In the process of close-range photogrammetry, it is hard to stick markers directly on the surface of the object to be measured at times. Projecting optical markers is a good solution. However, there are some problems ...
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ISBN:
(纸本)9789813294417;9789813294400
In the process of close-range photogrammetry, it is hard to stick markers directly on the surface of the object to be measured at times. Projecting optical markers is a good solution. However, there are some problems for the existing optical markers such as difficulty in automatic matching and splicing. Therefore, this paper proposes the design and detection algorithm of white-light markers. White-light marker is composed of collar coded targets and circular non-coded targets. Collar coded targets are designed in the middle of the white-light marker, which can enhance the brightness of the coded strip and improve the recognition accuracy. Circular non-coded targets are designed around the collar coded targets, which can realize matching of non-coded targets among multiple images. Based on Canny operator, feature edges are extracted from the images. According to the criterions of scale, form, etc., the edges of markers are screened out. Markers containing coded strip is decoded to determine the identity. Center of gravity method is used to make the center position of white-light makers come true. The designed white-light marker is applied to the deformation detection experiment of crane girder. Its deformation curve is basically similar with the curve of sticking markers, which verifies the feasibility of the deformation detection of crane girder based on white-light markers.
Detecting a target out of its surrounding background is a major problem in various infrared seekers. The cluttered scenarios present extreme challenges for the modern IR seekers and are the focus of technology efforts...
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ISBN:
(纸本)0819455954
Detecting a target out of its surrounding background is a major problem in various infrared seekers. The cluttered scenarios present extreme challenges for the modern IR seekers and are the focus of technology efforts. So, a complete performance evaluation model should include all of the following elements: i) the background ii) the target, iii) the atmosphere, iv) the sensor, and v) the image processing algorithms. Since the staring IR seeker systems are emerging as the latest application of the thermal infrared technology, it suffers the most from the lack of complete performance evaluation models. We present a robust performance evaluation technique for staring IR seekers based on signal-to-interference ratio (SIR), with the quantitative description of the background clutter and detection algorithms emphasized. The power transfer functions of the optical system detector and electronic are established to describe energy transmission of the signal and interference (noise and clutter) through the IR seeker, and the targets' radiant intensity statistics as well as the noise's statistical characteristics are also taken into account. In order to quantify the background clutter, we use a clutter measure based on its energy content power spectral density (PSD). Based on this measure, a SIR is developed to analyze detection performance. Furthermore, the influence of several classical detection algorithms on the SIR is analyzed.
With the rapid development of dc system, the residual current in dc system has become an urgent problem to be solved. However, the type B residual current devices (RCD) for ac systems could not be directly used in dc ...
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ISBN:
(纸本)9781665422208
With the rapid development of dc system, the residual current in dc system has become an urgent problem to be solved. However, the type B residual current devices (RCD) for ac systems could not be directly used in dc systems. The ac residual current caused by distributed capacitance and the rectifier seriously interferes with the accurate detection of the dc residual current. A detection simulation model of dc residual current based on magnetic modulation was established. The authors also proposed detection algorithms based on Kalman filter and moving average filter separately. The experimental results showed that the proposed model and detection algorithms were effective. They could detect the residual current in the dc system under ac interferences.
The model we proposed synthesized the topological characteristics of the network to construct a multiindex evaluation matrix which was converted by Gaussian kernel function, and we got a new comprehensive and balanced...
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ISBN:
(纸本)9781845648299;9781845648282
The model we proposed synthesized the topological characteristics of the network to construct a multiindex evaluation matrix which was converted by Gaussian kernel function, and we got a new comprehensive and balanced multidimensional data by using the eigenvalues contribution as weights coefficient. We eventually obtained a one-dimensional evaluation vector based on the local optimization reconstruction of the data, and we verified the validity of the model using followed simulations. On the basis of the model, by defining a concept which called community element similarity, constructing a matrix of the community element importance and analyzing the dominate relationships between them, we proposed a new community detection algorithm. To verify the validity of the algorithm, some simulation experiments were conducted. The results indicate that the algorithm is rational and accurate.
A robust and real-time chipless radio-frequency identification (RFID) tag detection algorithm is presented in this paper. The detection technique is based on the analysis of both amplitude and phase response of freque...
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ISBN:
(纸本)9781728113098
A robust and real-time chipless radio-frequency identification (RFID) tag detection algorithm is presented in this paper. The detection technique is based on the analysis of both amplitude and phase response of frequency domain based chipless RFID tag to identify individual bits of tags reliably. An implementation of the proposed algorithm in low-cost Ultra-Wide Band (UWB) system as chipless RFID reader provides the flexibility of using for practical applications and replaces the expensive device such as Vector Network Analyzer (VNA). The laboratory experiment is conducted on fabricated co-polar and cross-polar chipless tags on Taconic CER-10 substrate as well as printed tags on the plastic film substrate. The multiple reading results show that the proposed detection algorithm has 99% reading accuracy for co-polar and cross-polar tag and 97% for a printed tag having low resolution.
Secondary ESD from a non-grounded decorative metal structure on an electronic device often leads to very large discharge currents and a fast rise time of less than 400 picoseconds. Due to the proximity of this seconda...
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ISBN:
(纸本)9781538666210
Secondary ESD from a non-grounded decorative metal structure on an electronic device often leads to very large discharge currents and a fast rise time of less than 400 picoseconds. Due to the proximity of this secondary ESD event to the electronics, it is likely to cause soft failures or latch-up. Secondary ESD can be detected in IEC 61000-4-2 setups by monitoring the currents, charge transfer, and sudden current increases due to the secondary ESD. An algorithm has been implemented in a test setup which automatically detects secondary ESD. However, due to pre-pulses, reignition of sparking within the relay, and other effects, the algorithm may lead to false positives and missed secondary ESD. This paper describes the implementation of the algorithm and presents the results of DUT testing.
The wide area monitoring system (WAMS) is critical for power system situational awareness, but represents a growing cybersecurity vulnerability. Malicious adversaries may seek to compromise one or more PMUs in order t...
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ISBN:
(纸本)9781728104072
The wide area monitoring system (WAMS) is critical for power system situational awareness, but represents a growing cybersecurity vulnerability. Malicious adversaries may seek to compromise one or more PMUs in order to effect control decisions that unnecessarily disrupt typical grid operations. One example of a particularly pernicious attack vector is the spoofing or replaying of a fault event using one or more compromised PMUs. This work documents the development and validation of a coherency-based cyberattack detection algorithm that integrates a sliding-window singular value decomposition (SVD) with physics-based partitioning analysis to achieve accurate classification of events. Special consideration is given to discerning a sophisticated fault-replay or fault spoofing attack from actual faults. A software-based cybersecurity testbed has been developed for rigorous testing of the algorithm. The algorithm is further validated using simulated synchrophasor datasets obtained from a MinniWECC 63-bus test system. Results show that the algorithm can successfully detect faultreplay attacks even when over half of the PMUs are compromised.
This paper presents an algorithm of hybrid collision detection. Firstly, the algorithm establishes sphere and OBB level bounding box for every model in virtual scene and then uses intersect test of sphere bounding box...
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ISBN:
(纸本)9780819489913
This paper presents an algorithm of hybrid collision detection. Firstly, the algorithm establishes sphere and OBB level bounding box for every model in virtual scene and then uses intersect test of sphere bounding box to exclude not intersect model. Between two model of maybe the intersection, it uses not intersect part of intersect test excluding model of OBB bounding box, reducing PSO searching space to inside of the nodes which collisions occur. The algorithm can exclude not intersect model quickly and avoid slowly and early maturity because of PSO target space bigger. Also, it reduces that level bounding box algorithm take a lot of memory and newer rate slow. At last, it certifies Hybrid Collision detection algorithm though laboratory and compared with based OBB and random collision detection algorithm which based on improved PSO algorithm.
One of the simplest ways of digital image forgery is a copy-move attack. The copy-move process consists of three stages: copy selected image fragment from one place, transform it using some image processing algorithm ...
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One of the simplest ways of digital image forgery is a copy-move attack. The copy-move process consists of three stages: copy selected image fragment from one place, transform it using some image processing algorithm and paste it to another place of the same image. Two main approaches to copy-move detection exist nowadays: feature-based and hash-based. Most of the algorithms are developed according to the feature-based approach, whereas the hash-based approach is used only for plain copymove detection (when the copied image fragment is not transformed). However, the main advantage of hash-based algorithms is low computational complexity. In this paper, we propose a new hash-based copy-move detection algorithm that can be applied to transformed duplicates detection due to a special preprocessing procedure. This procedure implements initial image transformation to incorporate the changes (affine transforms are not considered in this paper), produced by a transform algorithm on the second stage. Several preprocessing procedures are compared during experiments: image intensity range reduction, gradient calculation, expansion in orthonormal basis, adaptive linear contrast enhancement and local binary pattern. (C) 2017 The Authors. Published by Elsevier Ltd.
In order to find community structure that exists in complex network structure, this paper introduced K-means approach to the complex network community structure of the research. This paper studies the complex network ...
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ISBN:
(纸本)9783642293894
In order to find community structure that exists in complex network structure, this paper introduced K-means approach to the complex network community structure of the research. This paper studies the complex network of community structure detection algorithm, through the existing algorithm learn and study, proposed an improved algorithm based on K-means. Not know the premise of community structure for the complex networks division, the algorithm is simple and easy to understand, and the algorithm was used in karate network, through experimental verification, experimental results show that the algorithm is effective.
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