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35

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204

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## Publications

Publications (35)

Considering that a unit dual quaternion can describe elegantly the rigid transformation including rotation and translation, the point-wise weighted 3D coordinate transformation using a unit dual quaternion is formulated. The constructed transformation model by a unit dual quaternion does not need differential process to eliminate the three translat...

Most traditional methods have difficulty detecting landslide boundary accurately, and the existing methods based on deep learning often lead to insufficient training or overfitting due to insufficient samples. An end-to-end, semi-supervised adversarial network, which fully considers spectral and topographic features derived using unmanned aerial ve...

Considering coordinate errors of both control points and non-control points, and different weights between control points and non-control points, this contribution proposes an extended weighted total least squares (WTLS) iterative algorithm of 3D similarity transformation based on Gibbs vector. It treats the transformation parameters and the target...

The 3D similarity coordinate transformation is fundamental and frequently encountered in many areas of work such as geodesy, engineering surveying, LIDAR, terrestrial laser scanning, photogrammetry, machine vision, etc. The algorithms of 3D similarity transformation are divided into two categories. One is a closed-form algorithm that is straightfor...

Airborne vector gravimetric data have become increasingly available. A general band-limited horizontal boundary value problem using horizontal components of these vector gravimetric data is formulated and solved to compute regional geoid. The disturbing potential on the geoid is determined directly using the data in the air. This one-step approach...

Nonlinear geodetic datum transformation is particular suitable for the case of large rotation angles, and has been an active area of research in recent years. In this paper, we propose a new analytical solution. The method expresses the scale parameter and translation parameters as the function of rotation matrix, through the derivation process. Th...

Nonlinear exponential trend model is linearized into the linear model, then linearized model parameters are regarded as the state vector containing the dynamic noise to erect Kalman filter model based on exponential trend model to predict the deformation of the rock landslide. Deformation observation values of the landslide are regarded as a time s...

In this study, an approach using ground control point-free unmanned aerial vehicle (UAV)-based photogrammetry is proposed to estimate the volume of stockpiles carried on barges in a dynamic environment. Compared with similar studies regarding UAVs, an indirect absolute orientation based on the geometry of the vessel is used to establish a custom-bu...

In real-time cycle slip repair of undifferenced triple frequency Global Navigation Satellite Systems (GNSS) phase signals, ionospheric delay prediction is crucial in estimating the narrow lane part of the cycle slips. A quadratic model is recursively constructed using estimated ionospheric delays and used to perform one-step prediction. The model e...

Rigid transformation including rotation and translation can be elegantly represented by a unit dual quaternion. Thus, a non-differential model of the Helmert transformation (3D seven-parameter similarity transformation) is established based on unit dual quaternion. This paper presents a rigid iterative algorithm of the Helmert transformation using...

The rigid motion involving both rotation and translation in the 3D space can be simultaneously described by a unit dual quaternion. Considering this excellent property, the paper constructs the Helmert transformation (seven-parameter similarity transformation) model based on a unit dual quaternion and then presents a rigid iterative algorithm of He...

Aimed at the global registration problem of the single-closed ring multi-stations point cloud, a formula in order to calculate the error of rotation matrix was constructed according to the definition of error. The global registration algorithm of multi-station point cloud was derived to minimize the error of rotation matrix. And fast-computing form...

Based on the Lagrangian extremum law with the constraint that rotation matrix is an orthonormal matrix, the paper presents a new analytical algorithm of weighted 3D datum transformation. It is a stepwise algorithm. Firstly, the rotation matrix is computed using eigenvalue-eigenvector decomposition. Then, the scale parameter is computed with compute...

The analytical solution of 3D datum transformation with an isotropic weight has been elegantly presented based on Procrustes algorithm (singular value decomposition). But the existence of analytical solution of 3D datum transformation with a non-isotropic weight needs further investigation. Based on the Lagrangian extremum law, the paper derives th...

GPS is the most prevalent technology to monitor the surface deformation of landslide. The paper mainly intends to solve two critical issues of GPS data procedure. One is the inconsistent issue of control points, which may leads to a distorted monitoring network and wrong deformation value. The inconsistent control points can be detected by comparis...

Planar resection is a common surveying work. The paper introduces its frequently-used solution i.e. the iterative solution. However, the iterative solution needs linearization, initial value of parameter and iteration, unfortunately the initial value of parameter is hard to assess in advance, resultantly, the iteration will fail. Due to inexistence...

In this paper, the planar coordinate transformation model in the complex field is constructed. It is more concise than the traditional planar coordinate transformation model in the real field, because it combines the x and y coordinates as a whole. In order to carry out the complex parameter estimation, the paper introduces the complex least square...

Geodetic datum transformation and inverse transformation are very basic tasks in geodesy, and surveying engineering, etc. Considering the rotation angles are in seconds, the rotation matrix is simplified, and then the observation equation is easily linearized and solved by least squares technique. The inverse transformation is derived explicitly, w...

The paper introduces the Jacobi algorithm, and the Jacobi algorithm solution of linear intersection. A numerical cased is illustrated to validate the approach. The result shows the Jacobi algorithm solution is approximately equal to least squares (LS) solution, and needs no initial parameter value, and iteration. Thus, it is very important for the...

This paper presents a new form of quartic equation based on Lagrange's extremum law and a Groebner basis under the constraint that the geodetic height is the shortest distance between a given point and the reference ellipsoid. A very explicit and concise formulae of the quartic equation by Ferrari's line is found, which avoids the need of a good st...

Georobot is widely used to precision engineering measurement, especially in automatic continuous deformation monitoring, e.g. dam and landslide deformation monitoring, in virtue of the unique ATR and tracking technology. However it is hard to evaluate the actual tracking measurement precision because of the complex circumstance in specific applicat...

Linear intersection is a frequently encountered issue in surveying engineering. The paper firstly reviews the common analytical approaches, and then introduces a new analytical approach based on Sylvester resultant, which does not use differencing and substitution, thus is direct and faster, lastly it is very efficient to make the adjustment of mor...

The perspective 3-point problem is a basic issue in computer vision and photogrammetry, and in photogrammetry is called space resection in the case of three control points. The problem is usually solved iteratively with collinearity equations, but it usually does not succeed in the case of large pose angles because of an improper starting estimate...

Determination of Camera position and orientation is a basic research subject in photogrammetry and computer vision. This paper introduces a new explicit approach to determine the camera-point distances based on the computer algebraic software of Mat lab, then derives the basic mathematic model of pose estimation, and puts forward the analytical cal...

Absolute orientation is a fundamental and important task in photogrammetry and robotics. It aims to find the best transformation parameters which relate the stereo model coordinates and geodetic coordinates. The paper presents a simple and efficient direct solution based on optimization theory and rigid body transformation rule. It doesn't require...

Three-dimensional coordinate transformation problem is the most frequent problem in photogrammetry, geodesy, mapping, geographical information science (GIS), and computer vision. To overcome the drawback that traditional solution of the problem based on rotation angles depends strongly on initial value of parameter, which makes the method ineffecti...

Perspective 3-point problem (P3P) is one of the most fundamental issues in computer vision and photogrammetry. The paper puts forward the algebraic (multipolynomial) resultant to analytically determine the camera-point (camera projective center to control point) distances, and presents the closed form solution of camera position and orientation bas...

Space resection, also known as the camera exterior orientation, is a fundamental problem in photogrammetry, computer vision and other areas. In the case of arbitrary large posture image, the classical iterative method based on Euler angle using collinearity equations usually fail because the initial values are poor or unknown. For this reason, this...

Camera pose estimation is one of the oldest and most frequent tasks in computer vision and photogrammetry. The paper presents a three-step (namely determination of camera-point distances, pose angles and line elements) approach to camera pose estimation, and derives the basic mathematic models and introduces the computational method in each step; e...

Single-image space resection is a fundamental issue of photogrammetry. This paper designs an anti-symmetric matrix to constitute Rodrigues matrix, used to represent the rotation matrix, then establishes the mathematical model of space resection applied to pattern search method, further uses pattern search method to directly solve the three elements...

Nonlinear geodetic datum transformation is particular suitable for the case of large rotation angles, and has been an active area of research in recent years. In this paper, we propose a new analytical solution. The method expresses the scale parameter and translation parameters as the function of rotation matrix, through the derivation process. Th...

3D coordinate transformation is usually encountered issue in geodesy, photogrammetry, geographical information science (GIS) and computer vision. This paper simplifies the mathematical model of 3D similarity transformation by optimization process, which finally only has the parameter of rotation matrix. According to the orthogonality of rotation ma...

To solve the problem that traditional solution of coordinate transformation parameters based on rotation angles depends strongly on initial value of parameter, the paper adopts quaternion to represent 3D rotation matrix, then puts forward a quaternion-based solution of non-linear 3D coordinate transformation parameters. The case study shows that th...

In view of 3D coordinate transformation nonlinear model, in order to adapt direct search method to solve the transformation parameters, it is necessary to make the model simple and operand small by way of two step measurements as follows. One is to transform the 7 parameters model to 4 parameters model by eliminating translation 3 parameters; the o...

## Projects

Project (1)