1,004 research outputs found
Spatially Directional Predictive Coding for Block-based Compressive Sensing of Natural Images
A novel coding strategy for block-based compressive sens-ing named spatially
directional predictive coding (SDPC) is proposed, which efficiently utilizes
the intrinsic spatial cor-relation of natural images. At the encoder, for each
block of compressive sensing (CS) measurements, the optimal pre-diction is
selected from a set of prediction candidates that are generated by four
designed directional predictive modes. Then, the resulting residual is
processed by scalar quantiza-tion (SQ). At the decoder, the same prediction is
added onto the de-quantized residuals to produce the quantized CS measurements,
which is exploited for CS reconstruction. Experimental results substantiate
significant improvements achieved by SDPC-plus-SQ in rate distortion
performance as compared with SQ alone and DPCM-plus-SQ.Comment: 5 pages, 3 tables, 3 figures, published at IEEE International
Conference on Image Processing (ICIP) 2013 Code Avaiable:
http://idm.pku.edu.cn/staff/zhangjian/SDPC
Statistical Compressive Sensing of Gaussian Mixture Models
A new framework of compressive sensing (CS), namely statistical compressive
sensing (SCS), that aims at efficiently sampling a collection of signals that
follow a statistical distribution and achieving accurate reconstruction on
average, is introduced. For signals following a Gaussian distribution, with
Gaussian or Bernoulli sensing matrices of O(k) measurements, considerably
smaller than the O(k log(N/k)) required by conventional CS, where N is the
signal dimension, and with an optimal decoder implemented with linear
filtering, significantly faster than the pursuit decoders applied in
conventional CS, the error of SCS is shown tightly upper bounded by a constant
times the k-best term approximation error, with overwhelming probability. The
failure probability is also significantly smaller than that of conventional CS.
Stronger yet simpler results further show that for any sensing matrix, the
error of Gaussian SCS is upper bounded by a constant times the k-best term
approximation with probability one, and the bound constant can be efficiently
calculated. For signals following Gaussian mixture models, SCS with a piecewise
linear decoder is introduced and shown to produce for real images better
results than conventional CS based on sparse models
Image Compressive Sensing Recovery Using Adaptively Learned Sparsifying Basis via L0 Minimization
From many fewer acquired measurements than suggested by the Nyquist sampling
theory, compressive sensing (CS) theory demonstrates that, a signal can be
reconstructed with high probability when it exhibits sparsity in some domain.
Most of the conventional CS recovery approaches, however, exploited a set of
fixed bases (e.g. DCT, wavelet and gradient domain) for the entirety of a
signal, which are irrespective of the non-stationarity of natural signals and
cannot achieve high enough degree of sparsity, thus resulting in poor CS
recovery performance. In this paper, we propose a new framework for image
compressive sensing recovery using adaptively learned sparsifying basis via L0
minimization. The intrinsic sparsity of natural images is enforced
substantially by sparsely representing overlapped image patches using the
adaptively learned sparsifying basis in the form of L0 norm, greatly reducing
blocking artifacts and confining the CS solution space. To make our proposed
scheme tractable and robust, a split Bregman iteration based technique is
developed to solve the non-convex L0 minimization problem efficiently.
Experimental results on a wide range of natural images for CS recovery have
shown that our proposed algorithm achieves significant performance improvements
over many current state-of-the-art schemes and exhibits good convergence
property.Comment: 31 pages, 4 tables, 12 figures, to be published at Signal Processing,
Code available: http://idm.pku.edu.cn/staff/zhangjian/ALSB
Compressive Sensing Based Bio-Inspired Shape Feature Detection CMOS Imager
A CMOS imager integrated circuit using compressive sensing and bio-inspired detection is presented which integrates novel functions and algorithms within a novel hardware architecture enabling efficient on-chip implementation
Compressed Sensing Inspired Image Reconstruction from Overlapped Projections
The key idea discussed in this paper is to reconstruct an image from overlapped projections so that the data acquisition process can be shortened while the image quality remains essentially uncompromised. To perform image reconstruction from overlapped projections, the conventional reconstruction approach (e.g., filtered backprojection (FBP) algorithms) cannot be directly used because of two problems. First, overlapped projections represent an imaging system in terms of summed exponentials, which cannot be transformed into a linear form. Second, the overlapped measurement carries less information than the traditional line integrals. To meet these challenges, we propose a compressive sensing-(CS-) based iterative algorithm for reconstruction from overlapped data. This algorithm starts with a good initial guess, relies on adaptive linearization, and minimizes the total variation (TV). Then, we demonstrated the feasibility of this algorithm in numerical tests
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