Compression of the sign information of discrete cosine transform coefficients is an intractable problem in image compression schemes due to the equiprobable occurrence of the sign bits. To overcome this difficulty, we...
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ISBN:
(纸本)9781665441155
Compression of the sign information of discrete cosine transform coefficients is an intractable problem in image compression schemes due to the equiprobable occurrence of the sign bits. To overcome this difficulty, we propose an efficient compression method for such sign information based on phase retrieval, which is a classical signal restoration problem attempting to find the phase information of discrete Fourier transform coefficients from their magnitudes. In our compression strategy, the sign bits of all the AC components in the cosine domain are excluded from a bitstream at the encoder and are complemented at the decoder by solving a sign recovery problem, which we call sign retrieval. The experimental results demonstrate that the proposed method outperforms previous techniques for sign compression in terms of a rate-distortion criterion. Our method implemented in Python language is available from https://***/ctsutake/sr.
image reconstruction techniques from signals received by sensors find application in several fields, including radio interferometry for astronomical investigations and magnetic resonance imaging for medical applicatio...
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ISBN:
(纸本)9781509004805
image reconstruction techniques from signals received by sensors find application in several fields, including radio interferometry for astronomical investigations and magnetic resonance imaging for medical applications. This paper presents a novel method for image reconstruction based on the iterative scanning of a region of interest. A modified approximate message passing (AMP) algorithm is adopted to extract relevant image information with low computational complexity from signals received by sensors. The method is illustrated by simulations, with reference to the LOFAR radio interferometer, and compared in the case of radio astronomy with the CLEAN algorithm.
In this paper, we propose a novel approach for saliency detection for seismic applications using 3D-FFT local spectra and multi-dimensional plane projections. We develop a projection scheme by dividing a 3D-FFT local ...
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ISBN:
(纸本)9781509021758
In this paper, we propose a novel approach for saliency detection for seismic applications using 3D-FFT local spectra and multi-dimensional plane projections. We develop a projection scheme by dividing a 3D-FFT local spectrum of a data volume into three distinct components, each depicting changes along a different dimension of the data. The saliency detection results obtained using each projected component are then combined to yield a saliency map. To accommodate the directional nature of seismic data, in this work, we modify the center-surround model, proven to be biologically plausible for visual attention, to incorporate directional comparisons around each voxel in a 3D volume. Experimental results on real seismic dataset from the F3 block in Netherlands offshore in the North Sea prove that the proposed algorithm is effective, efficient, and scalable. Furthermore, a subjective comparison of the results shows that it outperforms the state-of-the-art methods for saliency detection.
In this paper we study common, camera-specific kinds of distortions and propose a no-reference image quality assessment algorithm for photographic images produced by consumer devices. Those real consumer-type images, ...
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ISBN:
(纸本)9781479999880
In this paper we study common, camera-specific kinds of distortions and propose a no-reference image quality assessment algorithm for photographic images produced by consumer devices. Those real consumer-type images, being different from simulated-distortion images, are with realistic artifacts and quality ranges. We find that the state-of-the-art no-reference image quality assessment approaches do not perform well on those photographic images, and propose an approach that achieves high prediction performance on a dataset of consumer-centric images. The proposed method, with no need for the original image, is able to reveal camera-specific problems and differentiate consumer cameras.
image inpainting technique uses structural and textural information to repair or fill missing regions of a picture. This paper focuses on novel image reconstruction method based on modified exemplar-based technique. T...
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ISBN:
(纸本)9781479921867
image inpainting technique uses structural and textural information to repair or fill missing regions of a picture. This paper focuses on novel image reconstruction method based on modified exemplar-based technique. The basic idea is to find an example (patch) from an image using local binary patterns, and replacing non-existed ('lost') data with it. We propose to use multiple criteria for a patch similarity search since often in practice existed exemplar-based methods produce unsatisfactory results. The proposed method is tested on various samples of images, with different geometrical features and compared with the state-of-the-art image inpainting methods.
Mobile reception of digital TV often suffers from lost blocks and slices due to suboptimal channels. Inter-sequence error concealment reconstructs lost image blocks of distorted high-resolution TV signals by inserting...
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ISBN:
(纸本)9781457705397
Mobile reception of digital TV often suffers from lost blocks and slices due to suboptimal channels. Inter-sequence error concealment reconstructs lost image blocks of distorted high-resolution TV signals by inserting corresponding error-free blocks of low-resolution reference signals. It is well-suited for automotive multi-broadcast receivers and can outperform state-of-the-art methods by up to 15 dB PSNRY. In this contribution, a novel spectral completion scheme is proposed which robustly estimates missing spatial frequencies of reconstructed blocks by extrapolation of difference images. Simulation results show that the proposed scheme can increase the reconstruction quality of inter-sequence error concealment by up to 3.2 dB. Also, the subjective quality is enhanced by significantly reducing blurring artifacts.
The application of one particular coherence measure in two-dimensional imageprocessing of seismograms is discussed. The coherence measure provides a quantitative method of estimating the similarity of the data among ...
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The application of one particular coherence measure in two-dimensional imageprocessing of seismograms is discussed. The coherence measure provides a quantitative method of estimating the similarity of the data among the channels in multichannel data. Estimates of directional coherence, expressed in signal-to-noise ratio, are applied as weights in a processing technique by which images are enhanced. The estimator and enhancement algorithms are presented, and the estimator properties are discussed. Both synthetic seismograms and field data are processed using the event detection, SNR estimation, and enhancement/extraction capabilities of the processing technique. Though the technique has been successfully applied to both vertical and horizontal profile data, only the horizontal data are treated here.
This paper introduces the Extended Kalman Filter (EKF) to realize high dynamic tracking of GPS signal. It's compared with the traditional tracking loop with a third-order phase-locked loop (PLL), which is assisted...
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ISBN:
(纸本)9781509023776
This paper introduces the Extended Kalman Filter (EKF) to realize high dynamic tracking of GPS signal. It's compared with the traditional tracking loop with a third-order phase-locked loop (PLL), which is assisted by a second-order frequency-locked loop (FLL) and a second-order delay-locked loop (DLL). It can estimate carrier phase, Doppler shift, rate of change of Doppler shift and code phase in real-time for higher dynamics. The results of simulation show that the new tracking method can not only improve the dynamic acceleration as high as 100g, also improve the tracking accuracy.
This work develops a very generalised and efficient cell-tracking framework that is based on the combination of a new repulsive snake model and the dynamic gradient-vector-flow (DGVF) technique. To the best knowledge ...
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ISBN:
(纸本)9781538603895
This work develops a very generalised and efficient cell-tracking framework that is based on the combination of a new repulsive snake model and the dynamic gradient-vector-flow (DGVF) technique. To the best knowledge of the authors, the introduction of DGVF into dense-population based tracking is the first. And, by integrating the proposed repulsion mechanism into snakes, incorrectly merged segmentation can be more effectively prevented compared with existing schemes. Our experiments included very challenging datasets with densely packed cells and poor image quality. In spite of that, the proposed approach has demonstrated excellent performances with reported tracking accuracies in the range [85.23% similar to 93.15%].
In the framework of model based imageprocessing, we propose a new parametric approach for classifying textured images. The image, considered as a two-dimensional stochastic process, is characterized by a set of refle...
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ISBN:
(纸本)0780324323
In the framework of model based imageprocessing, we propose a new parametric approach for classifying textured images. The image, considered as a two-dimensional stochastic process, is characterized by a set of reflection coefficients computed using a two-dimensional adaptive lattice filter based on RLS criterion. The corresponding algorithm is named Two-Dimensional Fast Lattice Recursive Least Squares. In order to evaluate this method, classification rates are calculated on a set of 8 different textures from the Brodatz album. We carry out performance comparisons with methods of characterization based on two-dimensional AR coefficients computed with two-dimensional transversal filters or based on statistical features calculated from co-occurrence matrices and neighbouring matrices.
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