To solve the problem of a compression sampling matching pursuit algorithm (CoSaMP) poor reconstruction result and inaccurate index selection, an improved reeonstruction algorithm, called residual descent OMP (RdOMP), ...
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ISBN:
(纸本)9781728132273
To solve the problem of a compression sampling matching pursuit algorithm (CoSaMP) poor reconstruction result and inaccurate index selection, an improved reeonstruction algorithm, called residual descent OMP (RdOMP), is proposed. The proposed algorithm introduces a residual comparison strategy to enhance the effectiveness of the backtracking indexes. This backtracking strategy, which is based on the residual descent, can flexibly select backtracking indexes. Without increasing the computational complexity, the proposed algorithm has a higher exact reconstruction rate. Different simulations show that the proposed algorithm can restore the sparse signal efficiently and reconstruct the sparse signal with a high probability.
Photoacoustic tomography is a quickly growing imaging method that can provide images of high spatial resolution and high contrast at a limited depths. Medical photoacoustic processing characteristics two main componen...
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ISBN:
(纸本)9781538662175
Photoacoustic tomography is a quickly growing imaging method that can provide images of high spatial resolution and high contrast at a limited depths. Medical photoacoustic processing characteristics two main components: A transducer is required to transmit laser pulses and acquire the reflected ultrasound signals and a back-end processing system that will generate the final reconstructed image. In this paper, we introduce an implementation of the receive part of proposed embedded system and briefly discuss reconstruction algorithms which are used in medical imaging systems. Furthermore, an intellectual property core (IP-core), which can be controlled and configured by a user application on Zynq-7000 System-On-Chip (SoC) via AXI-Lite Interface, that can receive multichannel digitized raw signals from Analog-Front-End (AFE) device via Low Voltage Differential Signal (LVDS), is proposed for photoacoustic imaging systems. Besides, block diagram of the system, the hardware design flow and the proposed IP-core are fully described in this paper. In order to effortlessly test and evaluate a wide variety of ultrasonic signal processing applications, 16 channel system is implemented and demonstrated by using TI AFE5816 Evaluation module (EVM) based on AFE5816 device and Xilinx ZC702 Evaluation Kit based on Zynq-7000 SoC. Apart from working on hardware, we review and commented on the proposed 3-Dimensional photoacoustic image reconstruction algorithm.
Acoustic temperature field reconstruction is an ill-posed problem. This means especially that their solution is unstable under data perturbations. Numerical methods that can cope with this problem are the so-called re...
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ISBN:
(纸本)9781467357913
Acoustic temperature field reconstruction is an ill-posed problem. This means especially that their solution is unstable under data perturbations. Numerical methods that can cope with this problem are the so-called regularization methods. The choice of a regularization parameter has an important influence on reconstruction accuracy. In this paper, a 3D acoustic temperature field reconstruction algorithm is proposed. It uses a new criterion for choosing the regularization parameter, which makes a good compromise between de-noise and detail reconstruction of the temperature field. reconstructions of a single-peak temperature field by using simulated travel-times corrupted with different level noises demonstrate that the new algorithm has high reconstruction accuracy and good anti-noise ability.
Flat-panel detectors (FPDs) have emerged as the next generation digital X-ray technology. They are more sensitive, faster and cheaper than film. Nowadays, FPDs are widely used in industrial radiography and medical ima...
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ISBN:
(纸本)9781467301206
Flat-panel detectors (FPDs) have emerged as the next generation digital X-ray technology. They are more sensitive, faster and cheaper than film. Nowadays, FPDs are widely used in industrial radiography and medical imaging. We design an experimental dental cone-beam CT (CBCT) system using a small size FPD off-center placed. The field of view (FOV) of detector can cover only half of the scanned object in every scan angle. Typical FDK reconstruction algorithm is not available in this system because of transversely truncated projections. A 3D BPF-type reconstruction algorithm using a modified finite Hilbert transform method is researched for this kind of CBCT system with off-center half-size FPD. This reconstruction method is validated by simulation study and practical experiments with an anthropomorphic tooth phantom. We compare the reconstruction results with the other methods. The preliminary experiment results prove its feasibility in reconstruction of CBCT with transversely truncated projections.
Compressed sensing for breakthrough Nyquist sampling theorem provides a strong theoretical, making compressive sampling for image signals to be carried out simultaneously. In traditional imaging procedures using compr...
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ISBN:
(数字)9781510617070
ISBN:
(纸本)9781510617070;9781510617063
Compressed sensing for breakthrough Nyquist sampling theorem provides a strong theoretical, making compressive sampling for image signals to be carried out simultaneously. In traditional imaging procedures using compressed sensing theory, not only can it reduces the storage space, but also can reduce the demand for detector resolution greatly. Using the sparsity of image signal, by solving the mathematical model of inverse reconfiguration, realize the super-resolution imaging. reconstruction algorithm is the most critical part of compression perception, to a large extent determine the accuracy of the reconstruction of the image. The reconstruction algorithm based on the total variation (TV) model is more suitable for the compression reconstruction of the two-dimensional image, and the better edge information can be obtained. In order to verify the performance of the algorithm, Simulation Analysis the reconstruction result in different coding mode of the reconstruction algorithm based on the TV reconstruction algorithm. The reconstruction effect of the reconfigurable algorithm based on TV based on the different coding methods is analyzed to verify the stability of the algorithm. This paper compares and analyzes the typical reconstruction algorithm in the same coding mode. On the basis of the minimum total variation algorithm, the Augmented Lagrangian function term is added and the optimal value is solved by the alternating direction method. Experimental results show that the reconstruction algorithm is compared with the traditional classical algorithm based on TV has great advantages, under the low measurement rate can be quickly and accurately recovers target image.
Inverse-geometry CT (IGCT) is a new type of volumetric CT geometry. Volumetric coverage and high isotropic resolution demand a fast 3D reconstruction algorithm. The purpose of this work is to evaluate a very fast algo...
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ISBN:
(纸本)9781424405619
Inverse-geometry CT (IGCT) is a new type of volumetric CT geometry. Volumetric coverage and high isotropic resolution demand a fast 3D reconstruction algorithm. The purpose of this work is to evaluate a very fast algorithm based on Defrise's Fourier Rebinning (FORE) algorithm for PET. IGCT employs a large array of focal spots opposite a detector array that shares the same axial extent as the source but is much smaller in the transverse direction. A single rotation is sufficient to acquire a 10 cm thick volume with isotropic resolution. A 3D reconstruction algorithm was developed based on FORE. For comparison, a Feldkamp-like algorithm was developed that generates an average of Feldkamp reconstructions from each source row. Projection data for a numerical torso phantom and a numerical "Defrise" phantom were simulated under the IGCT geometry. To evaluate the FORE algorithm on a real data set, a prototype IGCT system was assembled involving a 100x100 scanned-anode source array and a 48x48 photon-counting detector array mounted on a C-arm system (NovaRay, Inc., Palo Alto, CA). An anthropomorphic phantom containing a real porcine heart was scanned in a step-and- shoot mode with the C-arm in a horizontal orientation. The FORE algorithm averaged 30 sec/slice while Feldkamp averaged 30 min/slice. Like Feldkamp, FORE suffers from cone-beam blurring in z, however it does not suffer from cone-beam streaking artifacts. FORE proved to be both fast and reasonably accurate.
We propose an efficient implementation of an interior tomography reconstruction method based on a known subregion. This method iteratively refines a reconstruction, aiming at reducing the local tomography artifacts. T...
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We propose an efficient implementation of an interior tomography reconstruction method based on a known subregion. This method iteratively refines a reconstruction, aiming at reducing the local tomography artifacts. To cope with the ever increasing data volumes, this method is highly optimized on two aspects: firstly, the problem is reformulated to reduce the number of variables, and secondly, the operators involved in the optimization algorithms are efficiently implemented. Results show that 4096 2 slices can be processed in tens of seconds, while being beyond the reach of equivalent exact local tomography method.
As an important optical molecular imaging technique, bioluminescence tomography (BLT) offers an inexpensive and sensitive means for non-invasively imaging a variety of physiological and pathological activities at cell...
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ISBN:
(纸本)9780819498052
As an important optical molecular imaging technique, bioluminescence tomography (BLT) offers an inexpensive and sensitive means for non-invasively imaging a variety of physiological and pathological activities at cellular and molecular levels in living small animals. The key problem of BLT is to recover the distribution of the internal bioluminescence sources from limited measurements on the surface. Considering the sparsity of the light source distribution, we directly formulate the inverse problem of BLT into an l(0)-norm minimization model and present a smoothed l(0)-norm (SL0) based reconstruction algorithm. By approximating the discontinuous l(0) norm with a suitable continuous function, the SL0 norm method solves the problem of intractable computational load of the minimal l(0) search as well as high sensitivity of l(0)-norm to noise. Numerical experiments on a mouse atlas demonstrate that the proposed SL0 norm based reconstruction method can obtain whole domain reconstruction without any a priori knowledge of the source permissible region, yielding almost the same reconstruction results to those of l(1) norm methods.
Based on the iterative hard thresholding (IHT) algorithm, this paper presents the relaxed iterative thresholding algorithm which is a modified algorithm of the conventional IHT algorithm. By introducing the relaxed fa...
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ISBN:
(纸本)9783642352102
Based on the iterative hard thresholding (IHT) algorithm, this paper presents the relaxed iterative thresholding algorithm which is a modified algorithm of the conventional IHT algorithm. By introducing the relaxed factors, modifying the iterative formulae and proposing the relaxed algorithm correspondingly, we acquired the least number of iterations and error estimate required by the measurement matrices of satisfying the RIP. Compared with the IHT algorithm, the method presented in this paper not only has the advantages of keeping linear stability and clearly delimiting the upper limit of the number of iterations, but also obtains the same computational precision with the less number of iterations which saves the labor of calculation. Finally, taking the Hadamard orthogonal basis as sparse basis, the random Gaussian matrix as measurement matrix, we have verified the validity of the algorithm proposed above by experimental simulation.
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