Key Laboratory of Precise Engineering and Industry Surveying

Wuhan, China

Key Laboratory of Precise Engineering and Industry Surveying

Wuhan, China
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Mao G.,Wuhan University | Mao G.,Key Laboratory of Precise Engineering and Industry Surveying
Journal of Geomatics | Year: 2017

At present, we mainly rely on manual interpretation on digital radiography (DR) images to detect the defects for steel tube X-ray detection techniques. This method is easily affected by the subjectivity of the observer, and has excessive labor work and low efficiency. To substitute manual interpretation, according to the characteristics of DR images, this paper studies the steel tube defects detecting algorithm based on digital images processing. Experimental results show that, the algorithm introduced in this paper has good adaptability and have an advantage over manual interpretation in detecting tiny defects and detection efficiency, which satisfying the requirement to detect defects in real time.


Yang C.,Wuhan University | Yang C.,Key Laboratory of Precise Engineering and Industry Surveying | Liu G.,Wuhan University | Liu G.,Key Laboratory of Precise Engineering and Industry Surveying
Journal of Geomatics | Year: 2017

During the application of CP III plane control survey in high speed railway, there exists a large distance deviation between observation points in every direction. When GeoRobot is used to collect the data automatically, the 2C error between the long and short sides in one measuring-circle can be beyond the limit, which will seriously affect the working efficiency. By analyzing the mechanism of 2C and ATR error, and examining it with experiments, this paper proposes some suggestions for improvement in quality examination of obeservation data, which increases the efficiency of field work under the premise of satisfying the measurement precision.


Hu X.,Wuhan University | Huang S.,Wuhan University | Huang S.,Key Laboratory of Precise Engineering and Industry Surveying | Pang H.,Hebei Electrical Power Engineering Supervision Co.
Journal of Geomatics | Year: 2017

Wavelet denoising is a data processing method, whose choice of decomposition scale has influence on the denoising effect. This paper introduces the method based on RMSE (root mean square error) change rate, the method based on collective evaluation index, multi-index fusion method and composite evaluation index method, through the comparative analysis of the simulation experiment and the denoising of the deformation monitoring data, the results show that the methods based on the RMSE change rate has a good effect on the low-noise signal processing; the multi-index fusion method can only determine the approximate range of the wavelet decomposition scale, and the methods based on the collective evaluation index and composite evaluation index can accurately determine the wavelet decomposition scale, and are not affected by noise.


Xing W.,Wuhan University | Xing W.,Key Laboratory of Precise Engineering and Industry Surveying
Journal of Geomatics | Year: 2017

In the nuclear power industry, a feeding pipe of a charging machine is rotatable around its cylindrical axes during the feeding process. And shift errors may occur when the feeding pipe rotates. Aimed at measuring the shift error which is called roundness, a design plan based on computer image processing and wireless data transmission has been proposed. A fast and accurate real-time monitoring system for roundness measurement of charging machine has been realized, which is suitable for the application of nuclear power plants, and has the characteristics of high efficience, convenience, cost-effectiveness and safety.


Zhang T.,Wuhan University | Zhang T.,Key Laboratory of Precise Engineering and Industry Surveying | Li Z.,Daya Bay Nuclear Power Operations and Management Co.
Journal of Geomatics | Year: 2017

Aqueduct of nuclear power plant undertakes the cooling water transportation for the nuclear power plant, it is directly related to the safe operation of nuclear power plants. On the year a number of water erosion, so its safety monitoring has a lot of significance. In this paper, a aqueduct expansion joint monitoring system is designed and implemented, and some of the data are primarily analyzed, and we draw the conclusion that the width of aqueduct expansion joint has a direct relationship with temperature. The horizontal and vertical displacements of both sides of the expansion joint are also related to the temperature, but the displacement is small.


Sun X.,Wuhan University | Sun X.,Key Laboratory of Precise Engineering and Industry Surveying | Chen X.,Daya Bay Nuclear Power Operations and Management Co.
Journal of Geomatics | Year: 2017

Geometric correction is the process of eliminating geometric distortion from deformation pattern. We can detect cracks on nuclear power plant containment image automatically by image processing method. The images taken via photo total station will inevitably produce tilt, offset, distortion and other distortion due to photographing angle factors, shell cylinder downs and camera distortion, etc. Before the after-image stitching and analysis, it must be geometrically corrected at first. This paper generally introduces the method of containment equation establishing and photo total station calibration, and explains theoretical basis of geometric correction method based on collinear equation. The feasibility of the method is validated by simulation experiment.


Huang J.,Wuhan University | Xing C.,Key Laboratory of Precise Engineering and Industry Surveying
Journal of Geomatics | Year: 2017

As to the poor texture images on the surface of nuclear containment, this paper puts forward a fast image mosaic algorithm on the basis of position constraint. The constraint conditions are based on the fixed requirements of image acquisition, such as photographic distance, camera spacing, strip spacing, etc. For the images within strips, SURF feature matching, scaling and clipping is carried out. For the images between neighboring strips, clipping directly without feature matching. Experimental results show that this method is fast and effective, and can obtain a good visual effect.


Shi J.,Hubei University | Shi J.,Key Laboratory of Precise Engineering and Industry Surveying | Xu C.,Hubei University | Xu C.,Key Laboratory of Precise Engineering and Industry Surveying | And 2 more authors.
Journal of Geodesy | Year: 2015

Global Positioning System (GPS) has become a cost-effective tool to determine troposphere zenith total delay (ZTD) with accuracy comparable to other atmospheric sensors such as the radiosonde, the water vapor radiometer, the radio occultation and so on. However, the high accuracy of GPS troposphere ZTD estimates relies on the precise satellite orbit and clock products available with various latencies. Although the International GNSS Service (IGS) can provide predicted orbit and clock products for real-time applications, the predicted clock accuracy of 3 ns cannot always guarantee the high accuracy of troposphere ZTD estimates. Such limitations could be overcome by the use of the newly launched IGS real-time service which provides ∼5 cm orbit and 0.2–1.0 ns (an equivalent range error of 6–30 cm) clock products in real time. Considering the relatively larger magnitude of the clock error than that of the orbit error, this paper investigates the effect of real-time satellite clock errors on the GPS precise point positioning (PPP)-based troposphere ZTD estimation. Meanwhile, how the real-time satellite clock errors impact the GPS PPP-based troposphere ZTD estimation has also been studied to obtain the most precise ZTD solutions. First, two types of real-time satellite clock products are assessed with respect to the IGS final clock product in terms of accuracy and precision. Second, the real-time GPS PPP-based troposphere ZTD estimation is conducted using data from 34 selected IGS stations over three independent weeks in April, July and October, 2013. Numerical results demonstrate that the precision, rather than the accuracy, of the real-time satellite clock products impacts the real-time PPP-based ZTD solutions more significantly. In other words, the real-time satellite clock product with better precision leads to more precise real-time PPP-based troposphere ZTD solutions. Therefore, it is suggested that users should select and apply real-time satellite products with better clock precision to obtain more consistent real-time PPP-based ZTD solutions. © 2015, Springer-Verlag Berlin Heidelberg.


Xu Y.,Wuhan University | Xu Y.,Key Laboratory of Precise Engineering and Industry Surveying | Zhou J.,Wuhan University | Zhou J.,Key Laboratory of Precise Engineering and Industry Surveying | And 2 more authors.
IEEE Communications Letters | Year: 2014

In this letter we present a novel method for source node localization using received signal strength in situations where path-loss model parameters are unknown. First, a ratio approach is used to eliminate the transmitting power uncertainty, then, combined with a search method for path-loss exponent under certain constraints, linear least squares is utilized to determine the location of the source node. Simulations are used to demonstrate the feasibility and suitability of the proposed method. The simulation results indicate that the method presented outperforms other off-the-shelf source node localization algorithms intended for use when path-loss model parameters are unknown. © 2014 IEEE.


Zhang Z.,Wuhan University | Zhang Z.,Key Laboratory of Precise Engineering and Industry Surveying
Journal of Geomatics | Year: 2014

From the definition of engineering geodesy departure, the development history of engineering measurements is described combining with typical historical data. It is discussed that the relations of development status by engineering geodesy with the rapid progress and great development of science and engineering construction in nearly half a century. The development direction and character of this discipline are pointed out. Development trend of engineering geodesy is proposed. It is prospected that engineering geodesy will be further developed to the macro and micro aspects.

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