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Yang G.,University of Electronic Science and Technology of China | Yang G.,University of Sichuan | Yang G.,Provincial Key Laboratory of Digital Media | Li M.,University of Electronic Science and Technology of China | And 3 more authors.
Computational and Mathematical Methods in Medicine | Year: 2015

We propose a novel medical image fusion scheme based on the statistical dependencies between coefficients in the nonsubsampled contourlet transform (NSCT) domain, in which the probability density function of the NSCT coefficients is concisely fitted using generalized Gaussian density (GGD), as well as the similarity measurement of two subbands is accurately computed by Jensen-Shannon divergence of two GGDs. To preserve more useful information from source images, the new fusion rules are developed to combine the subbands with the varied frequencies. That is, the low frequency subbands are fused by utilizing two activity measures based on the regional standard deviation and Shannon entropy and the high frequency subbands are merged together via weight maps which are determined by the saliency values of pixels. The experimental results demonstrate that the proposed method significantly outperforms the conventional NSCT based medical image fusion approaches in both visual perception and evaluation indices. © 2015 Guocheng Yang et al. Source


Nie X.,University of Electronic Science and Technology of China | Nie X.,Provincial Key Laboratory of Digital Media | Chen L.,University of Electronic Science and Technology of China | Chen L.,Provincial Key Laboratory of Digital Media | Xiang T.,University of Electronic Science and Technology of China
International Journal of Computer Games Technology | Year: 2015

We present a parallel framework for simulating incompressible fluids with predictive-corrective incompressible smoothed particle hydrodynamics (PCISPH) on the GPU in real time. To this end, we propose an efficient GPU streaming pipeline to map the entire computational task onto the GPU, fully exploiting the massive computational power of state-of-the-art GPUs. In PCISPH-based simulations, neighbor search is the major performance obstacle because this process is performed several times at each time step. To eliminate this bottleneck, an efficient parallel sorting method for this time-consuming step is introduced. Moreover, we discuss several optimization techniques including using fast on-chip shared memory to avoid global memory bandwidth limitations and thus further improve performance on modern GPU hardware. With our framework, the realism of real-time fluid simulation is significantly improved since our method enforces incompressibility constraint which is typically ignored due to efficiency reason in previous GPU-based SPH methods. The performance results illustrate that our approach can efficiently simulate realistic incompressible fluid in real time and results in a speed-up factor of up to 23 on a high-end NVIDIA GPU in comparison to single-threaded CPU-based implementation. © 2015 Xiao Nie et al. Source


Yang G.,University of Electronic Science and Technology of China | Yang G.,University of Sichuan | Yang G.,Provincial Key Laboratory of Digital Media | Li M.,University of Electronic Science and Technology of China | And 3 more authors.
Journal of Electronic Imaging | Year: 2015

We present a multiexposure image fusion method that can enhance details, yet effectively improve brightness in the final result. In addition, a valid weight measurement is developed to remove motion objects in dynamic scenes. During the fusion process, each source image is first decomposed into one low-pass sub-band and a series of high-pass directional sub-bands using the nonsubsampled contourlet transform. Then the blended sub-bands are constructed by weight maps of the source images. To preserve the details of source images and adjust brightness of final image, gain control maps are used for each fused sub-band. Experimental results demonstrate that the proposed method significantly outperforms the traditional methods in terms of both visual inspection and objective evaluation, especially in cases which the regions of interest are in dark areas. © 2015 SPIE and IS&T. Source


Yang G.,University of Electronic Science and Technology of China | Yang G.,Luzhou Medical College | Yang G.,Provincial Key Laboratory of Digital Media | Chen L.,University of Electronic Science and Technology of China | And 2 more authors.
International Journal of Multimedia and Ubiquitous Engineering | Year: 2015

Multimodal medical image fusion technique plays an important role in clinical applications, such as pathologic diagnosis and surgical options. However, many traditional fusion methods cannot well preserve details of source images in the fused image. To address this problem, a detail-enhanced image fusion scheme based on non-subsampled contourlet transform (NSCT) and gain control (i.e., NCGC) is developed in this paper, which can effectively combine the spectral information and the spatial features of source images. The proposed method applies power law transformation to tune coefficients of each decomposed subband, and adjusts the strength of subband signals by smooth gain control. Eventually, the fused image with more anatomical details and functional information is constructed by the inverse NSCT. Three pairs of medical images with different modalities and three fusion metrics are applied to validate the feasibility of this algorithm. Experimental results demonstrate that the proposed method can achieve superior performance in both visual perception and objective assessment. © 2015 SERSC. Source


Nie X.,University of Electronic Science and Technology of China | Nie X.,Provincial Key Laboratory of Digital Media | Chen L.,University of Electronic Science and Technology of China | Chen L.,Provincial Key Laboratory of Digital Media | Xiang T.,University of Electronic Science and Technology of China
International Journal of Computer Games Technology | Year: 2014

We present a novel Smoothed Particle Hydrodynamics (SPH) based algorithm for efficiently simulating compressible and weakly compressible particle fluids. Prior particle-based methods simulate all fluid particles; however, in many cases some particles appearing to be at rest can be safely ignored without notably affecting the fluid flow behavior. To identify these particles, a novel sleepy strategy is introduced. By utilizing this strategy, only a portion of the fluid particles requires computational resources; thus an obvious performance gain can be achieved. In addition, in order to resolve unphysical clumping issue due to tensile instability in SPH based methods, a new artificial repulsive force is provided. We demonstrate that our approach can be easily integrated with existing SPH based methods to improve the efficiency without sacrificing visual quality. © 2014 Xiao Nie et al. Source

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