带声匹配板的Tonpilz压电水声换能器

1.引 言 宽带大功率水声换能器由于具有优良的脉冲响应特性,且能够接收和发射各种信号,它已不仅是高分辨力声纳的关键部件,而且已成为水下通信系统必不可少的关键部件。 本文所述的换能器是附加有声匹配板的Tonpilz换能器(Tonpilz换能器即串并联电路机械模拟换能器—译注),它是根据多模式滤波器合成理论设计的。

基于FFT的海底地形二维匹配技术

海底地图匹配技术是水下地形辅助导航的核心技术之一,它主要用来提高水下载体(AUV)的定位精度,提出了基于付立叶变换的海底地形二维匹配算法(FFT算法),通过FFT变换将频域中幅值引入匹配,设计了位置匹配圆板进行实时图位置匹配与方向搜索模板进行方向搜索。应用实际海图原始数据进行仿真,结果表明,该算法能够同时匹配出位置信息和方向信息,具有较高的匹配精度和抗差特性。

电除尘器线电流密度分布实验研究

在电除尘器板线匹配的研究中，电晕极线电流密度分布的研究是其中一方面。本实验在单通道电除尘器中，采用直接测量每根电晕极的电流的方法，分别板间距、线间距、施加电压和线型对线电流密度分布的影响。

A color based face detection system using multiple templates

A color based system using multiple templates was developed and implem ented for detecting human faces in color images. The algorithm consists of three image processing steps. The first step is human skin color statistics. Then it separates skin regions from non-skin regions. After that, it locates the fronta l human face(s) within the skin regions. In the first step, 250 skin samples from persons of different ethnicities are used to determine the color distribution o f human skin in chromatic color space in order to get a chroma chart showing lik elihoods of skin colors. This chroma chart is used to generate, from the origina l color image, a gray scale image whose gray value at a pixel shows its likelih ood of representing the skin. The algorithm uses an adaptive thresholding proces s to achieve the optimal threshold value for dividing the gray scale image into separate skin regions from non skin regions. Finally, multiple face templates ma tching is used to determine if a given skin region represents a frontal human fa ce or not. Test of the system with more than 400 color images showed that the re sulting detection rate was 83%, which is better than most color-based face dete c tion systems. The average speed for face detection is 0.8 second/image (400×300 pixels) on a Pentium 3 (800MHz) PC.

A novel algorithm for a rotation invariant template matching

A novel algorithm for a rotation invariant template matching is proposed when the fluctuating scope of the rotation angle is limited within the region of [-20°,20°]. The matching candidates are selected using a computationally low cost improved correlation algorithm. "AND" operation is adopted to reduce the computational cost. Therefore the algorithm improves the matching speed consumedly. The simulation results verify the efficiency of the proposed method. Moreover,when the size of reference image is fixed,the advantage of this time-saving algorithm is more obvious as the increase of the size of the real time image. The matching speed of the proposed method is over 20 times faster than the speed of the two-level pyramid decomposing accelerating method.

SYMBOL-RATE ESTIMATION BASED ON TEMPLATE MATCHING RULES

For non-cooperative communication, the symbol-rate estimation of digital communication signal is an important problem to be solved. In this letter, A new algorithm for the symbol-rate estimation of single-tone digitally modulated signal (i.e. MPSK/QAM) is proposed. Firstly a section from the received signal is cut as the template, and then the signal is matched sectionwise by making use of the signal selfsimilarity. So a signal con- taining the information of symbol jumping is got, and the symbol-rate can be estimated by DFT (Discrete Fou- rier Transformation). The validity of the new method has been verified by experiments.

A signal-substrate match in the substrate-borne component of a multimodal courtship display

The environment can impose strong limitations on the efficacy of signal transmission. In particular, for vibratory communication, the signaling environment is often extremely heterogeneous at small scales. Nevertheless, natural selection is expected to select for signals well-suited for effective transmission. Here, we test for substrate-dependent signal efficacy in the wolf spider Schizocosa stridulans Strattou 1991. We first explore the transmission characteristics of this important signaling mo- dality by playing recorded substrate-bome signals through three different substrates （leaf litter, pine litter, and red clay） and measuring the propagated signal. We found that the substrate-bome signal of S. stridulans attenuates the least on leaf litter, the substrate upon which the species is naturally found. Next, by assessing mating success with artificially muted and non-muted males across different signaling substrates （leaf litter, pine litter, and sand）, we explored the relationship between substrate-bome signaling and signaling substrate for mating success. We found that muted males were unsuccessful in obtaining copulations re- gardless of substrate, while mating success was dependent on the signaling substrate for non-muted males. For non-muted males, more males copulated on leaf litter than any other substrate. Taken together, these results confLrm the importance of sub- strate-bome signaling in S. stridulans and suggest a match between signal properties and signal efficacy - leaf litter transmits the signal most effectively and males are most successful in obtaining copulations on leaf litter [Current Zoology 56 （3）： 370-378, 2010].

Research on the measurement of belt speed by video in coal mine based on improved template matching algorithm

In order to improve the intelligence of video monitoring system of belt and make up the deficiency of higher failure rate and bad real-time performance in the traditional systems of measurement of belt speed, according to the fact that the light of coal mine is uneven, the strength of light changes greatly, the direction of belt movement is constant, and the position of camera was fixed, various algorithms of speed measurement by video were studied, and algorithm for template matching based on sum of absolute differences （SAD） and correlation coefficient was proposed and improved, besides, the tracking of feature regions was realized. Then, a camera calibration method using the invariance of the cross-ratio was adopted and the real-time measurement of belt speed by the hardware platform based on DM642 was realized. Finally, experiment results show that this method not only has advantages of high precision and strong anti-jamming capability but also can real-time reflect the changes of belt speed, so it has a comprehensive applicability.

Research on ultrasonic detection of complex surfaces

Parts of complex surface are widely used now in many fields, and their detection has caused much concern. In China many manufactories still carry on the traditional way of manual detection, which requires highly skilled personnel and efficiency is low. Some large manufactories have imported auto-detecting equipments, which require CAD data on the parts, or just divide the surface into several approximate planes for automatic detection. Phased-array system is seldom used, and the cost is high. Besides, most of the systems have not considered the automatic sensitivity compensation of parts with varying thickness. To improve the detection quality and efficiency of nondestructive test (NDT) of parts of complex surface, this paper puts forward an integrated ultrasonic NDT system characterized by: (1) Use of ultrasonic measurement and reverse of curved surface to solve the CAD data problem; (2) Use of an automatic sensitivity compensation algorithm (based on the part’s modelling information obtained in surface reverse) to fit the variety of the thickness; (3) Use of template matching and pseudo-color imaging to improve the quality of detection results. The system features integration of low cost mature technologies, and is suitable for detection of various parts of different complex surfaces in medium-and-small enterprises. The test results showed that the system can automatically detect parts of complex surface successfully, and that the inspection result is good and reliable.

Introducing semantic information into motion graph

To improve motion graph based motion synthesis,semantic control was introduced.Hybrid motion features including both numerical and user-defined semantic relational features were extracted to encode the characteristic aspects contained in the character's poses of the given motion sequences.Motion templates were then automatically derived from the training motions for capturing the spatio-temporal characteristics of an entire given class of semantically related motions.The data streams of motion documents were automatically annotated with semantic motion class labels by matching their respective motion class templates.Finally,the semantic control was introduced into motion graph based human motion synthesis.Experiments of motion synthesis demonstrate the effectiveness of the approach which enables users higher level of semantically intuitive control and high quality in human motion synthesis from motion capture database.

Joint detection method of pornographic images with skin-like color background

A novel approach is proposed to automatically detect pomographic images with skin-like color background on the Intemet using the locations of human faces and bodies. It has two separate skin-color detection steps： the first one is to quickly detect the potential human skin-color regions; and the second one is to use an off-the-shelf face detector to locate a human face and then apply hypothesis testing based on series of assumptions which take into account the face-height ratio, body orientation and modem photograph composition common sense, etc. After that, a template matching method is used to further discriminate normal images or pornographic ones. Experimental results show that the proposed method has high precision and real time speed.

Tracking Submicron Particles in Microchannel Flow by Microscopic Holography

Three-dimensional tracking of submicron particles in flows in a micro-channel was carried out using in-line holographic microscopy.A fixed single 0.5 μm fluorescent particle was identified and isolated from dust particles or overlapped particle pair using the laser induced fluorescent(LIF) method.Then in-line microscopic holograms of the fixed single particle were obtained at different positions on the optical axis,i.e.the defocus distances.The holograms of the single particle were used as the model templates with the known defocus distances.The particles in the in-line microscopic holograms of flow in the microchannel were then identified and located to obtain their two-dimensional positions.The defocus distances of those particles were determined by matching each hologram pattern to one of the model templates obtained in the single particle test.Finally the three-dimensional position and velocity of each particle were obtained.

AUTOMATIC TARGET RECOGNITION OF RADAR HRRP BASED ON HIGH ORDER CENTRAL MOMENTS FEATURES

The paper addresses the problem of target recognition using High-resolution Radar Range Profiles(HRRP).A novel approach of feature extraction and dimension reduction based on extended high order central moments is proposed in order to reduce the dimension of range profiles.Features extracted from radar HRRPs are normalized and smoothed,and then comparative analysis of the similar approaches is done.The range profiles are obtained by step frequency technique using the two-dimensional backscatters distribution data of four different aircraft models.The template matching method by nearest neighbor rules,which is based on the theory of kernel methods for pattern analysis,is used to classify and identify the range profiles from four different aircrafts.Numerical simulation results show that the proposed approach can achieve good performance of stability,shift independence and higher recognition rate.It is helpful for real-time identification and the engineering implements of automatic target recognition using HRRP.The number of required templates could be reduced con-siderably while maintaining an equivalent recognition rate.

Biological object recognition approach using space variant resolution and pigeon-inspired optimization for UAV

Recognizing the target from a rotated and scaled image is an important and difficult task for computer vision. Visual system of humans has a unique space variant resolution mechanism(SVR) and log-polar transformations(LPT) is a mapping method that is invariant to rotation and scale. Motivated by biological vision, we propose a novel global LPT based template-matching algorithm(GLPT-TM) which is invariant to rotational and scale changes; and with pigeon-inspired optimization(PIO) used to optimize search strategy, a hybrid model of SVR and pigeon-inspired optimization(SVRPIO) is proposed to accomplish object recognition for unmanned aerial vehicles(UAV) with rotational and scale changes of the target. To demonstrate the efficiency, effectiveness and reliability of the proposed method, a series of experiments are carried out. By rotating and scaling the sample image randomly and recognizing the target with the method, the experimental results demonstrate that our proposed method is not only efficient due to the optimization, but effective and accurate in recognizing the target for UAV.

A Real-Time Collision-Free Path Planning of a Rust Removal Robot Using an Improved Neural Network

In this paper, a real-time collision-free path planning of the rust removal robot in a ship environment is proposed, which is based on an improved biologically inspired neural network algorithm. This improved algorithm is based on the biologically inspired neural network and modified with obstacle detection sensors and kinematic state templates, and is implemented in a ship rust removal robot planning system for dynamic trajectory generation. The real-time optimal trajectory is generated by the biologically inspired neural network, and the moving obstacle detection process of a ship robot working on the wall is simulated with the obstacle detection sensors models. The local real-time trajectory can be re-planned by the updated local map information, where the obstacle detection sensors are used to inspect partial environment information and update the robot nearby information in real time in the original neural network algorithm. At the same time, the method of the kinematic state templates matching and searching is used to solve the pipes’ influence of the rust removal robot climbing on the wall, which can not only provide a smooth path, but also can judge the motion direction and turning angle of the robot. Comparison of the proposed approach with the simulation shows that the improved algorithm is capable of planning a real-time collision-free path with achieving the local environmental information and judging the rust removal robot’s motion direction and turning angle. This proposed algorithm can be good used in the ship rust removal robot. © 2017, Shanghai Jiaotong University and Springer-Verlag GmbH Germany.