Genetic algorithms for high-precision reconstructions of three-dimensional topographies using stereo fractographs

2000 ◽  
Vol 23 (5) ◽  
pp. 435-443 ◽  
Author(s):  
Minoshima ◽  
Suezaki ◽  
Komai
Author(s):  
Takehito Teraguchi ◽  
Hiromasa Yamashita ◽  
Ken Masamune ◽  
Takeyoshi Dohi ◽  
Hongen Liao

2021 ◽  
Vol 7 (6) ◽  
pp. eabe3902
Author(s):  
Martin Rieu ◽  
Thibault Vieille ◽  
Gaël Radou ◽  
Raphaël Jeanneret ◽  
Nadia Ruiz-Gutierrez ◽  
...  

While crucial for force spectroscopists and microbiologists, three-dimensional (3D) particle tracking suffers from either poor precision, complex calibration, or the need of expensive hardware, preventing its massive adoption. We introduce a new technique, based on a simple piece of cardboard inserted in the objective focal plane, that enables simple 3D tracking of dilute microparticles while offering subnanometer frame-to-frame precision in all directions. Its linearity alleviates calibration procedures, while the interferometric pattern enhances precision. We illustrate its utility in single-molecule force spectroscopy and single-algae motility analysis. As with any technique based on back focal plane engineering, it may be directly embedded in a commercial objective, providing a means to convert any preexisting optical setup in a 3D tracking system. Thanks to its precision, its simplicity, and its versatility, we envision that the technique has the potential to enhance the spreading of high-precision and high-throughput 3D tracking.


2007 ◽  
Vol 364-366 ◽  
pp. 80-85
Author(s):  
Su Ping Chang ◽  
Tie Bang Xie ◽  
Xuang Ze Wang ◽  
Jun Guo

White-light interferometric technique has been widely applied in the measurement of three-dimensional profiles and roughness with high-precision. Based on the characteristic of interferometric technique, a new method combined with image location and a three-dimensional stage is proposed to achieve the non-contact absolute shape measurement for aspheric and spherical surface in a slarge range. The interference fringes vary with the horizontal displacement of the measured surface, the surface information was obtained by locating the transformation of the maximal intensity in the interferograms. Two main influence factors are discussed; they are performance of the inerferimetric microscope and the stage. Since the performance of the stage directly determines the measurement precision, a three-dimensional displacement stage with a large range and a high precision was developed. Some experiments were carried out to verify the performance of the three-dimensional displacement stage and the validity of the new measurement method with satisfactory results.


Author(s):  
Eduardo Rodríguez ◽  
Gustavo Montero ◽  
Rafael Montenegro ◽  
José María Escobar ◽  
José María González-Yuste

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 531 ◽  
Author(s):  
Manuel Erena ◽  
José A. Domínguez ◽  
Joaquín F. Atenza ◽  
Sandra García-Galiano ◽  
Juan Soria ◽  
...  

The use of the new generation of remote sensors, such as echo sounders and Global Navigation Satellite System (GNSS) receivers with differential correction installed in a drone, allows the acquisition of high-precision data in areas of shallow water, as in the case of the channel of the Encañizadas in the Mar Menor lagoon. This high precision information is the first step to develop the methodology to monitor the bathymetry of the Mar Menor channels. The use of high spatial resolution satellite images is the solution for monitoring many hydrological changes and it is the basis of the three-dimensional (3D) numerical models used to study transport over time, environmental variability, and water ecosystem complexity.


Author(s):  
Karim A. Aguib ◽  
Keith A. Hekman ◽  
Ashraf O. Nassef

Camoids are three dimensional cams that can produce more complex follower output than plain disc cams. A camoid follower motion is described by a surface rather than a curve. The camoid profile can be directly synthesized once the follower surface is fully described. To define a camoid follower motion surface it is required that the surface pass by all predefined constraints. Constraints can be follower position, velocity and acceleration. These design constraints are scattered all along the camoid follower surface. Hence a fitting technique is needed to satisfy these constraints which include position and its derivatives (velocity and acceleration). Furthermore if the fitting function can be of a parametric nature, then it would be possible to optimize the follower surface to obtain better performance according to a specific objective. Previous research has established a method to fit camoid follower surface positions, but did not tackle the satisfaction of derivative constraints. This paper presents a method for defining a camoid follower characteristic surface B-Splines on two steps first synthesizing the sectional cam curves then using a surface interpolation technique to generate the follower characteristic surface. The fitting technique is parametric in nature which allows for its optimization. Real coded Genetic algorithms are used to optimize the parameters of the surface to meet a specified objective function. A demonstration problem to illustrate the suggested methodology is presented.


Sign in / Sign up

Export Citation Format

Share Document