visual cryptography scheme is a cryptographic technique which allows visual information to be encrypted in such a way that the decryption can be performed by the human visual system, without the aid of computers. In t...
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ISBN:
(纸本)9783642227134
visual cryptography scheme is a cryptographic technique which allows visual information to be encrypted in such a way that the decryption can be performed by the human visual system, without the aid of computers. In this article, we propose a novel scheme for copyright protection for digital images based on visual cryptography. The proposed method employs encoding of Most Significant bits of host image which is to be copyrighted, to form a master image share. The master share is encoded with a copyright image to form another share called ownership share. The master share is kept with a central authority and ownership share is kept by the copyright owner. In case of any dispute, the master shares and ownership shares can be stacked together to give the copyright image verifying the ownership about the host image. The important feature of our procedure is that we don not disturb the host image either during copyright generation nor during copyright verification. The proposed method is also independent of the size of secret image.
Quantization matrix is an important encoding tool for discrete cosine transform (DCT) based perceptual image / video encoding in that DCT coefficients can be quantized according to the sensitivity of the human visual ...
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ISBN:
(纸本)9780819469946
Quantization matrix is an important encoding tool for discrete cosine transform (DCT) based perceptual image / video encoding in that DCT coefficients can be quantized according to the sensitivity of the human visual system to the coefficients' corresponding spatial frequencies. A quadratic model is introduced to parameterize the quantization matrices. This model is then used to optimize quantization matrices for a specific bitrate or bitrate range by maximizing the expected encoding quality via a trial based multidimensional numerical search method. The model is simple yet it characterizes the slope and the convexity of the quantization matrices along the horizontal, the vertical and the diagonal directions. The advantage of the model for improving perceptual video encoding. quality is demonstrated with simulations using H.264 / AVC video encoding.
In order to solve the disadvantage of ignoring the visual feature in image retrieval, a novel method based on mutual information was presented incorporating the different sensitivity along variant directions of human ...
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ISBN:
(纸本)9781424437092
In order to solve the disadvantage of ignoring the visual feature in image retrieval, a novel method based on mutual information was presented incorporating the different sensitivity along variant directions of human visual system. Firstly, combining the visual feature with principle of the block truncation code (BTC), the significant image feature is extracted and a novel descriptor is defined. Based on the analysis of the characters of the descriptors, the mutual information is chosen to image retrieval. Compared with the other algorithms, experiments show the proposed approach has good performance.
The explosion in digital photography poses a significant challenge when it comes to photo storage for both personal devices and the Internet. In this paper, we propose a novel lossless compression method to further re...
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ISBN:
(纸本)9781479961399
The explosion in digital photography poses a significant challenge when it comes to photo storage for both personal devices and the Internet. In this paper, we propose a novel lossless compression method to further reduce the storage size of a set of JPEG coded correlated images. In this method, we propose jointly removing the inter-image redundancy in the feature, spatial, and frequency domains. For each album, we first organize the images into a pseudo video by minimizing the global predictive cost in the feature domain. We then introduce a disparity compensation method to enhance the spatial correlation between images. Finally, the redundancy between the compensated signal and the corresponding target image is adaptively reduced in the frequency domain. Moreover, our proposed scheme is able to losslessly recover not only raw images but also JPEG files. Experimental results demonstrate the efficiency of our proposed lossless compression, which achieves more than 12% bit-saving on average compared with JPEG coded albums.
In this paper, we present a novel approach to image-based rendering (IBR) that for generates an arbitrary view image with arbitrary focus for a scene consisting two approximately constant depths. The presented method ...
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ISBN:
(纸本)0819450235
In this paper, we present a novel approach to image-based rendering (IBR) that for generates an arbitrary view image with arbitrary focus for a scene consisting two approximately constant depths. The presented method differs from the conventional IBRs using multiple view images in that we acquire two differently focused images at each camera position and render parallax and focus effects on each object simply by linear filtering of the acquired images without segmentation. Experimental results on the real images acquired with 4 cameras located in parallel are presented.
The observed images are usually noisy due to data acquisition and transmission process. Therefore, image denoising is a necessary procedure prior to post-processing applications. The proposed algorithm exploits the se...
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ISBN:
(纸本)9781479902880
The observed images are usually noisy due to data acquisition and transmission process. Therefore, image denoising is a necessary procedure prior to post-processing applications. The proposed algorithm exploits the self-similarity based low rank technique to approximate the real-world image in the multivariate analysis sense. It consists of two successive steps: adaptive dimensionality reduction of similar patch groups, and the collaborative filtering. For each target patch, the singular value decomposition (SVD) is used to factorize the similar patch group collected in a local search window by block-matching. Parallel analysis automatically selects the principal signal components by discarding the nonsignificant singular values. After the inverse SVD transform, the denoised image is reconstructed by the weighted averaging approach. Finally, the collaborative Wiener filtering is applied to further remove the noise. Experimental results show that the proposed algorithm surpasses the state-of-the-art methods in most cases.
Along with the digital evolution, image post-production and indexing have become one of the most advanced and desired services in the lossless 3D image domain. The 3D context provides a significant gain in terms of se...
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ISBN:
(纸本)9781479961399
Along with the digital evolution, image post-production and indexing have become one of the most advanced and desired services in the lossless 3D image domain. The 3D context provides a significant gain in terms of semantics for scene representation. However, it also induces many drawbacks including monitoring visual degradation of compressed 3D image (especially upon edges), and increased complexity for scene representation. In this paper, we propose a semantic region representation and a scalable coding scheme. First, the semantic region representation scheme is based on a low resolution version of the 3D image. It provides the possibility to segment the image according to a desirable balance between 2D and depth. Second, the scalable coding scheme consists in selecting a number of regions as a Region of Interest (RoI), based on the region representation, in order to be refined at a higher bit-rate. Experiments show that the proposed scheme provides a high coherence between texture, depth and regions and ensures an efficient solution to the problems of compression and scene representation in the 3D image domain.
image retrieval and image compression are both very active fields of research. Unfortunately, in the past they were pursued independently leading to image indexing methods being both efficient and effective but restri...
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ISBN:
(纸本)0819444111
image retrieval and image compression are both very active fields of research. Unfortunately, in the past they were pursued independently leading to image indexing methods being both efficient and effective but restricted to uncompressed images. In this paper we introduce an image retrieval technique that operates in the compressed domain of vector quantised images. Vector quantisation (VQ) achieves compression by representing image blocks as indices into a codebook of prototype blocks. By realising that, if images are coded with their own VQ codebook then much of the image information is contained in the codebook itself, we propose the comparison of the codebooks, based on a Modified Hausdorff distance, as a novel method for compressed domain image retrieval. Experiments, based on an image database comprising many colourful pictures show this technique to give excellent results, outperforming classical colour indexing techniques.
In this paper we present a method of creating domain-based multiple descriptions of images and video. Descriptions are created by partitioning the domain of the signal into sets whose points are maximally separated fr...
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ISBN:
(纸本)0819444111
In this paper we present a method of creating domain-based multiple descriptions of images and video. Descriptions are created by partitioning the domain of the signal into sets whose points are maximally separated from each other. This property enables simple error concealment methods to produce good estimates of lost signal samples. We present the approach in the context of Internet transmission of subband-coded images and scalable motion compensated 3-D subband-coded video, but applications are not limited to these scenarios.
This paper proposes novel technique for elimination of moving objects self-generated illumination variations with respect to a fixed reference frame (background). In particular, proposed techniques can be used by a vi...
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ISBN:
(纸本)0819450235
This paper proposes novel technique for elimination of moving objects self-generated illumination variations with respect to a fixed reference frame (background). In particular, proposed techniques can be used by a video-based surveillance system able to automatically detect potentially dangerous or particular situations happening within a guarded area. Proposed techniques are based on chromatic properties of cast shadows and illumination and achieved results demonstrate that the proposed approach can greatly improve performances of a video-surveillance system in term of the precision of detected objects. Presented processing techniques are necessary in the case of a real system that must be able to work with good performances twenty-four hours a day.
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