scholarly journals Ronchi-Hartmann type null screens for testing a plano-freeform surface with a detection plane inside the caustic surface

2021 ◽  
Author(s):  
Maximino Avendaño Alejo ◽  
Jesús DelOlmo-Márquez ◽  
Gabriel Castillo-Santiago ◽  
Ivan Moreno ◽  
Edwin Román-Hernández ◽  
...  
Keyword(s):  
Freeform Surface ◽  
Caustic Surface ◽  
Detection Plane

CBED Shadow Images and Cs:Aberration Measurement

1982 ◽  
Vol 40 ◽  
pp. 696-697
Author(s):  
R. W. Carpenter ◽  
I.Y.T. Chan ◽  
J. M. Cowley
Keyword(s):  
Focal Point ◽  
Spherical Aberration ◽  
Optic Axis ◽  
Wide Angle ◽  
Caustic Surface ◽  
Convergent Beam

Wide-angle convergent beam shadow images(CBSI) exhibit several characteristic distortions resulting from spherical aberration. The most prominent is a circle of infinite magnification resulting from rays having equal values of a forming a cross-over on the optic axis at some distance before reaching the paraxial focal point. This distortion is called the tangential circle of infinite magnification; it can be used to align and stigmate a STEM and to determine Cs for the probe forming lens. A second distortion, the radial circle of infinite magnification, results from a cross-over on the lens caustic surface of rays with differing values of ∝a, also before the paraxial focal point of the lens.

Soft Twisting Pneumatic Actuators Enabled by Freeform Surface Design

2021 ◽  
pp. 1-1
Author(s):  
Feifei Chen ◽  
Yunpeng Miao ◽  
Guoying Gu ◽  
Xiangyang Zhu
Keyword(s):  
Freeform Surface ◽  
Surface Design ◽  
Pneumatic Actuators

scholarly journals Asymmetric Double Freeform Surface Lens for Integrated LED Automobile Headlamp

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 663
Author(s):  
Hui Zhang ◽  
Dengfei Liu ◽  
Yinwan Wei ◽  
Hong Wang
Keyword(s):  
Optical System ◽  
Design Method ◽  
Chromatic Dispersion ◽  
Electronic Devices ◽  
Color Temperature ◽  
Freeform Surface ◽  
United Nations Economic Commission ◽  
System A ◽  
Economic Commission ◽  
Key Points

We propose a design method of asymmetric double freeform surface lens for an integrated LED automobile headlamp and develop an integrated LED automobile optical system. A single asymmetric double freeform surface lens is designed to redistribute rays emitting from the light source for realizing both low and high beams. Moreover, a freeform surface reflector is used to improve the energy efficiency of high beams. The prism placed in the optical path can suppress chromatic dispersion on the edge of the target plane. Simulation and experimental results show that the illumination values and color temperature of the key points can fully meet the requirements of United Nations Economic Commission for Europe vehicle regulations (ECE) R112, 48, and 128. The volume of the whole optical system comprised of freeform surface elements is smaller than that of the low beam system of a traditional headlamp, resulting in saved space, in which other electronic devices can be installed for the safety of the driver, which indicates that the proposed method is practical in the field of automobile lighting.

Two-step carrier-wave stitching method for aspheric and freeform surface measurement with a standard spherical interferometer

2018 ◽  
Vol 57 (17) ◽  
pp. 4743 ◽  
Author(s):  
Qun Hao ◽  
Shaopu Wang ◽  
Yao Hu ◽  
Yifeng Tan ◽  
Tengfei Li ◽  
...  
Keyword(s):  
Freeform Surface ◽  
Surface Measurement ◽  
Carrier Wave

scholarly journals Bivariate splines over triangular meshes for freeform surface modeling with sharp features

2016 ◽  
Vol 14 (4) ◽  
pp. 498-506 ◽  
Author(s):  
Juan Cao ◽  
Jianmin Zheng
Keyword(s):  
Surface Modeling ◽  
Freeform Surface ◽  
Triangular Meshes ◽  
Bivariate Splines

Integrating Freeform and Feature-Based Fitting Methods

2004 ◽  
Author(s):  
H. James de St. Germain ◽  
David E. Johnson ◽  
Elaine Cohen
Keyword(s):  
Reverse Engineering ◽  
Surface Fitting ◽  
General Purpose ◽  
Freeform Surface ◽  
Domain Expert ◽  
Coordinate Measurement ◽  
Reverse Engineer ◽  
Model Based ◽  
Cad Models ◽  
Feature Based

Reverse engineering (RE) is the process of defining and instantiating a model based on the measurements taken from an exemplar object. Traditional RE is costly, requiring extensive time from a domain expert using calipers and/or coordinate measurement machines to create new design drawings/CAD models. Increasingly RE is becoming more automated via the use of mechanized sensing devices and general purpose surface fitting software. This work demonstrates the ability to reverse-engineer parts by combining feature-based techniques with freeform surface fitting to produce more accurate and appropriate CAD models than previously possible.

Prediction of surface reconstruction uncertainties for freeform surface inspection

Measurement ◽  
2013 ◽  
Vol 46 (8) ◽  
pp. 2682-2694 ◽  
Author(s):  
V. Mehrad ◽  
D. Xue ◽  
P. Gu
Keyword(s):  
Surface Reconstruction ◽  
Freeform Surface ◽  
Surface Inspection

Measurement of a highly freeform surface using a cylindrical null-screen

2021 ◽  
Author(s):  
Oliver Huerta-Carranza ◽  
Manuel Campos-García ◽  
Daniel Aguirre-Aguirre ◽  
Brenda Villalobos-Mendoza ◽  
Victor Ivan Moreno-Oliva
Keyword(s):  
Freeform Surface

An oriented feature extraction and recognition approach for concave-convex mixed interacting features in cast-then-machined parts

2018 ◽  
Vol 233 (4) ◽  
pp. 1269-1288 ◽  
Author(s):  
Haichao Wang ◽  
Jie Zhang ◽  
Xiaolong Zhang ◽  
Changwei Ren ◽  
Xiaoxi Wang ◽  
...  
Keyword(s):  
Feature Extraction ◽  
Computer Aided Design ◽  
Feature Recognition ◽  
Freeform Surface ◽  
Layer By Layer ◽  
Computer Aided Process Planning ◽  
Computer Aided ◽  
Machined Parts ◽  
Aided Design ◽  
Interacting Features

Feature recognition is an important technology of computer-aided design/computer-aided engineering/computer-aided process planning/computer-aided manufacturing integration in cast-then-machined part manufacturing. Graph-based approach is one of the most popular feature recognition methods; however, it cannot still solve concave-convex mixed interacting feature recognition problem, which is a common problem in feature recognition of cast-then-machined parts. In this study, an oriented feature extraction and recognition approach is proposed for concave-convex mixed interacting features. The method first extracts predefined features directionally according to the rules generated from attributed adjacency graphs–based feature library and peels off them from part model layer by layer. Sub-features in an interacting feature are associated via hints and organized as a feature tree. The time cost is reduced to less than [Formula: see text] by eliminating subgraph isomorphism and matching operations. Oriented feature extraction and recognition approach recognizes non-freeform-surface features directionally regardless of the part structure. Hence, its application scope can be extended to multiple kinds of non-freeform-surface parts by customizing. Based on our findings, implementations on prismatic, plate, fork, axlebox, linkage, and cast-then-machined parts prove that the proposed approach is applicable on non-freeform-surface parts and effectively recognize concave-convex mixed interacting feature in various mechanical parts.

Sign in / Sign up

Export Citation Format

Share Document