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A novel multi-view X-ray digital imaging stitching algorithm

JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2023年第1期31卷 153-166页

作者： Kang, Yang Wu, Rui Wu, Sen Li, Peizheng Li, Qingpei Cao, Kun Tan, Tingting Li, Yingrui Zha, Gangqiang Northwestern Polytech Univ State Key Lab Solidificat Proc 127 Youyi West Rd Xian 710072 Peoples R China Northwestern Polytech Univ MIIT Key Lab Radiat Detect Mat & Devices 127 Youyi West Rd Xian 710072 Peoples R China Northwestern Polytech Univ Shenzhen Res Inst Shenzhen Peoples R China

BACKGROUND: In fan beam X-ray imaging applications, several X-ray images sometimes need to be stitched together into a panoramic image because of the size limitations of the detector. OBJECTIVE: This study aims to propose a novel multi-view X-ray digital imaging stitching algorithm (MVS) based on the CdZnTe photon counting linear array detectors to solve the problem of fan beam X-ray stitching deformation. METHODS: The panoramic image is generated in four steps including (1) multi-view projection data acquisition, (2) overlapping positioning, (3) weighted fusion and (4) projected pixel value calculation. Images of a globe and foot are scanned by fan beam X-rays and a CdZnTe detector. The proposed method is applied to stitch together the scanned images of the globe. Three other methods are also used for comparison. Finally, this MVS algorithm is also used in the stitching of scanned images of the foot. RESULTS: Compared with the 50% stitching accuracy of other methods, the new MVS algorithm reached a stitching accuracy of 94.4%. Image distortion on the globe and feet is also eliminated and thus image quality is significantly improved. CONCLUSIONS: This study proposes a newmulti-viewX-ray digital imaging stitching algorithm. Study results demonstrate the superiority of this new algorithm and its feasibility in practical applications.

关键词： X-ray photon counting stitching algorithm CdZnTe detector

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A Moon stitching algorithm for the Meteosat Third Generation FCI instrument 24

A Moon stitching algorithm for the Meteosat Third Generation...

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Conference on Sensors, Systems, and Next-Generation Satellites XXIV

作者： Kazlova, A. Avbelj, J. Wagner, S. HE Space Flughafenallee 24 Bremen Germany EUMETSAT Eumetsat Allee 1 D-64295 Darmstadt Germany

ISBN: (纸本)9781510638747

Aboard the next generation of EUMETSAT geostationary satellites, the Flexible Combined Imager (FCI) will continue the current SEVIRI (Spinning Enhanced Visible and Infrared Imager) mission with enhanced temporal, spatial, and spectral capabilities. For monitoring the radiometric stability of the FCI reflective solar bands ranging from 0.4 to 2.2 mu m, the Moon acquisitions are planned to be used. The Moon will cross the FCI field-of-view on a regular basis, under different illumination conditions and elevations. The FCI scan mechanism will allow the acquisition of the Moon with two or three consecutive swaths at the most. Two challenges must be resolved to make use of Moon observations. First, consecutive swaths include an overlap region to avoid coverage gaps. It means that some Moon areas are observed twice. Second, the swaths make an angle with respect to the equatorial plane that varies with the elevation. Consequently, it is necessary to reconstruct the full Moon disc from those consecutive swaths before the total lunar irradiance can be calculated and compared to the current lunar calibration reference, the GIRO (GSICS Implementation of the ROLO) model. This paper presents the prototype developed to make use of Moon observations with FCI. It has two components: i) a Moon transit simulator that generates equivalent Level 1b data using Himawari-8/AHI data as an input, and ii) a Moon image-stitching algorithm, which re-builds the Moon image from the simulated Level 1b swaths. In order to assess the efficiency of the stitching algorithm, two methods to reconstruct the Moon image are implemented and compared. The first one makes full use of the information available from the Moon transit simulator. The second one is the stitching method that will be deployed during operations, i.e. using exclusively information from the Level 1b swaths.

关键词： SEVIRI MTG FCI Moon calibration stitching algorithm radiometric stability irradiance

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Network tomography application in mobile ad-hoc network using stitching algorithm

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JOURNAL OF NETWORK AND COMPUTER APPLICATIONS 2015年 56卷 77-87页

作者： Khan, M. S. S. Kumar, Anup Xie, Bin Sahood, Prasanna K. Texas A&M Univ Dept Elect Engn & Comp Sci Kingsville TX 78363 USA Univ Louisville Dept Comp Engn & Comp Sci Louisville KY 40292 USA InfoBeyond LLC Louisville KY USA Univ Louisville Dept Math Louisville KY 40292 USA

In this paper, a network tomography (NT) approach is proposed to study network performance in ad-hoc networks. An analysis of network performance is presented in a dynamic MANET. An expectation-maximization (EM) algorithm is used in NT to estimate the network performance parameter in accordance with network performance observations. Over the dynamic network, a new algorithm has been proposed, called the stitching algorithm, to aggregate dynamic performance values for network links. Specifically, the stitching algorithm gives local and global performance parameters such as link delays over specified time periods. Therefore, the network behavior as well as the corresponding local network performance in a mobile network can be derived over a continuous period. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： Mobile network Ad-hoc network EM MLE stitching algorithm

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Radius and roundness measurement of micro spheres based on a set of AFM surface scans

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MEASUREMENT SCIENCE AND TECHNOLOGY 2021年第4期32卷

作者： Oertel, Erik Manske, Eberhard Tech Univ Ilmenau Inst Proc Measurement & Sensor Technol D-98694 Ilmenau Germany

Micro coordinate measuring machines have been developed for the traceable characterization of small complex parts, due to the demand in research and industry. These machines require geometrically well characterized probing spheres of ever smaller radii. Currently, there is no established procedure for the measurement of such spheres below radii of 500 mu m. In this paper we, therefore, propose and investigate an approach which is based on a set of atomic force microscope (AFM) surface scans in conjunction with a stitching algorithm. The strategy was implemented on a nano measuring machine and investigated on a ruby sphere with a radius of 150 mu m. Although the strategy can generally be applied to the characterization of a full sphere, we limit ourselves to the measurement of one great circle (equator). The technique enables the measurement of micro spheres with a high lateral and vertical resolution. The mean radius of the ruby sphere was measured with a standard deviation of 3.7 nm over six repetitions. As our experiments have shown, the measurement procedure is at the moment mainly influenced by the shape of the AFM tip which requires further attention.

关键词： micro spheres stitching algorithm AFM roundness radius micro CMM nano CMM

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A Text Detection algorithm for Image of Student Exercises Based on CTPN and Enhanced YOLOv3

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IEEE ACCESS 2020年 8卷 176924-176934页

作者： Cao, Langcai Li, Hongwei Xie, Rongbiao Zhu, Jinrong Xiamen Univ Dept Automat Xiamen 361005 Peoples R China Xiamen Key Lab Big Data Intelligent Anal & Decis Xiamen 361005 Peoples R China

Intelligent learning system (ILS) has become a popular learning tool for students. It can collect students' wrong questions in exercises and dig out their unskilled knowledge points so that it can recommend personalized exercises for students. Detecting text accurately from images of students' exercises is significant and essential in an ILS. However, a big challenge of text detection is that traditional text detection algorithms can not detect complete text lines in an exercise scene, and their detection box always splits between Chinese and mathematical symbols. In this article, we propose a deep-learning-based approach for text detection, which improves You Only Look Once version 3 (YOLOv3) by changing the regression object from a single character to a fixed-width text and applies a stitching strategy to construct text lines based on the relation matrix, which improves the accuracy by 9.8%. Experimental results on both RCTW Chinese text detection dataset and real exercise scenario show that our model can improve detection effectiveness. In addition, we compare our method with two state-of-the-art approaches in applications of exercise text detection, and discuss its capability and limitations. We have also provided a platform which has implemented the proposal for detecting text lines in students' daily homework or examination papers, which enhances user experience well.

关键词： Text recognition Databases Splicing Detectors Feature extraction Object detection Detection algorithms Text detection exercise image YOLOv3 CTPN OCR platform stitching algorithm

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stitching algorithm: A Network Performance Analysis Tool for Dynamic Mobile Networks

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Procedia Technology 2012年 3卷 41-51页

作者： M.S.S. Khan Anup Kumar Bin Xie Duthie Center of Engineering Department of Computer Engineering and Computer Science University of Louisville Louisville KY 40292 USA InfoBeyonds Technology LLC Louisville KY USA

The performance analysis of the mobile ad-hoc network (MANET) is a challenging issue. In this paper, network tomography is studied to analyse the network performance in a dynamic MANET. For such a purpose, a network tomography analytical model is proposed for a dynamic network environment. Expected Maximization (EM) algorithm for network tomography is able to estimate the network performance parameter in accordance to network performance observations. Our study is different than current network tomography approaches where are applied for static wired network. Over the dynamic network, we proposed a new algorithm that is called stitching algorithm to aggregate the dynamic performance. Specifically, the stitching algorithm concatenates the performance parameter i.e. link delay, from distinguish time periods. Therefore, the network behaviour as well as the corresponding performance in a mobile ad-hoc network can be derived over a continuous period.

关键词： Mobile Networks Expected Maximization Maximum Likelihood Estimator stitching algorithm

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An automatic method for increasing the numerical aperture of a digital holography recording system

An automatic method for increasing the numerical aperture of...

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Conference on Modeling Aspects in Optical Metrology III

作者： Pelagotti, Anna Paturzo, Melania Locatelli, Massimiliano Geltrude, Andrea Finizio, Andrea Ferraro, Piero Finke, Grzegorz Kujawinska, Malgorzata CNR Ist Nazl Ott Largo E Fermi 6 I-50125 Florence Italy UOS Napoli CNR Ist Nazl Ott I-80078 Pozzuoli Italy Univ Firenze LENS Lab Europeo Spettroscopia Non Lineare I-50019 Sesto Fiorentino Italy arsaw Univ Technol Inst Micromech & Photon PL-02525 Warsaw Poland

ISBN: (纸本)9780819486790

A major issue so far for digital holography has been the limited number of pixels of currently available detectors, such as CCD sensors, which allows a spatial resolution significantly lower than that of a holographic plate. This is an even more sever limitation when IR sensors such as microbolometers are taken into consideration. In order to increase the numerical aperture of such systems, we developed an automatic technique which is capable to record several holograms and stitch them together before reconstruction. This method can cope with some of the inherent differences of the image structures and tone dynamics of recorded holograms. The joint holograms have been applied for reconstruction of an image by means of numerical and optoelectronic reconstruction processes and they show significant increase of quality.

关键词： Digital holograms stitching algorithm synthetic aperture IR holography optoelectronic reconstruction

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Analysis for the influencing factors to an annular sub-aperture stitching algorithm

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Guangdian Gongcheng/Opto-Electronic Engineering 2005年第3期32卷 20-24页

作者： Hou, Xi Wu, Fan Yang, Li Wu, Shi-Bin Chen, Qiang Inst. of Optics and Electron. Chinese Acad. of Sci. Chengdu 610209 China Graduate Sch. Chinese Acad. of Sci. Beijing 100039 China

Optimal stitching algorithm is extremely important for testing large-aperture aspherical optical elements by annular sub-aperture scanning technique. In view of an annular sub-aperture stitching algorithm based on discrete phase data, and accuracy evaluation criterion, numerical simulation and analysis for several main influencing factors such as random noise, high-order noise, overlapping width and sub-aperture number are carried out. Analysis results show that the algorithm is insensitive to both high-order noise and random noise. The influence of high-order noise is a bit larger than that of random noise. For aspherics with a large aperture and relative aperture, its overlapping coefficient of adjacent sub-apertures should be more than 0.15. For aspherics with small asphericity, its overlapping coefficient may be more than 0.25 and the stitching parameters with higher accuracy can be obtained.

关键词： Annular sub-aperture Aspheric mirrors measurement Large aspheric surfaces stitching algorithm

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Correlative stitching interferometer and its key techniques

Correlative stitching interferometer and its key techniques

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Conference on Interferometry XI Techniques, Analysis and Applications

作者： Yu, YJ Chen, MY Shanghai Univ Dept Precis Mech Engn Shanghai 200072 Peoples R China

ISBN: (纸本)0819445444

Correlative stitching is on the fact that the same area has the same information. This testing thought is meaningful in extending spatial measurement ranges, keeping high resolutions, high precision and low cost. So in order to test large-scale optical workpiece, people are designing large-scale interferometer, at the same time, they are also designing stitching interferometer. The keys to realize stitching measurement are to obtain high precision wavefront of each sub-aperture and apply appropriate stitching algorithm. There are many techniques to test sub-apertures, among which phase-shifting technique has high precision, and is applied widely. How to reduce its system error is a central problem. The paper will utilize difference of two testing results to remove the system error. How to reduce the accumulative error is a key problem in stitching. The paper will apply the stitching algorithm in Descartes coordinates presented by *** and *** to realize the connecting of sub-apertures. And the paper presents a method to deal with the main random errors in sub-aperture testing. Finally, the paper does some tests.

关键词： stitching interferometer profile measurement stitching algorithm system error reduction

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