scholarly journals Fast Quadratic Shape From Shading With Unknown Light Direction

2021 ◽  
Author(s):  
Kuros Yalpani
Keyword(s):  
Linear Optimization ◽  
Quadratic Function ◽  
Optimization Method ◽  
Shape From Shading ◽  
Surface Patch ◽  
Algebraic Complexity ◽  
Surface Patches ◽  
Quadratic Surface ◽  
Least Squares Optimization ◽  
Light Source Direction

An algorithm is proposed that extracts 3D shape from shading information in a digital image. The algorithm assumes that there is only a single source of light producing the image, that the surface of the shape giving rise to the image is Lambertian (matte) and that its shape can be locally approximated by a quadratic function. Previous work shows that under these assumptions, robust shape from shading is possible, though slow for large images because a non-linear optimization method is applied in order to estimate local quadratic surface patches from image intensities. The work presented here shows that local quadratic surface patch estimates can be computed, without prior knowledge of the light source direction, via a linear least squares optimization, thus greatly improving the algebraic complexity and run-time of this existing algorithms.

scholarly journals Fast Quadratic Shape From Shading With Unknown Light Direction

2021 ◽  
Author(s):  
Kuros Yalpani
Keyword(s):  
Linear Optimization ◽  
Quadratic Function ◽  
Optimization Method ◽  
Shape From Shading ◽  
Surface Patch ◽  
Algebraic Complexity ◽  
Surface Patches ◽  
Quadratic Surface ◽  
Least Squares Optimization ◽  
Light Source Direction

An algorithm is proposed that extracts 3D shape from shading information in a digital image. The algorithm assumes that there is only a single source of light producing the image, that the surface of the shape giving rise to the image is Lambertian (matte) and that its shape can be locally approximated by a quadratic function. Previous work shows that under these assumptions, robust shape from shading is possible, though slow for large images because a non-linear optimization method is applied in order to estimate local quadratic surface patches from image intensities. The work presented here shows that local quadratic surface patch estimates can be computed, without prior knowledge of the light source direction, via a linear least squares optimization, thus greatly improving the algebraic complexity and run-time of this existing algorithms.

scholarly journals Fast Quadratic Shape From Shading With Unknown Light Direction

2021 ◽  
Author(s):  
Kuros Yalpani
Keyword(s):  
Linear Optimization ◽  
Quadratic Function ◽  
Optimization Method ◽  
Shape From Shading ◽  
Surface Patch ◽  
Algebraic Complexity ◽  
Surface Patches ◽  
Quadratic Surface ◽  
Least Squares Optimization ◽  
Light Source Direction

An algorithm is proposed that extracts 3D shape from shading information in a digital image. The algorithm assumes that there is only a single source of light producing the image, that the surface of the shape giving rise to the image is Lambertian (matte) and that its shape can be locally approximated by a quadratic function. Previous work shows that under these assumptions, robust shape from shading is possible, though slow for large images because a non-linear optimization method is applied in order to estimate local quadratic surface patches from image intensities. The work presented here shows that local quadratic surface patch estimates can be computed, without prior knowledge of the light source direction, via a linear least squares optimization, thus greatly improving the algebraic complexity and run-time of the existing algorithms.

scholarly journals NSiteMatch: Prediction of Binding Sites of Nucleotides by Identifying the Structure Similarity of Local Surface Patches

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Jie Sun ◽  
Ke Chen
Keyword(s):  
Binding Sites ◽  
Surface Patch ◽  
Energy Calculation ◽  
Local Similarity ◽  
Success Rates ◽  
Biologically Relevant ◽  
Surface Patches ◽  
Extensive Evaluation ◽  
Structure Similarity ◽  
Global Similarity

Nucleotides play a central role in life-form metabolism, by interacting with proteins and mediating the function of proteins. It is estimated that nucleotides constitute about 15% of the biologically relevant ligands included in PDB. Prediction of binding sites of nucleotides is useful in understanding the function of proteins and can facilitate the in silico design of drugs. In this study, we propose a nucleotide-binding site predictor, namely, NSiteMatch. The NSiteMatch algorithm integrates three different strategies: geometrical analysis, energy calculation, and template comparison. Unlike a traditional template-based predictor, which identifies global similarity between target structure and template, NSiteMatch concerns the local similarity between a surface patch of the target protein and the binding sites of template. To this end, NSiteMatch identifies more templates than traditional template-based predictors. The NSiteMatch predictor is compared with three representative methods, Findsite, Q-SiteFinder, and MetaPocket. An extensive evaluation demonstrates that NSiteMatch achieves higher success rates than Findsite, Q-SiteFinder, and MetaPocket, in prediction of binding sites of ATP, ADP, and AMP.

Longitudinal Compensation Algorithm for the Stamping Fold Shift of Quadric Metal Curtain Walls

2018 ◽  
Vol 13 (10) ◽  
pp. 1584-1590
Author(s):  
Yalong Zhang ◽  
Xuan Ma ◽  
Xiaodan Jiang ◽  
Hisakazu Ogura
Keyword(s):  
Metal Plate ◽  
Surface Patch ◽  
Small Surface ◽  
Quadric Surfaces ◽  
Surface Patches ◽  
Forming Technology ◽  
Flat Shape ◽  
Building Surfaces ◽  
Asymmetric Stress ◽  
Limiting Case

Metal curtain walls are widely applied as decorative materials for the outer walls of large buildings. However, the application of such materials in curved building surfaces is relatively complicated. The whole curved surface is divided into several small surface patches according to a specific plan. Each surface patch is shaped by stamping with a certain-shaped plane metal plate. The calculation of the flat shape of a given surface patch is a key technology. Quadric surfaces are inextensible surfaces. Flat metal materials are folded when stamped into curved surfaces. Wrinkles are distributed unevenly because the curvature of surface patches is often asymmetric. Stress pushes wrinkles from high-density regions to low-density areas, at which point a uniform distribution pattern is reached under the limiting case. An accurate surface flattening method that compensates for fold shift is regarded as a difficult technology to develop. To address these problems, this study proposed an even flattening method for quadric surfaces. The proposed method simplifies the sheet metal forming technology and achieves satisfactory accuracy in the engineering process.

Optimal Outside Airflow Control of an Integrated Air-Handling Unit System for Large Office Buildings

2004 ◽  
Vol 126 (1) ◽  
pp. 614-619 ◽  
Author(s):  
L. Song ◽  
M. Liu
Keyword(s):  
Air Temperature ◽  
Linear Optimization ◽  
Optimization Method ◽  
Geometric Optimization ◽  
Variable Air Volume ◽  
Unit System ◽  
Analytical Functions ◽  
Air Handling Unit ◽  
Conventional Systems ◽  
Air Control

This paper presents optimal outside air control schedules for an integrated air-handling unit system for large commercial buildings (OAHU). The schedules are developed using the geometric linear optimization method and expressed as analytical functions of the outside air temperature and enthalpy, the interior zone airflow ratio, and the exterior zone supply air temperature. The optimal outside air control schedules can be applied to both constant and variable air volume systems. When the schedules are implemented, the OAHU system can significantly improve indoor air quality (IAQ) and use significantly less thermal energy than conventional systems. The geometric optimization method can also be used in other linear HVAC optimizations with non-liner constraint conditions.

scholarly journals Partial Least Squares Optimization Method and Path Analysis Integration for Chinese Medicine Data

2020 ◽  
Vol 32 (10) ◽  
pp. 3463
Author(s):  
Tianci Li ◽  
Wangping Xiong ◽  
Jianqiang Du ◽  
Bin Nie ◽  
Jigen Luo ◽  
...  
Keyword(s):  
Chinese Medicine ◽  
Path Analysis ◽  
Least Squares ◽  
Partial Least Squares ◽  
Optimization Method ◽  
Least Squares Optimization

scholarly journals A GC2 Joining Procedure for B-Spline Patches in Reverse Engineering

1997 ◽  
Author(s):  
Tachung Yang ◽  
Cheng-Chung Wang
Keyword(s):  
Reverse Engineering ◽  
Coordinate Measuring Machine ◽  
Surface Patch ◽  
Geometric Continuity ◽  
Huge Amount ◽  
B Spline ◽  
Surface Patches ◽  
Spline Surface ◽  
Surface Models ◽  
Measuring Machine

Reconstruction of surface models is a vital part in reverse engineering. Because of the huge amount of data from Coordinate Measuring Machine (CMM), processes for division of data into groups, surface patch reconstruction, and patch joining are inevitable in the CAD systems tailored for reverse engineering applications. Existing techniques of surface patch joining have the disadvantages, such as computational complication or lack of desired geometric continuity. A GC2 joining technique for B-spline surface patches by utilising a Bezier patch joining technique was proposed in this paper. This method possesses the merits in which only the control vertices near the joining boundaries of patches are modified and no additional blending surfaces at the joints of patches are created.

scholarly journals Technical Features of the Computing and Geo-Information System for Research of Prospective Interstate Power Grid Expansion

2021 ◽  
pp. 49-53
Author(s):  
Sergei V. Podkovalnikov ◽  
◽  
Ivan L. Trofimov ◽  
Leonid N. Trofimov
Keyword(s):  
Information System ◽  
Power Systems ◽  
Power Grid ◽  
Linear Optimization ◽  
Northeast Asia ◽  
Optimization Method ◽  
Electric Power System ◽  
Operating Modes ◽  
Technical Features ◽  
The Mathematical Model

The purpose of this paper is to present opportunities and technical features of the developed software for study of prospective Interstate Power Grid (ISPG) expansion in Northeast Asia. The mathematical model for optimization of power systems expansion and operating modes, which is the main part of the computing & geo-information system (CIS), is used. In this model, a linear optimization method is used to find optimal installed capacities by generation type mix; optimal electric ties transfer capabilities and operating modes for each electric power system in the ISPG. Annualized costs of the ISPG expansion as a whole are the value of the objective function. The obtained results of the model in tabular, graphic and cartographic forms are presented. Examples of the CIS usage for study of different scenarios of ISPG expansion in the Northeast Asia are shown.

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