• Title/Summary/Keyword: 기하학적 검정

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Evaluation for Geometric Calibration Accuracy of Zoom-lens CCD Camera (줌렌즈 CCD 카메라의 기하학적 검정 정확도 평가)

  • 유환희;정상용;김성삼
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.21 no.3
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    • pp.245-254
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    • 2003
  • Zoom lenses CCD(Charge Coupled Device) cameras have many desirable features but appear to be geometrically unstable and diffcult to calibrate. It is well blown that the zooming camera parameters change with zoom lens position. This paper presents a comparative study of two approaches, namely, DLT(Direct Linear Transformation) introduced by Abdel-Aziz and Karara and the model proposed by Tsai, to evaluate the camera parameters of zoom lenses CCD camera and 3D positioning accuracy. As a result, the accuracy for 3D positioning using Tsai and DLT model is similar in both methods when the set of GCPs and the object are arranged in the same space. However, Tsai model is more stable than DLT in the case that the object is apart from the set of GCPs. Also, the further study for the parameters optimization of conventional DLT is needed to improve accuracy for 3D positioning.

Geometrical description based on forward selection & backward elimination methods for regression models (다중회귀모형에서 전진선택과 후진제거의 기하학적 표현)

  • Hong, Chong-Sun;Kim, Moung-Jin
    • Journal of the Korean Data and Information Science Society
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    • v.21 no.5
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    • pp.901-908
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    • 2010
  • A geometrical description method is proposed to represent the process of the forward selection and backward elimination methods among many variable selection methods for multiple regression models. This graphical method shows the process of the forward selection and backward elimination on the first and second quadrants, respectively, of half circle with a unit radius. At each step, the SSR is represented by the norm of vector and the extra SSR or partial determinant coefficient is represented by the angle between two vectors. Some lines are dotted when the partial F test results are statistically significant, so that statistical analysis could be explored. This geometrical description can be obtained the final regression models based on the forward selection and backward elimination methods. And the goodness-of-fit for the model could be explored.

Scanner Calibration Method for Higher Accuracy at Acquisition of Digital Imagery Data in GSIS (지형공간정보체계에서 수치영상자료 취득의 정확도 향상을 위한 주사기의 검정 방법)

  • Choi, Chul-Sun
    • Journal of Korean Society for Geospatial Information Science
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    • v.1 no.2 s.2
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    • pp.153-158
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    • 1993
  • It is important to establish the transformational relation between scanned image coordinates and digital image coordinates because the coordinate system of digital image is transformed from scanned image coordinate system through scanning work. And, some researches are required in scanning works to correct the deformation that is due to the motion of scanner. In this study, some procedures are applied to determine the optimal calibration model equation which can calibrate the scanner. As a result the optimal calibration model equation for the object scanner is determined The procedure of this study can applied to the calibration of other types of scanner, because the procedures are done with the analysis of geometrical properties rather than the analysis of physical properties.

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Development of a Fruit Sorting System using Statistical Image Processing (통계적 영상처리를 이용한 과일 선별시스템 개발)

  • 임동훈
    • The Korean Journal of Applied Statistics
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    • v.16 no.1
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    • pp.129-140
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    • 2003
  • This study was to develop a fruit sorting system using statistical image processing. Histogram was used to compare fruit colors to standard fruit color and edge detector using Wilcoxon test was used to calculate an accurate geometrical characteristics of fruit including perimeter, area, major axis and minor axis length and roundness. The experimental result obtained from using our system for sorting apples was presented.

Comparison of KOMPSAT-2 Geometric Correction Imagery Accuracy by GCP Selection (지상기준점선택에 따른 KOMPSA를-2영상의 기하보정 정확도 비교)

  • Kee, Tae-Young;Hong, Min-Gee;Kim, Choen;Choi, Joon-Soo
    • Proceedings of the KSRS Conference
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    • 2009.03a
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    • pp.270-274
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    • 2009
  • 한반도의 정밀관측을 목적으로 개발된 KOMPSAT-2위성의 영상을 활용하기 위해서는 촬영 시 발생하는 기하학적 왜곡의 보정이 필요하다. 본 연구에서는 지상기준점(Ground Control Point: GCP) 선택의 세 가지 특성을 각각 적용하여 기하보정을 하였다. 보정 영상의 정확도 검정을 위하여 수치지도(digital map)를 이용한 평균제곱근오차(Root Mean Square Error: RMSE)와 육안검사를 통해 정확도를 비교하였다. 그 결과 영상의 중앙은 선형 교차점을 선택한 방법이 가장 정확하였고, 가장자리는 건물의 모서리 또는 건물의 중심을 선택한 방법이 우수하였다.

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Accuracy of Close-Range Industrial Photogrammetry Using CCTV Type CCD Camera (CCTV유형 CCD 카메라를 이용한 근거리 산업사진측량의 정확도)

  • 이진덕;최용진
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.19 no.3
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    • pp.283-290
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    • 2001
  • This paper demonstrates the performance of industrial precise measurement using the digital close-range photograrmmetric system based on a off-the-shelf CCTV-type CCD camera. The system was constructed with a CCD camera and a PC with a frame grabber, coupled with digital image mensuration and self-calibrating bundle adjustment techniques. An artificial fish reef with cubic shape was taken as an object for the application test of the system and the digital images were acquired on multi-station convergent network around the object. The geometric calibration of the CCD camera and the phototriangulation of the entire surface of the object was carried out simultaneously by means of self-calibrating bundle adjustment technique. Also the system comprising a high resolution still-video camera Kodak DCS, which high accuracy potential has been already established, were employed in similar network condition. Then the results from two different camera systems were compared in the accuracies of phototriangulation.

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Effective Application of Close-Range Photogrammetry with Digital Images in Industrial Precise Measurement (산업정밀측정에서 수치영상을 이용한 근접사진측량의 효율적 응용)

  • 이진덕
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.14 no.1
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    • pp.17-25
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    • 1996
  • The development of still video CCD cameras has simplified dramatically the digital imaging process. Still video cameras have flexibility that allows digital image acquisition and on-board image storage without being connected to a computer. The objective of this paper is to evaluate the performance of digital close-range photogrammetric system using the still video camera for dimensional inspection and structural monitoring being required in various industries. Some sub-pixel measurement techniques, which is indispensable for digital image measurement, were suggested. The author carried out the self-calibration of a high resolution DCS420 still video camera and then test application of a structure. The self-calibrating bundle adjustments resulted in object space accuracies which exceed 1 :46,000. It is ascertained that this digital close-range photogrammetric system has high accuracy potential and task effectiveness for industrial applications.

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Geometric calibration of digital photogrammetric camera in Sejong Test-bed (세종 테스트베드에서 항측용 디지털카메라의 기하학적 검정)

  • Seo, Sang-Il;Won, Jae-Ho;Lee, Jae-One;Park, Byoung-Uk
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.30 no.2
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    • pp.181-188
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    • 2012
  • The most recent, Digital photogrammetric camera, Airborne LiDAR and GPS/INS same sensors are used to acquire spatial information of various kinds in the field of aerial survey. In addition, Direct Georeferencing technology has been widely utilized with digital photogrammetric camera and GPS/INS. However, the sensor Calibration to be performed according to the combination of various sensors is followed by problems. Most of all, boresight calibration of integrated sensors is a critical element in the mapping process when using direct georeferencing or using the GPS/INS aerotriangulation. The establishment of a national test-bed in Sejong-si for aerial sensor calibration is absolutely necessary to solve this problem. And accurate calibration with used to integration of GPS/INS by aerotriangulation of aerial imagery was necessary for determination of system parameters, evaluation of systematic errors. Also, an investigation of efficient method for Direct georeferencing to determine the exterior orientation parameters and assessment of geometric accuracy of integrated sensors are performed.

Geometric Calibration and Accuracy Evaluation of Smartphone Camera (스마트폰 카메라의 기하학적 검정과 정확도 평가)

  • Kim, Jin-Soo;Jin, Cheong-Gil;Lee, Seong-Kyu;Lee, Sun-Gu;Choi, Chul-Uong
    • Journal of Korean Society for Geospatial Information Science
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    • v.19 no.3
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    • pp.115-125
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    • 2011
  • The smartphones which have been recently are embedded with high resolution quality camera, assisted GPS, accelerometer, gyroscope and various sensors including magnetometer sensor that could be directly used for measurement. This study aims to suggest the possible application of smartphone camera providing high resolution images in terms of photogrammetry by calibrating it and assessing its accuracy. First of all, prior to the accuracy assessment of smartphone camera, camera calibration was conducted to correct lens distortion of each camera and the accuracy of image coordinates and object coordinates calculated by bundle adjustment during this procedure was analyzed. Also regarding three-dimensional positioning, result analysis depending on considering lens distortion coefficients was conducted, and finally relative accuracy of smartphone camera on metric camera was assessed. The result showed that in terms of distortion correction of smartphone camera, also higher order symmetric radial lens distortion coefficients should be considered, and three dimensional position determined by smartphone images was a little difference from that by metric camera. Therefore it is expected that smartphone images have huge possibility to be used for photogrammetry.