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Simulation study of phase retrieval for hard X-ray in-line phase contrast imaging

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Science china(Physics,Mechanics & Astronomy) 2005年第4期48卷 450-458页

作者： YU Bin1,2. PENG Xiang1,2. TIAN Jindong1, NIU Hanben1, DIAO Luhong3.& LI Hua3.1. key {3. of Optoelectronic Devices and Systems of Ministry of Education, Institute of Optoelec- tronics, Shenzhen {2., Shenzhen 518060, china 2. state key {3. of precision measuring Technology and instruments,{13., tianjin 3.0072,china 3. key {3. of Intelligent Information Processing, Institute of Computing Technology, Chinese Academy of Sciences, Beijing 100080,china 1. key laboratory of Optoelectronic Devices and Systems of Ministry of Education Institute of Optoelectronics Shenzhen University 518060 Shenzhen China 2. state key {2. of precision measuring Technology and instruments Tianjin University 300072 Tianjin China 3. key laboratory of Intelligent Information Processing Institute of Computing Technology Chinese Academy of Sciences 100080 Beijing China

Two algorithms for the phase retrieval of hard X-ray in-line phase contrast imaging are presented. One is referred to as Iterative Angular Spectrum Algorithm (IASA) and the other is a hybrid algorithm that combines IASA with TIE (transport of intensity equation). The calculations of the algorithms are based on free space propagation of the angular spectrum. The new approaches are demonstrated with numerical simulations. Comparisons with other phase retrieval algorithms are also performed. It is shown that the phase retrieval method combining the IASA and TIE is a promising technique for the application of hard X-ray phase contrast imaging.

关键词： X-ray optics, phase contrast imaging, phase retrieval, angular spectrum, hard X-ray.

New Laser Interferometer with OPD Multiplication for Nanometer Measurement

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Chinese Journal of Lasers 1999年第5期8卷 3-5页

作者： ZHAO Meirong QU Xinghua WANG Hailong LU Boyin(state key {2. of {3. measuring Technology and instruments,tianjin university, tianjin 3.0072, china) 天津大学精密测试技术及仪器国家重点实验室天津

By using coupled differential interferometry a new laser displacement measurement interferometer with nanometric accuracy has been developed The resolution and the stability of the interferometer are improved by multiplicating the optical path difference (OPD). The new interferometer is simple in concept, symmetric in optical paths, without optical deadpath, easy to set up and align. λ/1600 resolution and nanometric accuracy are achieved within the measurement range of 10mm.

关键词： nanometer nanometroolgy laser interferometer displacement measurement differential interfrometry OPD multiplication

The Optical Characteristics of the Acousto-optic Tunable Filter with the Equivalent Point

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Chinese Journal of Lasers 2002年第2期11卷 55-60页

作者： XU Kexin NI Yong XUE Bin JIANG Chengzhi HU Xiaotang( state key {2. of {3. measuring Technology and instruments, tianjin university, tianjin 3.0072, china) tianjin university State Key Laboratory of Precision Measuring Technology and Instruments 天津 300072

In this paper, the interaction curves of acoustic and optical waves in a non-collinear AOTF (acousto-optic tunable filter) cell under the parallel-tangent momentum matching condition are analyzed systematically. A new theory of equivalent point for AOTF design is put forward. The wavelength characteristics and the wavelength resolution of two diffraction beams with equivalent point design in AOTF are emphatically analyzed. The optical characteristics at δ = 0 (ideal case) and δ≠0 (real case) are also discussed. The advantages of the AOTF with equivalent point design include high wavelength resolution, more quantitative energy and larger incident angle aperture.

关键词： equivalent point momentum matching AOTF TeO2

Optic Fiber Interferometer for Absolute Distance Measurement

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Chinese Journal of Lasers 1997年第5期B6卷 435-440页

作者： WANG Zhong HONG Haitao XIAO Hai SUN Changku MENG Yan YE Shenghua (state key {2. of {3. measuring Technology and instruments,tianjin university, tianjin 3.0072, china) tianjin Univ Tianjin China

A synthesized scheme is presented to solve the ambiguity problems in ab-solute distance measurement, the principle and the structure of the system is introduced. The digital signal process for fast positioning is discussed in detail. Meanwhile, an expansion method is put forward to expand the dynamic range of the optic fiber interferometry system. Some experimental results are given.

关键词： absolute distance measurement optic fiber interferometer digital signal process

STUDY ON A PRECISE ON-SPOT CALIBRATION METHOD FOR DISTRIBUTED STEREO REFERENCE POSITION-SETTING

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Chinese Journal of Mechanical Engineering 2002年第4期15卷 324-327页

作者： Wang Zhong Kou Xinyu Chen Mingzhou Ye Shenghuastate key {2. of {3. measuring Technology and instruments, tianjin university,tianjin 3.0072, chinaXiong Chunbaotianjin university tianjin university State Key Laboratory of Precision Measuring Technology and Instruments 天津 300072

A high precision method used for on-spot calibration of distributed stereoreference position setting is presented. The high measuring accuracy in stereo reference calibrationis derived from using a high precision water level instrument and an accurate height verniercaliper. It settles the problem of reference calibration effectively and accurately, without usinglarge coordinate measuring machines (CMM). It is more adaptable and precise than traditionalcalibration methods applying theodolites or autocollimators. The error sources of this method areanalyzed in detail and several methods are developed to eliminate the calibration *** swallowtail-like anchor target is developed. Experiments show that the calibrationaccuracy can be limited within 0.06 mm in the range of 3.5 m and 0.03.mm with optimizing anchortarget. This method can be widely used in on-spot calibration.

关键词： position setting reference calibration water level on-spot inspection error analysis

A Rapid Calibration Technique for Scanning Line-Structured Laser Sensor

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光学学报 2003年第S1期23卷 839-840页

作者： Li Tao, Changku Sun, ZhiqinXu, Wei Wei state key {2. of {3. measuring Technology and instruments, tianjin university, tianjin 3.0072, china state key {2. of {3. measuring Technology and instruments Tianjin University Tianjin 300072 China

A novel procedure to calibrate the scanning line-structured laser sensor is presented. A drone composed of two orthogonal planes is designed, with the result that camera parameters and light-plane equation parameters ... 详细信息

关键词： for in of on be as line A Rapid Calibration Technique for Scanning Line-Structured Laser Sensor

COORDINATE measuring MACHINE PROBING ACCESSIBILITY

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Chinese Journal of Mechanical Engineering 2001年第1期14卷 45-50页

作者： Wu Yongqing Xie Zexiao Liu Shugui Zhang Guoxiong state key Laboritory of {2. {3. Technology and Instrument, tianjin university Department of Underwater Acoustical Technology Institute of Acoustics Academia Sinica Beijing China state key {2. of {3. measuring Technology and Instrument Tianjin University Tianjin China

The accessibility of coordinate measuring machines (CMMs) in dimensional inspection is studied. The problem of computing the global accessibility cone is solved using a method of angle representation. Otherwise, the length and volume of probe are considered sufficiently so that all the feasible probe orientations could be determined for the inspection of a workpiece when a touch trigger probe is used and the shortcoming of abstracting a probe as an infinite half line could be overcome completely. In the end, an example is given to explain the method.

关键词： Accessibility Probe orientation Collision Coordinate measuring machines(CMMs) Slot

A New Technique for CCD Camera Auto-Calibration

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光学学报 2003年第S1期23卷 799-800页

作者： Xiaodong Zhang, Changku Sun, Zhixiong Wang, Wei Wei state key {2. of {3. measuring Technology and instruments, tianjin university, Tainjin, china state key {2. of {3. measuring Technology and instruments Tianjin University Tainjin China

A novel feature-round-based coplanar drone for the CCD camera auto-calibration is designed. Based on the ellipse similarity, an ellipse recognition algorithm is proposed. The experiment indicates the calibration error... 详细信息

关键词： Auto CCD A New Technique for CCD Camera Auto-Calibration for

Automatic Recognition Method for Optical measuring instruments Based on Machine Vision

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Transactions of tianjin university 2008年第3期14卷 202-207页

作者：宋乐林玉池郝立果 state key {2. of {3. measuring Technology and instruments Tianjin University

Based on a comprehensive study of various algorithms, the automatic recognition of traditional ocular optical measuring instruments is realized. Taking a universal tools microscope(UTM) lens view image as an example, a 2.layer automatic recognition model for data reading is established after adopting a series of pre-processing algorithms. This model is an optimal combination of the correlation-based template matching method and a concurrent back propagation(BP) neural network. Multiple complementary feature extraction is used in generating the eigenvectors of the concurrent network. In order to improve fault-tolerance capacity, rotation invariant features based on Zernike moments are extracted from digit characters and a 4-dimensional group of the outline features is also obtained. Moreover, the operating time and reading accuracy can be adjusted dy-namically by setting the threshold value. The experimental result indicates that the newly developed algorithm has optimal recognition {2. and working speed. The average reading ratio can achieve 97.2.%. The recognition method can automatically obtain the results of optical measuring instruments rapidly and stably without modifying their original structure, which meets the application requirements.

关键词： automatic recognition optical measuring instruments template matching neural network