• Title/Summary/Keyword: Least Squares Adjustment

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A Comparison Study on Total Least Squares and Least Squares (토털최소제곱법과 최소제곱법의 비교연구)

  • 이임평;최윤수;권재현
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2003.10a
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    • pp.15-19
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    • 2003
  • The Total Least Squares (TLS) method is introduced in comparison with the conventional Least Squares (LS) method. The principles and mathematical models for both methods are summarized and the comparison results from their applications to a simple geometric example, fitting a straight line to a set of 2D points are presented. As conceptually reasoned, the results clearly indicate that LS is more susceptible of producing wrong parameters with worse precision rather than TLS. For many applications in surveying, can adjustment computation and parameter estimation based on TLS provide better results.

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Block Adjustment and Orthorectification for Multi-Orbit Satellite Images

  • Chen, Liang-Chien;Liu, Chien-Liang;Teo, Tee-Ann
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.888-890
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    • 2003
  • The objective of this investigation is to establish a simple yet effective block adjustment procedure for the orthorectification of multi-orbit satellite images. The major works of the proposed scheme are: (1) adjustment of satellite‘s orbit accurately, (2) calculation of the error vectors for each tie point using digital terrain model and ray tracing technique, (3) refining the orbit using the Least Squares Filtering technique and (4) generation of the orthophotos. In the process of least squares filtering, we use the residual vectors on ground control points and tie points to collocate the orbit. In orthorectification, we use the indirect method to generate the orthoimage. Test areas cover northern Taiwan. Test images are from SPOT 5 satellite. Experimental results indicate that proposed method improves the relative accuracy significantly.

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A Study on the Adjustment of Precise Leveling Nets by the Method of Dynamic Least Squares (동적최소(動的最小)제곱법(法)에 의한 정밀수준강(精密水準綱)의 조정(調整))

  • Lee, Kye Hak;Jang, Ji Won;Kang, Hee Bog;Sung, Soo Lyeon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.8 no.2
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    • pp.177-184
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    • 1988
  • The method of least squares has been applied to the static data, but it was not applications for the processing of observed values accompaning real-time variation. In this paper, having been considered all observations to be the function of time, leveling nets were analized dynamically by introducing the concept of time to conventional method of least squares. As a results, the method of dynamic least squares was well applicable to the adjustment of leveling nets.

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Effects of Edge Detection on Least-squares Model-image Fitting Algorithm

  • Wang, Sendo;Tseng, Yi-Hsing;Liou, Yan-Shiou
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.159-161
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    • 2003
  • Fitting the projected wire-frame model to the detected edge pixels on images by using least-squares approach, called Least-squares Model-image Fitting (LSMIF), is the key of the Model-based Building Extraction (MBBE). It is implemented by iteratively adjusting the model parameters to minimize the squares sum of distances from the extracted edge pixels to the projected wire-frame. This paper describes a series of experiments and studies on various factors affect the fitting results, including the edge detectors, the weighting rules, the initial value of parameters, and the number of overlapped images. The experimental result is not only helpful to clarify the influences of each factor, but is also able to enhance the robustness of the LSMIF algorithm.

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A Study On The Adaptive Equalizer Of Coefficient Adjustment In Mobile Communication Systems (이동 통신 시스템에서 조정 계수를 이용한 적응 등화기에 관한 연구)

  • 전상규;김노환
    • Journal of the Korea Society of Computer and Information
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    • v.1 no.1
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    • pp.53-64
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    • 1996
  • The methods for designing the adaptive filter performing DSP(digital signal processing)functions In mobile communication systems are Least-squares algorithm. Fast-Kalman and adaptive lattice algorithm. Least-squares algorithm It fast convergence algorithm for signal Processor of adaptive equallizer and used for eliminating inter symbol Interference which occur inmultiple path fading channel In mobille communication systems. In this paper. we propose the method of control adjustably algebra characteristics of signal vector that is sampling at some of new data sequence and confirm the improvement of fast convergence and iterative performance speed compared to existing algorithms by computer simulation.

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Performance Analysis of Least-Squares Estimation and LAMBDA Method for GPS Precise Positioning using Carrier Phase (GPS 반송파 위상을 이용한 정밀 측위의 최소자승법과 LAMBDA기법의 성능분석)

  • 박헌준;원종훈;고선준;이자성
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.146-146
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    • 2000
  • This paper presents field test results of the GPS precise positioning using carrier phase observable. The Least-squares AMBiguity Decorrelation Adjustment(LAMBDA) method is implemented to resolve integer ambiguity problem for two epoch Ll carrier phase measurement data. Field test results show that the GPS precise positioning of cm-level accuracy is obtainable with conventional low cost, single frequency C/A code GPS receivers.

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Building Reconstruction for 3D City Modeling in Korea (국내 실정에 맞는 삼차원 도시모델링을 위한 건물모델 생성방법에 관한 연구)

  • 조영욱;최재완;한동엽;김용일;유기윤
    • Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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    • 2004.10a
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    • pp.13-18
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    • 2004
  • In this study, a new method is proposed generating 3D wire-frames of building using the lowest level topology, points, which are input by human operators. Through the procedure, it is possible to make prediction occlusion points and generate the topology automatically among points, lines, surfaces from buildings. In order to adjust the error of initial values which are input manually, the least squares adjustment for model-image fitting is carried out using the edge information of aerial imagery. And also, model fitting procedure is done making all surfaces plane of buildings by the least squares adjustment. As a result of those procedure, 3D building models are refined similar to real figures of buildings.

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Accuracy Comparisons between Traditional Adjustment and Least Square Method (최소제곱법을 적용한 지적도근점측량 계산의 정확도 분석)

  • Lee, Jong-Min;Jung, Wan-Suk;Lee, Sa-Hyung
    • Journal of Cadastre & Land InformatiX
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    • v.45 no.2
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    • pp.117-130
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    • 2015
  • A least squares method for adjusting the horizontal network satisfies the conditions which is minimizing the sum of the squares of errors based on probability theory. This research compared accuracy of 3rd cadastral control points adjusted by traditional and least square method with respect to the result of Network-RTK. Test results showed the least square method more evenly distribute closure error than traditional method. Mean errors of least square and traditional adjusting method are 2.7cm, 2.2cm respectively. In addition, blunder in angle observations can be detected by comparing position errors which calculated by forward and backward initial coordinates. However, distance blunder cannot offer specific observation line occurred mistake because distance error propagates several observation lines which have similar directions.

An Introduction of General Least Squares on the Cadastral Survey Computation (지적측량계산에 일반최소제곱법의 도입 (도근측량방법 중 도선법 기준))

  • Song, Won-Ho;Cha, Deuk-Ki;Kim, Su-Jeong
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2010.04a
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    • pp.349-353
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    • 2010
  • The existing calculation methods of the cadastral traverse survey was established in 1910s and are mostly outdated. The quality of these methods are not adequate to satisfy today's surveyor's needs that use a simple calculation method to distribute the error values. Thus, the main objective of this research is to find a methodology for appropriate calculation methods of the cadastral traverse survey that uses the general least square adjustment method with weight. Consequently, least square adjustment method has a better result than the previous one.

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Sensors Comparison for Observation of floating structure's movement

  • Trieu, Hang Thi;Han, Dong Yeob
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2014.10a
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    • pp.219-221
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    • 2014
  • The objective of this paper is to simulate the dynamic behavior of a floating structure model, using image processing and close-range photogrammetry, instead of the contact sensors. Previously, the movement of structure was presented through the exterior orientation estimation of a single camera by space resection. The inverse resection yields the 6 orientation parameters of the floating structure, with respect to the camera coordinate system. The single camera solution is of interest in applications characterized by restriction in term of costs, unfavorable observation conditions, or synchronization demands when using multiple cameras. This article discusses the theoretical determinations of camera exterior orientation based on Direct Linear Transformation and photogrammetric resection using least squares adjustment. The proposed method was used to monitor the motion of a floating model. The results of six degrees of freedom (6-DOF) by inverse resection show that the appropriate initial values by DLT can be effectually applied in least squares adjustment, to obtain the precision of exterior orientation parameters. Additionally, a comparison between the close-range photogrammetry and total station results was feasibly verified. Therefore, the proposed method can be considered as an efficient solution to simulating the movement of floating structure.

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