Advanced Materials Research Vols. 945-949

Abstract: The generation of the OPC technology makes each data source communicate flexibly in the industrial control environment. This paper takes the no-load test platform of the metro bogie as an example to design a lower and upper computer measurement and control system which is consist of IPC and PLC by the OPC technology. The OPC client is developed based on the platform of Visual Basic. By using the different communication mode, it is realized to access the OPC server data.

Abstract: When optical 3D shape measurement equipment works, they gather dense point cloud using mark points as artificial feature for the purpose of global registration; as a result, rough registration error of multiple scans depends primarily on the location accuracy of these mark points. This paper analyses the 3D measuring error distribution law of the mark points in difference direction, proposes that the measurement error in z direction varies as positive proportion with z square, and inversely proportion with distance between two cameras.

Abstract: It is proved that in LOS detection,"moment of inertia based method" and "PCA based method" are in fact equivalent. Then the method is abstractly redefined as "distance variance extremum based method".

Abstract: Binocular stereo vision ranging method taking contour boundary center of measurement object as matching features was investigated. And experimental platform for binocular stereo vision ranging system was built up. The stereo vision ranging system comprised four modules: camera calibration, stereo calibration, stereo rectification and features extraction. Firstly, the intrinsic parameters of single camera were obtained by camera calibration and relative pose of two cameras was obtained by stereo calibration. Then the left and right images were rectified into a frontal parallel arrangement by Bouguet’s method. The edge pixels of contours were detected by image processing. Then the disparity and the distance was calculated taking contour center as matching features. Finally, measurement error analysis was performed to verify the proposed method with good practicability.

Abstract: For conveyor belt vertical tear fault, in order to shoot image the high speed camera of gigabit network which used in industry is used in this paper. And every frame image is transferred to PC, whether the image tear in the PC will be identified. Compare with the identifying tape image which is transferred to the PC of longitudinal tear in average filtering and median filtering is studied in this paper, to obtain the best way to detecting tear, and using C# language which is under Visual Studio to write image collection, processing, time-frequency transformation and recognition programs.

Abstract: Proximate analyzer is broadly used for determination of coal, so it is very important to evaluate its performance, orderly, the proximate analyzer is needed to be calibrated by metrology organizations. But there is no standard or regulation for proximate analyzer calibration in our country. On the basis of the function characteristics of proximate analyzer, the authors have suggested the calibration methods of temperature control performance, indication error and repeatability of ash and volatile, and the general technical requirement which includes appearance, insulation resistance, and insulation strength. The experimental results prove that this method can evaluate the performance of the proximate analyzer accurately and comprehensively.

Abstract: Waveform analysis method is widely used for feature extraction of liquid drop fingerprint, but it is easily affected by noise. To solve this problem, waveform fitting and analysis method based on polynomial fitting is proposed, though which the waveform of liquid drop fingerprint is fitted to be a smooth curve. Experimental results show that waveform fitting and analysis method is able to reduce the standard deviation and maximum difference of eigenvectors from the same kinds of liquid, and thus increase the recognition accuracy rate of 10 kinds of water based on BP neural network from 86.5% to 100%.

Abstract: sub-region stitching measurement of asphere by using the combination of digital moire patterns without compensator, auxiliary mirror and other assistant modules. This paper illustrated the principal theory. And use of digital filtering, phase shifting, the least square method and Zernike polynomial fitting to establish the reasonable mathematical model. Meanwhile the computer simulation experiment was carried on. the PV and RMS of the full aperture phase distribution residual error are 0.058λand 0.0087λ After this method processing.

Abstract: Based on the characteristics that ship underwater electric signal is waek, a kind of ship underwater electric signal acquisition equipment of hardware structure is designed. With instrumentation amplifier of high-precision and low noise and low pass filter module, the electric field signal collected by three dimension sensor is filtered and amplified. It ensures the integrity and validity of acquisition signal.

Abstract: Hydrophone arrays are generally used in modern sonar systems in which beam forming plays an important role. This paper analyzes the beam space MUSIC (multiple signal classification) algorithm for the weakly correlated sources according to changes in the statistical properties of signal and noise, then estimates the azimuth of multi-sources using array element space MUSIC algorithm and beam space MUSIC algorithm accurately, respectively. Finally, problems such as the computation cost of the algorithms, SNR resolution threshold and estimation deviation are discussed based on simulation tests. A conclusion could be drawn that beam space MUSIC algorithm is an effective way to resolve multiple targets in small angle domain.