechanisms. Specifically, there are three basic inter-layer prediction modes, inter-layer...
Based on the characteristic of striping noise in remote sensing images, a new destriping noise technique for the improved multi-threshold method using lifting wavelet transform applied to remote sensing imagery is presented in this letter. Have used the lifting wavelet decomposition algorithm, the thresholds are determined by corresponding wavelet coefficients in every scale. Remote sensing imagery...
Digital image steganography is the art of hiding information in other digital images. Moreover, image quality evaluation has many difficulties such as the amount of degradation or distortion induced in the reconstructed image. The peak signal-to-noise ratio (PSNR) is the most common metric used to evaluate the stego image quality. However, subjective evaluation is the most reliable method to measure...
To improve the prediction accuracy of visual quality metrics for video we propose two simple steps: temporal pooling in order to gain a set of parameters from one measured feature and a correction step using videos of known visual quality. We demonstrate this approach on the well known PSNR. Firstly, we achieve a more accurate quality prediction by replacing the mean luma PSNR by alternative PSNR-based...
Several image quality evaluation methods is analyzed, such as the conventional mathematical statistics methods, mean square error (MSE), peak signal to noise ratio (PSNR), as well as methods based on the HVS, structural similarity (SSIM), objective picture quality scale (PQS), wavelet and weighted mean square error (WWMSE), wavelet and energy -weighted mean square error (WEWMSE). The above objective...
This paper addresses the use of full reference metrics in the characterization of perceptual difference in a pair of images, in which one of them is degraded by additive white Gaussian noise (AWGN). Conventional (SNR, PSNR, and CC) and perceptual (MSSIM, IFC, VIF, and C4) full reference metrics are considered. The subjective experiment, which upholds the presented results, has been carried out with...
Current research on image quality assessment tends to include visual attention in objective metrics to further enhance their performance. A variety of computational models of visual attention are implemented in different metrics, but their accuracy in representing human visual attention is not fully proved yet. Thus, to provide more accurate evidence on whether and to what extent visual attention...
At low bit-rate video communications, packet loss may easily cause whole-frame loss that, in return, leads to annoying frame drop phenomenon. In this paper, a novel error concealment algorithm is specifically developed for stereoscopic video, called the disparity-based frame difference projection (DFDP), to recover the lost frames at the decoder. The proposed DFDP contains three key components: 1)...
The most important step in the development process of a video quality metric is its verification with regards to the subjective quality experience. Even though guidelines in the form of standards and recommendations are well known, there are still quite often shortcomings in the verification process of many metrics. In this contribution we revisit these rules, point out important details and review...
Full reference image quality indices assign a quality index to a pair of an undistorted reference image and a distorted image to be assessed; the quality of the index itself is then defined by its ability to predict the outcome of subjective tests performed by human observers judging the quality of the same image pair. In this article, a new DCT based image quality index is introduced whose complexity...
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