Extension of the registration possibilities and determination of the positioning precision of a multi-scale fringe projection system

2020 ◽  
Author(s):  
Sebastian Metzner ◽  
Tino Hausotte
Keyword(s):  
Fringe Projection ◽  
Projection System ◽  
Positioning Precision ◽  
Multi Scale

scholarly journals Qualification concept for optical multi-scale multi-sensor systems

2016 ◽  
Vol 5 (1) ◽  
pp. 1-8 ◽  
Author(s):  
A. Loderer ◽  
T. Hausotte
Keyword(s):  
Coordinate System ◽  
Fringe Projection ◽  
Data Sets ◽  
Measuring Systems ◽  
Projection System ◽  
Multi Scale ◽  
Measuring Procedure ◽  
Optical Measuring ◽  
Common Coordinate System ◽  
Current Measuring

Abstract. This article describes a new qualification concept for dimensional measurements on optical measuring systems. Using the example of a prototypical multi-scale multi-sensor fringe projection system for production-related inspections of sheet-bulk metal-formed parts, current measuring procedures of the optical system are introduced. Out of the shown procedures' deficiencies, a new concept is developed for determining the orientations and positions of the sensors' measuring ranges in a common coordinate system. The principle element of the concept is a newly developed flexible reference artefact, adapted to the measuring task of the fringe projection system. Due to its dull surface, the artefact is optimized for optical measuring systems, like the used fringe projection sensors. By measuring the reference artefact with each fringe projection sensor and aligning the resulting data sets on a digital reference model of the artefact, sensor-specific transformation matrices can be calculated which allow transformation of the sensors' data sets into a common coordinate system, without the need for any overlapping areas. This approach is concluded in an automated measuring procedure, using alignment algorithms from commercial available software where necessary. With the automated measuring procedure, geometrical relations between individual measured features can be determined and dimensional measuring beyond the measuring range of a sensor became possible. Due to a series of experiments, the advantages of the new qualification concept in comparison with the current measuring procedures are finally revealed.

scholarly journals A parametric prediction of the Young’s modulus of polymers enhanced with ΜWCNTs

2018 ◽  
Vol 233 ◽  
pp. 00025
Author(s):  
P.V. Polydoropoulou ◽  
K.I. Tserpes ◽  
Sp.G. Pantelakis ◽  
Ch.V. Katsiropoulos
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Experimental Results ◽  
Scale Model ◽  
Fe Model ◽  
Multi Scale ◽  
Unit Cells ◽  
Random Dispersion

In this work a multi-scale model simulating the effect of the dispersion, the waviness as well as the agglomerations of MWCNTs on the Young’s modulus of a polymer enhanced with 0.4% MWCNTs (v/v) has been developed. Representative Unit Cells (RUCs) have been employed for the determination of the homogenized elastic properties of the MWCNT/polymer. The elastic properties computed by the RUCs were assigned to the Finite Element (FE) model of a tension specimen which was used to predict the Young’s modulus of the enhanced material. Furthermore, a comparison with experimental results obtained by tensile testing according to ASTM 638 has been made. The results show a remarkable decrease of the Young’s modulus for the polymer enhanced with aligned MWCNTs due to the increase of the CNT agglomerations. On the other hand, slight differences on the Young’s modulus have been observed for the material enhanced with randomly-oriented MWCNTs by the increase of the MWCNTs agglomerations, which might be attributed to the low concentration of the MWCNTs into the polymer. Moreover, the increase of the MWCNTs waviness led to a significant decrease of the Young’s modulus of the polymer enhanced with aligned MWCNTs. The experimental results in terms of the Young’s modulus are predicted well by assuming a random dispersion of MWCNTs into the polymer.

scholarly journals Absolute Phase Retrieval Using One Coded Pattern and Geometric Constraints of Fringe Projection System

2018 ◽  
Vol 8 (12) ◽  
pp. 2673 ◽  
Author(s):  
Xu Yang ◽  
Chunnian Zeng ◽  
Jie Luo ◽  
Yu Lei ◽  
Bo Tao ◽  
...  
Keyword(s):  
Phase Shift ◽  
Phase Retrieval ◽  
Code Word ◽  
Geometric Constraints ◽  
Fringe Projection ◽  
Average Intensity ◽  
Fringe Order ◽  
Projection System ◽  
Absolute Phase ◽  
Three Phase

Fringe projection technologies have been widely used for three-dimensional (3D) shape measurement. One of the critical issues is absolute phase recovery, especially for measuring multiple isolated objects. This paper proposes a method for absolute phase retrieval using only one coded pattern. A total of four patterns including one coded pattern and three phase-shift patterns are projected, captured, and processed. The wrapped phase, as well as average intensity and intensity modulation, are calculated from three phase-shift patterns. A code word encrypted into the coded pattern can be calculated using the average intensity and intensity modulation. Based on geometric constraints of fringe projection system, the minimum fringe order map can be created, upon which the fringe order can be calculated from the code word. Compared with the conventional method, the measurement depth range is significantly improved. Finally, the wrapped phase can be unwrapped for absolute phase map. Since only four patterns are required, the proposed method is suitable for real-time measurement. Simulations and experiments have been conducted, and their results have verified the proposed method.

Accuracy Analysis of Fringe Projection Systems Based on Blue Light Technology

2014 ◽  
Vol 615 ◽  
pp. 9-14 ◽  
Author(s):  
Claudio Bernal ◽  
Beatriz de Agustina ◽  
Marta María Marín ◽  
Ana Maria Camacho
Keyword(s):  
Blue Light ◽  
Point Clouds ◽  
Fringe Projection ◽  
Accuracy Analysis ◽  
Scanning Procedure ◽  
Structured Light Scanner ◽  
Cloud Of Points ◽  
3D Digitizing

Some manufacturers of 3D digitizing systems are developing and market more accurate, fastest and affordable systems of fringe projection based on blue light technology. The aim of the present work is the determination of the quality and accuracy of the data provided by the LED structured light scanner Comet L3D (Steinbichler). The quality and accuracy of the cloud of points produced by the scanner is determined by measuring a number of gauge blocks of different sizes. The accuracy range of the scanner has been established through multiple digitizations showing the dependence on different factors such as the characteristics of the object and scanning procedure. Although many factors influence, accuracies announced by manufacturer have been achieved under optimal conditions and it has been noted that the quality of the point clouds (density, noise, dispersion of points) provided by this system is higher than that obtained with laser technology devices.

Grapho-Analytical Determination of the Profile Disc Tool for Manufacturing of Complex Helicoidal Surfaces

2013 ◽  
Vol 837 ◽  
pp. 164-169 ◽  
Author(s):  
Gheorghe Pleşu
Keyword(s):  
Point Of View ◽  
Disc Cutter ◽  
Analytical Determination ◽  
Great Effort ◽  
Numerical Determination ◽  
Projection System ◽  
Tool Profile ◽  
Helicoidal Surfaces ◽  
Helicoidal Surface

Helicoidal surfaces correspond to a cathegory of widely spread surfacesin the technical field. From the point of view of the manufacturing of helicoidal surfaces through the moving of a profile around the helix, the two elements defining such a surface can be distinguished: the profile and the helix. The numerical determination of the profile of the disc type tool drawn on an analytical method with a large number of points [1- (the number reaches even 1500 in some cases) implies a great effort so that the technician can verify the correctness of results, even in the present case when there is the possibility of the numerical determination through the resolution of the inverse problem of the frontal profile of the complex helicoidal surface. In order to facilitate this work and to give the possibility of introducing some new profiles in the projection system, some methods of grapho-analytical determination have been conceived to process the profiles of the complex helicoidal surfaces, as well as the profiles of the helicoidal surfaces for a given tool profile. This paper presents the graphic-analytical determination of the disc tool profile designed to dress the complex helicoidal surfaces. The methods referred to by using the possibilities provided by the programming environment AutoCAD and its development languages allow to determin numerically the profile of the disc-cutter with a high precision, above the precision level required in practice.

scholarly journals Concerted action of neuroepithelial basal shrinkage and active epithelial migration ensures efficient optic cup morphogenesis

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Jaydeep Sidhaye ◽  
Caren Norden
Keyword(s):  
Tissue Level ◽  
Cellular Mechanisms ◽  
Epithelial Migration ◽  
Multi Scale ◽  
Cell Matrix ◽  
Optic Cup ◽  
Correct Location ◽  
Spatiotemporal Coordination ◽  
Cellular Movement

Organ formation is a multi-scale event that involves changes at the intracellular, cellular and tissue level. Organogenesis often starts with the formation of characteristically shaped organ precursors. However, the cellular mechanisms driving organ precursor formation are often not clear. Here, using zebrafish, we investigate the epithelial rearrangements responsible for the development of the hemispherical retinal neuroepithelium (RNE), a part of the optic cup. We show that in addition to basal shrinkage of RNE cells, active migration of connected epithelial cells into the RNE is a crucial player in its formation. This cellular movement is driven by progressive cell-matrix contacts and actively translocates prospective RNE cells to their correct location before they adopt neuroepithelial fate. Failure of this migration during neuroepithelium formation leads to ectopic determination of RNE cells and consequently impairs optic cup formation. Overall, this study illustrates how spatiotemporal coordination between morphogenic movements and fate determination critically influences organogenesis.

scholarly journals Single image geometry inspection using inverse endoscopic fringe projection

ACTA IMEKO ◽  
2015 ◽  
Vol 4 (2) ◽  
pp. 4 ◽  
Author(s):  
Steffen Matthias ◽  
Christoph Ohrt ◽  
Andreas Pösch ◽  
Markus Kästner ◽  
Eduard Reithmeier
Keyword(s):  
Phase Measurement ◽  
Measurement Techniques ◽  
Measuring Method ◽  
Pattern Generation ◽  
Fringe Projection ◽  
Free Form ◽  
Projection System ◽  
New Device ◽  
Early Results ◽  
Geometry Inspection

Fringe projection is an important technology for the measurement of free form elements in several application fields. It can be applied for geometry elements smaller than one millimeter. In combination with deviation analysis algorithms, errors in fabrication lines can be found promptly to minimize rejections. However, some fields cannot be covered by the classical fringe projection approach. Due to shadowing, filigree form elements on narrow or internal carrier geometries cannot be captured. To overcome this limitation, a fiberscopic micro fringe projection sensor was developed. The new device is capable of resolutions of less than 15 µm with uncertainties of about 35 µm in a workspace of 3 × 3 × 3 mm³.<br />Using standard phase measurement techniques, such as Gray-code and cos²-patterns, measurement times of over a second are too high for in-situ operation. The following work will introduce a new approach of applying a new one image measuring method to the fiberscopic system, based on inverse fringe projection. The fiberscopic fringe projection system employs a laser light source in combination with a digital micro-mirror device (DMD) to generate fringe patterns. Fiber optical image bundles (FOIB) are used in combination with gradient-index lenses to project these patterns on the specimen. This advanced optical system creates high demands on the pattern generation algorithms to generate exact inverse patterns for arbitrary CAD-modelled geometries. Approaches of the optical simulations in the context of the complex beam path, together the drawbacks of the limited resolutions of the FOIBs shall be discussed. Early results of inverse pattern simulations using a ray tracing approach of a pinhole system model are presented.<br />

scholarly journals Single-shot 3D shape measurement of discontinuous objects based on a coaxial fringe projection system

2019 ◽  
Vol 58 (5) ◽  
pp. A169 ◽  
Author(s):  
Zhangying Wang ◽  
Zonghua Zhang ◽  
Nan Gao ◽  
Yanjun Xiao ◽  
Feng Gao ◽  
...  
Keyword(s):  
Fringe Projection ◽  
Shape Measurement ◽  
Single Shot ◽  
Projection System ◽  
3D Shape ◽  
3D Shape Measurement

scholarly journals Multiproduct biorefinery optimal design: application to the acetone-butanol-ethanol system

2020 ◽  
Vol 75 ◽  
pp. 9 ◽  
Author(s):  
Ségolène Belletante ◽  
Ludovic Montastruc ◽  
Michel Meyer ◽  
Heri Hermansyah ◽  
Stéphane Negny
Keyword(s):  
Decision Support ◽  
Optimal Design ◽  
Process Simulation ◽  
Decision Support Tool ◽  
Energy Integration ◽  
Support Tool ◽  
Multi Scale ◽  
Acetone Butanol Ethanol ◽  
Ethanol System

The bioproduct from biomass appears to be major interests for future years given the spectacular and fast advances in microbiology. But the industrial developments of the new bioproducts production struggle to follow this constant and massive creation. Therefore, to estimate the potential of new bioproducts is necessary to pre-design biorefineries with the highest relevance. This study proposes a methodology assessing the relevance of such industrialized production. The presented tool is a multi-scale methodology describing a decision-support tool for the determination of an optimal biorefinery from a superstructure through process simulation, and economic and environmental evaluations. To optimize the biorefinery, energy integration is also applied on the selected processes, because a biorefinery needs a large amount of energy to operate, especially in the pretreatment and purification steps of the process due to huge water flowrate. Thus, the tool designs an efficient, profitable and sustainable biorefinery. We demonstrate our methodology capabilities with the acetone, butanol and ethanol production (ABE system) from lignocellulosic biomass, especially from wood wastes.

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