• 제목/요약/키워드: Angle Measurement

검색결과 2,155건 처리시간 0.029초

Research on a Method for the Optical Measurement of the Rifling Angle of Artillery Based on Angle Error Correction

  • Zhang, Ye;Zheng, Yang
    • Current Optics and Photonics
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    • 제4권6호
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    • pp.500-508
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    • 2020
  • The rifling angle of artillery is an important parameter, and its determination plays a key role in the stability, hit rate, accuracy and service life of artillery. In this study, we propose an optical measurement method for the rifling angle based on angle error correction. The method is based on the principle of geometrical optics imaging, where the rifling on the inner wall of the artillery barrel is imaged on a CCD camera target surface by an optical system. When the measurement system moves in the barrel, the rifling image rotates accordingly. According to the relationship between the rotation angle of the rifling image and the travel distance of the measurement system, different types of rifling equations are established. Solving equations of the rifling angle are deduced according to the definition of the rifling angle. Furthermore, we added an angle error correction function to the method that is based on the theory of dynamic optics. This function can measure and correct the angle error caused by the posture change of the measurement system. Thus, the rifling angle measurement accuracy is effectively improved. Finally, we simulated and analyzed the influence of parameter changes of the measurement system on rifling angle measurement accuracy. The simulation results show that the rifling angle measurement method has high measurement accuracy, and the method can be applied to different types of rifling angle measurements. The method provides the theoretical basis for the development of a high-precision rifling measurement system in the future.

Tilt Angle Measurement Based on Arrayed Eddy Current Sensors

  • Chao, Xuewei;Li, Yang;Nie, Jing
    • Journal of Magnetics
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    • 제21권4호
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    • pp.524-528
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    • 2016
  • Eddy current (EC) sensor works based on the electromagnetic induction principle and has been widely applied in the industrial testing and evaluation due to its robustness and environmental adaptability. Meanwhile, tilt angle measurement is mainly based on the laser or visual method, which is strict with the measurement environment and not suitable for the industrial applications. In this paper, a novel tilt angle measurement method based on arrayed EC sensors is proposed. Both the simulation and experiments indicate that the measured error is approximately linear with tilt angle and the accuracy after compensation is $0.25^{\circ}$. In conclusion, this research cannot only broaden the scope of EC application, but also overcome the shortcomings of existing angle measurement methods.

종골의 사체 실측 결과와 방사선학적 측정 결과의 비교 (Comparison of the Results between Cadaveric and Radiological Measurements of Calcaneus)

  • 김정한;곽희철;이창락;정동우;노상명
    • 대한족부족관절학회지
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    • 제19권3호
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    • pp.102-106
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    • 2015
  • Purpose: We wanted to compare the results between cadaveric and radiological measurements of calcaneus. Materials and Methods: Sixty three calcaneus of 33 cadavers donated between December 2012 and December 2014 were actually measured. Computed tomography (CT) images of 244 calcaneus in 122 patients of the same age group with cadavers were radiologically measured. Maximum length, maximum width, maximum height, $B{\ddot{o}}hler$ angle, Gissane angle, Fowler-Phillip angle, and tala-articular angle were measured. Results: In cadaveric measurement, the mean maximal height, length, and width were $41.8{\pm}3.3mm$, $73.3{\pm}3.4mm$, and $40.7{\pm}2.2mm$, respectively. In radiological measurement, the mean maximal height, length, and width were $38.5{\pm}4.3mm$, $74.0{\pm}5.7mm$, and $44.7{\pm}1.4mm$, respectively. In cadaveric measurement, the mean $B\ddot{o}hler$ angle, Gissane angle, Fowler-Phillip angle, and tala-articular angle were $32.1^{\circ}{\pm}6.2^{\circ}$, $110.8^{\circ}{\pm}8.1^{\circ}$, $55.8^{\circ}{\pm}6.8^{\circ}$, and $59.7^{\circ}{\pm}4.6^{\circ}$, respectively. In radiological measurement the mean $B{\ddot{o}}hler$ angle, Gissane angle, Fowler-Phillip angle, and tala-articular angle were $32.6^{\circ}{\pm}3.8^{\circ}$, $113.7^{\circ}{\pm}5.7^{\circ}$, $62.2^{\circ}{\pm}3.9^{\circ}$, and $61.6^{\circ}{\pm}6.3^{\circ}$, respectively. The mean maximal height was significantly higher in the cadaveric measurement group (p<0.001) and the mean maximal length and width were significantly higher in the radiologic measurement group (p<0.001, p<0.001). The mean Gissane angle, Fowler-Philip angle, and $B{\ddot{o}}hler$ angle were significantly higher in the CT group (p=0.001, p<0.001, p=0.016, respectively). There was no significant difference in the mean tala-articular angle (p=0.352). Conclusion: Significant differences in length parameters were observed between the cadaveric measurement group and the radiologic measurement group. However, no significant differences in angular measurements were observed between the two groups. The authors carefully conclude that radiological measurement values may be different from actual values in the calcaneus.

나노섬유의 특성분석을 위한 레이저 접촉각 측정기의 효율성 연구 (Feasibility Study of Laser Contact Angle Measurement for Nano-fiber Characterization)

  • 신경인;안선훈;김성훈
    • 한국의류학회지
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    • 제27권5호
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    • pp.554-559
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    • 2003
  • A newly developed contact angle measurement instrument by laser beam projection allows for rapid and direct determination of contact angles. The instrument may have a possibility to characterize newly developed nano-fibers. When the laser beam impinges on an edge of an interface of liquid and solid, projected beam were split across and made two straight lines on a tangent screen. From the result, it could measure the contact angle directly by reading the angle between two split beams. The purpose of this study was to prove reliability and reproducibility of the contact angle measurement instrument by laser beam projection compare to the conventional one by microscope through the comparative experiment and questionnaire. Test samples were selected by consideration of hydrophilic and hydrophobic, such as nylon 6 and polypropylene, respectively. The laser contact angle measurement has accurate, fast and convenient method to measure contact angle, and it can be a unique method to characterize nano-fibers.

제5요추 - 제1천추간 후관절증후군 환자의 방사선학적 소견에 관한 임상적 연구 (Clinical Study on 5th Lumbar - 1st Sacrum Facet Syndrome Patients' Radiological Finding)

  • 최유석;김대필;금동호
    • 한방재활의학과학회지
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    • 제15권2호
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    • pp.183-191
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    • 2005
  • Objectives : The 5th lumbar - 1st sacrum facet joint is unstable area from an anatomical viewpoint, so that it is clinically major causes of low back pain. The purpose of this study is to assess the difference of the Van Akkerveeken measurement and intervertebral disc angle, Ferguson angle betwoon the 5th lumbar - 1st sacrum facet syndrome patients and sample group patients.Methods : Van Akkerveeken measurement, intervertebral disc angle and Ferguson angle were measured in 30 patients who had 5th lumbar - 1st sacrum facet syndrome and 31 sample group patients.Results :1. Van Akkerveeken measurement of 5th lumbar - 1st sacrum facet syndrome patients is statistically larger that of than sample group patients.2. Intervertebral disc angle of the 5th lumbar - 1st sacrum facet syndrome patients is statistically larger that of than sample group patients.3. Ferguson angle is the 5th lumbar - 1st sacrum facet syndrome patients is statistically larger than that of sample group patients.Conclusions : These results suggest that Van Akkerveeken measurement and intervertebral disc angle is able to be used for diagnosis of facet syndrome.

Reliability and Validity of Angle of Trunk Rotation Measurement Using Smartphone and 3D Printing Technology in Scoliosis

  • Geum-Dong Shin;Seong-gil Kim;Kyoung Kim
    • The Journal of Korean Physical Therapy
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    • 제34권6호
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    • pp.283-291
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    • 2022
  • Purpose: The purpose of this study was to compare and analyze the method of measuring the angle of the trunk rotation using a smartphone with 3D smartphone holder compared to a scoliometer, which is a measuring tool used as a method for diagnosing scoliosis in scoliosis patients. Methods: Angle of trunk rotation was measured in 21 subjects diagnosed with scoliosis. scoliometer measurement method, a smartphone measurement method with a 3D smartphone holder, a smartphone blind measurement method with a 3D smartphone holder, a smartphone measurement method without a smartphone holder, a smartphone blind measurement method without a smartphone holder, and a total of five measurement methods were repeated three times for comparison and analysis. Results: The smartphone measurement method with a 3D smartphone holder has excellent intra-rater reliability of angle of trunk rotation (Rater A; ICC3, 2≥0.993, Rater B; ICC3, 2≥0.992). The smartphone blind measurement method with a 3D smartphone holder has excellent inter-rater reliability of angle of trunk rotation (ICC2, 2≥0.968). The scoliometer measurement method had the highest validity (r=0.976) with the smartphone measurement method with a 3D smartphone holder, and the blind measurement method without a smartphone holder had the lowest validity (r=0.886). Conclusion: These findings, the angle of trunk rotation measured by the smartphone measurement method with a 3D smartphone holder in scoliosis patients showed high reliability and validity compared to the scoliometer measurement method.

Nozzle Swing Angle Measurement Involving Weighted Uncertainty of Feature Points Based on Rotation Parameters

  • Liang Wei;Ju Huo;Chen Cai
    • Current Optics and Photonics
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    • 제8권3호
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    • pp.300-306
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    • 2024
  • To solve the nozzle swing angle non-contact measurement problem, we present a nozzle pose estimation algorithm involving weighted measurement uncertainty based on rotation parameters. Firstly, the instantaneous axis of the rocket nozzle is constructed and used to model the pivot point and the nozzle coordinate system. Then, the rotation matrix and translation vector are parameterized by Cayley-Gibbs-Rodriguez parameters, and the novel object space collinearity error equation involving weighted measurement uncertainty of feature points is constructed. The nozzle pose is obtained at this step by the Gröbner basis method. Finally, the swing angle is calculated based on the conversion relationship between the nozzle static coordinate system and the nozzle dynamic coordinate system. Experimental results prove the high accuracy and robustness of the proposed method. In the space of 1.5 m × 1.5 m × 1.5 m, the maximum angle error of nozzle swing is 0.103°.

개선된 위상 측정 알고리즘과 오차 해석 (An Advanced Phase Angle Measurement Algorithm And Error Analysis)

  • 송영석;김재철;최인규;박종식
    • 전자공학회논문지SC
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    • 제41권3호
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    • pp.25-32
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    • 2004
  • 본 논문에서는 두 개의 사인파 신호의 위상 차이를 계산해 내기위한 개선된 위상 측정 알고리즘을 제안하였다. 이 알고리즘은 두 개의 입력신호의 양자화된 샘플링 데이터를 사용하여 위상과 크기를 구해낸다. 측정 알고리즘의 중요 파라메타들은 몇개의 해석식으로 표현되기 때문에 위상을 계산하기 위해 필요한 연산량이 상당히 줄어들고 따라서 더 빠른 속도로 위상을 계산해 낼 수 있게 되었다. 또한 본 논문에서 제시한 알고리즘을 사용하여 입력신호의 한주기 전체를 샘플링할 경우에는 입력신호에 harmonic distortion이 발생하더라도 위상 측정 오차가 전혀 발생하지 않음을 수식으로 증명하였으며 컴퓨터 시뮬레이션을 통하여 이를 확인하였다. 그리고 입력신호에 가우시안 백색 잡음(white gaussian noise)이 발생할 경우에 위상 측정 오차가 얼마나 발생하는 지에 대하여 여러 가지 관점에서 컴퓨터 시뮬레이션을 수행하고 그 결과를 분석하였다.

호의 측도로 도(Degree)와 라디안 이해하기 (Understanding of Degree and Radian by Measuring Arcs)

  • 최은아;강향임
    • 대한수학교육학회지:학교수학
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    • 제17권3호
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    • pp.447-467
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    • 2015
  • 본 연구의 목적은 도(degree)와 라디안을 호의 측도로 해석하는 것이 라디안과 각의 측정에 대한 개념적 이해에 어떠한 영향을 미치는지 살펴보는 것이다. 이에 호의 길이를 이용한 각의 측도에 대한 내용지식을 26명의 예비중등교사를 대상으로 조사하였으며, 그 결과를 반영하여 두 명의 중학생들을 대상으로 실험을 진행하였다. 예비교사들과 두 중학생의 반응을 분석한 결과, 도(degree)의 개념을 호의 측도로 해석한 경험이 라디안의 이해에 긍정적인 영향을 미쳤으며, 호의 측도로 각의 측도를 파악하는 과정이 '선형 측정'에 대한 개념적 이해를 가능하게 하였다. 또한 각에 관한 다양한 문제에서 원의 맥락과 호의 등분 전략이 효과적인 문제해결전략으로 작용하였으며, 각과 호의 측도 사이의 관계를 탐구할 수 있는 직접적인 조작활동을 제공하는 것이 각의 측정 개념에 대한 이해에 도움을 줄 수 있다는 것을 확인하였다.