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Foggy image enhancement based on adaptive Riesz fractional differential
LEI Sijia, ZHAO Fengqun
Journal of Computer Applications    2018, 38 (5): 1427-1431.   DOI: 10.11772/j.issn.1001-9081.2017102480
Abstract329)      PDF (794KB)(404)       Save
In order to improve clarity of foggy images and solve the problem of unicity of fractional order, a new adaptive fractional differential image enhancement method was proposed. Based on an approximate formula of Riesz fractional differential with six order accuracy, a new high precision fractional differential mask:RH operator (Riesz Higher order operator) was constructed, and the IRH operator (Improved Riesz Higher order operator) was proposed by improving RH operator. A fractional differential function was established based on image local features, and a selection criterion of fractional differential order was proposed, and then the adaptive selection method of order point by point was implemented. Combining with IRH operator, an adaptive fractional differential image enhancement algorithm was formed. For color images, due to low independence among components in RGB space, color distortion may occur after enhancement of each channel. Therefore, the image was converted from the RGB space to the HSV space and only the luminance channel was enhanced. A group of foggy images was selected compared with Tiansi operator, the segmentation-based adaptive fractional differential image enhancement algorithm and the adaptive fractional-differential compound bilateral filtering algorithm. The results show that the proposed method has obvious enhancement effect by calculating the information entropy and average gradient in comparison with methods in the reference, which further demonstrates the effectiveness of the proposed algorithm.
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Noise-suppression method for flicker pixels in dynamic outdoor scenes based on ViBe
ZHOU Xiao, ZHAO Feng, ZHU Yanlin
Journal of Computer Applications    2015, 35 (6): 1739-1743.   DOI: 10.11772/j.issn.1001-9081.2015.06.1739
Abstract675)      PDF (950KB)(424)       Save

Visual Background extractor (ViBe)model for moving target detection cannot avoid interference caused by irregular flicker pixels noise in dynamic outdoor scenes. In order to solve the issue, a flicker pixels noise-suppression method based on ViBe model algorithm was proposed. In the initial stage of background model, a fixed standard deviation of background model samples was used as the threshold value to limit the range of background model samples and get suitable background model samples for each pixel. In the foreground detection stage, an adaptive detection threshold was applied to improve the accuracy of detection result. Edge inhibition of image edge background pixels was executed to avoid error background sample values updating to the background model in the background model update process. On the basis of above, morphological operation was added to fix connected components to get more complete foreground images. Finally, the proposed method was compared with the original ViBe algorithm and the ViBe's improvement with morphology post-processing on the results of multiple video sequences. The experimental results show that the flicker pixels noise-suppression method can suppress flicker pixels noise effectively and get more accurate results.

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Memory scheduling strategy for virtual machine in private cloud platform
LI Dawei ZHAO Fengyu
Journal of Computer Applications    2014, 34 (9): 2523-2526.   DOI: 10.11772/j.issn.1001-9081.2014.09.2523
Abstract245)      PDF (793KB)(447)       Save

On the private cloud platform, it cannot be flexible to monitor and distribute the virtual machine memory resources effectively using the existing methods. To solve this problem, a Memory Monitor and Scheduler (MMS) model was put forward. And the real-time monitoring and dynamic scheduling of the virtual machine memory shortage and memory free were realized by using the libvirt function library and libxc function library provided by Xen. A small private cloud platform was built using Eucalyptus with regarding one physical machine as master node and two physical machines as child nodes. In the experiments, when the state of host was in memory shortage, MMS system effectively released the memory space by starting the virtual machine migration strategy; when the memory of the virtual machine was approaching the initial maximum memory, MMS system assigned it with a new maximum memory; when the occupied memory decreased, MMS system recycled part of free memory resource, which has little effect on the performance of virtual machines if the release memory did not exceed 150MB (maximum memory is 512MB). The results show that the MMS model of private cloud platform is effective for real-time monitoring and dynamic scheduling of the memory.

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Design of remote heart rate monitoring system based on GSM
ZHENG Zheng-bing ZHAO Feng
Journal of Computer Applications    2012, 32 (07): 2082-2084.   DOI: 10.3724/SP.J.1087.2012.02082
Abstract738)      PDF (487KB)(725)       Save
According to the electrocardiograph signal characteristics of human body, a wireless heart rate monitoring system based on Global System for Mobile communications (GSM) was proposed. It was composed of the acquisition terminal and the monitoring terminal. The optical pulse sensor HKG-07B of the acquisition terminal acquired pulse signal on the human body which was adjusted as the output signal and then the SPCE061A completed the data computation, storage, display and voice broadcast. On the basis of the calculated value of the heart rate, the TC35I module used the mean of short message to achieve the remote alarm received by the monitoring terminal. The experimental results show that: the accuracy of the acquired heart rate data meets the performance requirements, and real-time wireless heart rate monitoring can be achieved.
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HRRP feature extraction based on proportion of divergence criterion
LIU Jing ZHAO Feng LIU Yi
Journal of Computer Applications    2012, 32 (04): 1025-1029.   DOI: 10.3724/SP.J.1087.2012.01025
Abstract1122)      PDF (727KB)(325)       Save
Traditional Linear Discriminant Analysis (LDA) faces the problem of tending to keep the separability of the class pairs having large within-class distances, while discarding the separability of those having small within-class distances. Based on the viewpoint that the feature subspace should uniformly keep the separability of each class pair, a new criterion, i.e., the Proportion of Divergence (PD), was presented. PD criterion was the mean of the proportion of the subspace divergence to original space divergence of each class pair. The solution of the Linear Discriminant Analysis (LDA) maximizing PD criterion (PD-LDA) was also presented. PD-LDA was used to perform feature extraction in the amplitude spectrum space of High Resolution Range Profile (HRRP). Shortest Euclidian distance classifier and Support Vector Machine (SVM) classifier were designed to evaluate the recognition performance. The experimental results for measured data show that, compared with traditional LDA, PD-LDA reduces data dimension remarkably and improves recognition rate effectively.
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Methods of building the realistic graphics of natural objects with fractal feature using OpenGL
QIN Zhong-bao,SHI Huai-yu, HE Wei-ping, FANG Ya-dong, ZHAO Feng1
Journal of Computer Applications    2005, 25 (01): 202-205.   DOI: 10.3724/SP.J.1087.2005.0202
Abstract1347)      PDF (196KB)(1026)       Save
The advantages of fractal geometry in representing natural objects with scrambling features and building their geometric models were introduced and the methods of producing the geometric data models of the natural objects based on fBm with mountain were exemplified. Then, how OpenGL was applied to display and render the realistic graphics of the mountain terrain was investigated. Because of the fractal features of the mountain terrains, the default function of OpenGL that could be used to compute the normals of the surfaces of the fractal models was ineffective. Thus, an effective method to remedy the flaw above was suggested. In the end, in order to prove the validity of the methods above, a prototype program was developed and a few vivid graphics produced by the program were displayed.
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