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Linear perspective shape-from-shading method with two images

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Journal of Systems Engineering and Electronics 2015年第5期26卷 1080-1087页

作者： Lei Yang Ning Zhang Yanyun Ren Huosheng Hu Shanghai Key Laboratory of Power Station Automation Technology School of Mechatronics Engineering and AutomationShanghai University School of Computer Science and Electrical Engineering University of Essex

Shape-from-shading(SFS) is one of the important approaches of 3-D surface reconstruction in computer vision. Since reflectance map equation in SFS is a nonlinear partial differential equation(PDE) with two unknown variables, SFS with one image is ill-posed in mathematical sense. A linear perspective SFS method with two images is proposed to deal with the problem. We assume that two images with different light source directions are captured firstly. Orthogonal projection is not as accurate as perspective one to simulate imaging processes. Two reflectance map equations are established based on the Lambertian model under perspective projection, and the equations are further transformed into one linear PDE. Then the iterative semi-Lagrangian algorithm is used to approximate the solution. Finally, 3-D height values of pixel points in imaging planes are solved by the numerical interpolation method. Experimental results of both hemisphere and complex surfaces show that the proposed method can reconstruct surfaces accurately.

关键词： shape-from-shading(SFS) perspective projection semi-Lagrangian algorithm numerical interpolation method

Everything moves:The rapid changes in photogrammetry and remote sensing

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Geo-Spatial Information Science 2021年第1期24卷 33-49,I0007页

作者： Armin Gruen Department of Civil Engineering Environmental Engineering and GeomaticsETH ZurichSwitzerland

Changes in technology are coming at an ever increasing *** holds for photogrammetry and remote sensing as well.“Everything moves”-this is why I chose this topic to shed some light on some of the recent ***,this undertaking can never be complete in the sense of covering all developments in Photogrammetry and Remote ***,the impact of Deep Learning in photogrammetry is not mentioned in this *** is a very personal *** may not agree with some of my findings,but this is in the nature of *** any case,this contribution is meant as a tribute to Gottfried’s successful lifelong *** is not a scientific paper in the traditional sense but rather a collection of thoughts that emerged over the 50 years of my professional *** is also meant for an audience who has not necessarily a deep photogrammetric expert know-how.

关键词： History perspective projection photogrammetric pipeline automation 3D modeling

Photometric stereo for strong specular highlights

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Computational Visual Media 2018年第1期4卷 83-102页

作者： Maryam Khanian Ali Sharifi Boroujerdi Michael BreuB Chair of Applied Mathematics Brandenburg Universityof TechnologyCottbus 03046Germany

Photometric stereo is a fundamental technique in computer vision known to produce 3D shape with high accuracy. It uses several input images of a static scene taken from one and the same camera position but under varying illumination. The vast majority of studies in this 3D reconstruction method assume orthographic projection for the camera *** addition, they mainly use the Lambertian reflectance model as the way that light scatters at ***, providing reliable photometric stereo results from real world objects still remains a challenging task. We address 3D reconstruction by use of a more realistic set of assumptions, combining for the first time the complete Blinn–Phong reflectance model and perspective projection. Furthermore, we compare two different methods of incorporating the perspective projection into our model. Experiments are performed on both synthetic and real world images; the latter do not benefit from laboratory conditions. The results show the high potential of our method even for complex real world applications such as medical endoscopy images which may include many specular highlights.

关键词： photometric stereo(PS) complete Blinn–Phong model perspective projection diffuse reflection specular reflection

Linear perspective shape-from-shading method with two images

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Journal of Systems Science & Complexity 2015年第5期28卷 1080-1087页

关键词： shape-from-shading (SFS) perspective projection semi-Lagrangian algorithm numerical interpolation method

A Hidden-Removal Model of Dam perspective Drawing

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Computer Aided Drafting,Design and Manufacturing 2011年第1期21卷 13-17页

作者： WANG Zi-ru ZHOU Hui-cheng LI Ming-qiu Faculty of Infrastructure Engineering Dalian University of Technology Dalian 116024 China School of Foreign Languages Dalian Ocean University Dalian 116024 China

Aming at water conservancy project visualization, a hidden-removal method of dam perspective drawings is realized by building a hidden-removal mathematical model for overlapping points location to set up the hidden relationship among point and plane, plane and plane in space. On this basis, as an example of panel rockfill dam, a dam hidden-removal perspective drawing is generated in different directions and different visual angles through adapting VC＋＋ and OpenGL visualizing technology. The results show that the data construction of the model is simple which can overcome the disadvantages of considerable and complicated calculation. This method also provides the new means to draw hidden-removal perspective drawings for those landforms and ground objects.

关键词： dam perspective projection hidden removal overlapping points

Calibration method for multi-line structured light vision sensor based on Plücker line

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Journal of Measurement Science and Instrumentation 2020年第2期11卷 103-111页

作者： QIN Guan-yu WANG Xiang-jun YIN Lei State Key Laboratory of Precision Measuring Technology and Instruments Tianjin UniversityTianjin 300072China MOEMS Education Ministry Key Laboratory Tianjin UniversityTianjin 300072China

For the rapid calibration of multi-line structured light system,a method based on Plücker line was *** of the conventional line-structured light calibration methods extract the feature points and transform the coordinates of points to obtain the plane ***,a large number of points lead to complicated operation which is not suitable for the application scenarios of multi-line structured *** solve this issue,a new calibration method was proposed that applied the form of Plücker matrix throughout the whole calibration process,instead of using the point characteristics *** advantage of this method is that the light plane equation can be obtained quickly and accurately in the camera coordinate *** a planar target particularly for calibrating multi-line structured light was also *** regular lines were transformed into Plücker lines by extending the two-dimensional image plane and defining a new image *** transform the coordinate frame of Plücker lines,the perspective projection mathematical model was re-expressed based on the Plücker *** to the properties of the line and plane in the Plücker space,a linear matrix equation was efficiently constructed by combining the Plücker matrices of several coplanar lines so that the line-structured light plane equation could be furtherly *** experiments performed validate the proposed method and demonstrate the significant improvement in the calibration accuracy,when the test distance is 1.8 m,the root mean square(RMS)error of the three-dimensional point is within 0.08 mm.

关键词： multi-line structured light Plücker line calibration perspective projection plane fitting

DETERMINATION OF UNKNOWN CAMERA PARAMETERS FOR THE perspective IMAGES

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Transactions of Nanjing University of Aeronautics and Astronautics 1996年第2期13卷 95+91-94页

作者：昂海松南京航空航天大学飞行器系

To obtain an accurate 3 D object configuration from images,the essential perspective characteristics must be considered. Several new inverse transformation relations of the perspective image lines are given. Utilizing the analytic transformation relations, an optimization procedure for obtaining the unknown camera parameters of images is presented in this paper. A 3 D reproduction method and examples are introduced.

关键词： perspective projection optimization perspective image 3 D reproduction 