Shenzhen Key Laboratory of Visual Media Processing and Transmission

Shenzhen, China

Shenzhen Key Laboratory of Visual Media Processing and Transmission

Shenzhen, China
SEARCH FILTERS
Time filter
Source Type

Lu X.,Shenzhen Institute of Information Technology | Lu X.,Shenzhen Key Laboratory of Visual Media Processing and Transmission | Xu J.,Algorithm | Lin G.,Shenzhen Institute of Information Technology | And 2 more authors.
Advances in Information Sciences and Service Sciences | Year: 2011

Channel estimation is an important issue in any OFDMA system for demodulation and decoding. The channel estimation based on Comb type pilot arrangement in IEEE Std.802.16d/e is studied through different algorithms for both estimating channel at pilot frequencies and interpolating the channel. The estimation of channel at pilot frequencies is based on LS while the channel interpolation is done using linear interpolation, second-order interpolation and third-order interpolation. We have compared the performances of all schemes by measuring bit error rate with QPSK and BPSK as modulation schemes, and multipath Rayleigh fading channels as channel models. Theoretical analysis and computer simulations show that the third-order interpolation schemes can yield slightly better performance without considering the complexity.


Lu X.,Shenzhen Institute of Information Technology | Lu X.,Shenzhen Key Laboratory of Visual Media Processing and Transmission | Xu J.,Algorithm | Lin G.,Shenzhen Institute of Information Technology | And 2 more authors.
International Journal of Digital Content Technology and its Applications | Year: 2012

Channel estimation is an important issue in any OFDM system for demodulation and decoding. In this paper, the channel estimation based on LS(Least-squares Estimation) in IEEE Std.802.16d/e is studied to resolve the error floor for SUI-5 channel. Since the pilot allocation is solid, we can't modify it exhaustively. So we combine the preamble and pilot carrier to resolve the problem. Here we introduce preamble time-domain LS channel estimation algorithm based on short preamble and pilot for consult. Theoretical analysis and computer simulations show that if we select channel estimation algorithm properly, combing preamble and pilot can improve the performance. We also conclude that pilot only scheme exits error floor when the coherent bandwidth of channel is narrow, and preamble only scheme can decrease the error floor drastically when the coherent bandwidth of channel is narrow, however it can't trace the fast fading channel.


Hu T.,Shenzhen Institute of Information Technology | Hu T.,Shenzhen Key Laboratory of Visual Media Processing and Transmission | Ren X.-Y.,Shenzhen Institute of Information Technology | Ren X.-Y.,Shenzhen Key Laboratory of Visual Media Processing and Transmission | And 2 more authors.
Guangdian Gongcheng/Opto-Electronic Engineering | Year: 2013

The high-resolution PCB bare board images in online high-precision AOI detection system are up to 60000×60000 or more. In order to improve processing speed, image contours extraction and DP polyline simplification are used to reduce the amount of processing data. Distance measure of point to segment is one of determinants which affect the efficiency of DP algorithm. A new method to compute distance is proposed. Firstly, a rotating coordinate is established based on the two endpoints of curve, in which the new coordinate value is computed for each point and used to divide the points into three zones and calculate distance, and Manhattan distance is adopted in zone I and III, perpendicular distance in zone II. Compared with Dan Sunday's method, the proposed method takes full advantage of the computation result of the previous point, and the way to divide the points is more concise and efficient, the distance metric calculation amount for points in zone I and III basically keeps, but the amount for points in zone II which own highest proportion reduces significantly. Experimental results show that the improved distance measure method can improve the efficiency of DP polyline simplification algorithm for high resolution PCB bare board image contours.


Hu T.,Shenzhen Institute of Information Technology | Hu T.,Shenzhen Key Laboratory of Visual Media Processing and Transmission | Ren X.,Shenzhen Institute of Information Technology | Ren X.,Shenzhen Key Laboratory of Visual Media Processing and Transmission | And 4 more authors.
Guangdian Gongcheng/Opto-Electronic Engineering | Year: 2014

The most popular online high-precision Automatic Optical Inspection (AOI) detection system for PCB bare board adopts the inspection method based on contour vectorization and comparison, and arc detection is the key of realizing the contour vectorization. A new fast arc detection method is proposed. Firstly, segmentation primitives are obtained from contours by Douglas-Peucker polyline simplification algorithm and their normal angles are calculated. Then, the sum of difference between normal angles of each two adjacent primitives is calculated, which is used to build the normal angle transformation curve with the position of mid-point of primitive. Finally, DP algorithm is used again to detect the line segments in normal angle transformation curve to implement arc detection. The proposed algorithm simplifies the arc detection into two times line segment detection, and the complexity is O(n). Experimental results show that the proposed algorithm owns higher accuracy and lower cost time in comparison with the same module of Halcon software.


Guo S.,Shenzhen Institute of Information Technology | Guo S.,Shenzhen Key Laboratory of Visual Media Processing and Transmission | Chen S.-F.,Shenzhen Institute of Information Technology
Proceedings - International Conference on Machine Learning and Cybernetics | Year: 2012

In this paper, a new method is proposed to estimate crowd density based on binocular vision: according to the average parallax of the object in the two camera plane, first we calculate the correction parameters of monitoring location, then we fit the correction function based on the result of the correction parameters of the same target objects in different locations. By taking foreground pixels, foreground edge pixels of image as features of crowd density estimation, we could perform parameter correction. Experiments show that by comparing with existing methods, this method is effective in reducing the projective deformity and can improve the effectiveness of the features greatly. So it could enhance the accuracy of the estimation of population density. © 2012 IEEE.


Hu T.,Shenzhen Institute of Information Technology | Hu T.,Shenzhen Key Laboratory of Visual Media Processing and Transmission | Liu Z.,Shenzhen Institute of Information Technology | Cui J.,Shenzhen Institute of Information Technology | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

This paper introduces a coaxial visible and infrared dual-band imager, which utilizes the visible and infrared detection technology, uptakes the scenery radiation of different wavelengths or optical energy reflected, adopts transmission and secondary reflection theory to design the coaxial optical path, and realizes the dual-band imaging of same scene. The imager can acquire the registered visible and infrared images, and effectively solves the problem of registration for visible and infrared images in different-source image fusion. © 2013 SPIE.


Huang C.,Shenzhen Institute of Information Technology | Huang C.,Shenzhen Key Laboratory of Visual Media Processing and Transmission | Lu X.,Shenzhen Institute of Information Technology | Lu X.,Shenzhen Key Laboratory of Visual Media Processing and Transmission | And 2 more authors.
2010 2nd International Conference on Communication Systems, Networks and Applications, ICCSNA 2010 | Year: 2010

Resource Management in Differentiated Services (RMD) is a simple, scalable signaling method for resource reservation within a Differentiated Services domain. Currently, RMD is under the standardization in IETF Next Steps in Signaling (NSIS) working group. Based on the hypothesis of the network clock synchronization, this paper presents a new method for processing RMD QoS signaling. The new method can overcome some of the deficiencies of RMD and can be used as an alternative of the QoS signaling processing for RMD. The performance measurement and evaluation, comparing our method and RMD, are given by analysis and simulation. ©2010 IEEE.


Hu T.,Shenzhen Institute of Information Technology | Hu T.,Shenzhen Key Laboratory of Visual Media Processing and Transmission | Ren X.,Shenzhen Institute of Information Technology | Ren X.,Shenzhen Key Laboratory of Visual Media Processing and Transmission | And 2 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

Boundary extraction algorithm proposed by Capson can get the same or even better performance as the commercial software such as VisionPro andHalcon. Unfortunately, the algorithm cannot extract the inclusion relationship between boundaries, which greatly reduce its attractiveness. Two improvements is proposed to improve the original algorithm in this paper, one is to improve the precision of boundaries by splitting points and merging points, another one is to design new data-structure and rules to implement acquiring deep inclusion relationship between external and internal boundaries. Experimental results show that the improvements increase a little consuming time but make the original algorithm more attractive. © 2013 Springer-Verlag Berlin Heidelberg.


Guo S.,Shenzhen Institute of Information Technology | Guo S.,Shenzhen Key Laboratory of Visual Media Processing and Transmission | Chen S.,Shenzhen Institute of Information Technology | Chen S.,Shenzhen Key Laboratory of Visual Media Processing and Transmission | And 2 more authors.
Applied Mechanics and Materials | Year: 2013

When programming CUDA or OpenCL on multi-GPU systems, the programmers usually expect the GPUs on the same system can communicate fast with each other. For instance, they hope a device memory copy from GPU1s memory to GPU2s memory can be done inside the graphics card, and needn't to employ the PCIE, which is in relative low speed. In this paper, we propose an idea to add a multi-channel memory to the multi-GPU board, and this memory is only for transferring data between different GPUs. This multi-channel memory should have multiple interfaces, including one common interface shared by different GPUs, which is connected with a FPGA arbitration circuit and several other interfaces connected with dedicated GPUs frame buffer independently. To distinguish the shared memory of a stream multiprocessor, we call this memory Global Shared Memory. We analyze the performance improvement expectation with this global shared memory, with the case of accelerating computer tomography algebraic reconstruction on multi-GPU. © (2013) Trans Tech Publications, Switzerland.


Hu T.,Shenzhen Institute of Information Technology | Hu T.,Shenzhen Key Laboratory of Visual Media Processing and Transmission | Ren X.-Y.,Shenzhen Institute of Information Technology | Ren X.-Y.,Shenzhen Key Laboratory of Visual Media Processing and Transmission | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

Distance measure of point to segment is one of the determinants which affect the efficiency of DP (Douglas-Peucker) polyline simplification algorithm. Zone-divided distance measure instead of only perpendicular distance is proposed by Dan Sunday [1] to improve the deficiency of the original DP algorithm. A new efficiency zone-divided distance measure method is proposed in this paper. Firstly, a rotating coordinate is established based on the two endpoints of curve. Secondly, the new coordinate value in the rotating coordinate is computed for each point. Finally, the new coordinate values are used to divide points into three zones and to calculate distance, Manhattan distance is adopted in zone I and III, perpendicular distance in zone II. Compared with Dan Sunday's method, the proposed method can take full advantage of the computation result of previous point. The calculation amount basically keeps for points in zone I and III, and the calculation amount reduces significantly for points in zone II which own highest proportion. Experimental results show that the proposed distance measure method can improve the efficiency of original DP algorithm. © 2014 Copyright SPIE.

Loading Shenzhen Key Laboratory of Visual Media Processing and Transmission collaborators
Loading Shenzhen Key Laboratory of Visual Media Processing and Transmission collaborators