Tang Wenyan

Polarimetric Interferometric Eigenvalue Similarity Parameter and Its Application in Target Detection

Polarimetric synthetic aperture radar (SAR) interferometry (PolInSAR) combines SAR polarimetry and SAR interferometry and is much more sensitive to the distribution of orientated scatterers compared with polarimetric or interferometric data alone. The polarimetric similarity parameter is an efficient parameter to analyze target characteristics using the similarity between a target and the canonical target. In this letter, the polarimetric interferometric eigenvalue similarity parameter (PIESP) is proposed based on the similarity between two polarimetric SAR images obtained by two interferometric antennas. The PIESP is defined by the eigenvalues of two polarimetric coherence matrices in the PolInSAR system, and the eigenvalues of polarimetric coherence matrix are independent on the target orientation angle; therefore, the PIESP is rotation invariant. PolInSAR systems use two antennas to measure the same ground area with slightly different image geometry. Thus, the PIESP can be used to distinguish the target based on coherence and similarity. Then, the target detection method using the PIESP is implemented with the DLR experimental SAR L-band full polarized image of the Oberpfaffenhofen test site of Germany obtained on September 30, 2000. The results confirmed that the proposed model is accurate and effective for the detection and the analysis of buildings in urban areas.

Cutting edge sharpness measurement using angle limited total integrated scattering

This paper describes a new method for measuring the cutting edge sharpness by using angle limited total integrated scattering (ALTIS). Using this method, the radius of the cutting edges can be measured directly and assessed in numerical quantities. Hypothesizing that the normal cutting edges possess the elliptical profile, the relationship between the radius and the scattered light from the cutting edge is analyzed. Using the diode laser, three metal cutting tools are measured experimentally and the results are compared with those obtained from SEM.<<ETX>>

Flexible Measurement of Large Scale Column Structure's Centroid Based on Coordinate Measurement Equipment

A new measurement of large scale column structures centroid with coordinate measurement system was designed. The measure principle, equipment and measure process of this new method were discussed, and then the measurement uncertainty was analyzed. The results showed that this method has a high precision especially for the large scale column structure. So this method not only has the merit of flexible but also has broad application and development prospect.

Outlier Detection and Correction for the Deviations of Tooth Profiles of Gears

To decrease the influence of outlier on the measurement of tooth profiles, this paper proposes a method of outlier detection and correction based on the grey system theory. After studying the characteristics of outliers from the deviations of tooth profiles, this paper proposes a preprocessing method for the modeling data which include abnormal value, and establishes an outlier detection and correction model for the deviations of tooth profiles. Simulation results show that the precision of ONDGM(1,1)(one order and one variable non-homogenous discrete grey model whose outlier is processed by the preprocessing method proposed in this paper) is higher than that of NDGM(1,1)(one order and one variable non-homogenous discrete grey model), and the ONDGM(1,1) is more suitable than the NDGM(1,1) for dealing with the outliers from the deviations of tooth profiles. The experiment results show that the outlier detection and correction model detects and corrects the outliers from the deviations of tooth profiles, and the correction value of the outlier is basically in accordance with the actual deviation. Therefore, the method of outlier detection and correction decreases the influence of outlier and improves the precision in the measurement of tooth profiles.

Study on testing system of CW/QCW high-power laser diode array's divergence angle

A new testing system of CW/QCW high-power laser diode arrays (HLDA)s divergence angle was presented. The testing system included driving power, water cooling system, module of adjusting to center, detector and data acquisition module etc. The most important part of this testing system was detector for laser signal. It was designed by ourselves and made of two hemicycle probes. Two key problems of existing methods were resolved by this system. First, testing error induced by looking HLDA as point light source was reduced. Second, the problem that detector was shattered or burned because of high power was resolved. Besides data acquisition module contained two suits of disposing processes, in order to test divergence angle of either CW or QCW HLDA.