Papers by Author: S.H. Ye

Abstract: A novel diameter measurement device by laser scanning of which a flat-crystal was used as the core scanning part was designed. The device can generate high parallel scanning beam by means of the property that a beam won’t change its propagation direction after transmitting a flat-crystal. The influences on measurement error and range by using flat-crystal were analyzed in details. Theoretical analysis showed that the method was easy to realize and achieve high precision.

Abstract: It’s an important problem for power industry; energy industry, aviation and shipping to real-time measure the rotating blades’ tip clearance of engine. The conventional measurement techniques have different limitations. To achieve applied level for tip clearance measurement technique, according to the use request and application environment of tip clearance sensor, a new fiber-optic sensor was put forward to measure the blade tip radial clearance of engine in non-contact mode. The sensor was consist of single-bundle transmitting fiber in the center for laser beam delivery and three groups receiving fibers located in all around for collecting the scattered light. The sensor can not only eliminate the effect to measurement results of light source fluctuation and reflectivity variety of tip surface, but also reduce the effect of angle between the tip surface and sensor end face to measurement results. From the measurement results obtained from sensor on different clearance points, it proves that the sensor measuring system has well feasibility and reliability in blades tip clearance detection.

Abstract: This paper describes a method to characterizing the digital camera. The nonlinear relationship between the RGB signals generated by a digital camera and original image CIEXYZ values was obtained using the polynomial regression procedures. The reasonable structures of the polynomial were found for two digital cameras. The better number of polynomial terms was 19, yielding a modeling accuracy typically averaging 2.1~2.2 E ∆ units and maximally 9.5~10.9 E ∆ units. The experiments results showed that the polynomial regression could be used to characterize commonly digital camera.

Abstract: For 3D digital measurement of large scale objects, image mosaic is the key technology to achieve whole measurement for a small measuring field of the sensor unit. A viscous-target-based three-dimensional image mosaic technology is proposed. The screw theory is introduced to realize the spatial image mosaic. The method permits an automatic identification of targets and a better matching for the feature coded technology. In experiments, the method was proved to be valid, with a relatively high precision on three-dimensional image mosaic. The relative error of the space length measurement is less than 0.6%.

Abstract: Rapid progress in modern manufacturing demands for better measurement technique with on-line characteristics. This paper presents a systematic visual solution for on-line industrial 3D measurement. The solution comprises two parts, a multi-sensor visual inspecting station (MSVIS) and a digital close-range visual inspecting station (DCVIS). MSVIS is an integrated system with many sensors. It can meet the requirement of application with sparse measuring points distributed within a large volume. DCVIS only contains two digital cameras with one or more projectors. It has high relative accuracy and a small set up volume and is suitable for applications with dense measuring points. The combined use of MSVIS and DCVIS can provide a general solution for on-line industrial 3D measurement.

Abstract: Linearity is a very important parameter for seamless steel pipes. A real-time and on-line visual measurement system for seamless steel pipe linearity is presented. The system consists of several structured-light visual sensors. Each sensor can achieve the coordinate of the center of partial steel pipe in its local coordinate system. Through global calibration, all coordinates measured can be transformed into an integrated coordinate system. The linearity error of steel pipe can be assessed. This method can fulfill 100% on-line and real-time linearity measurement. A pair structure-light sensor is designed to improve accuracy and a suspension-wires method for sensor calibration and global calibration is used. Through experiments, it shows that the method not only meets the need of precise calibration but also significantly improves the efficiency and feasibility.

Abstract: In this paper, the main new point is the use of a non-contact combinational system with a capacitive sensor and eddy current sensors to acquire measurement signals and the use of LabVIEW software platform for real time data processing of plastic film thickness. Using a combinational measurement system to replace a traditional micrometer, the thickness of plastic film can be measured intelligently, real time, and in non-contact mode with high precision. The whole system consists of a test unit, a data acquisition unit, a motor driving unit, and a data processing unit. The test unit does measurement by means of capacitive sensor and eddy current sensors. The system is operated on the LabVIEW software platform for automatic control of the whole process. The measurement process is faster. The test results from the combinational measurement system are compared with the results from a micrometer. It shows that this measurement system has higher precision and better repeatability, reliability and feasibility.

Abstract: This paper describes a system that detects and categorizes workpieces with random defects on electrodeposits glossy metal surface. The system is developed on the basis of combination CCD photoelectricity inspection technology, image processing and automatic control technology. In the system, a special illumination apparatus with a light source of diffused light is designed. Workpieces with defects are automatically selected through measurement with image enhancement retreatment, gray scale analysis, image binaryzation, feature extraction and image recognition. Hardware comprises sections of optics, image collection, and control circuits. Software is programmed in Visual C++ and assembly language. The system can resolve the difficulty of detecting random defects on surface under the conditions of high reflection and complex surfaces.

Abstract: Porous silicon with pore size in the range of a few nanometers can be used as multifunctional material in different MEMS applications. Via an electrochemical etching method, porous silicon is fabricated on the silicon substrate and removed as a sacrificial layer by using KOH solution to form a micro structure. This technique is typical in micro fabrication. Three-dimensional size is the basic geometric feature to describe microstructure surface characteristics. It is important to investigate measurement methods for it. UBM Microfocus Measurement System based on defocusing error detection is adopted to measure eroded depth of silicon cup. The measured data in the experiments are analyzed. The influence of etching time, current density and silicon type on etching depth can be acquired. Effective reference data can be provided for studying micro fabrication methods.

Abstract: This paper provides a preprocessing flow for color three-dimension (3D) point cloud according to the characteristics of laser scanning data. The preprocessing methods and their functions are introduced in detail. Automatic system decision and manual polygon selection methods are applied to eliminate unwanted and noise data successfully, which possibly make improper color models reconstructed. A data reduction method is presented based on Grid reduction method considering color-boundary preservation. It can effectively avoid shape and color distortion in model reconstruction. Several experimental results are presented to indicate the feasibility and reliability of these methods, which can be broadly applied in various fields of products design, antiques and art wares digitization, etc.