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Region of interest (ROI) coding is a mechanism deployed in several image coding systems to enable different degrees of coding priority to specific regions of the image. JPEG2000 standard provides two ROI coding methods. However, both of them are based in mechanisms that scale the quantized coefficients. This compels to encode the additional bit-planes needed for the scaling, causing a penalization...
There are two main classes of decoding algorithms for "compressed sensing," those which run in time polynomial in the signal length and those which use sublinear resources. Most of the sublinear algorithms focus on signals which are compressible in either the Euclidean domain or the Fourier domain. Unfortunately, most practical signals are not sparse in either one of these domains. However,...
We studied the problem of distributed coding and transmission of inter-correlated sources with memory. Different from the conventional distributed source coding structure which relies on design of effective channel codes to model the inter-correlation and quantizer, the proposed system utilizes distributed compressed sensing [1] for signal dimension reduction through linear matrix operations and dimension...
Recently, many researchers started to question a long-standing paradox in the engineering practice of digital photography: oversampling followed by compression, and pursue more intelligent sparse sampling techniques. In this research we take a practical approach of uniform down sampling in image space, and the sampling is made adaptive by a spatially varying directional low-pass prefiltering. Since...
Recent developments in compressed sensing have shown that if a signal can be compressed in some basis, then it can be reconstructed in such basis from a certain number of random projections. Distributed compressed sensing, where several correlated signals are compressed in a distributed manner, has also been proposed in the literature. By allowing additional distortion, successful recovery in distributed...
We introduce a new variant of the popular Burrows-Wheeler transform (BWT) called geometric Burrows-Wheeler transform (GBWT). Unlike BWT, which merely permutes the text, GBWT converts the text into a set of points in 2-dimensional geometry. Using this transform, we can answer to many open questions in compressed text indexing: (1) can compressed data structures be designed in external memory with similar...
Experiments have been conducted based on the reference coder JM12.2 of H.264/AVC. Simulation results show that the subjective qualities of the decoded frames are improved without compromising PSNR. Fig.1. blow shows the subjective performance of the proposed scheme for 'Foreman' sequence. We can easily find that the perceptual quality of the detailed region (such as the wrinkles on the facial area)...
Depth movies provide 2-D representations of a time-varying 3D scene. Multistream depth movies arise in many structure-capturing setups and have been used for image based rendering. They are bulky and carry redundant information. We propose a proxy-based compression scheme for multistream depth movies of a scene involving dynamic human actors. The input to our system is depth movies from different...
In conventional video coding schemes such as H.264/AVC, prediction value p is obtained for the original pixel value x via inter/intra prediction and the prediction residue d = (x - p) is calculated prior to orthogonal transform and quantization. Encoding the prediction residue is nothing but ignoring the variety of distribution Pr(d\p) with respect to p, that is, using Pr(d) as a whole instead. Because...
The tool, CoTe (compression tester), is a stand-alone program aiding in preparation of the tests (that is, choosing a set of test programs, files and their locations, and setting run-time options), running the tests (executing the programs with appropriate command- line switches, measuring processing time and output file size, removing unnecessary files after the tests are finished), and maintaining...
We propose two algorithms for the direct suffix sorting problem. The first is a simple algorithm that runs in an O(n) average time and space complexity, but with a worst case complexity in O(n log n) time and O(n) space. The second algorithm improves the first algorithm to O(n) time and space in the worst case. The improved algorithm requires only 7n bytes of storage, including the n bytes for the...
The Shannon rate-distortion function R(D) of a random process provides a lower bound to the minimal average distortion given a constraint on the average rate. When a positive source coding theorem with a fidelity criterion applies, the lower bound is achievable in the limit of large block length and hence R(D) characterizes the optimal performance for source coding or lossy data compression. The source...
A fully automated architecture for object-based region of interest (ROI) detection is proposed. ROI's are defined as regions containing user defined objects of interest, and an efficient algorithm is developed for the detection of such regions. The algorithm is based on the principle of discriminant saliency, which defines as salient the image regions of strongest response to a set of features that...
This paper presents a proof of the rate distortion function of a Poisson process with a queuing distortion measure that is in complete analogy with the proofs associated with the rate distortion functions of a Bernoulli source with Hamming distortion measure and a Gaussian source with squared-error distortion measure. Analogous to those problems, the distortion measure that we consider is related...
In this paper a modification on the file syntax of the CCSDS recommendation for image data coding (CCSDS-122-B-1) is presented. With respect to the Recommendation, the proposed modification provides, among others, scalability by quality, spatial location, resolution, and component, and also allows multicomponent data coding. In addition, experimental results show that our proposal produces a meaningful...
We discuss the use of lattice vector quantizers in conjunction with a quadtree-based sorting algorithm for the compression of multidimensional data sets, as encountered, for example, when dealing with hyperspectral imagery. An extension of the SPECK algorithm is presented that deals with vector samples and is used to encode a group of successive spectral bands extracted from the hyperspectral image...
This paper proposes a new image compression scheme by introducing visual patterns to nonlinear interpolative vector quantization (IVQ). Input images are first distorted by a generic down-sampling so that some details are removed before compression. Then, the distorted images are compressed lossly by traditional image coding scheme and transmitted to the decoder. In the decoder side, VQ indices are...
In compressed sensing theory, small dictionary coherence is desirable in both obtaining and recovering sparse signal representations in a redundant system. It has been known that equiangular tight frames are optimal redundant systems with minmal coherence in M.
Images may contain blemishes or artificial structures which come from the processing or directly from the sensors, that decrease the quality of the images and can lead to analysis and interpretation problems. We are interested in detecting these defects automatically. The aim of our method will be to look for artifacts as too regular or too irregular image structures that will be detected using the...
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